<?php
/*=====================================================================*\
|| ###################################################################
|| # Blue Static ISSO Framework
|| # Copyright Š2002-[#]year[#] 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 [#]gpl[#] 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'))
{	
	/**
	* 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);
	
	/**
	* Index for relation
	*/
	define('F_RELATION', 3);
	
	/**
	* Relation index for file name, relative to ISSO->apppath
	*/
	define('F_RELATION_FILE', 0);
	
	/**
	* Relation index for class name
	*/
	define('F_RELATION_CLASS', 1);
	
	/**
	* Relation index for field-link alternate name
	*/
	define('F_RELATION_ALTFIELD', 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, delete, and
* insert.
*
* @author		Blue Static
* @copyright	Copyright Š2002 - [#]year[#], Blue Static
* @version		$Revision$
* @package		ISSO
* 
*/
class API
{
	/**
	* Registry object
	* @var	object
	* @access	protected
	*/
	var $registry = null;
	
	/**
	* 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
	* @access	protected
	*/
	var $fields = array();
	
	/**
	* Values array: sanitized and verified field values
	* @var	array
	* @access	public
	*/
	var $values = array();
	
	/**
	* Fields that were manually set with set(), not by using set_existing()
	* @var	array
	* @access	private
	*/
	var $setfields = array();
	
	/**
	* An array of all of the processed relations on an object
	* @var	array
	* @access	public
	*/
	var $relations = array();
	
	/**
	* WHERE condition
	* @var	string
	* @access	private
	*/
	var $condition = '';
	
	/**
	* The object table row; a fetched row that represents this instance
	* @var	array
	* @access	public
	*/
	var $objdata = array();
	
	/**
	* Insert ID from the insert() command
	* @var	integer
	* @access	public
	*/
	var $insertid = 0;
	
	/**
	* Pre- and post-action method stoppers
	* @var	array
	* @access	public
	*/
	var $norunners = array();
	
	/**
	* The relations to execute on
	* @var	array
	* @access	public
	*/
	var $dorelations = array('fetch');
	
	/**
	* Error list that has been generated
	* @var	array
	* @access	private
	*/
	var $errors = array();
	
	// ###################################################################
	/**
	* Constructor: cannot instantiate class directly
	*/
	function __construct(&$registry)
	{
		if (!is_subclass_of($this, 'API'))
		{
			trigger_error('Cannot instantiate the API module directly', E_USER_ERROR);
		}
		
		if (!is_object($registry))
		{
			trigger_error('The passed registry is not an object', E_USER_ERROR);
		}
		
		$this->registry =& $registry;
	}
	
	// ###################################################################
	/**
	* (PHP 4) Constructor
	*/
	function API(&$registry)
	{
		$this->__construct($registry);
	}
	
	// ###################################################################
	/**
	* Constructs an error for the error handler to receive
	*
	* @access	protected
	*
	* @param	string	Error message
	*/
	function error($message)
	{
		$this->errors[] = $message;
		
		// we want to explicitly specify silence
		if (APIError() == 'silent')
		{
			return;
		}
		
		if (!is_callable(APIError()))
		{
			trigger_error('No APIError() handler has been set', E_USER_WARNING);
		}
		
		call_user_func(APIError(), $message);
	}
	
	// ###################################################################
	/**
	* 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.
	*
	* @access	public
	*
	* @return	array	Array of errors
	*/
	function check_errors()
	{
		if (sizeof($this->errors) < 1)
		{
			return array();
		}
		
		return $this->errors;
	}
	
	// ###################################################################
	/**
	* Sets a value, sanitizes it, and verifies it
	*
	* @access	public
	*
	* @param	string	Field name
	* @param	mixed	Value
	* @param	bool	Do clean?
	* @param	bool	Do verify?
	*/
	function set($field, $value, $doclean = true, $doverify = true)
	{
		if (!isset($this->fields["$field"]))
		{
			trigger_error('Field `' . $field . '` is not valid', E_USER_WARNING);
			return;
		}
		
