invoice: customer, sequence, preview and issue commands

3 files changed, 2259 insertions, 5 deletions

diff --git a/docs/PROTOCOL.md b/docs/PROTOCOL.md
index 3f8aaff..e02d2f7 100644
--- a/docs/PROTOCOL.md
+++ b/docs/PROTOCOL.md
@@ -371,14 +371,17 @@ resolved rows in a dry run.
 | Command | Args | Notes |
 |---|---|---|
 | `settings.get` | — | effective org settings (defaults included) |
-| `settings.set` | `key`, `value` | known keys: `default_series`, `attachment_dir`, `bank_account` |
+| `settings.set` | `key`, `value` | known keys: `default_series`, `attachment_dir`, `bank_account`, `invoice_receivable_account`, `invoice_revenue_account` |
 
 `default_series` (1–8 characters, e.g. `A`, `V-`, `A `) is used when
 `voucher.post` carries no `series` and as the default series for new
 templates. `attachment_dir` (a path, up to 255 characters) is the folder the
 TUI file browser opens in when attaching underlag. `bank_account` (digits
 only, up to 10 characters, default `1930`) is the account `bank.import` uses
-when the request carries no `account`. Verification ids are the concatenation of series and number
+when the request carries no `account`. `invoice_receivable_account` (default
+`1510`) and `invoice_revenue_account` (default `3001`) are the receivable and
+default revenue account of invoice postings, digits only, up to 10
+characters. Verification ids are the concatenation of series and number
 (`V-8`), and series are free-form: only an unbroken numbering per series is
 required.
 
@@ -546,6 +549,65 @@ removes one link and is a `NOT_FOUND` when it does not exist. Both mutate
 `bank_matches` only and are audited (`bank.match`, `bank.unmatch`);
 `bank.import` is audited as `bank.import`.
 
+### 7.10 Invoicing (fakturering)
+
+| Command | Args | Result |
+|---|---|---|
+| `customer.list` | `active_only?` | `items[]` ordered by name |
+| `customer.get` | `id` | one customer |
+| `customer.create` | `name`; `address`, `postal_code`, `city`, `country`, `vat_nr`, `email`, `your_ref`, `notes`, `payment_days?` | the customer |
+| `customer.update` | `id` plus any field (merged) | the effective customer |
+| `customer.archive` | `id`, `active` | `id`, `active` |
+| `invoice.sequence_get` | — | `next_number` (1 when no row) |
+| `invoice.sequence_set` | `next_number` (owner) | `next_number` |
+| `invoice.preview` | draft (below) | `content_base64`, `number`, `ocr`, `net_ore`, `vat_ore`, `total_ore` |
+| `invoice.issue` | draft, `dry_run?` | `id`, `number`, `ocr`, `document_id`, `voucher_id`, totals |
+| `invoice.get` | `id` | header, `rows[]`, `document_id`, `voucher_id`, `last_sent_at`, `last_sent_to` |
+| `invoice.list` | `customer_id?`, `status?` (`issued`/`credited`), `limit?` | `items[]`, newest first |
+| `invoice.pdf` | `id` | stored PDF as `content_base64` |
+
+The draft object is the argument set shared by `invoice.preview` and
+`invoice.issue`:
+
+```json
+{"customer_id":2,"invoice_date":"2026-09-20","due_date":"2026-10-20",
+ "delivery_date":"2026-09-20","your_ref":"Lars","our_ref":"Anders",
+ "notes":"", "rows":[{"article_no":"","description":"Utvecklingsarbete",
+ "quantity":"61","unit":"tim","unit_price_ore":120000,"note":"",
+ "vat_code":"25","account":""}]}
+```
+
+`quantity` is a decimal string with at most three decimals (`61`, `61,5`,
+`0,25`); it must be greater than zero. `amount_ore =
+(quantity_milli * unit_price_ore + 500) / 1000` (round half up), and
+`unit_price_ore` must be a non-negative integer. `vat_code` is one of `25`,
+`12`, `6`, `0`, `rc`, `eu` (default `25`). An empty `account` uses the
+setting `invoice_revenue_account` (default `3001`); unknown or inactive
+accounts are `ACCOUNT_NOT_FOUND`/`ACCOUNT_INACTIVE`. The customer must exist
+and be active (`NOT_FOUND`). A draft whose rows do not fit the single page is
+rejected with `TOO_LARGE`.
+
+Numbering is a per-org, global series: `invoice_sequence.next_number` starts
+at 1, is set by the owner and is incremented by exactly one per issued
+invoice. The OCR reference is the number followed by its MOD10 (Luhn) check
+digit: `OCR = <number><check>`. `invoice.preview` renders the document with
+the next number but consumes nothing; `invoice.issue` takes the number,
+renders the PDF, stores it as an immutable `application/pdf` attachment
+(named `Faktura <number> <customer>.pdf`), posts the voucher and links
+invoice, document and voucher in one transaction. The voucher debits
+`invoice_receivable_account` (default `1510`) with the total and credits
+`2610`/`2620`/`2630` with the VAT per rate plus each row's revenue account
+with its net; its source is `invoice`. The renderer's totals equal the
+voucher rows exactly. `invoice.issue` ignores `client_ref` (the number series
+is the idempotency key).
+
+`invoice.preview` is a read. `customer.create/update/archive`,
+`invoice.sequence_set` and `invoice.issue` are audited; `invoice.issue`
+supports `dry_run`, which validates and renders but takes no number and
+writes nothing. `invoice.pdf` returns the stored document as base64
+(`JVBERi0` after decoding is the PDF magic). When the setting
+`invoice_bankgiro` is present it is printed in the document's Bankgiro field.
+
 ## 8. The TUI is just a client
 
 `bokftui` logs in over the same socket, picks an org and issues the same
diff --git a/src/commands.c b/src/commands.c
index 06a7725..72a8f70 100644
--- a/src/commands.c
+++ b/src/commands.c
@@ -15,6 +15,7 @@
 #include "config.h"
 #include "db.h"
 #include "formula.h"
+#include "invoice.h"
 #include "ledger.h"
 #include "log.h"
 #include "reports.h"
@@ -1615,6 +1616,9 @@ static const char AGENT_INSTRUCTIONS[] =
     "- Bank: `bank.import` stores a SEB CSV statement as read-only evidence and\n"
     "  `bank.list` suggests already-posted vouchers to match with `bank.match`;\n"
     "  reconciliation never posts vouchers by itself.\n"
+    "- Fakturering: `customer.create` keeps the customer register; `invoice.preview`\n"
+    "  renders a draft without consuming a number, and `invoice.issue` takes the\n"
+    "  next number, stores the PDF and posts the voucher in one transaction.\n"
     "\n"
     "## Discovery\n"
     "- `describe` lists every implemented command with permissions.\n"
@@ -2607,7 +2611,7 @@ static int parse_attachment_ids(struct req *r, int64_t **out, size_t *out_n)
 static yyjson_mut_val *h_settings_get(struct req *r)
 {
     yyjson_mut_val *o = yyjson_mut_obj(r->rdoc);
-    int have_default = 0, have_bank = 0;
+    int have_default = 0, have_bank = 0, have_receivable = 0, have_revenue = 0;
     sqlite3_stmt *st = NULL;
     if (sqlite3_prepare_v2(
             r->db, "SELECT key,value FROM settings WHERE org_id=?1", -1, &st,
@@ -2623,6 +2627,10 @@ static yyjson_mut_val *h_settings_get(struct req *r)
                     have_default = 1;
                 if (strcmp(k, "bank_account") == 0)
                     have_bank = 1;
+                if (strcmp(k, "invoice_receivable_account") == 0)
+                    have_receivable = 1;
+                if (strcmp(k, "invoice_revenue_account") == 0)
+                    have_revenue = 1;
             }
         }
         sqlite3_finalize(st);
@@ -2631,6 +2639,12 @@ static yyjson_mut_val *h_settings_get(struct req *r)
         yyjson_mut_obj_add_strcpy(r->rdoc, o, "default_series", "A");
     if (!have_bank)
         yyjson_mut_obj_add_strcpy(r->rdoc, o, "bank_account", "1930");
+    if (!have_receivable)
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "invoice_receivable_account",
+                                  "1510");
+    if (!have_revenue)
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "invoice_revenue_account",
+                                  "3001");
     return o;
 }
 
@@ -2646,7 +2660,9 @@ static yyjson_mut_val *h_settings_set(struct req *r)
         maxlen = 8;
     else if (strcmp(key, "attachment_dir") == 0)
         maxlen = 255;
-    else if (strcmp(key, "bank_account") == 0) {
+    else if (strcmp(key, "bank_account") == 0 ||
+             strcmp(key, "invoice_receivable_account") == 0 ||
+             strcmp(key, "invoice_revenue_account") == 0) {
         maxlen = 10;
         digits_only = 1;
     } else
@@ -2694,6 +2710,1570 @@ static yyjson_mut_val *h_settings_set(struct req *r)
 }
 
 /* ------------------------------------------------------------------ */
+/* customer register                                                   */
+/* ------------------------------------------------------------------ */
+
+#define CUSTOMER_COLUMNS                                                 \
+    "id,name,address,postal_code,city,country,vat_nr,email,your_ref,"    \
+    "payment_days,notes,active,created_at,COALESCE(updated_at,'')"
+
+static yyjson_mut_val *customer_json(struct req *r, sqlite3_stmt *st)
+{
+    yyjson_mut_val *o = yyjson_mut_obj(r->rdoc);
+    yyjson_mut_obj_add_int(r->rdoc, o, "id", sqlite3_column_int64(st, 0));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "name",
+                              sq(sqlite3_column_text(st, 1)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "address",
+                              sq(sqlite3_column_text(st, 2)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "postal_code",
+                              sq(sqlite3_column_text(st, 3)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "city",
+                              sq(sqlite3_column_text(st, 4)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "country",
+                              sq(sqlite3_column_text(st, 5)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "vat_nr",
+                              sq(sqlite3_column_text(st, 6)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "email",
+                              sq(sqlite3_column_text(st, 7)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "your_ref",
+                              sq(sqlite3_column_text(st, 8)));
+    yyjson_mut_obj_add_int(r->rdoc, o, "payment_days",
+                           sqlite3_column_int64(st, 9));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "notes",
+                              sq(sqlite3_column_text(st, 10)));
+    yyjson_mut_obj_add_bool(r->rdoc, o, "active",
+                            sqlite3_column_int(st, 11) != 0);
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "created_at",
+                              sq(sqlite3_column_text(st, 12)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "updated_at",
+                              sq(sqlite3_column_text(st, 13)));
+    return o;
+}
+
+struct customer_input {
+    const char *name;
+    const char *address;
+    const char *postal_code;
+    const char *city;
+    const char *country;
+    const char *vat_nr;
+    const char *email;
+    const char *your_ref;
+    const char *notes;
+    int64_t payment_days;
+    int have_payment;
+    int active;
+    int have_active;
+};
+
+static void customer_input_read(struct req *r, struct customer_input *in)
+{
+    memset(in, 0, sizeof *in);
+    in->name = arg_str(r->args, "name");
+    in->address = arg_str(r->args, "address");
+    in->postal_code = arg_str(r->args, "postal_code");
+    in->city = arg_str(r->args, "city");
+    in->country = arg_str(r->args, "country");
+    in->vat_nr = arg_str(r->args, "vat_nr");
+    in->email = arg_str(r->args, "email");
+    in->your_ref = arg_str(r->args, "your_ref");
+    in->notes = arg_str(r->args, "notes");
+    in->have_payment = arg_int(r->args, "payment_days", &in->payment_days);
+    in->have_active = arg_bool(r->args, "active", &in->active);
+}
+
+static int customer_input_validate(struct req *r,
+                                   const struct customer_input *in,
+                                   int is_create)
+{
+    if (is_create && (!in->name || !*in->name)) {
+        fail(r, "INVALID_ARGS", "name is required");
+        return -1;
+    }
+    if (in->name && !*in->name) {
+        fail(r, "INVALID_ARGS", "name cannot be empty");
+        return -1;
+    }
+    if (in->name && strlen(in->name) > 200) {
+        fail(r, "INVALID_ARGS", "name is too long");
+        return -1;
+    }
+    static const char *const names[] = {
+        "address", "postal_code", "city", "country", "vat_nr",
+        "email", "your_ref", "notes",
+    };
+    static const size_t maxlen[] = { 500, 32, 120, 64, 64, 254, 120, 2000 };
+    const char *values[] = { in->address, in->postal_code, in->city,
