<?php
/*=====================================================================*\
|| ###################################################################
|| # Blue Static ISSO Framework
|| # Copyright (c)2002-2007 Blue Static
|| #
|| # This program is free software; you can redistribute it and/or modify
|| # it under the terms of the GNU General Public License as published by
|| # the Free Software Foundation; version 2 of the License.
|| #
|| # This program is distributed in the hope that it will be useful, but
|| # WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
|| # or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
|| # more details.
|| #
|| # You should have received a copy of the GNU General Public License along
|| # with this program; if not, write to the Free Software Foundation, Inc.,
|| # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA
|| ###################################################################
\*=====================================================================*/

/**
* Abstract Datamanger API (api.php)
*
* @package	ISSO
*/

if (!defined('REQ_AUTO'))
{	
	/**
	* Yes, required
	*/
	define('REQ_YES', 1);
	
	/**
	* No, not required
	*/
	define('REQ_NO', 0);

	/**
	* Auto-increasing value
	*/
	define('REQ_AUTO', -1);
	
	/**
	* Set by a cusotm set_*() function
	*/
	define('REQ_SET', 2);
	
	/**
	* Index for cleaning type
	*/
	define('F_TYPE', 0);
	
	/**
	* Index for requirement type
	*/
	define('F_REQ', 1);
	
	/**
	* Index for verification type
	*/
	define('F_VERIFY', 2);
}

/**
* Abstract API
*
* Abstract class that is used as an API base for most common database interaction
* schemes. Creates a simple structure that holds data and can update, remove, and
* insert.
*
* @author		Blue Static
* @copyright	Copyright (c)2002 - 2007, Blue Static
* @package		ISSO
* 
*/
abstract class BSApi
{
	/**
	 * The callback function for the error handler
	 * @var string
	 */
	public static $errorHandler;
	
	/**
	* Fields: used for verification and sanitization
	* NAME => array(TYPE, REQUIRED, VERIFY METHOD (:self for self-named method), RELATION => array(FILE, CLASS IN FILE, ALTERNATE FIELD NAME))
	* @var	array
	*/
	protected $fields = array();
	
	/**
	* Values array: sanitized and verified field values
	* @var	array
	*/
	public $values = array();
	
	/**
	* Fields that were manually set with set(), not by using setExisting()
	* @var	array
	*/
	private $setfields = array();
	
	/**
	* WHERE condition
	* @var	string
	*/
	private $condition = '';
	
	/**
	* The object table row; a fetched row that represents this instance
	* @var	array
	*/
	public $objdata = array();
	
	/**
	* Insert ID from the insert() command
	* @var	integer
	*/
	public $insertid = 0;
	
	/**
	* Error queue that builds up errors
	* @var	array
	*/
	private $errors = array();
	
	// ###################################################################
	/**
	* Constructor: cannot instantiate class directly
	*/
	public function __construct()
	{
		BSApp::RequiredModules(array('Db', 'Input'));
	}
	
	// ###################################################################
	/**
	* Adds an error into the error queue that is then hit 
	*
	* @param	string	Error message
	*/
	protected function _error($message)
	{
		$this->errors[] = $message;
	}
	
	// ###################################################################
	/**
	* This runs through all the errors in the error queue and processes
	* them all at once. Error builders then get a list of all the errors,
	* and die-by-hit callbacks stop at the first one
	*
	* @param	string	A string param
	*
	* @return	integer	Return value
	*/
	private function _processErrorQueue()
	{
		// we want to explicitly specify silence
		if (self::$errorHandler == 'silent')
		{
			return;
		}
		
		if (!is_callable(self::$errorHandler))
		{
			throw new Exception('No BSApi::$errorHandler handler has been set');
		}
		
		foreach ($this->errors AS $e)
		{
			call_user_func(BSApi::$errorHandler, $e);
		}
	}
	
	// ###################################################################
	/**
	* Returns the error list. This is because we don't want people mucking
	* with the error system. It will return an empty array if there are
	* no errors.
	*
	* @return	array	Array of errors
	*/
	public function checkErrors()
	{
		if (sizeof($this->errors) < 1)
		{
			return array();
		}
		
		return $this->errors;
	}
	
	// ###################################################################
	/**
	* Sets a value, sanitizes it, and verifies it
	*
	* @param	string	Field name
	* @param	mixed	Value
	* @param	bool	Do clean?
	* @param	bool	Do verify?
	*/
	public function set($field, $value, $doclean = true, $doverify = true)
	{
		if (!isset($this->fields["$field"]))
		{
			throw new Exception('Field "' . $field . '" is not valid');
			return;
		}
		
