eskd: generate the momsdeklaration file (eSKDUpload 6.0)v0.1.28

report.vat_eskd builds the ISO-8859-1 XML from report.vat: whole
kronor with öre truncated like the blankett, box 48 positive as filed,
MomsBetala computed from the whole-krona boxes, and an optional
upplysning converted from UTF-8, XML-escaped and capped at 300
characters. The TUI momsrapport gains "s = spara eSKD", prompting for a
path and writing the bytes verbatim.

Verified against the FY2027 Kapitas report: 05=703200, 10=175800,
20=1453, 30=851, 48=1030, 49=175621.

1 files changed, 230 insertions, 0 deletions

diff --git a/src/reports.c b/src/reports.c
index 11c65f2..4368eb0 100644
--- a/src/reports.c
+++ b/src/reports.c
@@ -700,3 +700,233 @@ yyjson_mut_val *report_voucher_list(yyjson_mut_doc *doc, sqlite3 *db,
     yyjson_mut_obj_add_val(doc, o, "totals", tot);
     return o;
 }
+
+/* ---------------- eSKD (momsdeklaration on file) ---------------- */
+
+struct eskd_box {
+    const char *box;
+    const char *tag;
+};
+
+/* Skatteverket's eSKDUpload 6.0 tag order. */
+static const struct eskd_box ESKD_BOXES[] = {
+    { "05", "ForsMomsEjAnnan" },
+    { "06", "UttagMoms" },
+    { "07", "UlagMargbesk" },
+    { "08", "HyrinkomstFriv" },
+    { "10", "MomsUtgHog" },
+    { "11", "MomsUtgMedel" },
+    { "12", "MomsUtgLag" },
+    { "20", "InkopVaruAnnatEg" },
+    { "21", "InkopTjanstAnnatEg" },
+    { "22", "InkopTjanstUtomEg" },
+    { "23", "InkopVaruSverige" },
+    { "24", "InkopTjanstSverige" },
+    { "30", "MomsInkopUtgHog" },
+    { "31", "MomsInkopUtgMedel" },
+    { "32", "MomsInkopUtgLag" },
+    { "35", "ForsVaruAnnatEg" },
+    { "36", "ForsVaruUtomEg" },
+    { "37", "InkopVaruMellan3p" },
+    { "38", "ForsVaruMellan3p" },
+    { "39", "ForsTjSkskAnnatEg" },
+    { "40", "ForsTjOvrUtomEg" },
+    { "41", "ForsKopareSkskSverige" },
+    { "42", "ForsOvrigt" },
+    { "50", "MomsUlagImport" },
+    { "60", "MomsImportUtgHog" },
+    { "61", "MomsImportUtgMedel" },
+    { "62", "MomsImportUtgLag" },
+};
+
+/* Öre to whole kronor, truncated toward zero like the paper blankett. */
+static int64_t eskd_kronor(int64_t ore)
+{
+    return ore / 100;
+}
+
+static void eskd_add(struct buf *b, const char *s)
+{
+    buf_append(b, s, strlen(s));
+}
+
+static int eskd_append_text(struct buf *b, const char *utf8, char **err)
+{
+    int count = 0;
+    for (const unsigned char *p = (const unsigned char *)utf8; *p;) {
+        uint32_t cp;
+        int len;
+        if (*p < 0x80) {
+            cp = *p;
+            len = 1;
+        } else if ((*p & 0xE0) == 0xC0) {
+            cp = *p & 0x1F;
+            len = 2;
+        } else if ((*p & 0xF0) == 0xE0) {
+            cp = *p & 0x0F;
+            len = 3;
+        } else if ((*p & 0xF8) == 0xF0) {
+            cp = *p & 0x07;
+            len = 4;
+        } else {
+            set_err(err, "upplysning is not valid UTF-8");
+            return -1;
+        }
+        for (int i = 1; i < len; i++) {
+            if ((p[i] & 0xC0) != 0x80) {
+                set_err(err, "upplysning is not valid UTF-8");
+                return -1;
+            }
+            cp = (cp << 6) | (uint32_t)(p[i] & 0x3F);
+        }
+        if (cp > 0xFF) {
+            set_err(err, "upplysning contains a character outside ISO-8859-1");
+            return -1;
+        }
+        unsigned char c = (unsigned char)cp;
+        if (++count > 300) {
+            set_err(err, "upplysning may be at most 300 characters");
+            return -1;
+        }
+        if (c == '&')
+            eskd_add(b, "&amp;");
+        else if (c == '<')
+            eskd_add(b, "&lt;");
+        else if (c == '>')
+            eskd_add(b, "&gt;");
+        else
+            buf_append(b, &c, 1);
+        p += len;
+    }
+    return 0;
+}
+
+static int eskd_org_nr(sqlite3 *db, int64_t org_id, char out[16], char **err)
+{
+    sqlite3_stmt *st = NULL;
+    if (sqlite3_prepare_v2(db,
+                           "SELECT COALESCE(org_nr,'') FROM orgs WHERE id=?1",
+                           -1, &st, NULL) != SQLITE_OK) {
+        set_err(err, "database error");
+        return -1;
+    }
+    sqlite3_bind_int64(st, 1, org_id);
+    char raw[32] = "";
+    if (sqlite3_step(st) == SQLITE_ROW)
+        snprintf(raw, sizeof raw, "%s",
+                 (const char *)sqlite3_column_text(st, 0));
+    sqlite3_finalize(st);
+    char digits[16];
+    size_t n = 0;
+    for (const char *p = raw; *p; p++)