+                             in->country, in->vat_nr, in->email,
+                             in->your_ref, in->notes };
+    for (size_t i = 0; i < sizeof maxlen / sizeof maxlen[0]; i++) {
+        if (values[i] && strlen(values[i]) > maxlen[i]) {
+            failf(r, "INVALID_ARGS", "%s is too long", names[i]);
+            return -1;
+        }
+    }
+    if (in->have_payment && in->payment_days < 0) {
+        fail(r, "INVALID_ARGS", "payment_days must be >= 0");
+        return -1;
+    }
+    return 0;
+}
+
+static yyjson_mut_val *customer_lookup(struct req *r, int64_t id, int *found)
+{
+    sqlite3_stmt *st = NULL;
+    *found = 0;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "SELECT " CUSTOMER_COLUMNS " FROM customers"
+            " WHERE org_id=?1 AND id=?2",
+            -1, &st, NULL) != SQLITE_OK) {
+        *found = -1;
+        fail(r, "INTERNAL", "database error");
+        return NULL;
+    }
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_int64(st, 2, id);
+    if (sqlite3_step(st) != SQLITE_ROW) {
+        sqlite3_finalize(st);
+        return NULL;
+    }
+    yyjson_mut_val *o = customer_json(r, st);
+    sqlite3_finalize(st);
+    *found = 1;
+    return o;
+}
+
+static int customer_name_taken(struct req *r, const char *name, int64_t except_id)
+{
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "SELECT id FROM customers WHERE org_id=?1 AND name=?2"
+            " AND id<>?3",
+            -1, &st, NULL) != SQLITE_OK) {
+        fail(r, "INTERNAL", "database error");
+        return -1;
+    }
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_text(st, 2, name, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_int64(st, 3, except_id);
+    int taken = sqlite3_step(st) == SQLITE_ROW;
+    sqlite3_finalize(st);
+    return taken;
+}
+
+static yyjson_mut_val *h_customer_list(struct req *r)
+{
+    int active_only = 0;
+    arg_bool(r->args, "active_only", &active_only);
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "SELECT " CUSTOMER_COLUMNS " FROM customers WHERE org_id=?1"
+            " AND (?2=0 OR active=1) ORDER BY name COLLATE NOCASE, id",
+            -1, &st, NULL) != SQLITE_OK)
+        return fail(r, "INTERNAL", "database error");
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_int(st, 2, active_only);
+    yyjson_mut_val *items = yyjson_mut_arr(r->rdoc);
+    while (sqlite3_step(st) == SQLITE_ROW)
+        yyjson_mut_arr_add_val(items, customer_json(r, st));
+    sqlite3_finalize(st);
+    yyjson_mut_val *out = yyjson_mut_obj(r->rdoc);
+    yyjson_mut_obj_add_val(r->rdoc, out, "items", items);
+    return out;
+}
+
+static yyjson_mut_val *h_customer_get(struct req *r)
+{
+    int64_t id = 0;
+    if (!arg_int(r->args, "id", &id) || id <= 0)
+        return fail(r, "INVALID_ARGS", "id is required");
+    int found = 0;
+    yyjson_mut_val *o = customer_lookup(r, id, &found);
+    if (found < 0)
+        return NULL;
+    if (!found)
+        return fail(r, "NOT_FOUND", "customer not found");
+    return o;
+}
+
+static yyjson_mut_val *h_customer_create(struct req *r)
+{
+    struct customer_input in;
+    customer_input_read(r, &in);
+    if (customer_input_validate(r, &in, 1) != 0)
+        return NULL;
+    if (!in.have_payment)
+        in.payment_days = 30;
+    const char *address = in.address ? in.address : "";
+    const char *postal = in.postal_code ? in.postal_code : "";
+    const char *city = in.city ? in.city : "";
+    const char *country = in.country ? in.country : "SE";
+    const char *vat = in.vat_nr ? in.vat_nr : "";
+    const char *email = in.email ? in.email : "";
+    const char *your_ref = in.your_ref ? in.your_ref : "";
+    const char *notes = in.notes ? in.notes : "";
+    int taken = customer_name_taken(r, in.name, 0);
+    if (taken < 0)
+        return NULL;
+    if (taken)
+        return fail(r, "CONFLICT", "a customer with this name already exists");
+
+    if (r->dry_run) {
+        yyjson_mut_val *o = yyjson_mut_obj(r->rdoc);
+        yyjson_mut_obj_add_int(r->rdoc, o, "id", 0);
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "name", in.name);
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "address", address);
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "postal_code", postal);
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "city", city);
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "country", country);
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "vat_nr", vat);
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "email", email);
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "your_ref", your_ref);
+        yyjson_mut_obj_add_int(r->rdoc, o, "payment_days", in.payment_days);
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "notes", notes);
+        yyjson_mut_obj_add_bool(r->rdoc, o, "active", true);
+        yyjson_mut_obj_add_bool(r->rdoc, o, "dry_run", true);
+        return o;
+    }
+
+    char ts[32];
+    util_iso8601(util_now(), ts, sizeof ts);
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "INSERT INTO customers(org_id,name,address,postal_code,city,country,"
+            "vat_nr,email,your_ref,payment_days,notes,created_at)"
+            " VALUES(?1,?2,?3,?4,?5,?6,?7,?8,?9,?10,?11,?12)",
+            -1, &st, NULL) != SQLITE_OK)
+        return fail(r, "INTERNAL", "database error");
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_text(st, 2, in.name, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 3, address, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 4, postal, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 5, city, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 6, country, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 7, vat, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 8, email, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 9, your_ref, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_int64(st, 10, in.payment_days);
+    sqlite3_bind_text(st, 11, notes, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 12, ts, -1, SQLITE_TRANSIENT);
+    int rc = sqlite3_step(st);
+    sqlite3_finalize(st);
+    if (rc != SQLITE_DONE) {
+        if ((rc & 0xff) == SQLITE_CONSTRAINT)
+            return fail(r, "CONFLICT", "a customer with this name already exists");
+        return fail(r, "INTERNAL", sqlite3_errmsg(r->db));
+    }
+    int64_t id = db_last_id(r->db);
+    char *reqjson = audit_args_json(r->args);
+    audit_append(r->db, r->org_id, r->sess->user_id, r->sess->token_id,
+                 "customer.create", reqjson, "OK", NULL);
+    free(reqjson);
+    int found = 0;
+    yyjson_mut_val *o = customer_lookup(r, id, &found);
+    if (found < 0)
+        return NULL;
+    if (!found)
+        return fail(r, "INTERNAL", "could not read the new customer");
+    return o;
+}
+
+static yyjson_mut_val *h_customer_update(struct req *r)
+{
+    int64_t id = 0;
+    if (!arg_int(r->args, "id", &id) || id <= 0)
+        return fail(r, "INVALID_ARGS", "id is required");
+    struct customer_input in;
+    customer_input_read(r, &in);
+    if (customer_input_validate(r, &in, 0) != 0)
+        return NULL;
+    if (!in.name && !in.address && !in.postal_code && !in.city && !in.country &&
+        !in.vat_nr && !in.email && !in.your_ref && !in.notes &&
+        !in.have_payment && !in.have_active)
+        return fail(r, "INVALID_ARGS", "nothing to update");
+
+    int found = 0;
+    yyjson_mut_val *existing = customer_lookup(r, id, &found);
+    (void)existing;
+    if (found < 0)
+        return NULL;
+    if (!found)
+        return fail(r, "NOT_FOUND", "customer not found");
+    if (in.name) {
+        int taken = customer_name_taken(r, in.name, id);
+        if (taken < 0)
+            return NULL;
+        if (taken)
+            return fail(r, "CONFLICT", "a customer with this name already exists");
+    }
+
+    if (r->dry_run) {
+        sqlite3_stmt *st = NULL;
+        if (sqlite3_prepare_v2(
+                r->db,
+                "SELECT id,COALESCE(?3,name),COALESCE(?4,address),"
+                "COALESCE(?5,postal_code),COALESCE(?6,city),"
+                "COALESCE(?7,country),COALESCE(?8,vat_nr),"
+                "COALESCE(?9,email),COALESCE(?10,your_ref),"
+                "CASE WHEN ?11<0 THEN payment_days ELSE ?11 END,"
+                "COALESCE(?12,notes),"
+                "CASE WHEN ?13<0 THEN active ELSE ?13 END,"
+                "created_at,COALESCE(updated_at,'')"
+                " FROM customers WHERE org_id=?1 AND id=?2",
+                -1, &st, NULL) != SQLITE_OK)
+            return fail(r, "INTERNAL", "database error");
+        sqlite3_bind_int64(st, 1, r->org_id);
+        sqlite3_bind_int64(st, 2, id);
+        const char *texts[] = { in.name, in.address, in.postal_code, in.city,
+                                in.country, in.vat_nr, in.email, in.your_ref,
+                                in.notes };
+        static const int bind_index[] = { 3, 4, 5, 6, 7, 8, 9, 10, 12 };
+        for (size_t i = 0; i < sizeof texts / sizeof texts[0]; i++) {
+            if (texts[i])
+                sqlite3_bind_text(st, bind_index[i], texts[i], -1,
+                                  SQLITE_TRANSIENT);
+            else
+                sqlite3_bind_null(st, bind_index[i]);
+        }
+        sqlite3_bind_int64(st, 11, in.have_payment ? in.payment_days : -1);
+        sqlite3_bind_int64(st, 13, in.have_active ? in.active : -1);
+        yyjson_mut_val *o = NULL;
+        if (sqlite3_step(st) == SQLITE_ROW)
+            o = customer_json(r, st);
+        sqlite3_finalize(st);
+        if (!o)
+            return fail(r, "NOT_FOUND", "customer not found");
+        yyjson_mut_obj_add_bool(r->rdoc, o, "dry_run", true);
+        return o;
+    }
+
+    char ts[32];
+    util_iso8601(util_now(), ts, sizeof ts);
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "UPDATE customers SET"
+            " name=COALESCE(?3,name), address=COALESCE(?4,address),"
+            " postal_code=COALESCE(?5,postal_code), city=COALESCE(?6,city),"
+            " country=COALESCE(?7,country), vat_nr=COALESCE(?8,vat_nr),"
+            " email=COALESCE(?9,email), your_ref=COALESCE(?10,your_ref),"
+            " payment_days=CASE WHEN ?11<0 THEN payment_days ELSE ?11 END,"
+            " notes=COALESCE(?12,notes),"
+            " active=CASE WHEN ?13<0 THEN active ELSE ?13 END,"
+            " updated_at=?14 WHERE org_id=?1 AND id=?2",
+            -1, &st, NULL) != SQLITE_OK)
+        return fail(r, "INTERNAL", "database error");
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_int64(st, 2, id);
+    const char *texts[] = { in.name, in.address, in.postal_code, in.city,
+                            in.country, in.vat_nr, in.email, in.your_ref,
+                            in.notes };
+    static const int text_index[] = { 3, 4, 5, 6, 7, 8, 9, 10, 12 };
+    for (size_t i = 0; i < sizeof texts / sizeof texts[0]; i++) {
+        if (texts[i])
+            sqlite3_bind_text(st, text_index[i], texts[i], -1,
+                              SQLITE_TRANSIENT);
+        else
+            sqlite3_bind_null(st, text_index[i]);
+    }
+    sqlite3_bind_int64(st, 11, in.have_payment ? in.payment_days : -1);
+    sqlite3_bind_int64(st, 13, in.have_active ? in.active : -1);
+    sqlite3_bind_text(st, 14, ts, -1, SQLITE_TRANSIENT);
+    int rc = sqlite3_step(st);
+    sqlite3_finalize(st);
+    if (rc != SQLITE_DONE) {
+        if ((rc & 0xff) == SQLITE_CONSTRAINT)
+            return fail(r, "CONFLICT", "a customer with this name already exists");
+        return fail(r, "INTERNAL", sqlite3_errmsg(r->db));
+    }
+    if (sqlite3_changes(r->db) == 0)
+        return fail(r, "NOT_FOUND", "customer not found");
+    char *reqjson = audit_args_json(r->args);
+    audit_append(r->db, r->org_id, r->sess->user_id, r->sess->token_id,
+                 "customer.update", reqjson, "OK", NULL);
+    free(reqjson);
+    found = 0;
+    yyjson_mut_val *o = customer_lookup(r, id, &found);
+    if (found < 0)
+        return NULL;
+    if (!found)
+        return fail(r, "INTERNAL", "could not read the customer");
+    return o;
+}
+
+static yyjson_mut_val *h_customer_archive(struct req *r)
+{
+    int64_t id = 0;
+    int active = 0;
+    if (!arg_int(r->args, "id", &id) || id <= 0 ||
+        !arg_bool(r->args, "active", &active))
+        return fail(r, "INVALID_ARGS", "id and active are required");
