<?php
/**
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @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\console\Controller;
use yii\db\Connection;
use yii\db\Query;
use yii\util\ArrayHelper;

/**
 * This command 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 this command is executed.
 * You may also manually create it with the following structure:
 *
 * ~~~
 * CREATE TABLE tbl_migration (
 *     version varchar(255) PRIMARY KEY,
 *     apply_time integer
 * )
 * ~~~
 *
 * Below are some common usages of this command:
 *
 * ~~~
 * # creates a new migration named 'create_user_table'
 * yiic migrate/create create_user_table
 *
 * # applies ALL new migrations
 * yiic migrate
 *
 * # reverts the last applied migration
 * yiic migrate/down
 * ~~~
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class MigrateController extends Controller
{
	/**
	 * The name of the dummy migration that marks the beginning of the whole migration history.
	 */
	const BASE_MIGRATION = 'm000000_000000_base';

	/**
	 * @var string the default command action.
	 */
	public $defaultAction = 'up';
	/**
	 * @var string the directory storing the migration classes. This can be either
	 * a path alias or a directory.
	 */
	public $migrationPath = '@app/migrations';
	/**
	 * @var string the name of the table for keeping applied migration information.
	 */
	public $migrationTable = 'tbl_migration';
	/**
	 * @var string the component ID that specifies the database connection for
	 * storing migration information.
	 */
	public $connectionID = 'db';
	/**
	 * @var string the template file for generating new migrations.
	 * This can be either a path alias (e.g. "@app/migrations/template.php")
	 * or a file path.
	 */
	public $templateFile = '@yii/views/migration.php';
	/**
	 * @var boolean whether to execute the migration in an interactive mode.
	 */
	public $interactive = true;
	/**
	 * @var Connection the DB connection used for storing migration history.
	 * @see connectionID
	 */
	public $db;

	/**
	 * Returns the names of the global options for this command.
	 * @return array the names of the global options for this command.
	 */
	public function globalOptions()
	{
		return array('migrationPath', 'migrationTable', 'connectionID', 'templateFile', 'interactive');
	}

	/**
	 * 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 $action the action to be executed.
	 * @return boolean whether the action should continue to be executed.
	 * @throws Exception if the migration directory does not exist.
	 */
	public function beforeAction($action)
	{
		if (parent::beforeAction($action)) {
			$path = Yii::getAlias($this->migrationPath);
			if (!is_dir($path)) {
				throw new Exception("The migration directory \"{$this->migrationPath}\" does not exist.");
			}
			$this->migrationPath = $path;

			$this->db = Yii::$app->getComponent($this->connectionID);
			if (!$this->db instanceof Connection) {
				throw new Exception("Invalid DB connection \"{$this->connectionID}\".");
			}

			$version = Yii::getVersion();
			echo "Yii Migration Tool (based on Yii v{$version})\n\n";
			return true;
		} else {
			return false;
		}
	}

	/**
	 * Upgrades the application by applying new migrations.
	 * For example,
	 *
	 * ~~~
	 * yiic migrate     # apply all new migrations
	 * yiic migrate 3   # apply the first 3 new migrations
	 * ~~~
	 *
	 * @param integer $limit the number of new migrations to be applied. If 0, it means
	 * applying all available new migrations.
	 */
	public function actionUp($limit = 0)
	{
		if (($migrations = $this->getNewMigrations()) === array()) {
			echo "No new migration found. Your system is up-to-date.\n";
			Yii::$app->end();
		}

		$total = count($migrations);
		$limit = (int)$limit;
		if ($limit > 0) {
			$migrations = array_slice($migrations, 0, $limit);
		}

		$n = count($migrations);
		if ($n === $total) {
			echo "Total $n new " . ($n === 1 ? 'migration' : 'migrations') . " to be applied:\n";
		} else {
			echo "Total $n out of $total new " . ($total === 1 ? 'migration' : 'migrations') . " to be applied:\n";
		}

		foreach ($migrations as $migration) {
			echo "    $migration\n";
		}
		echo "\n";

		if ($this->confirm('Apply the above ' . ($n === 1 ? 'migration' : 'migrations') . "?")) {
			foreach ($migrations as $migration) {
				if (!$this->migrateUp($migration)) {
					echo "\nMigration failed. The rest of the migrations are canceled.\n";
					return;
				}
			}
			echo "\nMigrated up successfully.\n";
		}
	}

