<?php
/**
 * MySQL layer for DBO
 *
 * PHP 5
 *
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright 2005-2011, Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright 2005-2011, Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @package       Cake.Model.Datasource.Database
 * @since         CakePHP(tm) v 0.10.5.1790
 * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
 */

App::uses('DboSource', 'Model/Datasource');

/**
 * MySQL DBO driver object
 *
 * Provides connection and SQL generation for MySQL RDMS
 *
 * @package       Cake.Model.Datasource.Database
 */
class Mysql extends DboSource {

/**
 * Datasource description
 *
 * @var string
 */
	public $description = "MySQL DBO Driver";

/**
 * Base configuration settings for MySQL driver
 *
 * @var array
 */
	protected $_baseConfig = array(
		'persistent' => true,
		'host' => 'localhost',
		'login' => 'root',
		'password' => '',
		'database' => 'cake',
		'port' => '3306'
	);

/**
 * Reference to the PDO object connection
 *
 * @var PDO $_connection
 */
	protected $_connection = null;

/**
 * Start quote
 *
 * @var string
 */
	public $startQuote = "`";

/**
 * End quote
 *
 * @var string
 */
	public $endQuote = "`";

/**
 * use alias for update and delete. Set to true if version >= 4.1
 *
 * @var boolean
 * @access protected
 */
	protected $_useAlias = true;

/**
 * Index of basic SQL commands
 *
 * @var array
 * @access protected
 */
	protected $_commands = array(
		'begin'    => 'START TRANSACTION',
		'commit'   => 'COMMIT',
		'rollback' => 'ROLLBACK'
	);

/**
 * List of engine specific additional field parameters used on table creating
 *
 * @var array
 * @access public
 */
	public $fieldParameters = array(
		'charset' => array('value' => 'CHARACTER SET', 'quote' => false, 'join' => ' ', 'column' => false, 'position' => 'beforeDefault'),
		'collate' => array('value' => 'COLLATE', 'quote' => false, 'join' => ' ', 'column' => 'Collation', 'position' => 'beforeDefault'),
		'comment' => array('value' => 'COMMENT', 'quote' => true, 'join' => ' ', 'column' => 'Comment', 'position' => 'afterDefault')
	);

/**
 * List of table engine specific parameters used on table creating
 *
 * @var array
 * @access public
 */
	public $tableParameters = array(
		'charset' => array('value' => 'DEFAULT CHARSET', 'quote' => false, 'join' => '=', 'column' => 'charset'),
		'collate' => array('value' => 'COLLATE', 'quote' => false, 'join' => '=', 'column' => 'Collation'),
		'engine' => array('value' => 'ENGINE', 'quote' => false, 'join' => '=', 'column' => 'Engine')
	);

/**
 * MySQL column definition
 *
 * @var array
 */
	public $columns = array(
		'primary_key' => array('name' => 'NOT NULL AUTO_INCREMENT'),
		'string' => array('name' => 'varchar', 'limit' => '255'),
		'text' => array('name' => 'text'),
		'integer' => array('name' => 'int', 'limit' => '11', 'formatter' => 'intval'),
		'float' => array('name' => 'float', 'formatter' => 'floatval'),
		'datetime' => array('name' => 'datetime', 'format' => 'Y-m-d H:i:s', 'formatter' => 'date'),
		'timestamp' => array('name' => 'timestamp', 'format' => 'Y-m-d H:i:s', 'formatter' => 'date'),
		'time' => array('name' => 'time', 'format' => 'H:i:s', 'formatter' => 'date'),
		'date' => array('name' => 'date', 'format' => 'Y-m-d', 'formatter' => 'date'),
		'binary' => array('name' => 'blob'),
		'boolean' => array('name' => 'tinyint', 'limit' => '1')
	);