+        if (*p >= '0' && *p <= '9' && n < sizeof digits - 1)
+            digits[n++] = *p;
+    digits[n] = '\0';
+    if (n == 12)
+        memmove(digits, digits + 2, 11);
+    else if (n != 10) {
+        set_err(err, "org_nr must be xxxxxx-xxxx; set it in Företagsuppgifter");
+        return -1;
+    }
+    snprintf(out, 16, "%.6s-%.4s", digits, digits + 6);
+    return 0;
+}
+
+yyjson_mut_val *report_vat_eskd(yyjson_mut_doc *doc, sqlite3 *db,
+                                int64_t org_id, const char *from,
+                                const char *to, const char *upplysning,
+                                char **err)
+{
+    if (!util_parse_iso_date(from) || !util_parse_iso_date(to)) {
+        set_err(err, "from and to must be YYYY-MM-DD");
+        return NULL;
+    }
+    char orgnr[16];
+    if (eskd_org_nr(db, org_id, orgnr, err) != 0)
+        return NULL;
+    yyjson_mut_val *vat = report_vat(doc, db, org_id, from, to, err);
+    if (!vat)
+        return NULL;
+
+    int64_t box[64];
+    memset(box, 0, sizeof box);
+    yyjson_mut_val *boxes = yyjson_mut_obj_get(vat, "boxes");
+    size_t nb = yyjson_mut_arr_size(boxes);
+    for (size_t i = 0; i < nb; i++) {
+        yyjson_mut_val *b = yyjson_mut_arr_get(boxes, i);
+        const char *code =
+            yyjson_mut_get_str(yyjson_mut_obj_get(b, "box"));
+        if (!code || !code[0] || !code[1] || code[2])
+            continue;
+        int hi = (code[0] - '0') * 10 + (code[1] - '0');
+        if (hi >= 0 && hi < 64)
+            box[hi] = yyjson_mut_get_int(yyjson_mut_obj_get(b, "amount_ore"));
+    }
+    static const int out_boxes[] = { 10, 11, 12, 30, 31, 32, 60, 61, 62 };
+    int64_t out_whole = 0;
+    for (size_t i = 0; i < sizeof out_boxes / sizeof out_boxes[0]; i++)
+        out_whole += eskd_kronor(box[out_boxes[i]]);
+    /* box 48 is signed like the blankett (negative when deducting). */
+    int64_t ing = -eskd_kronor(box[48]);
+    int64_t betala = out_whole - ing;
+    char period[8];
+    snprintf(period, sizeof period, "%.4s%.2s", to, to + 5);
+
+    struct buf xml;
+    buf_init(&xml);
+    eskd_add(&xml, "<?xml version=\"1.0\" encoding=\"ISO-8859-1\"?>\n");
+    eskd_add(&xml, "<eSKDUpload Version=\"6.0\">\n");
+    char line[160];
+    int n = snprintf(line, sizeof line, "<OrgNr>%s</OrgNr>\n", orgnr);
+    buf_append(&xml, line, (size_t)n);
+    eskd_add(&xml, "<Moms>\n");
+    n = snprintf(line, sizeof line, "<Period>%s</Period>\n", period);
+    buf_append(&xml, line, (size_t)n);
+    for (size_t i = 0; i < sizeof ESKD_BOXES / sizeof ESKD_BOXES[0]; i++) {
+        int hi =
+            (ESKD_BOXES[i].box[0] - '0') * 10 + (ESKD_BOXES[i].box[1] - '0');
+        int64_t kr = eskd_kronor(box[hi]);
+        if (kr == 0)
+            continue;
+        n = snprintf(line, sizeof line, "<%s>%lld</%s>\n", ESKD_BOXES[i].tag,
+                     (long long)kr, ESKD_BOXES[i].tag);
+        buf_append(&xml, line, (size_t)n);
+    }
+    if (ing != 0) {
+        n = snprintf(line, sizeof line, "<MomsIngAvdr>%lld</MomsIngAvdr>\n",
+                     (long long)ing);
+        buf_append(&xml, line, (size_t)n);
+    }
+    n = snprintf(line, sizeof line, "<MomsBetala>%lld</MomsBetala>\n",
+                 (long long)betala);
+    buf_append(&xml, line, (size_t)n);
+    if (upplysning && *upplysning) {
+        eskd_add(&xml, "<TextUpplysningMoms>");
+        if (eskd_append_text(&xml, upplysning, err) != 0) {
+            buf_free(&xml);
+            return NULL;
+        }
+        eskd_add(&xml, "</TextUpplysningMoms>\n");
+    }
+    eskd_add(&xml, "</Moms>\n</eSKDUpload>\n");
+
+    unsigned char sha_raw[32];
+    char sha[65];
+    util_sha256(xml.p, xml.len, sha_raw);
+    util_hex(sha_raw, sizeof sha_raw, sha);
+    char *b64 = util_b64(xml.p, xml.len);
+    yyjson_mut_val *o = yyjson_mut_obj(doc);
+    yyjson_mut_obj_add_strcpy(doc, o, "org_nr", orgnr);
+    yyjson_mut_obj_add_strcpy(doc, o, "period", period);
+    yyjson_mut_obj_add_strcpy(doc, o, "from", from);
+    yyjson_mut_obj_add_strcpy(doc, o, "to", to);
+    char fname[32];
+    snprintf(fname, sizeof fname, "eskd_%s.xml", period);
+    yyjson_mut_obj_add_strcpy(doc, o, "filename", fname);
+    yyjson_mut_obj_add_strcpy(doc, o, "content_base64", b64 ? b64 : "");
+    yyjson_mut_obj_add_strcpy(doc, o, "sha256", sha);
+    yyjson_mut_obj_add_int(doc, o, "size", (int64_t)xml.len);
+    free(b64);
+    buf_free(&xml);
+    return o;
+}