		$this->values["$field"] = ($doclean ? $this->registry->clean($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
	*
	* @access	public
	*
	* @param	mixed	String with WHERE condition; array of fields to use for WHERE builder
	*/
	function set_condition($condition = '')
	{
		if (is_array($condition) AND sizeof($condition) > 0)
		{
			$this->condition = '';
			
			foreach ($condition AS $field)
			{
				if (!$this->values["$field"])
				{
					trigger_error('The specified field `' . $field . '` for the condition could not be found as it is not set', E_USER_WARNING);
					continue;
				}
				
				$condbits[] = "$field = " . $this->prepare_field_for_sql($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"])
					{
						trigger_error('Cannot determine condition from the REQ_AUTO field because it is not set', E_USER_WARNING);
						continue;
					}
					
					$this->condition = "$name = " . $this->prepare_field_for_sql($name);
				}
			}
			
			if ($this->condition == '')
			{
				trigger_error('No REQ_AUTO fields are present and therefore the condition cannot be created', E_USER_WARNING);
			}
		}
	}
	
	// ###################################################################
	/**
	* Sets existing data into $values where it's not already present
	*
	* @access	public
	*/
	function set_existing()
	{
		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	Populate $this->values[] with data, along with $this->objdata[] ?
	*
	* @access	public
	*/
	function fetch($populate = false)
	{
		if ($this->condition == '')
		{
			trigger_error('Condition is empty: cannot fetch', E_USER_ERROR);
		}
		
		$this->run_action_method('pre_fetch');
		
		$result = $this->registry->modules[ISSO_DB_LAYER]->query_first("SELECT * FROM {$this->prefix}{$this->table} WHERE {$this->condition}");
		if (!$result)
		{
			$this->error(_('No records were returned'));
			return;
		}
		
		$this->run_action_method('post_fetch');
		
		$this->objdata = $result;
		
		if ($populate)
		{
			foreach ($this->objdata AS $key => $value)
			{
				if (!isset($this->values["$key"]))
				{
					$this->values["$key"] = $value;
				}
			}
		}
		
		$this->call_relations('fetch');		
	}
	
	// ###################################################################
	/**
	* Inserts a record in the database
	*
	* @access	public
	*/
	function insert()
	{
		$this->verify();
		
		$this->run_action_method('pre_insert');
		
		foreach ($this->setfields AS $field)
		{
			$fields[] = $field;
			$values[] = $this->prepare_field_for_sql($field);
		}
		
		$this->registry->modules[ISSO_DB_LAYER]->query("INSERT INTO {$this->prefix}{$this->table} (" . implode(',', $fields) . ") VALUES (" . implode(',', $values) . ")");
		
		if (strcasecmp(ISSO_DB_LAYER, 'DB_PostgreSQL') == 0)
		{
			foreach ($this->fields AS $field => $info)
			{
				if ($info[F_REQ] == REQ_AUTO)
				{
					$autofield = $field;
					break;
				}
			}
			
			$this->insertid = $this->registry->modules[ISSO_DB_LAYER]->insert_id($this->prefix . $this->table, $autofield);
		}
		else
		{
			$this->insertid = $this->registry->modules[ISSO_DB_LAYER]->insert_id();
		}
		
		$this->run_action_method('post_insert');
	}
	
	// ###################################################################
	/**
	* Updates a record in the database using the data in $vaues
	*
	* @access	public
	*/
	function update()
	{
		if ($this->condition == '')
		{
			trigger_error('Condition is empty: cannot update', E_USER_ERROR);
		}

		$this->run_action_method('pre_update');
		
		foreach ($this->setfields AS $field)
		{
			$updates[] = "$field = " . $this->prepare_field_for_sql($field);
		}
		$updates = implode(', ', $updates);
		
		$this->registry->modules[ISSO_DB_LAYER]->query("UPDATE {$this->prefix}{$this->table} SET $updates WHERE {$this->condition}");
		
		$this->run_action_method('post_update');
	}
	
	// ###################################################################
	/**
	* Deletes a record
	*
	* @access	public
	*
	* @param	bool	Run API->set_existing()?
	*/
	function delete($runset = true)
	{
		if ($this->condition == '')
		{
			trigger_error('Condition is empty: cannot delete', E_USER_ERROR);
		}
		
		if ($runset)
		{
			$this->set_existing();
		}
		
		$this->run_action_method('pre_delete');
		