+    int found = 0;
+    yyjson_mut_val *existing = customer_lookup(r, id, &found);
+    (void)existing;
+    if (found < 0)
+        return NULL;
+    if (!found)
+        return fail(r, "NOT_FOUND", "customer not found");
+
+    if (r->dry_run) {
+        yyjson_mut_val *o = yyjson_mut_obj(r->rdoc);
+        yyjson_mut_obj_add_int(r->rdoc, o, "id", id);
+        yyjson_mut_obj_add_bool(r->rdoc, o, "active", active != 0);
+        yyjson_mut_obj_add_bool(r->rdoc, o, "dry_run", true);
+        return o;
+    }
+
+    char ts[32];
+    util_iso8601(util_now(), ts, sizeof ts);
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "UPDATE customers SET active=?3, updated_at=?4"
+            " WHERE org_id=?1 AND id=?2",
+            -1, &st, NULL) != SQLITE_OK)
+        return fail(r, "INTERNAL", "database error");
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_int64(st, 2, id);
+    sqlite3_bind_int(st, 3, active);
+    sqlite3_bind_text(st, 4, ts, -1, SQLITE_TRANSIENT);
+    int rc = sqlite3_step(st);
+    sqlite3_finalize(st);
+    if (rc != SQLITE_DONE)
+        return fail(r, "INTERNAL", sqlite3_errmsg(r->db));
+    if (sqlite3_changes(r->db) == 0)
+        return fail(r, "NOT_FOUND", "customer not found");
+    char *reqjson = audit_args_json(r->args);
+    audit_append(r->db, r->org_id, r->sess->user_id, r->sess->token_id,
+                 "customer.archive", reqjson, "OK", NULL);
+    free(reqjson);
+    yyjson_mut_val *o = yyjson_mut_obj(r->rdoc);
+    yyjson_mut_obj_add_int(r->rdoc, o, "id", id);
+    yyjson_mut_obj_add_bool(r->rdoc, o, "active", active != 0);
+    return o;
+}
+
+/* ------------------------------------------------------------------ */
+/* invoice sequence                                                    */
+/* ------------------------------------------------------------------ */
+
+static int64_t invoice_next_number(struct req *r)
+{
+    sqlite3_stmt *st = NULL;
+    int64_t next = 1;
+    if (sqlite3_prepare_v2(
+            r->db, "SELECT next_number FROM invoice_sequence WHERE org_id=?1",
+            -1, &st, NULL) != SQLITE_OK)
+        return next;
+    sqlite3_bind_int64(st, 1, r->org_id);
+    if (sqlite3_step(st) == SQLITE_ROW)
+        next = sqlite3_column_int64(st, 0);
+    sqlite3_finalize(st);
+    return next > 0 ? next : 1;
+}
+
+static int invoice_take_number(struct req *r, int64_t *out)
+{
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(
+            r->db, "SELECT next_number FROM invoice_sequence WHERE org_id=?1",
+            -1, &st, NULL) != SQLITE_OK) {
+        fail(r, "INTERNAL", "database error");
+        return -1;
+    }
+    sqlite3_bind_int64(st, 1, r->org_id);
+    int have = sqlite3_step(st) == SQLITE_ROW;
+    int64_t number = have ? sqlite3_column_int64(st, 0) : 1;
+    sqlite3_finalize(st);
+    if (have) {
+        if (sqlite3_prepare_v2(
+                r->db,
+                "UPDATE invoice_sequence SET next_number=next_number+1"
+                " WHERE org_id=?1",
+                -1, &st, NULL) != SQLITE_OK) {
+            fail(r, "INTERNAL", "database error");
+            return -1;
+        }
+        sqlite3_bind_int64(st, 1, r->org_id);
+        int rc = sqlite3_step(st);
+        sqlite3_finalize(st);
+        if (rc != SQLITE_DONE) {
+            fail(r, "DB_BUSY", sqlite3_errmsg(r->db));
+            return -1;
+        }
+    } else {
+        if (sqlite3_prepare_v2(
+                r->db,
+                "INSERT INTO invoice_sequence(org_id,next_number) VALUES(?1,2)",
+                -1, &st, NULL) != SQLITE_OK) {
+            fail(r, "INTERNAL", "database error");
+            return -1;
+        }
+        sqlite3_bind_int64(st, 1, r->org_id);
+        int rc = sqlite3_step(st);
+        sqlite3_finalize(st);
+        if (rc != SQLITE_DONE) {
+            fail(r, "DB_BUSY", sqlite3_errmsg(r->db));
+            return -1;
+        }
+    }
+    *out = number;
+    return 0;
+}
+
+static yyjson_mut_val *h_invoice_sequence_get(struct req *r)
+{
+    yyjson_mut_val *o = yyjson_mut_obj(r->rdoc);
+    yyjson_mut_obj_add_int(r->rdoc, o, "next_number", invoice_next_number(r));
+    return o;
+}
+
+static yyjson_mut_val *h_invoice_sequence_set(struct req *r)
+{
+    int64_t next = 0;
+    if (!arg_int(r->args, "next_number", &next) || next <= 0)
+        return fail(r, "INVALID_ARGS",
+                    "next_number must be a positive integer");
+    if (r->dry_run) {
+        yyjson_mut_val *o = yyjson_mut_obj(r->rdoc);
+        yyjson_mut_obj_add_int(r->rdoc, o, "next_number", next);
+        yyjson_mut_obj_add_bool(r->rdoc, o, "dry_run", true);
+        return o;
+    }
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "INSERT INTO invoice_sequence(org_id,next_number) VALUES(?1,?2)"
+            " ON CONFLICT(org_id) DO UPDATE SET next_number=excluded.next_number",
+            -1, &st, NULL) != SQLITE_OK)
+        return fail(r, "INTERNAL", "database error");
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_int64(st, 2, next);
+    int rc = sqlite3_step(st);
+    sqlite3_finalize(st);
+    if (rc != SQLITE_DONE)
+        return fail(r, "INTERNAL", sqlite3_errmsg(r->db));
+    char *reqjson = audit_args_json(r->args);
+    audit_append(r->db, r->org_id, r->sess->user_id, r->sess->token_id,
+                 "invoice.sequence_set", reqjson, "OK", NULL);
+    free(reqjson);
+    yyjson_mut_val *o = yyjson_mut_obj(r->rdoc);
+    yyjson_mut_obj_add_int(r->rdoc, o, "next_number", next);
+    return o;
+}
+
+/* ------------------------------------------------------------------ */
+/* invoice drafts, rendering and issue                                 */
+/* ------------------------------------------------------------------ */
+
+struct draft_line {
+    const char *article_no;
+    const char *description;
+    int64_t quantity_milli;
+    const char *unit;
+    int64_t unit_price_ore;
+    int64_t amount_ore;
+    const char *note;
+    const char *vat_code;
+    char account[16];
+};
+
+struct invoice_draft {
+    int64_t customer_id;
+    const char *invoice_date;
+    const char *due_date;
+    const char *delivery_date;
+    const char *your_ref;
+    const char *our_ref;
+    const char *notes;
+    struct draft_line *lines;
+    size_t nlines;
+};
+
+static void invoice_draft_free(struct invoice_draft *d)
+{
+    free(d->lines);
+    d->lines = NULL;
+    d->nlines = 0;
+}
+
+static int parse_quantity(const char *s, int64_t *out)
+{
+    if (!s || !*s || strlen(s) > 24)
+        return -1;
+    int64_t whole = 0, frac = 0;
+    size_t int_digits = 0, frac_digits = 0;
+    int seen_sep = 0;
+    for (const char *p = s; *p; p++) {
+        char c = *p;
+        if (c == ',' || c == '.') {
+            if (seen_sep)
+                return -1;
+            seen_sep = 1;
+            continue;
+        }
+        if (c < '0' || c > '9')
+            return -1;
+        if (!seen_sep) {
+            if (int_digits >= 18)
+                return -1;
+            whole = whole * 10 + (c - '0');
+            int_digits++;
+        } else {
+            if (frac_digits >= 3)
+                return -1;
+            frac = frac * 10 + (c - '0');
+            frac_digits++;
+        }
+    }
+    if (!int_digits || (seen_sep && !frac_digits))
+        return -1;
+    for (size_t i = frac_digits; i < 3; i++)
+        frac *= 10;
+    if (whole > (INT64_MAX - frac) / 1000)
+        return -1;
+    int64_t v = whole * 1000 + frac;
+    if (v <= 0)
+        return -1;
+    *out = v;
+    return 0;
+}
+
+static int draft_line_parse(struct req *r, yyjson_val *item, size_t no,
+                            const char *default_account, struct draft_line *l,
+                            int64_t *net_total)
+{
+    const char *description = arg_str(item, "description");
+    if (!description || !*description) {
+        failf(r, "INVALID_ARGS", "row %zu: description is required", no);
+        return -1;
+    }
+    const char *qty = arg_str(item, "quantity");
+    int64_t quantity_milli = 0;
+    if (parse_quantity(qty, &quantity_milli) != 0) {
+        failf(r, "INVALID_ARGS",
+              "row %zu: quantity must be a positive decimal with at most 3"
+              " decimals",
+              no);
+        return -1;
+    }
+    int64_t price = 0;
+    if (!arg_int(item, "unit_price_ore", &price) || price < 0) {
+        failf(r, "INVALID_ARGS",
+              "row %zu: unit_price_ore must be a non-negative integer", no);
+        return -1;
+    }
+    const char *vat = arg_str(item, "vat_code");
+    if (!vat || !*vat)
+        vat = "25";
+    if (strcmp(vat, "25") != 0 && strcmp(vat, "12") != 0 &&
+        strcmp(vat, "6") != 0 && strcmp(vat, "0") != 0 &&
+        strcmp(vat, "rc") != 0 && strcmp(vat, "eu") != 0) {
+        failf(r, "INVALID_ARGS",
+              "row %zu: vat_code must be one of 25, 12, 6, 0, rc, eu", no);
+        return -1;
+    }
+    const char *account = arg_str(item, "account");
+    if (account && !*account)
+        account = NULL;
+    if (account) {
+        if (!is_digits(account) || strlen(account) > 10) {
+            failf(r, "INVALID_ARGS", "row %zu: account must be 1-10 digits",
+                  no);
+            return -1;
+        }
+        snprintf(l->account, sizeof l->account, "%s", account);
+    } else {
+        snprintf(l->account, sizeof l->account, "%s", default_account);
+    }
+    l->article_no = arg_str(item, "article_no");
+    l->description = description;
+    l->quantity_milli = quantity_milli;
+    const char *unit = arg_str(item, "unit");
+    l->unit = unit && *unit ? unit : "st";
+    l->unit_price_ore = price;
+    l->note = arg_str(item, "note");
+    l->vat_code = vat;
+    int64_t product = 0;
+    if (__builtin_mul_overflow(quantity_milli, price, &product) ||
+        __builtin_add_overflow(product, (int64_t)500, &product)) {
+        failf(r, "INVALID_ARGS", "row %zu: amount overflows", no);
+        return -1;
+    }
+    l->amount_ore = product / 1000;
+    if (__builtin_add_overflow(*net_total, l->amount_ore, net_total) ||
+        *net_total > INT64_MAX / 100) {
+        failf(r, "INVALID_ARGS", "row %zu: invoice total overflows", no);
+        return -1;
+    }
+    return 0;
+}
+
+static int parse_invoice_draft(struct req *r, struct invoice_draft *d)
+{
+    memset(d, 0, sizeof *d);
+    if (!arg_int(r->args, "customer_id", &d->customer_id) ||
+        d->customer_id <= 0) {
+        fail(r, "INVALID_ARGS", "customer_id is required");
+        return -1;
+    }
+    d->invoice_date = arg_str(r->args, "invoice_date");
+    d->due_date = arg_str(r->args, "due_date");
+    d->delivery_date = arg_str(r->args, "delivery_date");
+    if (!d->invoice_date || !util_parse_iso_date(d->invoice_date)) {
+        fail(r, "INVALID_ARGS", "invoice_date must be YYYY-MM-DD");
+        return -1;
+    }
+    if (!d->due_date || !util_parse_iso_date(d->due_date)) {
+        fail(r, "INVALID_ARGS", "due_date must be YYYY-MM-DD");
+        return -1;
+    }
+    if (!d->delivery_date)
+        d->delivery_date = "";
+    if (*d->delivery_date && !util_parse_iso_date(d->delivery_date)) {
+        fail(r, "INVALID_ARGS", "delivery_date must be YYYY-MM-DD");
+        return -1;
+    }
+    d->your_ref = arg_str(r->args, "your_ref");
+    d->our_ref = arg_str(r->args, "our_ref");
+    d->notes = arg_str(r->args, "notes");
+    if (!d->your_ref)
+        d->your_ref = "";
+    if (!d->our_ref)
+        d->our_ref = "";
+    if (!d->notes)
+        d->notes = "";
+
+    yyjson_val *rows = r->args ? yyjson_obj_get(r->args, "rows") : NULL;
+    if (!rows || !yyjson_is_arr(rows) || yyjson_arr_size(rows) == 0) {
+        fail(r, "INVALID_ARGS", "rows must be a non-empty array");
+        return -1;
+    }
+    char *revenue = db_setting(r->db, r->org_id, "invoice_revenue_account");
+    const char *default_account =
+        revenue && *revenue ? revenue : "3001";
+    size_t n = yyjson_arr_size(rows);
+    struct draft_line *lines = xcalloc(n, sizeof *lines);
+    size_t k = 0;
+    int64_t net_total = 0;
+    yyjson_arr_iter it = yyjson_arr_iter_with(rows);
+    yyjson_val *item;
+    while ((item = yyjson_arr_iter_next(&it))) {
+        if (!yyjson_is_obj(item)) {
+            failf(r, "INVALID_ARGS", "row %zu: must be an object", k + 1);
+            free(lines);
+            free(revenue);
+            return -1;
+        }