	/**
	 * Downgrades the application by reverting old migrations.
	 * For example,
	 *
	 * ~~~
	 * yiic migrate/down     # revert the last migration
	 * yiic migrate/down 3   # revert the last 3 migrations
	 * ~~~
	 *
	 * @param integer $limit the number of migrations to be reverted. Defaults to 1,
	 * meaning the last applied migration will be reverted.
	 * @throws Exception if the number of the steps specified is less than 1.
	 */
	public function actionDown($limit = 1)
	{
		$limit = (int)$limit;
		if ($limit < 1) {
			throw new Exception("The step argument must be greater than 0.");
		}

		if (($migrations = $this->getMigrationHistory($limit)) === array()) {
			echo "No migration has been done before.\n";
			return;
		}
		$migrations = array_keys($migrations);

		$n = count($migrations);
		echo "Total $n " . ($n === 1 ? 'migration' : 'migrations') . " to be reverted:\n";
		foreach ($migrations as $migration) {
			echo "    $migration\n";
		}
		echo "\n";

		if ($this->confirm('Revert the above ' . ($n === 1 ? 'migration' : 'migrations') . "?")) {
			foreach ($migrations as $migration) {
				if (!$this->migrateDown($migration)) {
					echo "\nMigration failed. The rest of the migrations are canceled.\n";
					return;
				}
			}
			echo "\nMigrated down successfully.\n";
		}
	}

	/**
	 * Redoes the last few migrations.
	 *
	 * This command will first revert the specified migrations, and then apply
	 * them again. For example,
	 *
	 * ~~~
	 * yiic migrate/redo     # redo the last applied migration
	 * yiic migrate/redo 3   # redo the last 3 applied migrations
	 * ~~~
	 *
	 * @param integer $limit the number of migrations to be redone. Defaults to 1,
	 * meaning the last applied migration will be redone.
	 * @throws Exception if the number of the steps specified is less than 1.
	 */
	public function actionRedo($limit = 1)
	{
		$limit = (int)$limit;
		if ($limit < 1) {
			throw new Exception("The step argument must be greater than 0.");
		}

		if (($migrations = $this->getMigrationHistory($limit)) === array()) {
			echo "No migration has been done before.\n";
			return;
		}
		$migrations = array_keys($migrations);

		$n = count($migrations);
		echo "Total $n " . ($n === 1 ? 'migration' : 'migrations') . " to be redone:\n";
		foreach ($migrations as $migration) {
			echo "    $migration\n";
		}
		echo "\n";

		if ($this->confirm('Redo the above ' . ($n === 1 ? 'migration' : 'migrations') . "?")) {
			foreach ($migrations as $migration) {
				if (!$this->migrateDown($migration)) {
					echo "\nMigration failed. The rest of the migrations are canceled.\n";
					return;
				}
			}
			foreach (array_reverse($migrations) as $migration) {
				if (!$this->migrateUp($migration)) {
					echo "\nMigration failed. The rest of the migrations migrations are canceled.\n";
					return;
				}
			}
			echo "\nMigration redone successfully.\n";
		}
	}

	/**
	 * Upgrades or downgrades till the specified version of migration.
	 *
	 * This command will first revert the specified migrations, and then apply
	 * them again. For example,
	 *
	 * ~~~
	 * yiic migrate/to 101129_185401                      # using timestamp
	 * yiic migrate/to m101129_185401_create_user_table   # using full name
	 * ~~~
	 *
	 * @param string $version the version name that the application should be migrated to.
	 * This can be either the timestamp or the full name of the migration.
	 * @throws Exception if the version argument is invalid
	 */
	public function actionTo($version)
	{
		$originalVersion = $version;
		if (preg_match('/^m?(\d{6}_\d{6})(_.*?)?$/', $version, $matches)) {
			$version = 'm' . $matches[1];
		} else {
			throw new Exception("The version argument must be either a timestamp (e.g. 101129_185401)\nor the full name of a migration (e.g. m101129_185401_create_user_table).");
		}

		// try migrate up
		$migrations = $this->getNewMigrations();
		foreach ($migrations as $i => $migration) {
			if (strpos($migration, $version . '_') === 0) {
				$this->actionUp($i + 1);
				return;
			}
		}

		// try migrate down
		$migrations = array_keys($this->getMigrationHistory(-1));
		foreach ($migrations as $i => $migration) {
			if (strpos($migration, $version . '_') === 0) {
				if ($i === 0) {
					echo "Already at '$originalVersion'. Nothing needs to be done.\n";
				} else {
					$this->actionDown($i);
				}
				return;
			}
		}

		throw new Exception("Unable to find the version '$originalVersion'.");
	}

	/**
	 * Modifies the migration history to the specified version.
	 *
	 * No actual migration will be performed.
	 *
	 * ~~~
	 * yiic migrate/mark 101129_185401                      # using timestamp
	 * yiic migrate/mark m101129_185401_create_user_table   # using full name
	 * ~~~
	 *
	 * @param string $version the version at which the migration history should be marked.
	 * This can be either the timestamp or the full name of the migration.
	 * @throws Exception if the version argument is invalid or the version cannot be found.
	 */
	public function actionMark($version)
	{
		$originalVersion = $version;
		if (preg_match('/^m?(\d{6}_\d{6})(_.*?)?$/', $version, $matches)) {
			$version = 'm' . $matches[1];
		} else {
			throw new Exception("The version argument must be either a timestamp (e.g. 101129_185401)\nor the full name of a migration (e.g. m101129_185401_create_user_table).");
		}

