<?php


/**


 * CodeIgniter


 *


 * An open source application development framework for PHP


 *


 * This content is released under the MIT License (MIT)


 *


 * Copyright (c) 2014 - 2019, British Columbia Institute of Technology


 *


 * Permission is hereby granted, free of charge, to any person obtaining a copy


 * of this software and associated documentation files (the "Software"), to deal


 * in the Software without restriction, including without limitation the rights


 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell


 * copies of the Software, and to permit persons to whom the Software is


 * furnished to do so, subject to the following conditions:


 *


 * The above copyright notice and this permission notice shall be included in


 * all copies or substantial portions of the Software.


 *


 * 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.


 *


 * @package	CodeIgniter


 * @author	EllisLab Dev Team


 * @copyright	Copyright (c) 2008 - 2014, EllisLab, Inc. (https://ellislab.com/)


 * @copyright	Copyright (c) 2014 - 2019, British Columbia Institute of Technology (https://bcit.ca/)


 * @license	https://opensource.org/licenses/MIT	MIT License


 * @link	https://codeigniter.com


 * @since	Version 3.0.0


 * @filesource


 */


defined('BASEPATH') OR exit('No direct script access allowed');





/**


 * Migration Class


 *


 * All migrations should implement this, forces up() and down() and gives


 * access to the CI super-global.


 *


 * @package		CodeIgniter


 * @subpackage	Libraries


 * @category	Libraries


 * @author		Reactor Engineers


 * @link


 */


class CI_Migration {





	/**


	 * Whether the library is enabled


	 *


	 * @var bool


	 */


	protected $_migration_enabled = FALSE;





	/**


	 * Migration numbering type


	 *


	 * @var	bool


	 */


	protected $_migration_type = 'sequential';





	/**


	 * Path to migration classes


	 *


	 * @var string


	 */


	protected $_migration_path = NULL;





	/**


	 * Current migration version


	 *


	 * @var mixed


	 */


	protected $_migration_version = 0;





	/**


	 * Database table with migration info


	 *


	 * @var string


	 */


	protected $_migration_table = 'migrations';





	/**


	 * Whether to automatically run migrations


	 *


	 * @var	bool


	 */


	protected $_migration_auto_latest = FALSE;





	/**


	 * Migration basename regex


	 *


	 * @var string


	 */


	protected $_migration_regex;





	/**


	 * Error message


	 *


	 * @var string


	 */


	protected $_error_string = '';





	/**


	 * Initialize Migration Class


	 *


	 * @param	array	$config


	 * @return	void


	 */


	public function __construct($config = array())


	{


		// Only run this constructor on main library load


		if ( ! in_array(get_class($this), array('CI_Migration', config_item('subclass_prefix').'Migration'), TRUE))


		{


			return;


		}





		foreach ($config as $key => $val)


		{


			$this->{'_'.$key} = $val;


		}





		log_message('info', 'Migrations Class Initialized');





		// Are they trying to use migrations while it is disabled?


		if ($this->_migration_enabled !== TRUE)


		{


			show_error('Migrations has been loaded but is disabled or set up incorrectly.');


		}





		// If not set, set it


		$this->_migration_path !== '' OR $this->_migration_path = APPPATH.'migrations/';





		// Add trailing slash if not set


		$this->_migration_path = rtrim($this->_migration_path, '/').'/';





		// Load migration language


		$this->lang->load('migration');





		// They'll probably be using dbforge


		$this->load->dbforge();





		// Make sure the migration table name was set.


		if (empty($this->_migration_table))


		{


			show_error('Migrations configuration file (migration.php) must have "migration_table" set.');


		}





		// Migration basename regex


		$this->_migration_regex = ($this->_migration_type === 'timestamp')


			? '/^\d{14}_(\w+)$/'


			: '/^\d{3}_(\w+)$/';





		// Make sure a valid migration numbering type was set.


		if ( ! in_array($this->_migration_type, array('sequential', 'timestamp')))


		{


			show_error('An invalid migration numbering type was specified: '.$this->_migration_type);


		}





		// If the migrations table is missing, make it


		if ( ! $this->db->table_exists($this->_migration_table))


		{


			$this->dbforge->add_field(array(


				'version' => array('type' => 'BIGINT', 'constraint' => 20),


			));





			$this->dbforge->create_table($this->_migration_table, TRUE);





			$this->db->insert($this->_migration_table, array('version' => 0));


		}





		// Do we auto migrate to the latest migration?


		if ($this->_migration_auto_latest === TRUE && ! $this->latest())


		{


			show_error($this->error_string());


		}


	}





	// --------------------------------------------------------------------





	/**


	 * Migrate to a schema version


	 *


	 * Calls each migration step required to get to the schema version of


	 * choice


	 *


	 * @param	string	$target_version	Target schema version


	 * @return	mixed	TRUE if no migrations are found, current version string on success, FALSE on failure


	 */


	public function version($target_version)


	{


		// Note: We use strings, so that timestamp versions work on 32-bit systems


		$current_version = $this->_get_version();





		if ($this->_migration_type === 'sequential')


		{


			$target_version = sprintf('%03d', $target_version);


		}


		else


		{


			$target_version = (string) $target_version;


		}





		$migrations = $this->find_migrations();





		if ($target_version > 0 && ! isset($migrations[$target_version]))


		{


			$this->_error_string = sprintf($this->lang->line('migration_not_found'), $target_version);


			return FALSE;


		}





		if ($target_version > $current_version)


		{


			$method = 'up';


		}


		elseif ($target_version < $current_version)


		{


			$method = 'down';


			// We need this so that migrations are applied in reverse order


			krsort($migrations);


		}


		else


		{


			// Well, there's nothing to migrate then ...


			return TRUE;


		}





		// Validate all available migrations within our target range.


