<?php

// +----------------------------------------------------------------------
// | ThinkPHP [ WE CAN DO IT JUST THINK ]
// +----------------------------------------------------------------------
// | Copyright (c) 2006~2025 http://thinkphp.cn All rights reserved.
// +----------------------------------------------------------------------
// | Licensed ( http://www.apache.org/licenses/LICENSE-2.0 )
// +----------------------------------------------------------------------
// | Author: liu21st <liu21st@gmail.com>
// +----------------------------------------------------------------------

namespace think\db\connector;

use PDO;
use think\db\PDOConnection;

/**
 * Sqlite数据库驱动.
 */
class Sqlite extends PDOConnection
{
    /**
     * 解析pdo连接的dsn信息.
     *
     * @param array $config 连接信息
     *
     * @return string
     */
    protected function parseDsn(array $config): string
    {
        return 'sqlite:' . $config['database'];
    }

    /**
     * 取得数据表的字段信息.
     *
     * @param string $tableName
     *
     * @return array
     */
    public function getFields(string $tableName): array
    {
        [$tableName] = explode(' ', $tableName);

        $sql    = 'PRAGMA table_info( \'' . $tableName . '\' )';
        $pdo    = $this->getPDOStatement($sql);
        $result = $pdo->fetchAll(PDO::FETCH_ASSOC);
        $info   = [];

        if (!empty($result)) {
            foreach ($result as $key => $val) {
                $val = array_change_key_case($val);

                $info[$val['name']] = [
                    'name'    => $val['name'],
                    'type'    => $val['type'],
                    'notnull' => 1 === $val['notnull'],
                    'default' => $val['dflt_value'],
                    'primary' => '1' == $val['pk'],
                    'autoinc' => '1' == $val['pk'],
                ];
            }
        }

        return $this->fieldCase($info);
    }

    /**
     * 取得数据库的表信息.
     *
     * @param string $dbName
     *
     * @return array
     */
    public function getTables(string $dbName = ''): array
    {
        $sql = "SELECT name FROM sqlite_master WHERE type='table' "
            . 'UNION ALL SELECT name FROM sqlite_temp_master '
            . "WHERE type='table' ORDER BY name";

        $pdo    = $this->getPDOStatement($sql);
        $result = $pdo->fetchAll(PDO::FETCH_ASSOC);
        $info   = [];

        foreach ($result as $key => $val) {
            $info[$key] = current($val);
        }

        return $info;
    }

    protected function supportSavepoint(): bool
    {
        return true;
    }

    /**
     * 获取设置时区的SQL语句.
     *
     * @param string $timezone 时区名称，如 'Asia/Shanghai' 或 '+08:00'
     *
     * @return string SQLite 不支持时区设置，返回空字符串
     */
    protected function getSetTimezoneSql(string $timezone): string
    {
        // SQLite 是嵌入式数据库，不支持时区设置
        // 建议在应用层处理时区转换
        return '';
    }
}