+        if (draft_line_parse(r, item, k + 1, default_account, &lines[k],
+                             &net_total) != 0) {
+            free(lines);
+            free(revenue);
+            return -1;
+        }
+        k++;
+    }
+    free(revenue);
+    if (net_total <= 0) {
+        fail(r, "INVALID_ARGS", "invoice total must be greater than zero");
+        free(lines);
+        return -1;
+    }
+    d->lines = lines;
+    d->nlines = k;
+    return 0;
+}
+
+struct invoice_view {
+    struct invoice_doc doc;
+    struct invoice_line *lines;
+    char number_str[32];
+    char ocr[40];
+    char filename[600];
+    char description[600];
+    char seller_name[256];
+    char seller_address[1024];
+    char seller_postal[64];
+    char seller_city[128];
+    char seller_phone[64];
+    char seller_email[256];
+    char seller_org_nr[64];
+    char seller_vat_nr[64];
+    char bankgiro[64];
+    char customer_name[256];
+    char customer_address[1024];
+    char customer_postal[64];
+    char customer_city[128];
+    char customer_vat_nr[64];
+};
+
+static void invoice_view_free(struct invoice_view *v)
+{
+    free(v->lines);
+    v->lines = NULL;
+}
+
+static int invoice_view_fill(struct req *r, const struct invoice_draft *d,
+                             int64_t number, struct invoice_view *v)
+{
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "SELECT COALESCE(name,''),COALESCE(address,''),"
+            "COALESCE(postal_code,''),COALESCE(city,''),"
+            "COALESCE(phone,''),COALESCE(email,''),COALESCE(org_nr,''),"
+            "COALESCE(vat_nr,'') FROM orgs WHERE id=?1",
+            -1, &st, NULL) != SQLITE_OK) {
+        fail(r, "INTERNAL", "database error");
+        return -1;
+    }
+    sqlite3_bind_int64(st, 1, r->org_id);
+    int have_org = sqlite3_step(st) == SQLITE_ROW;
+    if (have_org) {
+        snprintf(v->seller_name, sizeof v->seller_name, "%s",
+                 sq(sqlite3_column_text(st, 0)));
+        snprintf(v->seller_address, sizeof v->seller_address, "%s",
+                 sq(sqlite3_column_text(st, 1)));
+        snprintf(v->seller_postal, sizeof v->seller_postal, "%s",
+                 sq(sqlite3_column_text(st, 2)));
+        snprintf(v->seller_city, sizeof v->seller_city, "%s",
+                 sq(sqlite3_column_text(st, 3)));
+        snprintf(v->seller_phone, sizeof v->seller_phone, "%s",
+                 sq(sqlite3_column_text(st, 4)));
+        snprintf(v->seller_email, sizeof v->seller_email, "%s",
+                 sq(sqlite3_column_text(st, 5)));
+        snprintf(v->seller_org_nr, sizeof v->seller_org_nr, "%s",
+                 sq(sqlite3_column_text(st, 6)));
+        snprintf(v->seller_vat_nr, sizeof v->seller_vat_nr, "%s",
+                 sq(sqlite3_column_text(st, 7)));
+    }
+    sqlite3_finalize(st);
+    if (!have_org) {
+        fail(r, "NOT_FOUND", "org not found");
+        return -1;
+    }
+
+    int64_t payment_days = 30;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "SELECT name,address,postal_code,city,vat_nr,payment_days,active"
+            " FROM customers WHERE org_id=?1 AND id=?2",
+            -1, &st, NULL) != SQLITE_OK) {
+        fail(r, "INTERNAL", "database error");
+        return -1;
+    }
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_int64(st, 2, d->customer_id);
+    if (sqlite3_step(st) != SQLITE_ROW || !sqlite3_column_int(st, 6)) {
+        sqlite3_finalize(st);
+        fail(r, "NOT_FOUND", "customer not found");
+        return -1;
+    }
+    snprintf(v->customer_name, sizeof v->customer_name, "%s",
+             sq(sqlite3_column_text(st, 0)));
+    snprintf(v->customer_address, sizeof v->customer_address, "%s",
+             sq(sqlite3_column_text(st, 1)));
+    snprintf(v->customer_postal, sizeof v->customer_postal, "%s",
+             sq(sqlite3_column_text(st, 2)));
+    snprintf(v->customer_city, sizeof v->customer_city, "%s",
+             sq(sqlite3_column_text(st, 3)));
+    snprintf(v->customer_vat_nr, sizeof v->customer_vat_nr, "%s",
+             sq(sqlite3_column_text(st, 4)));
+    payment_days = sqlite3_column_int64(st, 5);
+    sqlite3_finalize(st);
+
+    char *bankgiro = db_setting(r->db, r->org_id, "invoice_bankgiro");
+    snprintf(v->bankgiro, sizeof v->bankgiro, "%s",
+             bankgiro && *bankgiro ? bankgiro : "");
+    free(bankgiro);
+
+    v->lines = xcalloc(d->nlines, sizeof *v->lines);
+    for (size_t i = 0; i < d->nlines; i++) {
+        v->lines[i].article_no = d->lines[i].article_no;
+        v->lines[i].description = d->lines[i].description;
+        v->lines[i].quantity_milli = d->lines[i].quantity_milli;
+        v->lines[i].unit = d->lines[i].unit;
+        v->lines[i].unit_price_ore = d->lines[i].unit_price_ore;
+        v->lines[i].amount_ore = d->lines[i].amount_ore;
+        v->lines[i].note = d->lines[i].note;
+        v->lines[i].vat_code = d->lines[i].vat_code;
+    }
+
+    v->doc.seller.name = v->seller_name;
+    v->doc.seller.address = v->seller_address;
+    v->doc.seller.postal_code = v->seller_postal;
+    v->doc.seller.city = v->seller_city;
+    v->doc.seller.phone = v->seller_phone;
+    v->doc.seller.email = v->seller_email;
+    v->doc.seller.org_nr = v->seller_org_nr;
+    v->doc.seller.vat_nr = v->seller_vat_nr;
+    v->doc.seller.bankgiro = v->bankgiro;
+    v->doc.customer.name = v->customer_name;
+    v->doc.customer.address = v->customer_address;
+    v->doc.customer.postal_code = v->customer_postal;
+    v->doc.customer.city = v->customer_city;
+    v->doc.customer.vat_nr = v->customer_vat_nr;
+    v->doc.number = number;
+    v->doc.ocr = v->ocr;
+    v->doc.invoice_date = d->invoice_date;
+    v->doc.due_date = d->due_date;
+    v->doc.delivery_date = d->delivery_date;
+    v->doc.our_ref = d->our_ref;
+    v->doc.your_ref = d->your_ref;
+    v->doc.notes = d->notes;
+    v->doc.payment_days = (int)payment_days;
+    v->doc.lines = v->lines;
+    v->doc.nlines = d->nlines;
+
+    snprintf(v->number_str, sizeof v->number_str, "%lld", (long long)number);
+    int check = invoice_ocr_check(v->number_str);
+    snprintf(v->ocr, sizeof v->ocr, "%s%c", v->number_str,
+             (char)('0' + (check > 0 ? check : 0)));
+    char safe_name[256];
+    snprintf(safe_name, sizeof safe_name, "%s", v->customer_name);
+    for (char *p = safe_name; *p; p++)
+        if (*p == '/')
+            *p = '-';
+    snprintf(v->filename, sizeof v->filename, "Faktura %lld %s.pdf",
+             (long long)number, safe_name);
+    snprintf(v->description, sizeof v->description, "Faktura %lld %s",
+             (long long)number, safe_name);
+    return 0;
+}
+
+/* Mirrors invoice.c vat_part(): round half up per rate base. */
+static int64_t invoice_vat_part(int64_t net, int64_t rate)
+{
+    int64_t v = net * rate;
+    if (v >= 0)
+        return (v + 50) / 100;
+    return -((-v + 50) / 100);
+}
+
+static int invoice_build_pdf(struct req *r, struct invoice_view *v,
+                             struct invoice_totals *t, unsigned char **out,
+                             size_t *out_len)
+{
+    invoice_totals(&v->doc, t);
+    *out = NULL;
+    *out_len = 0;
+    if (invoice_render_pdf(&v->doc, out, out_len) != 0 || !*out) {
+        free(*out);
+        *out = NULL;
+        fail(r, "TOO_LARGE", "invoice does not fit on one page");
+        return -1;
+    }
+    return 0;
+}
+
+static int invoice_prepare(struct req *r, struct invoice_draft *d,
+                           int64_t number, struct invoice_view *v,
+                           struct invoice_totals *t, unsigned char **pdf,
+                           size_t *pdf_len)
+{
+    memset(v, 0, sizeof *v);
+    if (invoice_view_fill(r, d, number, v) != 0)
+        return -1;
+    if (invoice_build_pdf(r, v, t, pdf, pdf_len) != 0) {
+        invoice_view_free(v);
+        return -1;
+    }
+    return 0;
+}
+
+static yyjson_mut_val *h_invoice_preview(struct req *r)
+{
+    struct invoice_draft d;
+    if (parse_invoice_draft(r, &d) != 0)
+        return NULL;
+    int64_t number = invoice_next_number(r);
+    struct invoice_view v;
+    struct invoice_totals t;
+    unsigned char *pdf = NULL;
+    size_t pdf_len = 0;
+    int rc = invoice_prepare(r, &d, number, &v, &t, &pdf, &pdf_len);
+    invoice_draft_free(&d);
+    if (rc != 0)
+        return NULL;
+    char *b64 = util_b64(pdf, pdf_len);
+    free(pdf);
+    if (!b64) {
+        invoice_view_free(&v);
+        return fail(r, "INTERNAL", "could not encode the PDF");
+    }
+    yyjson_mut_val *o = yyjson_mut_obj(r->rdoc);
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "content_base64", b64);
+    yyjson_mut_obj_add_int(r->rdoc, o, "number", number);
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "ocr", v.ocr);
+    yyjson_mut_obj_add_int(r->rdoc, o, "net_ore", t.net_ore);
+    yyjson_mut_obj_add_int(r->rdoc, o, "vat_ore", t.vat_ore);
+    yyjson_mut_obj_add_int(r->rdoc, o, "total_ore", t.total_ore);
+    free(b64);
+    invoice_view_free(&v);
+    return o;
+}
+
+static int invoice_store_attachment(struct req *r, const struct invoice_view *v,
+                                    const unsigned char *pdf, size_t pdf_len,
+                                    int64_t *out_id)
+{
+    unsigned char hash[32];
+    util_sha256(pdf, pdf_len, hash);
+    char ts[32];
+    util_iso8601(util_now(), ts, sizeof ts);
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "INSERT INTO attachments(org_id,sha256,filename,mime,size_bytes,"
+            "content,created_at,created_by)"
+            " VALUES(?1,?2,?3,'application/pdf',?4,?5,?6,?7)",
+            -1, &st, NULL) != SQLITE_OK) {
+        fail(r, "INTERNAL", "database error");
+        return -1;
+    }
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_blob(st, 2, hash, 32, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 3, v->filename, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_int64(st, 4, (int64_t)pdf_len);
+    sqlite3_bind_blob(st, 5, pdf, (int)pdf_len, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 6, ts, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_int64(st, 7, r->sess->user_id);
+    int rc = sqlite3_step(st);
+    sqlite3_finalize(st);
+    if (rc != SQLITE_DONE) {
+        fail(r, "DB_BUSY", sqlite3_errmsg(r->db));
+        return -1;
+    }
+    *out_id = db_last_id(r->db);
+    return 0;
+}
+
+static int invoice_store_invoice(struct req *r, const struct invoice_draft *d,
+                                 const struct invoice_totals *t, int64_t number,
+                                 int64_t document_id, int64_t voucher_id,
+                                 int64_t *out_id)
+{
+    char ts[32];
+    util_iso8601(util_now(), ts, sizeof ts);
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "INSERT INTO invoices(org_id,customer_id,number,ocr,invoice_date,"
+            "due_date,delivery_date,your_ref,our_ref,notes,net_ore,vat_ore,"
+            "total_ore,document_id,voucher_id,created_at,created_by)"
+            " VALUES(?1,?2,?3,?4,?5,?6,?7,?8,?9,?10,?11,?12,?13,?14,?15,?16,"
+            "?17)",
+            -1, &st, NULL) != SQLITE_OK) {
+        fail(r, "INTERNAL", "database error");
+        return -1;
+    }
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_int64(st, 2, d->customer_id);
+    sqlite3_bind_int64(st, 3, number);
+    char number_str[32];
+    snprintf(number_str, sizeof number_str, "%lld", (long long)number);
+    int check = invoice_ocr_check(number_str);
+    char ocr[40];
+    snprintf(ocr, sizeof ocr, "%s%c", number_str,
+             (char)('0' + (check > 0 ? check : 0)));
+    sqlite3_bind_text(st, 4, ocr, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 5, d->invoice_date, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 6, d->due_date, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 7, d->delivery_date, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 8, d->your_ref, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 9, d->our_ref, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_text(st, 10, d->notes, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_int64(st, 11, t->net_ore);
+    sqlite3_bind_int64(st, 12, t->vat_ore);
+    sqlite3_bind_int64(st, 13, t->total_ore);
+    sqlite3_bind_int64(st, 14, document_id);
+    sqlite3_bind_int64(st, 15, voucher_id);
+    sqlite3_bind_text(st, 16, ts, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_int64(st, 17, r->sess->user_id);