		// try mark up
		$migrations = $this->getNewMigrations();
		foreach ($migrations as $i => $migration) {
			if (strpos($migration, $version . '_') === 0) {
				if ($this->confirm("Set migration history at $originalVersion?")) {
					$command = $this->db->createCommand();
					for ($j = 0; $j <= $i; ++$j) {
						$command->insert($this->migrationTable, array(
							'version' => $migrations[$j],
							'apply_time' => time(),
						))->execute();
					}
					echo "The migration history is set at $originalVersion.\nNo actual migration was performed.\n";
				}
				return;
			}
		}

		// try mark down
		$migrations = array_keys($this->getMigrationHistory(-1));
		foreach ($migrations as $i => $migration) {
			if (strpos($migration, $version . '_') === 0) {
				if ($i === 0) {
					echo "Already at '$originalVersion'. Nothing needs to be done.\n";
				} else {
					if ($this->confirm("Set migration history at $originalVersion?")) {
						$command = $this->db->createCommand();
						for ($j = 0; $j < $i; ++$j) {
							$command->delete($this->migrationTable, array(
								'version' => $migrations[$j],
							))->execute();
						}
						echo "The migration history is set at $originalVersion.\nNo actual migration was performed.\n";
					}
				}
				return;
			}
		}

		throw new Exception("Unable to find the version '$originalVersion'.");
	}

	/**
	 * Displays the migration history.
	 *
	 * This command will show the list of migrations that have been applied
	 * so far. For example,
	 *
	 * ~~~
	 * yiic migrate/history     # showing the last 10 migrations
	 * yiic migrate/history 5   # showing the last 5 migrations
	 * yiic migrate/history 0   # showing the whole history
	 * ~~~
	 *
	 * @param integer $limit the maximum number of migrations to be displayed.
	 * If it is 0, the whole migration history will be displayed.
	 */
	public function actionHistory($limit = 10)
	{
		$limit = (int)$limit;
		$migrations = $this->getMigrationHistory($limit);
		if ($migrations === array()) {
			echo "No migration has been done before.\n";
		} else {
			$n = count($migrations);
			if ($limit > 0) {
				echo "Showing the last $n applied " . ($n === 1 ? 'migration' : 'migrations') . ":\n";
			} else {
				echo "Total $n " . ($n === 1 ? 'migration has' : 'migrations have') . " been applied before:\n";
			}
			foreach ($migrations as $version => $time) {
				echo "    (" . date('Y-m-d H:i:s', $time) . ') ' . $version . "\n";
			}
		}
	}

	/**
	 * Displays the un-applied new migrations.
	 *
	 * This command will show the new migrations that have not been applied.
	 * For example,
	 *
	 * ~~~
	 * yiic migrate/new     # showing the first 10 new migrations
	 * yiic migrate/new 5   # showing the first 5 new migrations
	 * yiic migrate/new 0   # showing all new migrations
	 * ~~~
	 *
	 * @param integer $limit the maximum number of new migrations to be displayed.
	 * If it is 0, all available new migrations will be displayed.
	 */
	public function actionNew($limit = 10)
	{
		$limit = (int)$limit;
		$migrations = $this->getNewMigrations();
		if ($migrations === array()) {
			echo "No new migrations found. Your system is up-to-date.\n";
		} else {
			$n = count($migrations);
			if ($limit > 0 && $n > $limit) {
				$migrations = array_slice($migrations, 0, $limit);
				echo "Showing $limit out of $n new " . ($n === 1 ? 'migration' : 'migrations') . ":\n";
			} else {
				echo "Found $n new " . ($n === 1 ? 'migration' : 'migrations') . ":\n";
			}

			foreach ($migrations as $migration) {
				echo "    " . $migration . "\n";
			}
		}
	}

	/**
	 * Creates a new migration.
	 *
	 * This command creates a new migration using the available migration template.
	 * After using this command, developers should modify the created migration
	 * skeleton by filling up the actual migration logic.
	 *
	 * ~~~
	 * yiic migrate/create create_user_table
	 * ~~~
	 *
	 * @param string $name the name of the new migration. This should only contain
	 * letters, digits and/or underscores.
	 * @throws Exception if the name argument is invalid.
	 */
	public function actionCreate($name)
	{
		if (!preg_match('/^\w+$/', $name)) {
			throw new Exception("The migration name should contain letters, digits and/or underscore characters only.");
		}