		$this->values["$field"] = ($doclean ? BSApp::GetType('Input')->clean($value, $this->fields["$field"][F_TYPE]) : $value);
		
		$this->setfields["$field"] = $field;
		
		if (isset($this->fields["$field"][F_VERIFY]) AND $doverify)
		{
			if ($this->fields["$field"][F_VERIFY] == ':self')
			{
				$verify = $this->{"verify_$field"}($field);
			}
			else
			{
				$verify = $this->{$this->fields["$field"][F_VERIFY]}($field);
			}
			
			if ($verify !== true)
			{
				if ($verify === false)
				{
					$this->_error(sprintf(_('Validation of "%1$s" failed'), $field));
				}
				else
				{
					$this->_error($verify);
				}
			}
		}
	}
	
	// ###################################################################
	/**
	* Sets the condition to use in the WHERE clause; if not passed, then
	* it calculates it from the REQ_AUTO field
	*
	* @param	mixed	String with WHERE condition; array of fields to use for WHERE builder
	*/
	public function setCondition($condition = '')
	{
		if (is_array($condition) AND sizeof($condition) > 0)
		{
			$this->condition = '';
			
			foreach ($condition AS $field)
			{
				if (!$this->values["$field"])
				{
					throw new Exception('The specified field "' . $field . '" for the condition could not be found as it is not set');
					continue;
				}
				
				$condbits[] = "$field = " . $this->_prepareFieldForSql($field);
			}
			$this->condition = implode(' AND ', $condbits);
		}
		else if ($condition != '')
		{
			$this->condition = $condition;
		}
		else 
		{
			foreach ($this->fields AS $name => $options)
			{
				if ($options[F_REQ] == REQ_AUTO)
				{
					if (!$this->values["$name"])
					{
						throw new Exception('Cannot determine condition from the REQ_AUTO field because it is not set');
						continue;
					}
					
					$this->condition = "$name = " . $this->_prepareFieldForSql($name);
				}
			}
			
			if ($this->condition == '')
			{
				throw new Exception('No REQ_AUTO fields are present and therefore the condition cannot be created');
			}
		}
	}
	
	// ###################################################################
	/**
	* Sets existing data into $values where it's not already present
	*/
	public function setExisting()
	{
		static $run;
		if ($run)
		{
			return;
		}
		
		$this->fetch();
		
		foreach ($this->objdata AS $field => $value)
		{
			if (!isset($this->values["$field"]))
			{
				$this->values["$field"] = $value;
			}
		}
		
		$run = true;
	}
	
	// ###################################################################
	/**
	* Fetches a record based on the condition
	*
	* @param	bool	Run pre_fetch()?
	* @param	bool	Run post_fetch()?
	*
	* @return	boolean	Whether or not the row was successfully fetched
	*/
	public function fetch($doPre = true, $doPost = true)
	{
		if ($this->condition == '')
		{
			$this->setCondition();
		}
		
		// reset the error queue due to any validation errors caused by fetchable fields
		$this->errors = array();
		
		$this->_runActionMethod('pre_fetch', $doPre);
		
		$result = BSApp::GetType('Db')->queryFirst("SELECT * FROM {$this->prefix}{$this->table} WHERE {$this->condition}");
		if (!$result)
		{
			return false;
		}
		
		$this->_runActionMethod('post_fetch', $doPost);
		
		$this->objdata = $result;
		
		return true;
	}
	
	// ###################################################################
	/**
	* Inserts a record in the database
	*
	* @param	bool	Run pre_insert()?
	* @param	bool	Run post_insert()?
	*/
	public function insert($doPre = true, $doPost = true)
	{
		$this->verify();
		$this->_processErrorQueue();
		
		$this->_runActionMethod('pre_insert', $doPre);
		
		foreach ($this->setfields AS $field)
		{
			$fields[] = $field;
			$values[] = $this->_prepareFieldForSql($field);
		}
		
		BSApp::GetType('Db')->query("INSERT INTO {$this->prefix}{$this->table} (" . implode(',', $fields) . ") VALUES (" . implode(',', $values) . ")");
		
		if (BSApp::GetType('DbPostgreSql'))
		{
			foreach ($this->fields AS $field => $info)
			{
				if ($info[F_REQ] == REQ_AUTO)
				{
					$autofield = $field;
					break;
				}
			}
			