		$this->registry->modules[ISSO_DB_LAYER]->query("DELETE FROM {$this->prefix}{$this->table} WHERE {$this->condition}");
		
		$this->run_action_method('post_delete');
	}
	
	// ###################################################################
	/**
	* Verifies that all required fields are set
	*
	* @access	private
	*/
	function verify()
	{
		foreach ($this->fields AS $name => $options)
		{
			if ($options[F_REQ] == REQ_YES)
			{
				if (!isset($this->values["$name"]))
				{
					$this->error(sprintf(_('Required field %1$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
	*
	* @access	private
	*
	* @param	string	Action to run
	*/
	function run_action_method($method)
	{
		if (in_array($method, $this->norunners))
		{
			return;
		}
		
		$actmethod = (method_exists($this, $method) ? $this->$method() : '');
	}
	
	// ###################################################################
	/**
	* Determines if it's safe to run a relation; if so, it will return
	* the WHERE SQL clause
	*
	* @access	public
	*
	* @param	string	Operation to run
	*/
	function call_relations($method)
	{
		if (!is_array($this->dorelations) OR !in_array($method, $this->dorelations))
		{
			return;
		}
		
		foreach ($this->fields AS $field => $info)
		{
			$value = (isset($this->values["$field"]) ? $this->values["$field"] : $this->objdata["$field"]);
			if ($value == null OR !is_array($info[F_RELATION]))
			{
				continue;
			}
			
			if (!file_exists($this->registry->getAppPath() . $info[F_RELATION][F_RELATION_FILE]))
			{
				trigger_error("Could not load the relation file for field '$field'");
			}
			
			require_once($this->registry->getAppPath() . $info[F_RELATION][F_RELATION_FILE]);
			
			$this->relations["$field"] = new $info[F_RELATION][F_RELATION_CLASS]($this->registry);
			$this->relations["$field"]->set(($info[F_RELATION][F_RELATION_ALTFIELD] ? $info[F_RELATION][F_RELATION_ALTFIELD] : $field), $value);
			$this->relations["$field"]->set_condition();
			$this->relations["$field"]->$method();
		}
	}
	
	// ###################################################################
	/**
	* Prepares a value for use in a SQL query; it encases and escapes
	* strings and string-like values
	*
	* @access	private
	*
	* @param	string	Field name
	*
	* @return	string	Prepared value entry
	*/
	function prepare_field_for_sql($name)
	{
		$type = $this->fields["$name"][F_TYPE];
		
		if ($type == TYPE_NOCLEAN OR $type == TYPE_STR OR $type == TYPE_STRUN)
		{
			return "'" . $this->registry->db->escape_string($this->values["$name"]) . "'";
		}
		else if ($type == TYPE_BOOL)
		{
			return ($this->values["$name"] == true ? "'1'" : "'0'");
		}
		else if ($type == TYPE_BIN)
		{
			return "'" . $this->registry->db->escape_binary($this->values["$name"]) . "'";
		}
		else
		{
			return $this->values["$name"];
		}
	}
	
	// ###################################################################
	/**
	* Verify field: not a zero value
	*
	* @access	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
	*
	* @access	protected
	*/
	function verify_noempty($field)
	{
		if (empty($this->values["$field"]))
		{
			return sprintf(_('The field "%1$s" cannot be empty'), $field);
		}
		
		return true;
	}
}

// ###################################################################
/**
* Setter and getter method for the API error reporting system. Passing
* a name will cause the set, no arguments will cause the get.
*
* @access	public
*
* @param	mixed	Method name in callable form
*
* @return	mixed	Method name in callable form
*/
function APIError($new = null)
{
	static $caller, $prev;
	
	if ($new === -1)
	{
		$caller = $prev;
	}
	else if ($new !== null)
	{
		$prev = $caller;
		$caller = $new;
	}
	
	return $caller;
}

/*=====================================================================*\
|| ###################################################################
|| # $HeadURL$
|| # $Id$
|| ###################################################################
\*=====================================================================*/
?>