#include <dirent.h>
#include <errno.h>
#include <locale.h>
#include <math.h>
#include <ncursesw/ncurses.h>
#include <stdarg.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <sys/stat.h>
#include <sys/wait.h>
#include <time.h>
#include <unistd.h>

#include "client.h"
#include "tui.h"
#include "formula.h"
#include "util.h"
#include "version.h"
#include "yyjson.h"
#include "ui.h"

/* ------------------------------------------------------------------ */
/* ingående balans (series IB)                                         */
/* ------------------------------------------------------------------ */

struct tui_ibrow {
    char account[16];
    char amount[32];
    char text[64];
};

/* Loads the net IB per account for the active fiscal year. */
/* Effective opening balances of the selected year: the year's IB vouchers
   plus all earlier movements, exactly what the reports show. */
static int ib_load(struct app *a, char ***out_acc, int64_t **out_amt,
                   int *out_n)
{
    *out_acc = NULL;
    *out_amt = NULL;
    *out_n = 0;
    char args[128];
    snprintf(args, sizeof args,
             "{\"fiscal_year\":%lld,\"include_zero\":true}",
             (long long)a->fy);
    char *resp = client_rpc(&a->conn, "report.trial_balance", a->session,
                            a->org, args);
    if (!resp || !client_ok(resp)) {
        show_error("Ingående balans", resp);
        free(resp);
        return -1;
    }
    size_t n = jarr_size(resp, "result.accounts");
    char **accs = xcalloc(n ? n : 1, sizeof(char *));
    int64_t *amts = xcalloc(n ? n : 1, sizeof(int64_t));
    int count = 0;
    for (size_t i = 0; i < n; i++) {
        char path[64];
        snprintf(path, sizeof path, "result.accounts.%zu.ib_ore", i);
        int64_t ib = jint_val(resp, path, 0);
        if (ib == 0)
            continue;
        snprintf(path, sizeof path, "result.accounts.%zu.account", i);
        char *acc = jstr_dup(resp, path);
        if (!acc)
            continue;
        accs[count] = acc;
        amts[count] = ib;
        count++;
    }
    free(resp);
    *out_acc = accs;
    *out_amt = amts;
    *out_n = count;
    return 0;
}

static int64_t ib_old_lookup(char **accs, int64_t *amts, int n,
                             const char *account)
{
    for (int i = 0; i < n; i++)
        if (strcmp(accs[i], account) == 0)
            return amts[i];
    return 0;
}

struct ibform {
    struct app *a;
    struct tui_rt rt;
    struct tui_ibrow rows[64];
    char **old_acc;
    int64_t *old_amt;
    int nold;
};

static void ib_cell(void *ud, int row, int col, char **buf, size_t *cap)
{
    struct ibform *ib = ud;
    struct tui_ibrow *r = &ib->rows[row];
    if (col == 0) {
        *buf = r->account;
        *cap = sizeof r->account;
    } else if (col == 2) {
        *buf = r->amount;
        *cap = sizeof r->amount;
    } else {
        *buf = r->text;
        *cap = sizeof r->text;
    }
}

static void ib_info(void *ud, int row, char *buf, size_t n)
{
    struct ibform *ib = ud;
    const char *nm = acct_name(ib->a, ib->rows[row].account);
    snprintf(buf, n, "%s", nm ? nm : "");
}

static void ib_footer(void *ud, char *buf, size_t n)
{
    (void)ud;
    snprintf(buf, n, "Positiva belopp = debet, negativa = kredit. Summan ska"
                     " bli noll.");
}

static const char *ib_check(struct ibform *ib, int *used_out, char *msg,
                            size_t msglen)
{
    int64_t sum = 0;
    int used = 0;
    for (int i = 0; i < ib->rt.nrows; i++) {
        if (!ib->rows[i].account[0])
            continue;
        if (!acct_exists(ib->a, ib->rows[i].account)) {
            snprintf(msg, msglen, "Konto %.15s finns inte (rad %d).",
                     ib->rows[i].account, i + 1);
            return msg;
        }
        double kr = 0;
        if (ib->rows[i].amount[0] &&
            !parse_x_double(ib->rows[i].amount, &kr)) {
            snprintf(msg, msglen, "Ogiltigt belopp på rad %d: '%.20s'.", i + 1,
                     ib->rows[i].amount);
            return msg;
        }
        sum += (int64_t)llround(kr * 100.0);
        used++;
    }
    if (used == 0)
        return "Ange minst ett konto.";
    if (sum != 0) {
        snprintf(msg, msglen, "Summan måste bli noll (nu %lld öre).",
                 (long long)sum);
        return msg;
    }
    *used_out = used;
    return NULL;
}

