<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\console\controllers;

use Yii;
use yii\console\Exception;
use yii\db\Connection;
use yii\db\Query;
use yii\helpers\ArrayHelper;

/**
 * Manages application migrations.
 *
 * A migration means a set of persistent changes to the application environment
 * that is shared among different developers. For example, in an application
 * backed by a database, a migration may refer to a set of changes to
 * the database, such as creating a new table, adding a new table column.
 *
 * This command provides support for tracking the migration history, upgrading
 * or downloading with migrations, and creating new migration skeletons.
 *
 * The migration history is stored in a database table named
 * as [[migrationTable]]. The table will be automatically created the first time
 * this command is executed, if it does not exist. You may also manually
 * create it as follows:
 *
 * ~~~
 * CREATE TABLE migration (
 *     version varchar(180) PRIMARY KEY,
 *     apply_time integer
 * )
 * ~~~
 *
 * Below are some common usages of this command:
 *
 * ~~~
 * # creates a new migration named 'create_user_table'
 * yii migrate/create create_user_table
 *
 * # applies ALL new migrations
 * yii migrate
 *
 * # reverts the last applied migration
 * yii migrate/down
 * ~~~
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class MigrateController extends BaseMigrateController
{
    /**
     * @var string the name of the table for keeping applied migration information.
     */
    public $migrationTable = '{{%migration}}';
    /**
     * @inheritdoc
     */
    public $templateFile = '@yii/views/migration.php';
    /**
     * @var Connection|string the DB connection object or the application
     * component ID of the DB connection.
     */
    public $db = 'db';

    /**
     * @inheritdoc
     */
    public function options($actionId)
    {
        return array_merge(
            parent::options($actionId),
            ['migrationTable', 'db'] // global for all actions
        );
    }

    /**
     * This method is invoked right before an action is to be executed (after all possible filters.)
     * It checks the existence of the [[migrationPath]].
     * @param \yii\base\Action $action the action to be executed.
     * @throws Exception if db component isn't configured
     * @return boolean whether the action should continue to be executed.
     */
    public function beforeAction($action)
    {
        if (parent::beforeAction($action)) {
            if ($action->id !== 'create') {
                if (is_string($this->db)) {
                    $this->db = Yii::$app->get($this->db);
                }
                if (!$this->db instanceof Connection) {
                    throw new Exception("The 'db' option must refer to the application component ID of a DB connection.");
                }
            }
            return true;
        } else {
            return false;
        }
    }

    /**
     * Creates a new migration instance.
     * @param string $class the migration class name
     * @return \yii\db\Migration the migration instance
     */
    protected function createMigration($class)
    {
        $file = $this->migrationPath . DIRECTORY_SEPARATOR . $class . '.php';
        require_once($file);

        return new $class(['db' => $this->db]);
    }

    /**
     * @inheritdoc
     */
    protected function getMigrationHistory($limit)
    {
        if ($this->db->schema->getTableSchema($this->migrationTable, true) === null) {
            $this->createMigrationHistoryTable();
        }
        $query = new Query;
        $rows = $query->select(['version', 'apply_time'])
            ->from($this->migrationTable)
            ->orderBy('version DESC')
            ->limit($limit)
            ->createCommand($this->db)
            ->queryAll();
        $history = ArrayHelper::map($rows, 'version', 'apply_time');
        unset($history[self::BASE_MIGRATION]);

        return $history;
    }

    /**
     * Creates the migration history table.
     */
    protected function createMigrationHistoryTable()
    {
        $tableName = $this->db->schema->getRawTableName($this->migrationTable);
        echo "Creating migration history table \"$tableName\"...";
        $this->db->createCommand()->createTable($this->migrationTable, [
            'version' => 'varchar(180) NOT NULL PRIMARY KEY',
            'apply_time' => 'integer',
        ])->execute();
        $this->db->createCommand()->insert($this->migrationTable, [
            'version' => self::BASE_MIGRATION,
            'apply_time' => time(),
        ])->execute();
        echo "done.\n";
    }

    /**
     * @inheritdoc
     */
    protected function addMigrationHistory($version)
    {
        $command = $this->db->createCommand();
        $command->insert($this->migrationTable, [
            'version' => $version,
            'apply_time' => time(),
        ])->execute();
    }

    /**
     * @inheritdoc
     */
    protected function removeMigrationHistory($version)
    {
        $command = $this->db->createCommand();
        $command->delete($this->migrationTable, [
            'version' => $version,
        ])->execute();
    }
}