/**
 * Connects to the database using options in the given configuration array.
 *
 * @return boolean True if the database could be connected, else false
 */
	public function connect() {
		$config = $this->config;
		$this->connected = false;
		try {
			$flags = array(
				PDO::ATTR_PERSISTENT => $config['persistent'],
				PDO::MYSQL_ATTR_USE_BUFFERED_QUERY => true
			);
			if (!empty($config['encoding'])) {
				$flags[PDO::MYSQL_ATTR_INIT_COMMAND] = 'SET NAMES ' . $config['encoding'];
			}
			$this->_connection = new PDO(
				"mysql:host={$config['host']};port={$config['port']};dbname={$config['database']}",
				$config['login'],
				$config['password'],
				$flags
			);
			$this->connected = true;
		} catch (PDOException $e) {
			throw new MissingConnectionException(array('class' => $e->getMessage()));
		}

		$this->_useAlias = (bool)version_compare($this->getVersion(), "4.1", ">=");

		return $this->connected;
	}

/**
 * Check whether the MySQL extension is installed/loaded
 *
 * @return boolean
 */
	public function enabled() {
		return in_array('mysql', PDO::getAvailableDrivers());
	}

/**
 * Returns an array of sources (tables) in the database.
 *
 * @return array Array of tablenames in the database
 */
	public function listSources($data = null) {
		$cache = parent::listSources();
		if ($cache != null) {
			return $cache;
		}
		$result = $this->_execute('SHOW TABLES FROM ' . $this->name($this->config['database']));

		if (!$result) {
			$result->closeCursor();
			return array();
		} else {
			$tables = array();

			while ($line = $result->fetch()) {
				$tables[] = $line[0];
			}

			$result->closeCursor();
			parent::listSources($tables);
			return $tables;
		}
	}

/**
 * Builds a map of the columns contained in a result
 *
 * @param PDOStatement $results
 */
	public function resultSet($results) {
		$this->map = array();
		$numFields = $results->columnCount();
		$index = 0;

		while ($numFields-- > 0) {
			$column = $results->getColumnMeta($index);
			if (empty($column['native_type'])) {
				$type = ($column['len'] == 1) ? 'boolean' : 'string';
			} else {
				$type = $column['native_type'];
			}
			if (!empty($column['table']) && strpos($column['name'], $this->virtualFieldSeparator) === false) {
				$this->map[$index++] = array($column['table'], $column['name'], $type);
			} else {
				$this->map[$index++] = array(0, $column['name'], $type);
			}
		}
	}

/**
 * Fetches the next row from the current result set
 *
 * @return mixed array with results fetched and mapped to column names or false if there is no results left to fetch
 */
	public function fetchResult() {
		if ($row = $this->_result->fetch()) {
			$resultRow = array();
			foreach ($this->map as $col => $meta) {
				list($table, $column, $type) = $meta;
				$resultRow[$table][$column] = $row[$col];
				if ($type === 'boolean' && $row[$col] !== null) {
					$resultRow[$table][$column] = $this->boolean($resultRow[$table][$column]);
				}
			}
			return $resultRow;
		}
		$this->_result->closeCursor();
		return false;
	}

/**
 * Gets the database encoding
 *
 * @return string The database encoding
 */
	public function getEncoding() {
		return $this->_execute('SHOW VARIABLES LIKE ?', array('character_set_client'))->fetchObject()->Value;
	}

/**
 * Gets the version string of the database server
 *
 * @return string The database encoding
 */
	public function getVersion() {
		return $this->_connection->getAttribute(PDO::ATTR_SERVER_VERSION);
	}

/**
 * Query charset by collation
 *
 * @param string $name Collation name
 * @return string Character set name
 */
	public function getCharsetName($name) {
		if ((bool)version_compare($this->getVersion(), "5", ">=")) {
			$r = $this->_execute('SELECT CHARACTER_SET_NAME FROM INFORMATION_SCHEMA.COLLATIONS WHERE COLLATION_NAME = ?', array($name));
			$cols = $r->fetch();

			if (isset($cols['CHARACTER_SET_NAME'])) {
				return $cols['CHARACTER_SET_NAME'];
			}
		}
		return false;
	}

