<?php
/*************************************************************
# 076 License

Copyright (c) テクニカル諏訪子

Permission is hereby granted to any person obtaining a copy of the software
Little Beast (the "Software") to use, modify, merge, copy, publish, distribute,
sublicense, and/or sell copies of the Software, subject to the following conditions:

    1. **Origin Attribution**:
       - You must not misrepresent the origin of the Software; you must not claim
         you created the original Software.
       - If the Software is used in a product, you must either:
         a. Provide clear attribution in the product's documentation, user interface,
            or other visible areas, **OR**
         b. Pay the original developers a fee they specify in writing.
    2. **Usage Restriction**:
       - The Software, or any derivative works, dependencies, or libraries
         incorporating it, must not be used for censorship or to suppress freedom of
         speech, expression, or creativity. Prohibited uses include, but are not
         limited to:
         - Censorship of so-called "hate speech", visuals, non-mainstream opinions,
           ideas, or objective reality.
         - Tools or systems designed to restrict access to information or
           artistic works.
    3. **Notice Preservation**:
       - This license and the above copyright notice must remain intact in all copies
         of the source code.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE
OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
namespace Std\Lib;

use Std\Lib\Db\DbInterface;
use Std\Lib\Db\Mysql;
use Std\Lib\Db\Pgsql;
use Std\Lib\Db\Sqlite;

/**
 * データベース
 *
 * DBINFOの「driver」でドライバ（Std\Lib\Db\の中）を選ぶ。接続は最初のクエリの時に自動で行う。
 *
 * 使い方：
 *   $db = new Db();
 *   $users = $db->query('SELECT * FROM users WHERE role > ?', [0])['rows'];
 *   $id = $db->query('INSERT INTO users (name) VALUES (?)', ['諏訪子'])['insertId']; // MySQL・SQLite（PostgreSQLはRETURNINGを使う）
 *   $db->transaction(function(Db $db): void {
 *     $db->query('UPDATE users SET points = points - ? WHERE id = ?', [100, 1]);
 *     $db->query('UPDATE users SET points = points + ? WHERE id = ?', [100, 2]);
 *   });
 */
class Db {
  private const SUPPORTED = [
    'mysql'      => Mysql::class,
    'mariadb'    => Mysql::class,
    'pgsql'      => Pgsql::class,
    'postgres'   => Pgsql::class,
    'postgresql' => Pgsql::class,
    'sqlite'     => Sqlite::class,
    'sqlite3'    => Sqlite::class,
  ];

  public string $driverName;
  private DbInterface $driver;

  /**
   * コンストラクタ
   *
   * @param array|null $info  設定（省略するとDBINFO）。driver（mysql等）、その他はドライバ毎
   * @throws \Exception  $infoを省略し、DB_ENABLEDが無効な場合
   * @throws \RuntimeException  未対応のドライバの場合
   */
  public function __construct(?array $info = null) {
    if ($info === null && !(defined('DB_ENABLED') && DB_ENABLED)) {
      throw new \Exception('データベースは無効です。');
    }

    $info ??= DBINFO;
    $this->driverName = strtolower((string)($info['driver'] ?? 'mysql'));
    $class = self::SUPPORTED[$this->driverName] ?? null;
    if (!$class) throw new \RuntimeException("未対応のデータベース： {$this->driverName}");
    $this->driver = new $class($info);
  }

  /**
   * ドライバに対応しているかどうか
   *
   * @param string $driver  ドライバ名
   * @return bool
   */
  public static function isSupported(string $driver): bool {
    return isset(self::SUPPORTED[strtolower($driver)]);
  }

  /**
   * ドライバ（ドライバ毎の機能用、例：MysqlのsetDebug()）
   *
   * @return DbInterface
   */
  public function driver(): DbInterface {
    return $this->driver;
  }

  public function connect(): bool {
    return $this->driver->connect();
  }

  public function close(): void {
    $this->driver->close();
  }

  public function isConnected(): bool {
    return $this->driver->isConnected();
  }

  public function ping(): bool {
    return $this->driver->ping();
  }

  /**
   * SQLを実行する
   *
   * パラメータがある場合はプリペアドステートメント（プレースホルダは「?」）で実行するので、
   * 値をエスケープする必要はない。
   *
   * @param string $sql  SQL
   * @param array $params  パラメータ（順番通り）
   * @return array  結果（fields、rows、affectedRows、insertId、warningCount等、DbInterfaceを参照）
   * @throws Db\DbException  失敗した場合
   */
  public function query(string $sql, array $params = []): array {
    $this->driver->connect();
    if (empty($params)) return $this->driver->query($sql);

    $id = $this->driver->prepare($sql);
    try {
      return $this->driver->execute($id, $params);
    } finally {
      $this->driver->demolish($id);
    }
  }

  /**
   * 何回も実行するSQLを準備する（終わったらdemolish()）
   *
   * @param string $sql  SQL
   * @return int  ステートメントID
   * @throws Db\DbException
   */
  public function prepare(string $sql): int {
    $this->driver->connect();
    return $this->driver->prepare($sql);
  }

  public function execute(int $statementId, array $params = []): array {
    return $this->driver->execute($statementId, $params);
  }

  public function demolish(int $statementId): bool {
    return $this->driver->demolish($statementId);
  }

  /**
   * トランザクションの中で実行する
   *
   * 例外が出たらロールバックして、その例外を投げ直す。それ以外はコミットする。
   *
   * @param callable $fn  function(Db $db): mixed
   * @return mixed  $fnの戻り値
   * @throws \Throwable  $fnの例外
   */
  public function transaction(callable $fn): mixed {
    $this->beginTransaction();

    try {
      $res = $fn($this);
    } catch (\Throwable $e) {
      if ($this->driver->isConnected()) {
        try {
          $this->driver->rollback();
        } catch (\Throwable $ignore) {
          // 接続が切れた場合等：元の例外を優先する
        }
      }
      throw $e;
    }

    $this->driver->commit();
    return $res;
  }

  public function beginTransaction(): bool {
    $this->driver->connect();
    return $this->driver->beginTransaction();
  }

  public function commit(): bool {
    return $this->driver->commit();
  }

  public function rollback(): bool {
    return $this->driver->rollback();
  }

  public function inTransaction(): bool {
    return $this->driver->inTransaction();
  }

  public function quoteIdentifier(string $name): string {
    return $this->driver->quoteIdentifier($name);
  }
}