#include "seed.h"

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>

#include "config.h"
#include "log.h"
#include "util.h"

static void set_err(char **err, const char *fmt, ...)
    __attribute__((format(printf, 2, 3)));

static void set_err(char **err, const char *fmt, ...)
{
    if (!err || *err)
        return;
    char buf[512];
    va_list ap;
    va_start(ap, fmt);
    vsnprintf(buf, sizeof buf, fmt, ap);
    va_end(ap);
    *err = xstrdup(buf);
}

struct chart_entry {
    const char *number;
    const char *name;
    const char *type;
};

/* Minimal fallback used only when no chart file can be read. The full
   BAS chart ships in data/bas_k2.csv and data/bas_k3.csv. */
static const struct chart_entry FALLBACK[] = {
    { "1220", "Inventarier och verktyg", "asset" },
    { "1240", "Bilar och andra transportmedel", "asset" },
    { "1250", "Datorer", "asset" },
    { "1510", "Kundfordringar", "asset" },
    { "1650", "Momsfordran", "asset" },
    { "1710", "Förutbetalda kostnader och upplupna intäkter", "asset" },
    { "1930", "Företagskonto/checkkonto", "asset" },
    { "1940", "Övriga bankkonton", "asset" },
    { "2010", "Eget kapital", "equity" },
    { "2013", "Egna uttag", "equity" },
    { "2091", "Balanserad vinst eller förlust", "equity" },
    { "2099", "Årets resultat", "equity" },
    { "2440", "Leverantörsskulder", "liability" },
    { "2510", "Skatteskulder", "liability" },
    { "2610", "Utgående moms 25%", "liability" },
    { "2620", "Utgående moms 12%", "liability" },
    { "2630", "Utgående moms 6%", "liability" },
    { "2640", "Ingående moms", "liability" },
    { "2650", "Redovisningskonto för moms", "liability" },
    { "2710", "Personalskatt", "liability" },
    { "3001", "Försäljning varor 25%", "revenue" },
    { "3002", "Försäljning tjänster 25%", "revenue" },
    { "3021", "Försäljning varor 12%", "revenue" },
    { "3022", "Försäljning tjänster 12%", "revenue" },
    { "3031", "Försäljning varor 6%", "revenue" },
    { "3032", "Försäljning tjänster 6%", "revenue" },
    { "4010", "Inköp varor", "expense" },
    { "5010", "Lokalhyra", "expense" },
    { "5410", "Förbrukningsinventarier", "expense" },
    { "5460", "Förbrukningsmaterial", "expense" },
    { "6110", "Kontorsmaterial", "expense" },
    { "6310", "Företagsförsäkringar", "expense" },
    { "6530", "Redovisningstjänster", "expense" },
    { "6540", "IT-tjänster", "expense" },
    { "6570", "Bankkostnader", "expense" },
    { "7010", "Löner till kollektivanställda", "expense" },
    { "7510", "Arbetsgivaravgifter", "expense" },
    { "8999", "Årets resultat", "expense" },
};

/* Splits one CSV line in place. Handles quoted fields and doubled quotes. */
static int csv_split(char *line, char **fields, int max, int *out_n)
{
    int n = 0;
    char *p = line;
    while (*p && n < max) {
        char *start = p;
        char *w = p;
        if (*p == '"') {
            p++;
            while (*p) {
                if (*p == '"') {
                    if (p[1] == '"') {
                        *w++ = '"';
                        p += 2;
                        continue;
                    }
                    p++;
                    break;
                }
                *w++ = *p++;
            }
            *w = '\0';
            if (*p == ',')
                p++;
        } else {
            while (*p && *p != ',')
                *w++ = *p++;
            int had_comma = *p == ',';
            if (had_comma)
                p++;
            *w = '\0';
        }
        fields[n++] = start;
    }
    *out_n = n;
    return 0;
}