/**
 * Returns an array of the fields in given table name.
 *
 * @param mixed $tableName Name of database table to inspect or model instance
 * @return array Fields in table. Keys are name and type
 */
	public function describe($model) {
		$cache = parent::describe($model);
		if ($cache != null) {
			return $cache;
		}
		$fields = false;
		$cols = $this->_execute('SHOW FULL COLUMNS FROM ' . $this->fullTableName($model));
		if (!$cols) {
			throw new CakeException(__d('cake_dev', 'Could not describe table for %s', $model->name));
		}

		foreach ($cols as $column) {
			$fields[$column->Field] = array(
				'type' => $this->column($column->Type),
				'null' => ($column->Null === 'YES' ? true : false),
				'default' => $column->Default,
				'length' => $this->length($column->Type),
			);
			if (!empty($column->Key) && isset($this->index[$column->Key])) {
				$fields[$column->Field]['key'] = $this->index[$column->Key];
			}
			foreach ($this->fieldParameters as $name => $value) {
				if (!empty($column->{$value['column']})) {
					$fields[$column->Field][$name] = $column->{$value['column']};
				}
			}
			if (isset($fields[$column->Field]['collate'])) {
				$charset = $this->getCharsetName($fields[$column->Field]['collate']);
				if ($charset) {
					$fields[$column->Field]['charset'] = $charset;
				}
			}
		}
		$this->__cacheDescription($this->fullTableName($model, false), $fields);
		$cols->closeCursor();
		return $fields;
	}

/**
 * Generates and executes an SQL UPDATE statement for given model, fields, and values.
 *
 * @param Model $model
 * @param array $fields
 * @param array $values
 * @param mixed $conditions
 * @return array
 */
	public function update($model, $fields = array(), $values = null, $conditions = null) {
		if (!$this->_useAlias) {
			return parent::update($model, $fields, $values, $conditions);
		}

		if ($values == null) {
			$combined = $fields;
		} else {
			$combined = array_combine($fields, $values);
		}

		$alias = $joins = false;
		$fields = $this->_prepareUpdateFields($model, $combined, empty($conditions), !empty($conditions));
		$fields = implode(', ', $fields);
		$table = $this->fullTableName($model);

		if (!empty($conditions)) {
			$alias = $this->name($model->alias);
			if ($model->name == $model->alias) {
				$joins = implode(' ', $this->_getJoins($model));
			}
		}
		$conditions = $this->conditions($this->defaultConditions($model, $conditions, $alias), true, true, $model);

		if ($conditions === false) {
			return false;
		}

		if (!$this->execute($this->renderStatement('update', compact('table', 'alias', 'joins', 'fields', 'conditions')))) {
			$model->onError();
			return false;
		}
		return true;
	}

/**
 * Generates and executes an SQL DELETE statement for given id/conditions on given model.
 *
 * @param Model $model
 * @param mixed $conditions
 * @return boolean Success
 */
	public function delete($model, $conditions = null) {
		if (!$this->_useAlias) {
			return parent::delete($model, $conditions);
		}
		$alias = $this->name($model->alias);
		$table = $this->fullTableName($model);
		$joins = implode(' ', $this->_getJoins($model));

		if (empty($conditions)) {
			$alias = $joins = false;
		}
		$complexConditions = false;
		foreach ((array)$conditions as $key => $value) {
			if (strpos($key, $model->alias) === false) {
				$complexConditions = true;
				break;
			}
		}
		if (!$complexConditions) {
			$joins = false;
		}

		$conditions = $this->conditions($this->defaultConditions($model, $conditions, $alias), true, true, $model);
		if ($conditions === false) {
			return false;
		}
		if ($this->execute($this->renderStatement('delete', compact('alias', 'table', 'joins', 'conditions'))) === false) {
			$model->onError();
			return false;
		}
		return true;
	}

/**
 * Sets the database encoding
 *
 * @param string $enc Database encoding
 */
	public function setEncoding($enc) {
		return $this->_execute('SET NAMES ' . $enc) !== false;
	}

