/*
 * nanobbs, a tiny forums software.
 * Copyright (C) 2025-2026  Xavier Del Campo Romero
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#define _POSIX_C_SOURCE 200809L

#include "db.h"
#include "defs.h"
#include <dynstr.h>
#include <sqlite3.h>
#include <sys/stat.h>
#include <errno.h>
#include <stddef.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

static int column(sqlite3 *const db, sqlite3_stmt *const stmt,
    const char *const name)
{
    const int n = sqlite3_data_count(stmt);

    if (!n)
    {
        fprintf(stderr, "%s: sqlite3_data_count: %s\n", __func__,
                sqlite3_errmsg(db));
        return -1;
    }

    for (int i = 0; i < n; i++)
    {
        const char *const col = sqlite3_column_name(stmt, i);

        if (!col)
        {
            fprintf(stderr, "%s: sqlite3_column_name: %s\n", __func__,
                sqlite3_errmsg(db));
            return -1;
        }
        else if (!strcmp(col, name))
            return i;
    }

    fprintf(stderr, "%s: could not find column \"%s\"\n", __func__, name);
    return -1;
}

int db_int(sqlite3 *const db, sqlite3_stmt *const stmt, const char *const name,
    int *const out)
{
    const int col = column(db, stmt, name);

    if (col < 0)
        return -1;

    *out = sqlite3_column_int(stmt, col);
    return 0;
}

int db_uint(sqlite3 *const db, sqlite3_stmt *const stmt, const char *const name,
    unsigned *const out)
{
    int v;

    if (db_int(db, stmt, name, &v))
        return -1;
    else if (v < 0)
    {
        fprintf(stderr, "%s: unexpected negative value for %s: %d\n", __func__,
            name, v);
        return -1;
    }

    *out = v;
    return 0;
}

int db_bigint(sqlite3 *const db, sqlite3_stmt *const stmt,
    const char *const name, long long *const out)
{
    const int col = column(db, stmt, name);

    if (col < 0)
        return -1;

    *out = sqlite3_column_int64(stmt, col);
    return 0;
}

int db_biguint(sqlite3 *const db, sqlite3_stmt *const stmt,
    const char *const name, unsigned long long *const out)
{
    const int col = column(db, stmt, name);
    sqlite3_int64 v;

    if (col < 0 || (v = sqlite3_column_int64(stmt, col)) < 0)
        return -1;

    *out = v;
    return 0;
}

char *db_str(sqlite3 *const db, sqlite3_stmt *const stmt,
    const char *const name)
{
    char *ret = NULL;
    const int col = column(db, stmt, name);

    if (col < 0)
        return NULL;

    const unsigned char *const s = sqlite3_column_text(stmt, col);

    if (!s)
    {
        fprintf(stderr, "%s: sqlite3_column_text: %s\n", __func__,
            sqlite3_errmsg(db));
        goto failure;
    }
    else if (!(ret = strndup((const char *)s, sqlite3_column_bytes(stmt, col))))
    {
        fprintf(stderr, "%s: strndup(3): %s\n", __func__, strerror(errno));
        goto failure;
    }

    return ret;

failure:
    free(ret);
    return NULL;
}

int db_rollback(sqlite3 *const db)
{
    char *msg = NULL;
    const int e = sqlite3_exec(db, "ROLLBACK;", NULL, NULL, &msg);

    if (e != SQLITE_OK)
        fprintf(stderr, "%s: sqlite3_exec: %s, msg=%s\n", __func__,
            sqlite3_errstr(e), msg);

    sqlite3_free(msg);
    return e != SQLITE_OK;
}

int db_open(const char *const dir, sqlite3 **const out)
{
    int ret = SQLITE_ERROR;
    sqlite3 *db;
    struct dynstr d;
    const mode_t m = umask(S_IWGRP | S_IWOTH | S_IROTH);

    dynstr_init(&d);

    if (dynstr_append(&d, "%s/" PROJECT_NAME ".db", dir))
    {
        fprintf(stderr, "%s: dynstr_append failed\n", __func__);
        goto end;
    }
    else if ((ret = sqlite3_open(d.str, &db)) != SQLITE_OK)
    {
        fprintf(stderr, "%s: sqlite3_open %s: %s\n", __func__, d.str,
            sqlite3_errstr(ret));
        goto end;
    }

    *out = db;
    ret = 0;

end:
    umask(m);
    dynstr_free(&d);
    return ret;
}