+    int rc = sqlite3_step(st);
+    sqlite3_finalize(st);
+    if (rc != SQLITE_DONE) {
+        if ((rc & 0xff) == SQLITE_CONSTRAINT) {
+            fail(r, "CONFLICT", "invoice number already exists");
+            return -1;
+        }
+        fail(r, "DB_BUSY", sqlite3_errmsg(r->db));
+        return -1;
+    }
+    int64_t id = db_last_id(r->db);
+    for (size_t i = 0; i < d->nlines; i++) {
+        const struct draft_line *l = &d->lines[i];
+        if (sqlite3_prepare_v2(
+                r->db,
+                "INSERT INTO invoice_rows(org_id,invoice_id,line_no,article_no,"
+                "description,quantity_milli,unit,unit_price_ore,amount_ore,note,"
+                "vat_code,account)"
+                " VALUES(?1,?2,?3,?4,?5,?6,?7,?8,?9,?10,?11,?12)",
+                -1, &st, NULL) != SQLITE_OK) {
+            fail(r, "INTERNAL", "database error");
+            return -1;
+        }
+        sqlite3_bind_int64(st, 1, r->org_id);
+        sqlite3_bind_int64(st, 2, id);
+        sqlite3_bind_int64(st, 3, (int64_t)i + 1);
+        sqlite3_bind_text(st, 4, l->article_no ? l->article_no : "", -1,
+                          SQLITE_TRANSIENT);
+        sqlite3_bind_text(st, 5, l->description, -1, SQLITE_TRANSIENT);
+        sqlite3_bind_int64(st, 6, l->quantity_milli);
+        sqlite3_bind_text(st, 7, l->unit, -1, SQLITE_TRANSIENT);
+        sqlite3_bind_int64(st, 8, l->unit_price_ore);
+        sqlite3_bind_int64(st, 9, l->amount_ore);
+        sqlite3_bind_text(st, 10, l->note ? l->note : "", -1, SQLITE_TRANSIENT);
+        sqlite3_bind_text(st, 11, l->vat_code, -1, SQLITE_TRANSIENT);
+        sqlite3_bind_text(st, 12, l->account, -1, SQLITE_TRANSIENT);
+        rc = sqlite3_step(st);
+        sqlite3_finalize(st);
+        if (rc != SQLITE_DONE) {
+            fail(r, "DB_BUSY", sqlite3_errmsg(r->db));
+            return -1;
+        }
+    }
+    *out_id = id;
+    return 0;
+}
+
+static yyjson_mut_val *invoice_issue_result(struct req *r, int dry_run,
+                                            int64_t id, int64_t number,
+                                            const char *ocr, int64_t document_id,
+                                            int64_t voucher_id,
+                                            const struct invoice_totals *t)
+{
+    yyjson_mut_val *o = yyjson_mut_obj(r->rdoc);
+    if (dry_run) {
+        yyjson_mut_obj_add_bool(r->rdoc, o, "dry_run", true);
+        yyjson_mut_obj_add_int(r->rdoc, o, "id", 0);
+    } else {
+        yyjson_mut_obj_add_int(r->rdoc, o, "id", id);
+    }
+    yyjson_mut_obj_add_int(r->rdoc, o, "number", number);
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "ocr", ocr);
+    if (dry_run) {
+        yyjson_mut_obj_add_null(r->rdoc, o, "document_id");
+        yyjson_mut_obj_add_null(r->rdoc, o, "voucher_id");
+    } else {
+        yyjson_mut_obj_add_int(r->rdoc, o, "document_id", document_id);
+        yyjson_mut_obj_add_int(r->rdoc, o, "voucher_id", voucher_id);
+    }
+    yyjson_mut_obj_add_int(r->rdoc, o, "net_ore", t->net_ore);
+    yyjson_mut_obj_add_int(r->rdoc, o, "vat_ore", t->vat_ore);
+    yyjson_mut_obj_add_int(r->rdoc, o, "total_ore", t->total_ore);
+    return o;
+}
+
+static yyjson_mut_val *h_invoice_issue(struct req *r)
+{
+    struct invoice_draft d;
+    if (parse_invoice_draft(r, &d) != 0)
+        return NULL;
+    char *rec_setting =
+        db_setting(r->db, r->org_id, "invoice_receivable_account");
+    char receivable[16];
+    snprintf(receivable, sizeof receivable, "%s",
+             rec_setting && *rec_setting ? rec_setting : "1510");
+    free(rec_setting);
+
+    yyjson_mut_val *res = NULL;
+    struct invoice_view v;
+    struct invoice_totals t;
+    memset(&v, 0, sizeof v);
+    memset(&t, 0, sizeof t);
+    unsigned char *pdf = NULL;
+    size_t pdf_len = 0;
+    char *voucher_json = NULL;
+    struct ledger_row *vrows = NULL;
+    int64_t number = 0, attachment_id = 0, voucher_id = 0, invoice_id = 0;
+    int in_tx = 0;
+
+    if (db_exec(r->db, "BEGIN IMMEDIATE", NULL) != 0) {
+        invoice_draft_free(&d);
+        return fail(r, "DB_BUSY", "could not start transaction");
+    }
+    in_tx = 1;
+
+    if (r->dry_run)
+        number = invoice_next_number(r);
+    else if (invoice_take_number(r, &number) != 0)
+        goto done;
+
+    if (invoice_prepare(r, &d, number, &v, &t, &pdf, &pdf_len) != 0)
+        goto done;
+
+    size_t cap = 1 + 3 + d.nlines;
+    vrows = xcalloc(cap, sizeof *vrows);
+    size_t vn = 0;
+    vrows[vn].account = receivable;
+    vrows[vn].debit_ore = t.total_ore;
+    vrows[vn].description = NULL;
+    vn++;
+    struct {
+        int rate;
+        const char *account;
+        int64_t net;
+    } legs[3] = {
+        { 25, "2610", t.net_25 },
+        { 12, "2620", t.net_12 },
+        { 6, "2630", t.net_6 },
+    };
+    int64_t vat_sum = 0;
+    for (size_t i = 0; i < 3; i++) {
+        int64_t vat = invoice_vat_part(legs[i].net, legs[i].rate);
+        if (vat <= 0)
+            continue;
+        vrows[vn].account = legs[i].account;
+        vrows[vn].credit_ore = vat;
+        if (i == 0)
+            vrows[vn].description = "Moms 25%";
+        else if (i == 1)
+            vrows[vn].description = "Moms 12%";
+        else
+            vrows[vn].description = "Moms 6%";
+        vat_sum += vat;
+        vn++;
+    }
+    for (size_t i = 0; i < d.nlines; i++) {
+        if (d.lines[i].amount_ore <= 0)
+            continue;
+        vrows[vn].account = d.lines[i].account;
+        vrows[vn].credit_ore = d.lines[i].amount_ore;
+        vrows[vn].description = d.lines[i].description;
+        vn++;
+    }
+    int64_t sum_debit = 0, sum_credit = 0;
+    for (size_t i = 0; i < vn; i++) {
+        sum_debit += vrows[i].debit_ore;
+        sum_credit += vrows[i].credit_ore;
+    }
+    if (vat_sum != t.vat_ore || sum_debit != t.total_ore ||
+        sum_debit != sum_credit) {
+        fail(r, "INTERNAL", "invoice totals do not match the voucher");
+        goto done;
+    }
+
+    if (!r->dry_run &&
+        invoice_store_attachment(r, &v, pdf, pdf_len, &attachment_id) != 0)
+        goto done;
+
+    struct ledger_post_opts o;
+    memset(&o, 0, sizeof o);
+    o.org_id = r->org_id;
+    o.user_id = r->sess->user_id;
+    o.token_id = r->sess->token_id;
+    o.date = d.invoice_date;
+    o.description = v.description;
+    o.rows = vrows;
+    o.nrows = vn;
+    o.source = "invoice";
+    o.dry_run = r->dry_run;
+    o.already_in_tx = 1;
+    struct ledger_error e;
+    if (ledger_post(r->db, &o, &e, &voucher_json) != 0) {
+        fail(r, e.code ? e.code : "INTERNAL", e.msg);
+        goto done;
+    }
+
+    if (!r->dry_run) {
+        if (!voucher_json) {
+            fail(r, "INTERNAL", "empty voucher result");
+            goto done;
+        }
+        yyjson_doc *vd = yyjson_read(voucher_json, strlen(voucher_json), 0);
+        if (vd) {
+            yyjson_val *idv = yyjson_obj_get(yyjson_doc_get_root(vd), "id");
+            if (idv && yyjson_is_int(idv))
+                voucher_id = yyjson_get_int(idv);
+            yyjson_doc_free(vd);
+        }
+        if (voucher_id <= 0) {
+            fail(r, "INTERNAL", "voucher id missing from the posting");
+            goto done;
+        }
+        if (invoice_store_invoice(r, &d, &t, number, attachment_id, voucher_id,
+                                  &invoice_id) != 0)
+            goto done;
+        if (sqlite3_exec(r->db, "COMMIT", NULL, NULL, NULL) != SQLITE_OK) {
+            fail(r, "DB_BUSY", "commit failed");
+            goto done;
+        }
+        in_tx = 0;
+        char *reqjson = audit_args_json(r->args);
+        audit_append(r->db, r->org_id, r->sess->user_id, r->sess->token_id,
+                     "invoice.issue", reqjson, "OK", NULL);
+        free(reqjson);
+    }
+
+    res = invoice_issue_result(r, r->dry_run, invoice_id, number, v.ocr,
+                               attachment_id, voucher_id, &t);
+
+done:
+    if (in_tx)
+        sqlite3_exec(r->db, "ROLLBACK", NULL, NULL, NULL);
+    free(pdf);
+    free(voucher_json);
+    free(vrows);
+    invoice_draft_free(&d);
+    invoice_view_free(&v);
+    return res;
+}
+
+static yyjson_mut_val *invoice_row_json(struct req *r, sqlite3_stmt *st)
+{
+    yyjson_mut_val *o = yyjson_mut_obj(r->rdoc);
+    yyjson_mut_obj_add_int(r->rdoc, o, "line_no",
+                           sqlite3_column_int64(st, 0));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "article_no",
+                              sq(sqlite3_column_text(st, 1)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "description",
+                              sq(sqlite3_column_text(st, 2)));
+    yyjson_mut_obj_add_int(r->rdoc, o, "quantity_milli",
+                           sqlite3_column_int64(st, 3));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "unit",
+                              sq(sqlite3_column_text(st, 4)));
+    yyjson_mut_obj_add_int(r->rdoc, o, "unit_price_ore",
+                           sqlite3_column_int64(st, 5));
+    yyjson_mut_obj_add_int(r->rdoc, o, "amount_ore",
+                           sqlite3_column_int64(st, 6));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "note",
+                              sq(sqlite3_column_text(st, 7)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "vat_code",
+                              sq(sqlite3_column_text(st, 8)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "account",
+                              sq(sqlite3_column_text(st, 9)));
+    return o;
+}
+
+#define INVOICE_ROW_COLUMNS                                               \
+    "line_no,article_no,description,quantity_milli,unit,unit_price_ore,"  \
+    "amount_ore,note,vat_code,account"
+
+static yyjson_mut_val *h_invoice_get(struct req *r)
+{
+    int64_t id = 0;
+    if (!arg_int(r->args, "id", &id) || id <= 0)
+        return fail(r, "INVALID_ARGS", "id is required");
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "SELECT i.id,i.customer_id,c.name,i.number,i.ocr,i.invoice_date,"
+            "i.due_date,i.delivery_date,i.your_ref,i.our_ref,i.notes,i.net_ore,"
+            "i.vat_ore,i.total_ore,i.status,i.document_id,i.voucher_id,"
+            "i.last_sent_at,i.last_sent_to,i.created_at,i.created_by"
+            " FROM invoices i JOIN customers c"
+            " ON c.org_id=i.org_id AND c.id=i.customer_id"
+            " WHERE i.org_id=?1 AND i.id=?2",
+            -1, &st, NULL) != SQLITE_OK)
+        return fail(r, "INTERNAL", "database error");
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_int64(st, 2, id);
+    if (sqlite3_step(st) != SQLITE_ROW) {
+        sqlite3_finalize(st);
+        return fail(r, "NOT_FOUND", "invoice not found");
+    }
+    yyjson_mut_val *o = yyjson_mut_obj(r->rdoc);
+    yyjson_mut_obj_add_int(r->rdoc, o, "id", sqlite3_column_int64(st, 0));
+    yyjson_mut_obj_add_int(r->rdoc, o, "customer_id",
+                           sqlite3_column_int64(st, 1));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "customer_name",
+                              sq(sqlite3_column_text(st, 2)));
+    yyjson_mut_obj_add_int(r->rdoc, o, "number", sqlite3_column_int64(st, 3));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "ocr",
+                              sq(sqlite3_column_text(st, 4)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "invoice_date",
+                              sq(sqlite3_column_text(st, 5)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "due_date",
+                              sq(sqlite3_column_text(st, 6)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "delivery_date",
+                              sq(sqlite3_column_text(st, 7)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "your_ref",
+                              sq(sqlite3_column_text(st, 8)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "our_ref",
+                              sq(sqlite3_column_text(st, 9)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "notes",
+                              sq(sqlite3_column_text(st, 10)));
+    yyjson_mut_obj_add_int(r->rdoc, o, "net_ore",
+                           sqlite3_column_int64(st, 11));
+    yyjson_mut_obj_add_int(r->rdoc, o, "vat_ore",
+                           sqlite3_column_int64(st, 12));
+    yyjson_mut_obj_add_int(r->rdoc, o, "total_ore",