/* Posts the delta against the existing IB so nothing is ever edited. */
static int ib_post_delta(struct ibform *ib)
{
    struct app *a = ib->a;
    yyjson_mut_doc *d = yyjson_mut_doc_new(NULL);
    yyjson_mut_val *o = yyjson_mut_obj(d);
    yyjson_mut_doc_set_root(d, o);
    yyjson_mut_obj_add_strcpy(d, o, "date", a->fy_start);
    yyjson_mut_obj_add_strcpy(d, o, "description", "Ingående balans");
    yyjson_mut_obj_add_strcpy(d, o, "series", "IB");
    char *ref = util_random_id("tui-", 8);
    yyjson_mut_obj_add_strcpy(d, o, "client_ref", ref);
    free(ref);
    yyjson_mut_val *arr = yyjson_mut_arr(d);
    int posted = 0;
    for (int i = 0; i < ib->rt.nrows; i++) {
        if (!ib->rows[i].account[0])
            continue;
        double kr = 0;
        if (ib->rows[i].amount[0] &&
            !parse_x_double(ib->rows[i].amount, &kr))
            kr = 0;
        int64_t new_amt = (int64_t)llround(kr * 100.0);
        int64_t prev_amt =
            ib_old_lookup(ib->old_acc, ib->old_amt, ib->nold,
                          ib->rows[i].account);
        int64_t delta = new_amt - prev_amt;
        if (delta == 0)
            continue;
        yyjson_mut_val *ro = yyjson_mut_arr_add_obj(d, arr);
        yyjson_mut_obj_add_strcpy(d, ro, "account", ib->rows[i].account);
        yyjson_mut_obj_add_int(d, ro, "debit_ore", delta > 0 ? delta : 0);
        yyjson_mut_obj_add_int(d, ro, "credit_ore", delta < 0 ? -delta : 0);
        if (ib->rows[i].text[0])
            yyjson_mut_obj_add_strcpy(d, ro, "description",
                                      ib->rows[i].text);
        posted++;
    }
    for (int i = 0; i < ib->nold; i++) {
        int still = 0;
        for (int j = 0; j < ib->rt.nrows; j++)
            if (strcmp(ib->rows[j].account, ib->old_acc[i]) == 0) {
                still = 1;
                break;
            }
        if (!still && ib->old_amt[i] != 0) {
            yyjson_mut_val *ro = yyjson_mut_arr_add_obj(d, arr);
            yyjson_mut_obj_add_strcpy(d, ro, "account", ib->old_acc[i]);
            yyjson_mut_obj_add_int(d, ro, "debit_ore",
                                   ib->old_amt[i] < 0 ? -ib->old_amt[i] : 0);
            yyjson_mut_obj_add_int(d, ro, "credit_ore",
                                   ib->old_amt[i] > 0 ? ib->old_amt[i] : 0);
            posted++;
        }
    }
    if (posted == 0) {
        yyjson_mut_doc_free(d);
        tui_message("Ingående balans", "Ingen ändring.");
        return 0;
    }
    yyjson_mut_obj_add_val(d, o, "rows", arr);
    char *args = yyjson_mut_write(d, 0, NULL);
    yyjson_mut_doc_free(d);
    char *resp =
        client_rpc(&a->conn, "voucher.post", a->session, a->org, args);
    free(args);
    if (resp && client_ok(resp)) {
        int64_t num = jint_val(resp, "result.number", 0);
        tui_message("Ingående balans",
                    "Sparat som IB %lld (%d justerade rader).",
                    (long long)num, posted);
        free(resp);
        return 1;
    }
    show_error("Kunde inte spara ingående balans", resp);
    free(resp);
    return 0;
}