			$this->insertid = BSApp::GetType('Db')->insertId($this->prefix . $this->table, $autofield);
		}
		else
		{
			$this->insertid = BSApp::GetType('Db')->insertId();
		}
		
		$this->_runActionMethod('post_insert', $doPost);
	}
	
	// ###################################################################
	/**
	* Updates a record in the database using the data in $vaues
	*
	* @param	bool	Run pre_update()?
	* @param	bool	Run post_update()?
	*/
	public function update($doPre = true, $doPost = true)
	{
		if ($this->condition == '')
		{
			$this->setCondition();
		}
		
		$this->_processErrorQueue();
		
		$this->_runActionMethod('pre_update', $doPre);
		
		foreach ($this->setfields AS $field)
		{
			$updates[] = "$field = " . $this->_prepareFieldForSql($field);
		}
		$updates = implode(', ', $updates);
		
		BSApp::GetType('Db')->query("UPDATE {$this->prefix}{$this->table} SET $updates WHERE {$this->condition}");
		
		$this->_runActionMethod('post_update', $doPost);
	}
	
	// ###################################################################
	/**
	* Deletes a record
	*
	* @param	bool	Run pre_remove()?
	* @param	bool	Run post_remove()?
	*/
	public function remove($doPre = true, $doPost = true)
	{
		if ($this->condition == '')
		{
			$this->setCondition();
		}
		
		$this->fetch();
		
		$this->_runActionMethod('pre_remove', $doPre);
		
		BSApp::GetType('Db')->query("DELETE FROM {$this->prefix}{$this->table} WHERE {$this->condition}");
		
		$this->_runActionMethod('post_remove', $doPost);
	}
	
	// ###################################################################
	/**
	* Verifies that all required fields are set
	*/
	private function verify()
	{
		foreach ($this->fields AS $name => $options)
		{
			if ($options[F_REQ] == REQ_YES)
			{
				if (!isset($this->values["$name"]))
				{
					$this->_error(sprintf(_('The required field "%1$s" was not set'), $name));
				}
			}
			else if ($options[F_REQ] == REQ_SET)
			{
				$this->{"set_$name"}();
			}
		}
	}
	
	// ###################################################################
	/**
	* Runs a pre- or post-action method for database commands
	*
	* @param	string	Action to run
	* @param	bool	Actually run it?
	*/
	private function _runActionMethod($method, $doRun)
	{
		if (!$doRun)
		{
			return;
		}
		
		$actmethod = (method_exists($this, $method) ? $this->$method() : '');
	}
	
	// ###################################################################
	/**
	* Prepares a value for use in a SQL query; it encases and escapes
	* strings and string-like values
	*
	* @param	string	Field name
	*
	* @return	string	Prepared value entry
	*/
	private function _prepareFieldForSql($name)
	{
		$type = $this->fields["$name"][F_TYPE];
		
		if ($type == TYPE_NONE OR $type == TYPE_STR OR $type == TYPE_STRUN)
		{
			return "'" . BSApp::GetType('Db')->escapeString($this->values["$name"]) . "'";
		}
		else if ($type == TYPE_BOOL)
		{
			return ($this->values["$name"] == true ? "'1'" : "'0'");
		}
		else if ($type == TYPE_BIN)
		{
			return "'" . BSApp::GetType('Db')->escapeBinary($this->values["$name"]) . "'";
		}
		else
		{
			return $this->values["$name"];
		}
	}
	
	// ###################################################################
	/**
	* Verify field: not a zero value
	*/
	protected function verify_nozero($field)
	{
		if ($this->values["$field"] == 0)
		{
			return sprintf(_('The field "%1$s" cannot be zero'), $field);
		}
		
		return true;
	}
	
	// ###################################################################
	/**
	* Verify field: not empty
	*/
	protected function verify_noempty($field)
	{
		if (empty($this->values["$field"]))
		{
			return sprintf(_('The field "%1$s" cannot be empty'), $field);
		}
		
		return true;
	}
	
	// ###################################################################
	/**
	* Verify field: unique
	*/
	protected function verify_unique($field)
	{
		$res = BSApp::GetType('Db')->queryFirst("SELECT $field FROM {$this->prefix}{$this->table} WHERE $field = " . $this->_prepareFieldForSql($field) . (empty($this->condition) ? "" : " AND !({$this->condition})"));
		if ($res)
		{
			return sprintf(_('The "%1$s" field must contain a unique value'), $field);
		}
		
		return true;
	}
}

?>