static int insert_account(sqlite3 *db, int64_t org_id, const char *number,
                          const char *name, const char *type, const char *ts)
{
    sqlite3_stmt *st = NULL;
    if (sqlite3_prepare_v2(
            db,
            "INSERT OR IGNORE INTO accounts(org_id,number,name,type,created_at)"
            " VALUES(?1,?2,?3,?4,?5)",
            -1, &st, NULL) != SQLITE_OK)
        return -1;
    sqlite3_bind_int64(st, 1, org_id);
    sqlite3_bind_text(st, 2, number, -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(st, 3, name, -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(st, 4, type, -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(st, 5, ts, -1, SQLITE_TRANSIENT);
    int rc = sqlite3_step(st);
    sqlite3_finalize(st);
    return rc == SQLITE_DONE ? 0 : -1;
}

static int valid_type(const char *t)
{
    return t && (!strcmp(t, "asset") || !strcmp(t, "liability") ||
                 !strcmp(t, "equity") || !strcmp(t, "revenue") ||
                 !strcmp(t, "expense"));
}

static FILE *open_chart(const char *configured, const char *fallback_name)
{
    if (configured && *configured) {
        FILE *f = fopen(configured, "r");
        if (f)
            return f;
        char alt[512];
        snprintf(alt, sizeof alt, "data/%s", fallback_name);
        f = fopen(alt, "r");
        if (f)
            return f;
    }
    return NULL;
}

static int seed_accounts(sqlite3 *db, int64_t org_id, const char *framework,
                         const char *ts, char **err)
{
    int is_k3 = framework && strcmp(framework, "K3") == 0;
    const char *path = is_k3 ? g_cfg.chart_k3_file : g_cfg.chart_k2_file;
    const char *name = is_k3 ? "bas_k3.csv" : "bas_k2.csv";
    FILE *f = open_chart(path, name);
    if (!f) {
        log_warn("chart file not found; using built-in starter chart");
        for (size_t i = 0; i < sizeof FALLBACK / sizeof FALLBACK[0]; i++)
            if (insert_account(db, org_id, FALLBACK[i].number, FALLBACK[i].name,
                               FALLBACK[i].type, ts) != 0) {
                set_err(err, "could not seed account %s", FALLBACK[i].number);
                return -1;
            }
        return 0;
    }
    char *line = NULL;
    size_t cap = 0;
    ssize_t len;
    int line_no = 0;
    int count = 0;
    while ((len = getline(&line, &cap, f)) > 0) {
        line_no++;
        if (len > 0 && line[len - 1] == '\n')
            line[--len] = '\0';
        if (len > 0 && line[len - 1] == '\r')
            line[--len] = '\0';
        char *fields[8];
        int n = 0;
        csv_split(line, fields, 8, &n);
        if (n < 3)
            continue;
        if (line_no == 1 && strcmp(fields[0], "number") == 0)
            continue;
        if (!valid_type(fields[2]))
            continue;
        if (insert_account(db, org_id, fields[0], fields[1], fields[2], ts) !=
            0) {
            set_err(err, "could not seed account %s (line %d)", fields[0],
                    line_no);
            free(line);
            fclose(f);
            return -1;
        }
        count++;
    }
    free(line);
    fclose(f);
    log_info("seeded %d accounts from %s", count, path);
    return 0;
}

struct vat_rule {
    const char *box;
    const char *match_type;
    const char *pattern;
    int sign;
    int sort_order;
};

/* Starter mapping from BAS account ranges to momsdeklaration boxes. It
   covers the common domestic cases only and must be reviewed against the
   current Skatteverket blankett before filing. */
static const struct vat_rule VAT_RULES[] = {
    { "05", "range", "3001-3019", -1, 10 },
    { "06", "range", "3021-3029", -1, 20 },
    { "07", "range", "3031-3039", -1, 30 },
    { "10", "range", "2610-2619", -1, 40 },
    { "11", "range", "2620-2629", -1, 50 },
    { "12", "range", "2630-2639", -1, 60 },
    { "48", "range", "2640-2649", 1, 70 },
};

