<?php
/**
* CodeIgniter
*
* An open source application development framework for PHP
*
* This content is released under the MIT License (MIT)
*
* Copyright (c) 2014 - 2015, 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. (http://ellislab.com/)
* @copyright Copyright (c) 2014 - 2015, British Columbia Institute of Technology (http://bcit.ca/)
* @license http://opensource.org/licenses/MIT MIT License
* @link http://codeigniter.com
* @since Version 1.0.0
* @filesource
*/
defined('BASEPATH') OR exit('No direct script access allowed');

/**
* MySQL Forge Class
*
* @category Database
* @author EllisLab Dev Team
* @link http://codeigniter.com/user_guide/database/
*/
class CI_DB_mysql_forge extends CI_DB_forge {

/**
* CREATE DATABASE statement
*
* @var string
*/
protected $_create_database = 'CREATE DATABASE %s CHARACTER SET %s COLLATE %s';

/**
* CREATE TABLE keys flag
*
* Whether table keys are created from within the
* CREATE TABLE statement.
*
* @var bool
*/
protected $_create_table_keys = TRUE;

/**
* UNSIGNED support
*
* @var array
*/
protected $_unsigned = array(
'TINYINT',
'SMALLINT',
'MEDIUMINT',
'INT',
'INTEGER',
'BIGINT',
'REAL',
'DOUBLE',
'DOUBLE PRECISION',
'FLOAT',
'DECIMAL',
'NUMERIC'
);

/**
* NULL value representation in CREATE/ALTER TABLE statements
*
* @var string
*/
protected $_null = 'NULL';

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

/**
* CREATE TABLE attributes
*
* @param array $attributes Associative array of table attributes
* @return string
*/
protected function _create_table_attr($attributes)
{
$sql = '';

foreach (array_keys($attributes) as $key)
{
if (is_string($key))
{
$sql .= ' '.strtoupper($key).' = '.$attributes[$key];
}
}

if ( ! empty($this->db->char_set) && ! strpos($sql, 'CHARACTER SET') && ! strpos($sql, 'CHARSET'))
{
$sql .= ' DEFAULT CHARACTER SET = '.$this->db->char_set;
}

if ( ! empty($this->db->dbcollat) && ! strpos($sql, 'COLLATE'))
{
$sql .= ' COLLATE = '.$this->db->dbcollat;
}

return $sql;
}

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

/**
* ALTER TABLE
*
* @param string $alter_type ALTER type
* @param string $table Table name
* @param mixed $field Column definition
* @return string|string[]
*/
protected function _alter_table($alter_type, $table, $field)
{
if ($alter_type === 'DROP')
{
return parent::_alter_table($alter_type, $table, $field);
}

$sql = 'ALTER TABLE '.$this->db->escape_identifiers($table);
for ($i = 0, $c = count($field); $i < $c; $i++)
{
if ($field[$i]['_literal'] !== FALSE)
{
$field[$i] = ($alter_type === 'ADD')
? "\n\tADD ".$field[$i]['_literal']
: "\n\tMODIFY ".$field[$i]['_literal'];
}
else
{
if ($alter_type === 'ADD')
{
$field[$i]['_literal'] = "\n\tADD ";
}
else
{
$field[$i]['_literal'] = empty($field[$i]['new_name']) ? "\n\tMODIFY " : "\n\tCHANGE ";
}

$field[$i] = $field[$i]['_literal'].$this->_process_column($field[$i]);
}
}

return array($sql.implode(',', $field));
}

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

/**
* Process column
*
* @param array $field
* @return string
*/
protected function _process_column($field)
{
$extra_clause = isset($field['after'])
? ' AFTER '.$this->db->escape_identifiers($field['after']) : '';

if (empty($extra_clause) && isset($field['first']) && $field['first'] === TRUE)
{
$extra_clause = ' FIRST';
}


return $this->db->escape_identifiers($field['name'])
.(empty($field['new_name']) ? '' : ' '.$this->db->escape_identifiers($field['new_name']))
.' '.$field['type'].$field['length']
.$field['unsigned']
.$field['null']
.$field['default']
.$field['auto_increment']
.$field['unique']
.(empty($field['comment']) ? '' : ' COMMENT '.$field['comment'])
.$extra_clause;
}

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

/**
* Process indexes
*
* @param string $table (ignored)
* @return string
*/
protected function _process_indexes($table)
{
$sql = '';

for ($i = 0, $c = count($this->keys); $i < $c; $i++)
{
if (is_array($this->keys[$i]))
{
for ($i2 = 0, $c2 = count($this->keys[$i]); $i2 < $c2; $i2++)
{
if ( ! isset($this->fields[$this->keys[$i][$i2]]))
{
unset($this->keys[$i][$i2]);
continue;
}
}
}
elseif ( ! isset($this->fields[$this->keys[$i]]))
{
unset($this->keys[$i]);
continue;
}

is_array($this->keys[$i]) OR $this->keys[$i] = array($this->keys[$i]);

$sql .= ",\n\tKEY ".$this->db->escape_identifiers(implode('_', $this->keys[$i]))
.' ('.implode(', ', $this->db->escape_identifiers($this->keys[$i])).')';
}

$this->keys = array();

return $sql;
}

}