/**
 * Returns an array of the indexes in given datasource name.
 *
 * @param string $model Name of model to inspect
 * @return array Fields in table. Keys are column and unique
 */
	public function index($model) {
		$index = array();
		$table = $this->fullTableName($model);
		$old = version_compare($this->getVersion(), '4.1', '<=');
		if ($table) {
			$indices = $this->_execute('SHOW INDEX FROM ' . $table);
			while ($idx = $indices->fetch()) {
				if ($old) {
					$idx = (object) current((array)$idx);
				}
				if (!isset($index[$idx->Key_name]['column'])) {
					$col = array();
					$index[$idx->Key_name]['column'] = $idx->Column_name;
					$index[$idx->Key_name]['unique'] = intval($idx->Non_unique == 0);
				} else {
					if (!empty($index[$idx->Key_name]['column']) && !is_array($index[$idx->Key_name]['column'])) {
						$col[] = $index[$idx->Key_name]['column'];
					}
					$col[] = $idx->Column_name;
					$index[$idx->Key_name]['column'] = $col;
				}
			}
			$indices->closeCursor();
		}
		return $index;
	}

/**
 * Generate a MySQL Alter Table syntax for the given Schema comparison
 *
 * @param array $compare Result of a CakeSchema::compare()
 * @return array Array of alter statements to make.
 */
	public function alterSchema($compare, $table = null) {
		if (!is_array($compare)) {
			return false;
		}
		$out = '';
		$colList = array();
		foreach ($compare as $curTable => $types) {
			$indexes = $tableParameters = $colList = array();
			if (!$table || $table == $curTable) {
				$out .= 'ALTER TABLE ' . $this->fullTableName($curTable) . " \n";
				foreach ($types as $type => $column) {
					if (isset($column['indexes'])) {
						$indexes[$type] = $column['indexes'];
						unset($column['indexes']);
					}
					if (isset($column['tableParameters'])) {
						$tableParameters[$type] = $column['tableParameters'];
						unset($column['tableParameters']);
					}
					switch ($type) {
						case 'add':
							foreach ($column as $field => $col) {
								$col['name'] = $field;
								$alter = 'ADD ' . $this->buildColumn($col);
								if (isset($col['after'])) {
									$alter .= ' AFTER ' . $this->name($col['after']);
								}
								$colList[] = $alter;
							}
						break;
						case 'drop':
							foreach ($column as $field => $col) {
								$col['name'] = $field;
								$colList[] = 'DROP ' . $this->name($field);
							}
						break;
						case 'change':
							foreach ($column as $field => $col) {
								if (!isset($col['name'])) {
									$col['name'] = $field;
								}
								$colList[] = 'CHANGE ' . $this->name($field) . ' ' . $this->buildColumn($col);
							}
						break;
					}
				}
				$colList = array_merge($colList, $this->_alterIndexes($curTable, $indexes));
				$colList = array_merge($colList, $this->_alterTableParameters($curTable, $tableParameters));
				$out .= "\t" . implode(",\n\t", $colList) . ";\n\n";
			}
		}
		return $out;
	}

/**
 * Generate a MySQL "drop table" statement for the given Schema object
 *
 * @param CakeSchema $schema An instance of a subclass of CakeSchema
 * @param string $table Optional.  If specified only the table name given will be generated.
 *                      Otherwise, all tables defined in the schema are generated.
 * @return string
 */
	public function dropSchema(CakeSchema $schema, $table = null) {
		$out = '';
		foreach ($schema->tables as $curTable => $columns) {
			if (!$table || $table === $curTable) {
				$out .= 'DROP TABLE IF EXISTS ' . $this->fullTableName($curTable) . ";\n";
			}
		}
		return $out;
	}