static int seed_rules(sqlite3 *db, int64_t org_id, char **err)
{
    for (size_t i = 0; i < sizeof VAT_RULES / sizeof VAT_RULES[0]; i++) {
        sqlite3_stmt *st = NULL;
        if (sqlite3_prepare_v2(
                db,
                "INSERT INTO report_rules(org_id,report,box,match_type,pattern,"
                "sign,sort_order) VALUES(?1,'vat',?2,?3,?4,?5,?6)",
                -1, &st, NULL) != SQLITE_OK) {
            set_err(err, "could not seed moms rules: %s", sqlite3_errmsg(db));
            return -1;
        }
        sqlite3_bind_int64(st, 1, org_id);
        sqlite3_bind_text(st, 2, VAT_RULES[i].box, -1, SQLITE_TRANSIENT);
        sqlite3_bind_text(st, 3, VAT_RULES[i].match_type, -1, SQLITE_TRANSIENT);
        sqlite3_bind_text(st, 4, VAT_RULES[i].pattern, -1, SQLITE_TRANSIENT);
        sqlite3_bind_int(st, 5, VAT_RULES[i].sign);
        sqlite3_bind_int(st, 6, VAT_RULES[i].sort_order);
        int rc = sqlite3_step(st);
        sqlite3_finalize(st);
        if (rc != SQLITE_DONE) {
            set_err(err, "could not seed moms rules: %s", sqlite3_errmsg(db));
            return -1;
        }
    }
    return 0;
}

static int seed_default_fiscal_year(sqlite3 *db, int64_t org_id,
                                    int fy_start_month, int64_t *out_fy,
                                    char **err)
{
    time_t t = time(NULL);
    struct tm tm;
    gmtime_r(&t, &tm);
    int y = tm.tm_year + 1900;
    int m = tm.tm_mon + 1;
    int start_year = m >= fy_start_month ? y : y - 1;

    char start[16], end[16];
    util_date_fmt(start_year, fy_start_month, 1, start, sizeof start);
    util_date_add_months(start, 12, end, sizeof end);
    util_date_add_days(end, -1, end, sizeof end);
    int ey, em, ed;
    util_date_parse(end, &ey, &em, &ed);

    char label[32];
    if (fy_start_month == 1)
        snprintf(label, sizeof label, "%d", ey);
    else
        snprintf(label, sizeof label, "%d/%d", start_year, ey);

    char ts[32];
    util_iso8601(util_now(), ts, sizeof ts);
    sqlite3_stmt *st = NULL;
    if (sqlite3_prepare_v2(
            db,
            "INSERT INTO fiscal_years(org_id,label,start_date,end_date,"
            "created_at) VALUES(?1,?2,?3,?4,?5)",
            -1, &st, NULL) != SQLITE_OK) {
        set_err(err, "could not create fiscal year: %s", sqlite3_errmsg(db));
        return -1;
    }
    sqlite3_bind_int64(st, 1, org_id);
    sqlite3_bind_text(st, 2, label, -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(st, 3, start, -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(st, 4, end, -1, SQLITE_TRANSIENT);
    sqlite3_bind_text(st, 5, ts, -1, SQLITE_TRANSIENT);
    int rc = sqlite3_step(st);
    sqlite3_finalize(st);
    if (rc != SQLITE_DONE) {
        set_err(err, "could not create fiscal year: %s", sqlite3_errmsg(db));
        return -1;
    }
    if (out_fy)
        *out_fy = sqlite3_last_insert_rowid(db);
    log_info("org %lld: fiscal year %s (%s .. %s)", (long long)org_id, label,
             start, end);
    return 0;
}

int seed_org(sqlite3 *db, int64_t org_id, const char *framework,
             int fy_start_month, int64_t *out_fy_id, char **err)
{
    char ts[32];
    util_iso8601(util_now(), ts, sizeof ts);
    if (seed_accounts(db, org_id, framework, ts, err) != 0)
        return -1;
    if (seed_rules(db, org_id, err) != 0)
        return -1;
    if (seed_default_fiscal_year(db, org_id, fy_start_month, out_fy_id, err) !=
        0)
        return -1;
    return 0;
}