		//


		// Unfortunately, we'll have to use another loop to run them


		// in order to avoid leaving the procedure in a broken state.


		//


		// See https://github.com/bcit-ci/CodeIgniter/issues/4539


		$pending = array();


		foreach ($migrations as $number => $file)


		{


			// Ignore versions out of our range.


			//


			// Because we've previously sorted the $migrations array depending on the direction,


			// we can safely break the loop once we reach $target_version ...


			if ($method === 'up')


			{


				if ($number <= $current_version)


				{


					continue;


				}


				elseif ($number > $target_version)


				{


					break;


				}


			}


			else


			{


				if ($number > $current_version)


				{


					continue;


				}


				elseif ($number <= $target_version)


				{


					break;


				}


			}





			// Check for sequence gaps


			if ($this->_migration_type === 'sequential')


			{


				if (isset($previous) && abs($number - $previous) > 1)


				{


					$this->_error_string = sprintf($this->lang->line('migration_sequence_gap'), $number);


					return FALSE;


				}





				$previous = $number;


			}





			include_once($file);


			$class = 'Migration_'.ucfirst(strtolower($this->_get_migration_name(basename($file, '.php'))));





			// Validate the migration file structure


			if ( ! class_exists($class, FALSE))


			{


				$this->_error_string = sprintf($this->lang->line('migration_class_doesnt_exist'), $class);


				return FALSE;


			}


			elseif ( ! is_callable(array($class, $method)))


			{


				$this->_error_string = sprintf($this->lang->line('migration_missing_'.$method.'_method'), $class);


				return FALSE;


			}





			$pending[$number] = array($class, $method);


		}





		// Now just run the necessary migrations


		foreach ($pending as $number => $migration)


		{


			log_message('debug', 'Migrating '.$method.' from version '.$current_version.' to version '.$number);





			$migration[0] = new $migration[0];


			call_user_func($migration);


			$current_version = $number;


			$this->_update_version($current_version);


		}





		// This is necessary when moving down, since the the last migration applied


		// will be the down() method for the next migration up from the target


		if ($current_version <> $target_version)


		{


			$current_version = $target_version;


			$this->_update_version($current_version);


		}





		log_message('debug', 'Finished migrating to '.$current_version);


		return $current_version;


	}





	// --------------------------------------------------------------------





	/**


	 * Sets the schema to the latest migration


	 *


	 * @return	mixed	Current version string on success, FALSE on failure


	 */


	public function latest()


	{


		$migrations = $this->find_migrations();





		if (empty($migrations))


		{


			$this->_error_string = $this->lang->line('migration_none_found');


			return FALSE;


		}





		$last_migration = basename(end($migrations));





		// Calculate the last migration step from existing migration


		// filenames and proceed to the standard version migration


		return $this->version($this->_get_migration_number($last_migration));


	}





	// --------------------------------------------------------------------





	/**


	 * Sets the schema to the migration version set in config


	 *


	 * @return	mixed	TRUE if no migrations are found, current version string on success, FALSE on failure


	 */


	public function current()


	{


		return $this->version($this->_migration_version);


	}





	// --------------------------------------------------------------------





	/**


	 * Error string


	 *


	 * @return	string	Error message returned as a string


	 */


	public function error_string()


	{


		return $this->_error_string;


	}





	// --------------------------------------------------------------------





	/**


	 * Retrieves list of available migration scripts


	 *


	 * @return	array	list of migration file paths sorted by version


	 */


	public function find_migrations()


	{


		$migrations = array();





		// Load all *_*.php files in the migrations path


		foreach (glob($this->_migration_path.'*_*.php') as $file)


		{


			$name = basename($file, '.php');





			// Filter out non-migration files


			if (preg_match($this->_migration_regex, $name))


			{


				$number = $this->_get_migration_number($name);





				// There cannot be duplicate migration numbers


				if (isset($migrations[$number]))


				{


					$this->_error_string = sprintf($this->lang->line('migration_multiple_version'), $number);


					show_error($this->_error_string);


				}





				$migrations[$number] = $file;


			}


		}





		ksort($migrations);


		return $migrations;


	}





	// --------------------------------------------------------------------





	/**


	 * Extracts the migration number from a filename


	 *


	 * @param	string	$migration


	 * @return	string	Numeric portion of a migration filename


	 */


	protected function _get_migration_number($migration)


	{


		return sscanf($migration, '%[0-9]+', $number)


			? $number : '0';


	}





	// --------------------------------------------------------------------





	/**


	 * Extracts the migration class name from a filename


	 *


	 * @param	string	$migration


	 * @return	string	text portion of a migration filename


	 */


	protected function _get_migration_name($migration)


	{


		$parts = explode('_', $migration);


		array_shift($parts);


		return implode('_', $parts);


	}





	// --------------------------------------------------------------------





	/**


	 * Retrieves current schema version


	 *


	 * @return	string	Current migration version


	 */


	protected function _get_version()


	{


		$row = $this->db->select('version')->get($this->_migration_table)->row();


		return $row ? $row->version : '0';


	}





	// --------------------------------------------------------------------





	/**


	 * Stores the current schema version


	 *


	 * @param	string	$migration	Migration reached


	 * @return	void


	 */


	protected function _update_version($migration)


	{


		$this->db->update($this->_migration_table, array(


			'version' => $migration


		));


	}





	// --------------------------------------------------------------------





	/**


	 * Enable the use of CI super-global


	 *


	 * @param	string	$var


	 * @return	mixed


	 */


	public function __get($var)


	{


		return get_instance()->$var;


	}





}