		$name = 'm' . gmdate('ymd_His') . '_' . $name;
		$file = $this->migrationPath . DIRECTORY_SEPARATOR . $name . '.php';

		if ($this->confirm("Create new migration '$file'?")) {
			$content = $this->renderFile(Yii::getAlias($this->templateFile), array(
				'className' => $name,
			));
			file_put_contents($file, $content);
			echo "New migration created successfully.\n";
		}
	}

	/**
	 * Upgrades with the specified migration class.
	 * @param string $class the migration class name
	 * @return boolean whether the migration is successful
	 */
	protected function migrateUp($class)
	{
		if ($class === self::BASE_MIGRATION) {
			return true;
		}

		echo "*** applying $class\n";
		$start = microtime(true);
		$migration = $this->createMigration($class);
		if ($migration->up() !== false) {
			$this->db->createCommand()->insert($this->migrationTable, array(
				'version' => $class,
				'apply_time' => time(),
			))->execute();
			$time = microtime(true) - $start;
			echo "*** applied $class (time: " . sprintf("%.3f", $time) . "s)\n\n";
			return true;
		} else {
			$time = microtime(true) - $start;
			echo "*** failed to apply $class (time: " . sprintf("%.3f", $time) . "s)\n\n";
			return false;
		}
	}

	/**
	 * Downgrades with the specified migration class.
	 * @param string $class the migration class name
	 * @return boolean whether the migration is successful
	 */
	protected function migrateDown($class)
	{
		if ($class === self::BASE_MIGRATION) {
			return true;
		}

		echo "*** reverting $class\n";
		$start = microtime(true);
		$migration = $this->createMigration($class);
		if ($migration->down() !== false) {
			$this->db->createCommand()->delete($this->migrationTable, array(
				'version' => $class,
			))->execute();
			$time = microtime(true) - $start;
			echo "*** reverted $class (time: " . sprintf("%.3f", $time) . "s)\n\n";
			return true;
		} else {
			$time = microtime(true) - $start;
			echo "*** failed to revert $class (time: " . sprintf("%.3f", $time) . "s)\n\n";
			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(array(
			'db' => $this->db,
		));
	}


	/**
	 * @return Connection the database connection that is used to store the migration history.
	 * @throws Exception if the database connection ID is invalid.
	 */
	protected function getDb()
	{
		if ($this->db !== null) {
			return $this->db;
		} else {
			$this->db = Yii::$app->getComponent($this->connectionID);
			if ($this->db instanceof Connection) {
				return $this->db;
			} else {
				throw new Exception("Invalid DB connection: {$this->connectionID}.");
			}
		}
	}

	/**
	 * Returns the migration history.
	 * @param integer $limit the maximum number of records in the history to be returned
	 * @return array the migration history
	 */
	protected function getMigrationHistory($limit)
	{
		if ($this->db->schema->getTableSchema($this->migrationTable) === null) {
			$this->createMigrationHistoryTable();
		}
		$query = new Query;
		$rows = $query->select(array('version', 'apply_time'))
			->from($this->migrationTable)
			->orderBy('version DESC')
			->limit($limit)
			->createCommand()
			->queryAll();
		$history = ArrayHelper::map($rows, 'version', 'apply_time');
		unset($history[self::BASE_MIGRATION]);
		return $history;
	}

	/**
	 * Creates the migration history table.
	 */
	protected function createMigrationHistoryTable()
	{
		echo 'Creating migration history table "' . $this->migrationTable . '"...';
		$this->db->createCommand()->createTable($this->migrationTable, array(
			'version' => 'varchar(255) NOT NULL PRIMARY KEY',
			'apply_time' => 'integer',
		))->execute();
		$this->db->createCommand()->insert($this->migrationTable, array(
			'version' => self::BASE_MIGRATION,
			'apply_time' => time(),
		))->execute();
		echo "done.\n";
	}

	/**
	 * Returns the migrations that are not applied.
	 * @return array list of new migrations
	 */
	protected function getNewMigrations()
	{
		$applied = array();
		foreach ($this->getMigrationHistory(-1) as $version => $time) {
			$applied[substr($version, 1, 13)] = true;
		}

		$migrations = array();
		$handle = opendir($this->migrationPath);
		while (($file = readdir($handle)) !== false) {
			if ($file === '.' || $file === '..') {
				continue;
			}
			$path = $this->migrationPath . DIRECTORY_SEPARATOR . $file;
			if (preg_match('/^(m(\d{6}_\d{6})_.*?)\.php$/', $file, $matches) && is_file($path) && !isset($applied[$matches[2]])) {
				$migrations[] = $matches[1];
			}
		}
		closedir($handle);
		sort($migrations);
		return $migrations;
	}
}