<?php

declare(strict_types=1);

/**
 * @copyright 2021 Christoph Wurst <christoph@winzerhof-wurst.at>
 *
 * @author Christoph Wurst <christoph@winzerhof-wurst.at>
 *
 * @license GNU AGPL version 3 or any later version
 *
 * 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 <http://www.gnu.org/licenses/>.
 *
 */
namespace OCP\DB;

use Exception as BaseException;

/**
 * Database exception
 *
 * Thrown by Nextcloud's database abstraction layer. This is the base class that
 * any specific exception will extend. Use this class in your try-catch to catch
 * *any* error related to the database. Use any of the subclasses in the same
 * namespace if you are only interested in specific errors.
 *
 * @psalm-immutable
 * @since 21.0.0
 */
class Exception extends BaseException {

	/**
	 * Nextcloud lost connection to the database
	 *
	 * @since 21.0.0
	 */
	public const REASON_CONNECTION_LOST = 1;

	/**
	 * A database constraint was violated
	 *
	 * @since 21.0.0
	 */
	public const REASON_CONSTRAINT_VIOLATION = 2;

	/**
	 * A database object (table, column, index) already exists
	 *
	 * @since 21.0.0
	 */
	public const REASON_DATABASE_OBJECT_EXISTS = 3;

	/**
	 * A database object (table, column, index) can't be found
	 *
	 * @since 21.0.0
	 */
	public const REASON_DATABASE_OBJECT_NOT_FOUND = 4;

	/**
	 * The database ran into a deadlock
	 *
	 * @since 21.0.0
	 */
	public const REASON_DEADLOCK = 5;

	/**
	 * The database driver encountered an issue
	 *
	 * @since 21.0.0
	 */
	public const REASON_DRIVER = 6;

	/**
	 * A foreign key constraint was violated
	 *
	 * @since 21.0.0
	 */
	public const REASON_FOREIGN_KEY_VIOLATION = 7;

	/**
	 * An invalid argument was passed to the database abstraction
	 *
	 * @since 21.0.0
	 */
	public const REASON_INVALID_ARGUMENT = 8;

	/**
	 * A field name was invalid
	 *
	 * @since 21.0.0
	 */
	public const REASON_INVALID_FIELD_NAME = 9;

	/**
	 * A name in the query was ambiguous
	 *
	 * @since 21.0.0
	 */
	public const REASON_NON_UNIQUE_FIELD_NAME = 10;

	/**
	 * A not null contraint was violated
	 *
	 * @since 21.0.0
	 */
	public const REASON_NOT_NULL_CONSTRAINT_VIOLATION = 11;

	/**
	 * A generic server error was encountered
	 *
	 * @since 21.0.0
	 */
	public const REASON_SERVER = 12;

	/**
	 * A syntax error was reported by the server
	 *
	 * @since 21.0.0
	 */
	public const REASON_SYNTAX_ERROR = 13;

	/**
	 * A unique constraint was violated
	 *
	 * @since 21.0.0
	 */
	public const REASON_UNIQUE_CONSTRAINT_VIOLATION = 14;

	/**
	 * @return int|null
	 * @psalm-return Exception::REASON_*
	 * @since 21.0.0
	 */
	public function getReason(): ?int {
		return null;
	}
}