static int ib_form(struct app *a, char **old_acc, int64_t *old_amt, int nold)
{
    struct ibform ib;
    memset(&ib, 0, sizeof ib);
    ib.a = a;
    ib.old_acc = old_acc;
    ib.old_amt = old_amt;
    ib.nold = nold;
    if (nold > 63) {
        tui_message("Ingående balans",
                "För många konton (%d) för att redigera här.", nold);
        return 0;
    }
    for (int i = 0; i < nold && i < 63; i++) {
        snprintf(ib.rows[i].account, sizeof ib.rows[i].account, "%s",
                 old_acc[i]);
        tui_kr_format(old_amt[i], ib.rows[i].amount,
                      sizeof ib.rows[i].amount);
    }
    int text_w = COLS - 51;
    if (text_w < 6)
        text_w = 6;
    struct tui_rt_col cols[4] = {
        { "Konto", 2, 6, TUI_RT_EDIT },
        { "Namn", 9, 24, TUI_RT_INFO },
        { "Belopp", 34, 14, TUI_RT_EDIT },
        { "Text", 49, text_w, TUI_RT_EDIT },
    };
    tui_rt_init(&ib.rt, nold > 0 ? nold : 1, 64, 4, cols, 5, ib_cell, ib_info,
                &ib);
    tui_rt_set_footer(&ib.rt, ib_footer);

    for (;;) {
        int rr = tui_rt_run("Ingående balans", &ib.rt,
                            "Tab = byta fält  F5 = validera  ^X = rensa rad"
                            "  ^Enter = spara  Esc = avbryt");
        if (rr == -1)
            return 0;
        char msg[256];
        int used = 0;
        const char *problem = ib_check(&ib, &used, msg, sizeof msg);
        if (problem) {
            tui_message("Ingående balans", "%s", problem);
            continue;
        }
        if (rr == -2) {
            tui_message("Validering OK", "%d konton, summan är noll.", used);
            continue;
        }
        if (ib_post_delta(&ib))
            return 1;
    }
}

struct ibpager {
    struct app *a;
    char **accs;
    int64_t *amts;
    int n;
};

static int ib_view_key(void *ud, int ch)
{
    struct ibpager *p = ud;
    if (ch == 'e' || ch == 'E' || ch == TUI_KEY_CTRL_N) {
        if (ib_form(p->a, p->accs, p->amts, p->n))
            return TUI_HOOK_REFRESH;
        return TUI_HOOK_STAY;
    }
    return TUI_HOOK_NONE;
}

/* The list is a read-only table with no selection: tui_pager shows the
   columns and the sum as plain text, and the e/^N keys run the editor. */
void ib_screen(struct app *a)
{
    for (;;) {
        char **accs = NULL;
        int64_t *amts = NULL;
        int n = 0;
        if (ib_load(a, &accs, &amts, &n) != 0)
            return;
        struct buf t;
        buf_init(&t);
        buf_line(&t, "Räkenskapsår %s   ingående balans (effektiv)\n\n",
                 a->fy_label);
        buf_line(&t, "%-7s%-53s%s\n\n", "Konto", "Namn", "Belopp");
        int64_t sum = 0;
        for (int i = 0; i < n; i++) {
            sum += amts[i];
            char amount[32], nbuf[128];
            tui_kr_format(amts[i], amount, sizeof amount);
            const char *nm = acct_name(a, accs[i]);
            snprintf(nbuf, sizeof nbuf, "%s", nm ? nm : "");
            tui_pad_field(nbuf, sizeof nbuf, 50);
            buf_line(&t, "%-6s %s %14s\n", accs[i], nbuf, amount);
        }
        if (n == 0)
            buf_line(&t, "Ingen ingående balans registrerad ännu.\n");
        char sumbuf[32];
        tui_kr_format(sum, sumbuf, sizeof sumbuf);
        buf_line(&t, "\nSumma: %s\n", sumbuf);
        buf_append(&t, "\0", 1);
        struct ibpager p = { a, accs, amts, n };
        int ret = tui_pager_hook("Ingående balans", (const char *)t.p,
                                 "e/^N = redigera", 0, ib_view_key, &p);
        buf_free(&t);
        for (int i = 0; i < n; i++)
            free(accs[i]);
        free(accs);
        free(amts);
        if (ret == 0)
            return;
    }
}