+                           sqlite3_column_int64(st, 13));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "status",
+                              sq(sqlite3_column_text(st, 14)));
+    if (sqlite3_column_type(st, 15) == SQLITE_NULL)
+        yyjson_mut_obj_add_null(r->rdoc, o, "document_id");
+    else
+        yyjson_mut_obj_add_int(r->rdoc, o, "document_id",
+                               sqlite3_column_int64(st, 15));
+    if (sqlite3_column_type(st, 16) == SQLITE_NULL)
+        yyjson_mut_obj_add_null(r->rdoc, o, "voucher_id");
+    else
+        yyjson_mut_obj_add_int(r->rdoc, o, "voucher_id",
+                               sqlite3_column_int64(st, 16));
+    if (sqlite3_column_type(st, 17) == SQLITE_NULL)
+        yyjson_mut_obj_add_null(r->rdoc, o, "last_sent_at");
+    else
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "last_sent_at",
+                                  sq(sqlite3_column_text(st, 17)));
+    if (sqlite3_column_type(st, 18) == SQLITE_NULL)
+        yyjson_mut_obj_add_null(r->rdoc, o, "last_sent_to");
+    else
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "last_sent_to",
+                                  sq(sqlite3_column_text(st, 18)));
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "created_at",
+                              sq(sqlite3_column_text(st, 19)));
+    yyjson_mut_obj_add_int(r->rdoc, o, "created_by",
+                           sqlite3_column_int64(st, 20));
+    sqlite3_finalize(st);
+
+    yyjson_mut_val *rows = yyjson_mut_arr(r->rdoc);
+    if (sqlite3_prepare_v2(
+            r->db,
+            "SELECT " INVOICE_ROW_COLUMNS " FROM invoice_rows"
+            " WHERE org_id=?1 AND invoice_id=?2 ORDER BY line_no",
+            -1, &st, NULL) == SQLITE_OK) {
+        sqlite3_bind_int64(st, 1, r->org_id);
+        sqlite3_bind_int64(st, 2, id);
+        while (sqlite3_step(st) == SQLITE_ROW)
+            yyjson_mut_arr_add_val(rows, invoice_row_json(r, st));
+        sqlite3_finalize(st);
+    }
+    yyjson_mut_obj_add_val(r->rdoc, o, "rows", rows);
+    return o;
+}
+
+static yyjson_mut_val *h_invoice_list(struct req *r)
+{
+    int64_t customer_id = 0, limit = 200;
+    arg_int(r->args, "customer_id", &customer_id);
+    arg_int(r->args, "limit", &limit);
+    const char *status = arg_str(r->args, "status");
+    if (!status)
+        status = "";
+    if (limit < 1)
+        limit = 200;
+    if (limit > 1000)
+        limit = 1000;
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "SELECT i.id,i.number,i.ocr,i.customer_id,c.name,i.invoice_date,"
+            "i.due_date,i.total_ore,i.status,i.document_id,i.voucher_id,"
+            "i.last_sent_at,i.last_sent_to"
+            " FROM invoices i JOIN customers c"
+            " ON c.org_id=i.org_id AND c.id=i.customer_id"
+            " WHERE i.org_id=?1"
+            " AND (?2=0 OR i.customer_id=?2)"
+            " AND (?3='' OR i.status=?3)"
+            " ORDER BY i.number DESC, i.id DESC LIMIT ?4",
+            -1, &st, NULL) != SQLITE_OK)
+        return fail(r, "INTERNAL", "database error");
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_int64(st, 2, customer_id);
+    sqlite3_bind_text(st, 3, status, -1, SQLITE_TRANSIENT);
+    sqlite3_bind_int64(st, 4, limit);
+    yyjson_mut_val *items = yyjson_mut_arr(r->rdoc);
+    while (sqlite3_step(st) == SQLITE_ROW) {
+        yyjson_mut_val *o = yyjson_mut_arr_add_obj(r->rdoc, items);
+        yyjson_mut_obj_add_int(r->rdoc, o, "id", sqlite3_column_int64(st, 0));
+        yyjson_mut_obj_add_int(r->rdoc, o, "number",
+                               sqlite3_column_int64(st, 1));
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "ocr",
+                                  sq(sqlite3_column_text(st, 2)));
+        yyjson_mut_obj_add_int(r->rdoc, o, "customer_id",
+                               sqlite3_column_int64(st, 3));
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "customer_name",
+                                  sq(sqlite3_column_text(st, 4)));
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "invoice_date",
+                                  sq(sqlite3_column_text(st, 5)));
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "due_date",
+                                  sq(sqlite3_column_text(st, 6)));
+        yyjson_mut_obj_add_int(r->rdoc, o, "total_ore",
+                               sqlite3_column_int64(st, 7));
+        yyjson_mut_obj_add_strcpy(r->rdoc, o, "status",
+                                  sq(sqlite3_column_text(st, 8)));
+        if (sqlite3_column_type(st, 9) == SQLITE_NULL)
+            yyjson_mut_obj_add_null(r->rdoc, o, "document_id");
+        else
+            yyjson_mut_obj_add_int(r->rdoc, o, "document_id",
+                                   sqlite3_column_int64(st, 9));
+        if (sqlite3_column_type(st, 10) == SQLITE_NULL)
+            yyjson_mut_obj_add_null(r->rdoc, o, "voucher_id");
+        else
+            yyjson_mut_obj_add_int(r->rdoc, o, "voucher_id",
+                                   sqlite3_column_int64(st, 10));
+        if (sqlite3_column_type(st, 11) == SQLITE_NULL)
+            yyjson_mut_obj_add_null(r->rdoc, o, "last_sent_at");
+        else
+            yyjson_mut_obj_add_strcpy(r->rdoc, o, "last_sent_at",
+                                      sq(sqlite3_column_text(st, 11)));
+        if (sqlite3_column_type(st, 12) == SQLITE_NULL)
+            yyjson_mut_obj_add_null(r->rdoc, o, "last_sent_to");
+        else
+            yyjson_mut_obj_add_strcpy(r->rdoc, o, "last_sent_to",
+                                      sq(sqlite3_column_text(st, 12)));
+    }
+    sqlite3_finalize(st);
+    yyjson_mut_val *out = yyjson_mut_obj(r->rdoc);
+    yyjson_mut_obj_add_val(r->rdoc, out, "items", items);
+    return out;
+}
+
+static yyjson_mut_val *h_invoice_pdf(struct req *r)
+{
+    int64_t id = 0;
+    if (!arg_int(r->args, "id", &id) || id <= 0)
+        return fail(r, "INVALID_ARGS", "id is required");
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "SELECT document_id FROM invoices WHERE org_id=?1 AND id=?2", -1,
+            &st, NULL) != SQLITE_OK)
+        return fail(r, "INTERNAL", "database error");
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_int64(st, 2, id);
+    if (sqlite3_step(st) != SQLITE_ROW) {
+        sqlite3_finalize(st);
+        return fail(r, "NOT_FOUND", "invoice not found");
+    }
+    int64_t document_id = sqlite3_column_type(st, 0) == SQLITE_NULL
+                              ? 0
+                              : sqlite3_column_int64(st, 0);
+    sqlite3_finalize(st);
+    if (document_id <= 0)
+        return fail(r, "NOT_FOUND", "invoice has no stored PDF");
+    const void *content = NULL;
+    size_t len = 0;
+    if (sqlite3_prepare_v2(
+            r->db,
+            "SELECT content FROM attachments WHERE org_id=?1 AND id=?2", -1,
+            &st, NULL) != SQLITE_OK)
+        return fail(r, "INTERNAL", "database error");
+    sqlite3_bind_int64(st, 1, r->org_id);
+    sqlite3_bind_int64(st, 2, document_id);
+    if (sqlite3_step(st) != SQLITE_ROW) {
+        sqlite3_finalize(st);
+        return fail(r, "NOT_FOUND", "invoice PDF not found");
+    }
+    content = sqlite3_column_blob(st, 0);
+    len = (size_t)sqlite3_column_bytes(st, 0);
+    char *b64 = util_b64(content ? content : (const unsigned char *)"", len);
+    sqlite3_finalize(st);
+    if (!b64)
+        return fail(r, "INTERNAL", "could not encode the PDF");
+    yyjson_mut_val *o = yyjson_mut_obj(r->rdoc);
+    yyjson_mut_obj_add_strcpy(r->rdoc, o, "content_base64", b64);
+    free(b64);
+    return o;
+}
+
+/* ------------------------------------------------------------------ */
 /* report rules (per-org moms mapping)                                 */
 /* ------------------------------------------------------------------ */
 
@@ -6057,7 +7637,8 @@ static const struct cmd_arg args_bokslut_post[] = {
 
 static const struct cmd_arg args_settings_set[] = {
     { "key", ARG_STR, 1, NULL, NULL,
-      "default_series, attachment_dir or bank_account" },
+      "default_series, attachment_dir, bank_account,"
+      " invoice_receivable_account or invoice_revenue_account" },
     { "value", ARG_STR, 1, NULL, NULL, "Setting value" },
 };
 
@@ -6255,6 +7836,74 @@ static const struct cmd_arg args_sie_import[] = {
       "Server-side path; alternative to content_base64" },
 };
 
+static const struct cmd_arg args_customer_list[] = {
+    { "active_only", ARG_BOOL, 0, NULL, NULL, "Only active customers" },
+};
+
+static const struct cmd_arg args_customer_get[] = {
+    { "id", ARG_INT, 1, NULL, NULL, "Customer id" },
+};
+
+static const struct cmd_arg args_customer_create[] = {
+    { "name", ARG_STR, 1, NULL, NULL, "Customer name, unique per org" },
+    { "address", ARG_STR, 0, NULL, NULL, "Street address; may contain newlines" },
+    { "postal_code", ARG_STR, 0, NULL, NULL, "Postal code" },
+    { "city", ARG_STR, 0, NULL, NULL, "City" },
+    { "country", ARG_STR, 0, "SE", NULL, "Country code" },
+    { "vat_nr", ARG_STR, 0, NULL, NULL, "VAT number" },
+    { "email", ARG_STR, 0, NULL, NULL, "E-mail address" },
+    { "your_ref", ARG_STR, 0, NULL, NULL, "Customer reference" },
+    { "notes", ARG_STR, 0, NULL, NULL, "Free-text notes" },
+    { "payment_days", ARG_INT, 0, "30", NULL, "Payment terms in days" },
+};
+
+static const struct cmd_arg args_customer_update[] = {
+    { "id", ARG_INT, 1, NULL, NULL, "Customer id" },
+    { "name", ARG_STR, 0, NULL, NULL, "Customer name, unique per org" },
+    { "address", ARG_STR, 0, NULL, NULL, "Street address" },
+    { "postal_code", ARG_STR, 0, NULL, NULL, "Postal code" },
+    { "city", ARG_STR, 0, NULL, NULL, "City" },
+    { "country", ARG_STR, 0, NULL, NULL, "Country code" },
+    { "vat_nr", ARG_STR, 0, NULL, NULL, "VAT number" },
+    { "email", ARG_STR, 0, NULL, NULL, "E-mail address" },
+    { "your_ref", ARG_STR, 0, NULL, NULL, "Customer reference" },
+    { "notes", ARG_STR, 0, NULL, NULL, "Free-text notes" },
+    { "payment_days", ARG_INT, 0, NULL, NULL, "Payment terms in days" },
+    { "active", ARG_BOOL, 0, NULL, NULL, "Active flag" },
+};
+
+static const struct cmd_arg args_customer_archive[] = {
+    { "id", ARG_INT, 1, NULL, NULL, "Customer id" },
+    { "active", ARG_BOOL, 1, NULL, NULL, "false archives, true reactivates" },
+};
+
+static const struct cmd_arg args_invoice_sequence_set[] = {
+    { "next_number", ARG_INT, 1, NULL, NULL, "Next invoice number" },
+};
+
+static const struct cmd_arg args_invoice_draft[] = {
+    { "customer_id", ARG_INT, 1, NULL, NULL, "Customer id" },
+    { "invoice_date", ARG_DATE, 1, NULL, NULL, "Invoice date (YYYY-MM-DD)" },
+    { "due_date", ARG_DATE, 1, NULL, NULL, "Due date (YYYY-MM-DD)" },
+    { "delivery_date", ARG_STR, 0, NULL, NULL, "Delivery date or empty" },
+    { "your_ref", ARG_STR, 0, NULL, NULL, "Customer reference" },
+    { "our_ref", ARG_STR, 0, NULL, NULL, "Our reference" },
+    { "notes", ARG_STR, 0, NULL, NULL, "Free-text notes" },
+    { "rows", ARG_JSON, 1, NULL, NULL,
+      "Array of {article_no,description,quantity,unit,unit_price_ore,note,"
+      "vat_code,account}" },
+};
+
+static const struct cmd_arg args_invoice_get[] = {
+    { "id", ARG_INT, 1, NULL, NULL, "Invoice id" },
+};
+
+static const struct cmd_arg args_invoice_list[] = {
+    { "customer_id", ARG_INT, 0, NULL, NULL, "Customer filter" },
+    { "status", ARG_ENUM, 0, NULL, "issued,credited", "Status filter" },
+    { "limit", ARG_INT, 0, "200", NULL, "Page size, 1-1000" },
+};
+
 const struct command g_commands[] = {
     { "health", "Liveness probe", PERM_PUBLIC, 0, 0, 0, h_health, NULL, 0 },
     { "meta", "Server metadata and limits", PERM_PUBLIC, 0, 0, 0, h_meta, NULL,
@@ -6407,6 +8056,31 @@ const struct command g_commands[] = {
       CMD_ARGS(args_sie_export) },
     { "sie.import", "Import SIE 4 into an empty fiscal year", PERM_WRITE, 1, 1,
       1, h_sie_import, CMD_ARGS(args_sie_import) },
+    { "customer.list", "List customers ordered by name", PERM_READ, 1, 0, 0,
+      h_customer_list, CMD_ARGS(args_customer_list) },
+    { "customer.get", "Get one customer", PERM_READ, 1, 0, 0, h_customer_get,
+      CMD_ARGS(args_customer_get) },
+    { "customer.create", "Create a customer", PERM_WRITE, 1, 1, 1,
+      h_customer_create, CMD_ARGS(args_customer_create) },
+    { "customer.update", "Update a customer (merged)", PERM_WRITE, 1, 1, 1,
+      h_customer_update, CMD_ARGS(args_customer_update) },