/**
 * Generate MySQL table parameter alteration statementes for a table.
 *
 * @param string $table Table to alter parameters for.
 * @param array $parameters Parameters to add & drop.
 * @return array Array of table property alteration statementes.
 * @todo Implement this method.
 */
	protected function _alterTableParameters($table, $parameters) {
		if (isset($parameters['change'])) {
			return $this->buildTableParameters($parameters['change']);
		}
		return array();
	}

/**
 * Generate MySQL index alteration statements for a table.
 *
 * @param string $table Table to alter indexes for
 * @param array $new Indexes to add and drop
 * @return array Index alteration statements
 */
	protected function _alterIndexes($table, $indexes) {
		$alter = array();
		if (isset($indexes['drop'])) {
			foreach($indexes['drop'] as $name => $value) {
				$out = 'DROP ';
				if ($name == 'PRIMARY') {
					$out .= 'PRIMARY KEY';
				} else {
					$out .= 'KEY ' . $name;
				}
				$alter[] = $out;
			}
		}
		if (isset($indexes['add'])) {
			foreach ($indexes['add'] as $name => $value) {
				$out = 'ADD ';
				if ($name == 'PRIMARY') {
					$out .= 'PRIMARY ';
					$name = null;
				} else {
					if (!empty($value['unique'])) {
						$out .= 'UNIQUE ';
					}
				}
				if (is_array($value['column'])) {
					$out .= 'KEY '. $name .' (' . implode(', ', array_map(array(&$this, 'name'), $value['column'])) . ')';
				} else {
					$out .= 'KEY '. $name .' (' . $this->name($value['column']) . ')';
				}
				$alter[] = $out;
			}
		}
		return $alter;
	}

/**
 * Returns an detailed array of sources (tables) in the database.
 *
 * @param string $name Table name to get parameters
 * @return array Array of tablenames in the database
 */
	public function listDetailedSources($name = null) {
		$condition = '';
		$params = array();
		if (is_string($name)) {
			$condition = ' WHERE name = ?' ;
			$params = array($name);
		}
		$result = $this->_execute('SHOW TABLE STATUS ' . $condition, $params);

		if (!$result) {
			$result->closeCursor();
			return array();
		} else {
			$tables = array();
			while ($row = $result->fetch()) {
				$tables[$row->Name] = (array) $row;
				unset($tables[$row->Name]['queryString']);
				if (!empty($row->Collation)) {
					$charset = $this->getCharsetName($row->Collation);
					if ($charset) {
						$tables[$row->Name]['charset'] = $charset;
					}
				}
			}
			$result->closeCursor();
			if (is_string($name) && isset($tables[$name])) {
				return $tables[$name];
			}
			return $tables;
		}
	}

/**
 * Converts database-layer column types to basic types
 *
 * @param string $real Real database-layer column type (i.e. "varchar(255)")
 * @return string Abstract column type (i.e. "string")
 */
	public function column($real) {
		if (is_array($real)) {
			$col = $real['name'];
			if (isset($real['limit'])) {
				$col .= '(' . $real['limit'] . ')';
			}
			return $col;
		}

		$col = str_replace(')', '', $real);
		$limit = $this->length($real);
		if (strpos($col, '(') !== false) {
			list($col, $vals) = explode('(', $col);
		}

		if (in_array($col, array('date', 'time', 'datetime', 'timestamp'))) {
			return $col;
		}
		if (($col === 'tinyint' && $limit == 1) || $col === 'boolean') {
			return 'boolean';
		}
		if (strpos($col, 'int') !== false) {
			return 'integer';
		}
		if (strpos($col, 'char') !== false || $col === 'tinytext') {
			return 'string';
		}
		if (strpos($col, 'text') !== false) {
			return 'text';
		}
		if (strpos($col, 'blob') !== false || $col === 'binary') {
			return 'binary';
		}
		if (strpos($col, 'float') !== false || strpos($col, 'double') !== false || strpos($col, 'decimal') !== false) {
			return 'float';
		}
		if (strpos($col, 'enum') !== false) {
			return "enum($vals)";
		}
		return 'text';
	}
}