+    { "customer.archive", "Archive or reactivate a customer", PERM_WRITE, 1, 1,
+      1, h_customer_archive, CMD_ARGS(args_customer_archive) },
+    { "invoice.sequence_get", "Read the next invoice number", PERM_READ, 1, 0,
+      0, h_invoice_sequence_get, NULL, 0 },
+    { "invoice.sequence_set", "Set the next invoice number (owner)",
+      PERM_OWNER, 1, 1, 1, h_invoice_sequence_set,
+      CMD_ARGS(args_invoice_sequence_set) },
+    { "invoice.preview", "Render an invoice draft without storing it",
+      PERM_READ, 1, 0, 0, h_invoice_preview, CMD_ARGS(args_invoice_draft) },
+    { "invoice.issue", "Issue an invoice: number, PDF and voucher",
+      PERM_WRITE, 1, 1, 1, h_invoice_issue, CMD_ARGS(args_invoice_draft) },
+    { "invoice.get", "Get an invoice with rows", PERM_READ, 1, 0, 0,
+      h_invoice_get, CMD_ARGS(args_invoice_get) },
+    { "invoice.list", "List invoices, newest first", PERM_READ, 1, 0, 0,
+      h_invoice_list, CMD_ARGS(args_invoice_list) },
+    { "invoice.pdf", "Fetch the stored invoice PDF", PERM_READ, 1, 0, 0,
+      h_invoice_pdf, CMD_ARGS(args_invoice_get) },
 };
 
 const size_t g_commands_count = sizeof g_commands / sizeof g_commands[0];
diff --git a/tests/test_core.c b/tests/test_core.c
index a78a940..fa7b5e4 100644
--- a/tests/test_core.c
+++ b/tests/test_core.c
@@ -16,6 +16,7 @@
 #include "client.h"
 #include "config.h"
 #include "db.h"
+#include "invoice.h"
 #include "protocol.h"
 #include "sessions.h"
 #include "util.h"
@@ -2199,6 +2200,523 @@ int main(void)
     CHECK_STR(d, "result.items.0.account", "1940");
     yyjson_doc_free(d);
 
+    /* ---------------- invoicing: customers, sequence, issue ---------- */
+
+    d = call(reqf("{\"v\":1,\"id\":\"300\",\"cmd\":\"settings.get\","
+                  "\"session\":\"%s\",\"org\":%d}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    CHECK_STR(d, "result.invoice_receivable_account", "1510");
+    CHECK_STR(d, "result.invoice_revenue_account", "3001");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"301\",\"cmd\":\"customer.create\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"name\":"
+                  "\"Andra bygg AB\",\"address\":\"Storgatan 1\","
+                  "\"postal_code\":\"171 63\",\"city\":\"Solna\","
+                  "\"vat_nr\":\"SE559232855201\","
+                  "\"email\":\"faktura@andra.se\",\"your_ref\":\"Eric\","
+                  "\"payment_days\":30}}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    int64_t cust1 = jint(d, "result.id");
+    CHECK(cust1 > 0);
+    CHECK_STR(d, "result.name", "Andra bygg AB");
+    CHECK_STR(d, "result.city", "Solna");
+    CHECK_STR(d, "result.email", "faktura@andra.se");
+    CHECK(jint(d, "result.payment_days") == 30);
+    CHECK(jbool(d, "result.active"));
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"302\",\"cmd\":\"customer.create\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"name\":"
+                  "\"Andra bygg AB\"}}",
+                  g_session, (int)org_id));
+    CHECK_STR(d, "error.code", "CONFLICT");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"303\",\"cmd\":\"customer.create\","
+                  "\"session\":\"%s\",\"org\":%d,\"dry_run\":true,\"args\":"
+                  "{\"name\":\"Tillfällig AB\"}}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    CHECK(jbool(d, "result.dry_run"));
+    CHECK_STR(d, "result.name", "Tillfällig AB");
+    CHECK(jint(d, "result.payment_days") == 30);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"304\",\"cmd\":\"customer.create\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"name\":"
+                  "\"NZ Bygg AB\",\"city\":\"Bromma\"}}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    int64_t cust2 = jint(d, "result.id");
+    CHECK(cust2 > 0);
+    CHECK(jint(d, "result.payment_days") == 30);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"305\",\"cmd\":\"customer.get\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":%lld}}",
+                  g_session, (int)org_id, (long long)cust1));
+    CHECK_OK(d);
+    CHECK_STR(d, "result.name", "Andra bygg AB");
+    CHECK_STR(d, "result.address", "Storgatan 1");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"306\",\"cmd\":\"customer.get\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":999999}}",
+                  g_session, (int)org_id));
+    CHECK_STR(d, "error.code", "NOT_FOUND");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"307\",\"cmd\":\"customer.list\","
+                  "\"session\":\"%s\",\"org\":%d}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    CHECK(yyjson_arr_size(jget(d, "result.items")) == 2);
+    CHECK_STR(d, "result.items.0.name", "Andra bygg AB");
+    CHECK_STR(d, "result.items.1.name", "NZ Bygg AB");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"308\",\"cmd\":\"customer.update\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":%lld,"
+                  "\"city\":\"Sundbyberg\",\"your_ref\":\"Lars\"}}",
+                  g_session, (int)org_id, (long long)cust1));
+    CHECK_OK(d);
+    CHECK_STR(d, "result.city", "Sundbyberg");
+    CHECK_STR(d, "result.your_ref", "Lars");
+    CHECK_STR(d, "result.address", "Storgatan 1");
+    CHECK_STR(d, "result.name", "Andra bygg AB");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"309\",\"cmd\":\"customer.update\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":%lld,"
+                  "\"name\":\"Andra bygg AB\"}}",
+                  g_session, (int)org_id, (long long)cust2));
+    CHECK_STR(d, "error.code", "CONFLICT");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"310\",\"cmd\":\"customer.update\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":999999,"
+                  "\"city\":\"X\"}}",
+                  g_session, (int)org_id));
+    CHECK_STR(d, "error.code", "NOT_FOUND");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"311\",\"cmd\":\"customer.update\","
+                  "\"session\":\"%s\",\"org\":%d,\"dry_run\":true,\"args\":"
+                  "{\"id\":%lld,\"city\":\"Nacka\"}}",
+                  g_session, (int)org_id, (long long)cust1));
+    CHECK_OK(d);
+    CHECK(jbool(d, "result.dry_run"));
+    CHECK_STR(d, "result.city", "Nacka");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"312\",\"cmd\":\"customer.get\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":%lld}}",
+                  g_session, (int)org_id, (long long)cust1));
+    CHECK_OK(d);
+    CHECK_STR(d, "result.city", "Sundbyberg");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"313\",\"cmd\":\"customer.archive\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":%lld,"
+                  "\"active\":false}}",
+                  g_session, (int)org_id, (long long)cust2));
+    CHECK_OK(d);
+    CHECK(jint(d, "result.id") == cust2);
+    CHECK(!jbool(d, "result.active"));
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"314\",\"cmd\":\"customer.list\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":"
+                  "{\"active_only\":true}}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    CHECK(yyjson_arr_size(jget(d, "result.items")) == 1);
+    CHECK_STR(d, "result.items.0.name", "Andra bygg AB");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"315\",\"cmd\":\"customer.archive\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":999999,"
+                  "\"active\":false}}",
+                  g_session, (int)org_id));
+    CHECK_STR(d, "error.code", "NOT_FOUND");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"320\",\"cmd\":\"invoice.sequence_get\","
+                  "\"session\":\"%s\",\"org\":%d}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    CHECK(jint(d, "result.next_number") == 1);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"321\",\"cmd\":\"invoice.sequence_set\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"next_number\":"
+                  "0}}",
+                  g_session, (int)org_id));
+    CHECK_STR(d, "error.code", "INVALID_ARGS");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"322\",\"cmd\":\"invoice.sequence_set\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"next_number\":"
+                  "17761}}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    CHECK(jint(d, "result.next_number") == 17761);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"323\",\"cmd\":\"invoice.sequence_get\","
+                  "\"session\":\"%s\",\"org\":%d}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    CHECK(jint(d, "result.next_number") == 17761);
+    yyjson_doc_free(d);
+
+    char draft_args[2048];
+    snprintf(draft_args, sizeof draft_args,
+             "{\"customer_id\":%lld,\"invoice_date\":\"2026-09-20\","
+             "\"due_date\":\"2026-10-20\",\"delivery_date\":\"2026-09-20\","
+             "\"your_ref\":\"Lars\",\"our_ref\":\"Anders\",\"notes\":\"\","
+             "\"rows\":[{\"article_no\":\"\",\"description\":"
+             "\"Utvecklingsarbete\",\"quantity\":\"61\",\"unit\":\"tim\","
+             "\"unit_price_ore\":120000,\"note\":\"\",\"vat_code\":\"25\","
+             "\"account\":\"\"}]}",
+             (long long)cust1);
+
+    d = call(reqf("{\"v\":1,\"id\":\"330\",\"cmd\":\"invoice.preview\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":%s}",
+                  g_session, (int)org_id, draft_args));
+    CHECK_OK(d);
+    CHECK(jint(d, "result.number") == 17761);
+    char number_str[32];
+    snprintf(number_str, sizeof number_str, "%lld",
+             (long long)jint(d, "result.number"));
+    char expect_ocr[40];
+    snprintf(expect_ocr, sizeof expect_ocr, "%s%d", number_str,
+             invoice_ocr_check(number_str));
+    CHECK_STR(d, "result.ocr", expect_ocr);
+    CHECK(jint(d, "result.net_ore") == 7320000);
+    CHECK(jint(d, "result.vat_ore") == 1830000);
+    CHECK(jint(d, "result.total_ore") == 9150000);
+    const char *pdf_b64 = jstr(d, "result.content_base64");
+    char *preview_b64 = pdf_b64 ? xstrdup(pdf_b64) : NULL;
+    CHECK(preview_b64 && strncmp(preview_b64, "JVBERi0", 7) == 0);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"331\",\"cmd\":\"invoice.preview\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":%s}",
+                  g_session, (int)org_id, draft_args));
+    CHECK_OK(d);
+    CHECK(preview_b64 && jstr(d, "result.content_base64") &&
+          strcmp(jstr(d, "result.content_base64"), preview_b64) == 0);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"332\",\"cmd\":\"invoice.sequence_get\","
+                  "\"session\":\"%s\",\"org\":%d}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    CHECK(jint(d, "result.next_number") == 17761);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"333\",\"cmd\":\"invoice.preview\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"customer_id\":"
+                  "%lld,\"invoice_date\":\"2026-09-20\",\"due_date\":"
+                  "\"2026-10-20\",\"rows\":[{\"description\":\"X\","
+                  "\"quantity\":\"1\",\"unit_price_ore\":100,"
+                  "\"vat_code\":\"99\"}]}}",
+                  g_session, (int)org_id, (long long)cust1));
+    CHECK_STR(d, "error.code", "INVALID_ARGS");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"334\",\"cmd\":\"invoice.preview\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"customer_id\":"
+                  "%lld,\"invoice_date\":\"2026-09-20\",\"due_date\":"
+                  "\"2026-10-20\",\"rows\":[{\"description\":\"X\","
+                  "\"quantity\":\"1,2345\",\"unit_price_ore\":100,"
+                  "\"vat_code\":\"25\"}]}}",
+                  g_session, (int)org_id, (long long)cust1));
+    CHECK_STR(d, "error.code", "INVALID_ARGS");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"335\",\"cmd\":\"invoice.preview\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"customer_id\":"
+                  "%lld,\"invoice_date\":\"2026-09-20\",\"due_date\":"
+                  "\"2026-10-20\",\"rows\":[{\"description\":\"X\","
+                  "\"quantity\":\"0\",\"unit_price_ore\":100,"
+                  "\"vat_code\":\"25\"}]}}",
+                  g_session, (int)org_id, (long long)cust1));
+    CHECK_STR(d, "error.code", "INVALID_ARGS");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"336\",\"cmd\":\"invoice.preview\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"customer_id\":"
+                  "999999,\"invoice_date\":\"2026-09-20\",\"due_date\":"
+                  "\"2026-10-20\",\"rows\":[{\"description\":\"X\","
+                  "\"quantity\":\"1\",\"unit_price_ore\":100,"
+                  "\"vat_code\":\"25\"}]}}",
+                  g_session, (int)org_id));
+    CHECK_STR(d, "error.code", "NOT_FOUND");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"337\",\"cmd\":\"invoice.preview\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"customer_id\":"
+                  "%lld,\"invoice_date\":\"2026-09-20\",\"due_date\":"
+                  "\"2026-10-20\",\"rows\":[{\"description\":\"X\","
+                  "\"quantity\":\"1\",\"unit_price_ore\":100,"
+                  "\"vat_code\":\"25\"}]}}",
+                  g_session, (int)org_id, (long long)cust2));
+    CHECK_STR(d, "error.code", "NOT_FOUND");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"337a\",\"cmd\":\"invoice.preview\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"customer_id\":"
+                  "%lld,\"invoice_date\":\"2026-09-20\",\"due_date\":"
+                  "\"2026-10-20\",\"rows\":[{\"description\":\"X\","
+                  "\"quantity\":\"1000\",\"unit_price_ore\":"
+                  "9223372036854775807,\"vat_code\":\"25\"}]}}",
+                  g_session, (int)org_id, (long long)cust1));
+    CHECK_STR(d, "error.code", "INVALID_ARGS");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"337b\",\"cmd\":\"invoice.preview\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"customer_id\":"
+                  "%lld,\"invoice_date\":\"2026-09-20\",\"due_date\":"
+                  "\"2026-10-20\",\"rows\":[{\"description\":\"X\","
+                  "\"quantity\":\"1\",\"unit_price_ore\":-1,"
+                  "\"vat_code\":\"25\"}]}}",
+                  g_session, (int)org_id, (long long)cust1));
+    CHECK_STR(d, "error.code", "INVALID_ARGS");
+    yyjson_doc_free(d);
+
+    {
+        char rows_json[8192];
+        size_t off = 0;
+        off += (size_t)snprintf(rows_json + off, sizeof rows_json - off, "[");
+        for (int i = 0; i < 20 && off < sizeof rows_json - 256; i++)
+            off += (size_t)snprintf(
+                rows_json + off, sizeof rows_json - off,
+                "%s{\"description\":\"Rad %d\",\"quantity\":\"1\","
+                "\"unit_price_ore\":100,\"vat_code\":\"25\"}",
+                i ? "," : "", i + 1);
+        snprintf(rows_json + off, sizeof rows_json - off, "]");
+        d = call(reqf("{\"v\":1,\"id\":\"337c\",\"cmd\":\"invoice.preview\","
+                      "\"session\":\"%s\",\"org\":%d,\"args\":{\"customer_id\":"
+                      "%lld,\"invoice_date\":\"2026-09-20\",\"due_date\":"
+                      "\"2026-10-20\",\"rows\":%s}}",
+                      g_session, (int)org_id, (long long)cust1, rows_json));
+        CHECK_STR(d, "error.code", "TOO_LARGE");
+        yyjson_doc_free(d);
+    }
+
+    d = call(reqf("{\"v\":1,\"id\":\"338\",\"cmd\":\"invoice.issue\","
+                  "\"session\":\"%s\",\"org\":%d,\"dry_run\":true,\"args\":"
+                  "{\"customer_id\":%lld,\"invoice_date\":\"2026-09-20\","
+                  "\"due_date\":\"2026-10-20\",\"rows\":[{\"description\":"
+                  "\"X\",\"quantity\":\"1\",\"unit_price_ore\":100,"
+                  "\"vat_code\":\"25\",\"account\":\"9999\"}]}}",
+                  g_session, (int)org_id, (long long)cust1));
+    CHECK_STR(d, "error.code", "ACCOUNT_NOT_FOUND");
+    yyjson_doc_free(d);
+
+    int64_t vouchers_before = db_count(g_db, "SELECT count(*) FROM vouchers");
+    int64_t attachments_before =
+        db_count(g_db, "SELECT count(*) FROM attachments");
+
+    d = call(reqf("{\"v\":1,\"id\":\"340\",\"cmd\":\"invoice.issue\","
+                  "\"session\":\"%s\",\"org\":%d,\"dry_run\":true,\"args\":%s}",
+                  g_session, (int)org_id, draft_args));
+    CHECK_OK(d);
+    CHECK(jbool(d, "result.dry_run"));
+    CHECK(jint(d, "result.number") == 17761);
+    CHECK_STR(d, "result.ocr", expect_ocr);
+    CHECK(jint(d, "result.net_ore") == 7320000);
+    CHECK(jint(d, "result.vat_ore") == 1830000);
+    CHECK(jint(d, "result.total_ore") == 9150000);
+    yyjson_val *dry_doc = jget(d, "result.document_id");
+    CHECK(dry_doc && yyjson_is_null(dry_doc));
+    yyjson_doc_free(d);
+    CHECK(db_count(g_db, "SELECT count(*) FROM vouchers") == vouchers_before);
+    CHECK(db_count(g_db, "SELECT count(*) FROM attachments") ==
+          attachments_before);
+
+    d = call(reqf("{\"v\":1,\"id\":\"341\",\"cmd\":\"invoice.sequence_get\","
+                  "\"session\":\"%s\",\"org\":%d}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    CHECK(jint(d, "result.next_number") == 17761);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"350\",\"cmd\":\"invoice.issue\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":%s}",
+                  g_session, (int)org_id, draft_args));
+    CHECK_OK(d);
+    int64_t inv1 = jint(d, "result.id");
+    int64_t doc1 = jint(d, "result.document_id");
+    int64_t vou1 = jint(d, "result.voucher_id");
+    CHECK(inv1 > 0);
+    CHECK(doc1 > 0);
+    CHECK(vou1 > 0);
+    CHECK(jint(d, "result.number") == 17761);
+    CHECK_STR(d, "result.ocr", expect_ocr);
+    CHECK(jint(d, "result.net_ore") == 7320000);
+    CHECK(jint(d, "result.vat_ore") == 1830000);
+    CHECK(jint(d, "result.total_ore") == 9150000);
+    yyjson_doc_free(d);
+    CHECK(db_count(g_db, "SELECT count(*) FROM vouchers") == vouchers_before + 1);
+    CHECK(db_count(g_db, "SELECT count(*) FROM attachments") ==
+          attachments_before + 1);
+
+    d = call(reqf("{\"v\":1,\"id\":\"351\",\"cmd\":\"voucher.get\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":%lld}}",
+                  g_session, (int)org_id, (long long)vou1));
+    CHECK_OK(d);
+    CHECK_STR(d, "result.source", "invoice");
+    CHECK_STR(d, "result.date", "2026-09-20");
+    CHECK(find_amount(d, "result.rows", "account", "1510", "debit_ore") ==
+          9150000);
+    CHECK(find_amount(d, "result.rows", "account", "3001", "credit_ore") ==
+          7320000);
+    CHECK(find_amount(d, "result.rows", "account", "2610", "credit_ore") ==
+          1830000);
+    CHECK(find_amount(d, "result.rows", "account", "1510", "credit_ore") == 0);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"352\",\"cmd\":\"invoice.get\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":%lld}}",
+                  g_session, (int)org_id, (long long)inv1));
+    CHECK_OK(d);
+    CHECK_STR(d, "result.status", "issued");
+    CHECK(jint(d, "result.customer_id") == cust1);
+    CHECK_STR(d, "result.customer_name", "Andra bygg AB");
+    CHECK_STR(d, "result.ocr", expect_ocr);
+    CHECK(jint(d, "result.document_id") == doc1);
+    CHECK(jint(d, "result.voucher_id") == vou1);
+    CHECK(yyjson_arr_size(jget(d, "result.rows")) == 1);
+    CHECK(jint(d, "result.rows.0.quantity_milli") == 61000);
+    CHECK(jint(d, "result.rows.0.amount_ore") == 7320000);
+    CHECK_STR(d, "result.rows.0.vat_code", "25");
+    CHECK_STR(d, "result.rows.0.account", "3001");
+    CHECK_STR(d, "result.rows.0.unit", "tim");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"353\",\"cmd\":\"invoice.pdf\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":%lld}}",
+                  g_session, (int)org_id, (long long)inv1));
+    CHECK_OK(d);
+    const char *stored = jstr(d, "result.content_base64");
+    CHECK(stored && preview_b64 && strcmp(stored, preview_b64) == 0);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"355\",\"cmd\":\"invoice.issue\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"customer_id\":"
+                  "%lld,\"invoice_date\":\"2026-09-21\",\"due_date\":"
+                  "\"2026-10-21\",\"rows\":[{\"description\":\"Konsult\","
+                  "\"quantity\":\"2,5\",\"unit\":\"tim\","
+                  "\"unit_price_ore\":100000,\"vat_code\":\"12\","
+                  "\"account\":\"3002\"}]}}",
+                  g_session, (int)org_id, (long long)cust1));
+    CHECK_OK(d);
+    int64_t inv2 = jint(d, "result.id");
+    int64_t doc2 = jint(d, "result.document_id");
+    int64_t vou2 = jint(d, "result.voucher_id");
+    CHECK(inv2 > inv1);
+    CHECK(doc2 > doc1);
+    CHECK(vou2 > vou1);
+    CHECK(jint(d, "result.number") == 17762);
+    CHECK(jint(d, "result.net_ore") == 250000);
+    CHECK(jint(d, "result.vat_ore") == 30000);
+    CHECK(jint(d, "result.total_ore") == 280000);
+    yyjson_doc_free(d);
+    CHECK(db_count(g_db, "SELECT count(*) FROM vouchers") == vouchers_before + 2);
+    CHECK(db_count(g_db, "SELECT count(*) FROM attachments") ==
+          attachments_before + 2);
+
+    d = call(reqf("{\"v\":1,\"id\":\"356\",\"cmd\":\"voucher.get\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":%lld}}",
+                  g_session, (int)org_id, (long long)vou2));
+    CHECK_OK(d);
+    CHECK_STR(d, "result.source", "invoice");
+    CHECK(find_amount(d, "result.rows", "account", "1510", "debit_ore") ==
+          280000);
+    CHECK(find_amount(d, "result.rows", "account", "2620", "credit_ore") ==
+          30000);
+    CHECK(find_amount(d, "result.rows", "account", "3002", "credit_ore") ==
+          250000);
+    CHECK(find_amount(d, "result.rows", "account", "2610", "credit_ore") == -1);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"357\",\"cmd\":\"invoice.list\","
+                  "\"session\":\"%s\",\"org\":%d}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    CHECK(yyjson_arr_size(jget(d, "result.items")) == 2);
+    CHECK(jint(d, "result.items.0.number") == 17762);
+    CHECK(jint(d, "result.items.1.number") == 17761);
+    CHECK_STR(d, "result.items.0.customer_name", "Andra bygg AB");
+    CHECK_STR(d, "result.items.0.status", "issued");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"358\",\"cmd\":\"invoice.list\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"customer_id\":"
+                  "%lld}}",
+                  g_session, (int)org_id, (long long)cust1));
+    CHECK_OK(d);
+    CHECK(yyjson_arr_size(jget(d, "result.items")) == 2);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"359\",\"cmd\":\"invoice.list\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"customer_id\":"
+                  "%lld}}",
+                  g_session, (int)org_id, (long long)cust2));
+    CHECK_OK(d);
+    CHECK(yyjson_arr_size(jget(d, "result.items")) == 0);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"360\",\"cmd\":\"invoice.list\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"status\":"
+                  "\"credited\"}}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    CHECK(yyjson_arr_size(jget(d, "result.items")) == 0);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"361\",\"cmd\":\"invoice.list\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"limit\":1}}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    CHECK(yyjson_arr_size(jget(d, "result.items")) == 1);
+    CHECK(jint(d, "result.items.0.number") == 17762);
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"362\",\"cmd\":\"invoice.list\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"status\":"
+                  "\"nope\"}}",
+                  g_session, (int)org_id));
+    CHECK_STR(d, "error.code", "INVALID_ARGS");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"363\",\"cmd\":\"invoice.get\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":999999}}",
+                  g_session, (int)org_id));
+    CHECK_STR(d, "error.code", "NOT_FOUND");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"364\",\"cmd\":\"invoice.pdf\","
+                  "\"session\":\"%s\",\"org\":%d,\"args\":{\"id\":999999}}",
+                  g_session, (int)org_id));
+    CHECK_STR(d, "error.code", "NOT_FOUND");
+    yyjson_doc_free(d);
+
+    d = call(reqf("{\"v\":1,\"id\":\"365\",\"cmd\":\"invoice.sequence_get\","
+                  "\"session\":\"%s\",\"org\":%d}",
+                  g_session, (int)org_id));
+    CHECK_OK(d);
+    CHECK(jint(d, "result.next_number") == 17763);
+    yyjson_doc_free(d);
+
+    free(preview_b64);
+
     /* ---------------- moms rules: ranges merge per box ------------- */
     d = call(reqf("{\"v\":1,\"id\":\"110\",\"cmd\":\"org.create\","
                   "\"session\":\"%s\",\"args\":{\"name\":\"Moms AB\"}}",