<?php
// (c) Copyright by authors of the Tiki Wiki CMS Groupware Project
//
// All Rights Reserved. See copyright.txt for details and a complete list of authors.
// Licensed under the GNU LESSER GENERAL PUBLIC LICENSE. See license.txt for details.
// $Id$

/**
 * TransitionLib
 *
 */
class TransitionLib
{
	private $transitionType;

	/**
	 * @param $transitionType
	 */
	function __construct($transitionType)
	{
		$this->transitionType = $transitionType;
	}

	/**
	 * @param $object
	 * @param null $type
	 * @return array
	 */
	function getAvailableTransitions($object, $type = null)
	{
		$states = $this->getCurrentStates($object, $type);

		$transitions = $this->getTransitionsFromStates($states);
		$transitions = Perms::filter(
			['type' => 'transition'],
			'object',
			$transitions,
			['object' => 'transitionId'],
			'trigger_transition'
		);

		foreach ($transitions as & $tr) {
			$object = new Tiki_Transition($tr['from'], $tr['to']);
			$object->setStates($states);
			foreach ($tr['guards'] as $guard) {
				call_user_func_array([$object, 'addGuard' ], $guard);
			}

			$tr['enabled'] = $object->isReady();
			$tr['explain'] = $object->explain();
		}

		return $transitions;
	}

	/**
	 * @param $state
	 * @param $object
	 * @param null $type
	 * @return array
	 */
	function getAvailableTransitionsFromState($state, $object, $type = null)
	{
		$transitions = $this->getAvailableTransitions($object, $type);

		$out = [];
		foreach ($transitions as $tr) {
			if ($tr['from'] == $state) {
				$out[$tr['transitionId']] = $tr['name'];
			}
		}

		return $out;
	}

	/**
	 * @param $transitionId
	 * @param $object
	 * @param null $type
	 * @return bool
	 */
	function triggerTransition($transitionId, $object, $type = null)
	{
		// Make sure the transition exists
		if (! $transition = $this->getTransition($transitionId)) {
			return false;
		}

		// Make sure the user can use it
		$perms = Perms::get(['type' => 'transition', 'object' => $transitionId]);
		if (! $perms->trigger_transition) {
			return false;
		}

		// Verify that the states are consistent
		$states = $this->getCurrentStates($object, $type);

		$tr = new Tiki_Transition($transition['from'], $transition['to']);
		$tr->setStates($states);

		foreach ($transition['guards'] as $guard) {
			call_user_func_array([$tr, 'addGuard'], $guard);
		}

		if (! $tr->isReady()) {
			return false;
		}

		$this->addState($transition['to'], $object, $type);
		if (! $transition['preserve']) {
			$this->removeState($transition['from'], $object, $type);
		}

		return true;
	}

	/**
	 * @param $states
	 * @return array
	 */
	function listTransitions($states)
	{
		$db = TikiDb::get();

		if (empty($states)) {
			return [];
		}

		$bindvars = [$this->transitionType];
		$query = "SELECT `transitionId`, `preserve`, `name`, `from`, `to`, `guards` FROM `tiki_transitions` WHERE `type` = ? AND ( " .
						$db->in('from', $states, $bindvars) .
						' OR ' . $db->in('to', $states, $bindvars) . ')';

		$result = $db->fetchAll($query, $bindvars);

		return array_map([$this, 'expandGuards'], $result);
	}

	// Database interaction

	/**
	 * @param $from
	 * @param $to
	 * @param $name
	 * @param bool $preserve
	 * @param array $guards
	 * @return mixed
	 */
	function addTransition($from, $to, $name, $preserve = false, array $guards = [])
	{
		$db = TikiDb::get();

		$db->query(
			"INSERT INTO `tiki_transitions` ( `type`, `from`, `to`, `name`, `preserve`, `guards`) VALUES( ?, ?, ?, ?, ?, ? )",
			[$this->transitionType, $from, $to, $name, (int) $preserve, json_encode($guards)]
		);

		return $db->getOne('SELECT MAX(`transitionId`) FROM `tiki_transitions`');
	}

	/**
	 * @param $transitionId
	 * @param $from
	 * @param $to
	 * @param $label
	 * @param $preserve
	 */
	function updateTransition($transitionId, $from, $to, $label, $preserve)
	{
		$db = TikiDb::get();
		$db->query(
			'UPDATE `tiki_transitions` SET `name` = ?, `from` = ?, `to` = ?, `preserve` = ? WHERE `transitionId` = ?',
			[$label, $from, $to, (int) $preserve, (int) $transitionId]
		);
	}

	/**
	 * @param $transitionId
	 * @param array $guards
	 */
	function updateGuards($transitionId, array $guards)
	{
		$db = TikiDb::get();
		$db->query(
			'UPDATE `tiki_transitions` SET `guards` = ? WHERE `transitionId` = ?',
			[json_encode($guards), (int) $transitionId]
		);
	}

	/**
	 * @param $transitionId
	 */
	function removeTransition($transitionId)
	{
		$db = TikiDb::get();

		$db->query('DELETE FROM `tiki_transitions` WHERE `transitionId` = ?', [$transitionId]);
	}

	/**
	 * @param $states
	 * @return array
	 */
	private function getTransitionsFromStates($states)
	{
		$db = TikiDb::get();

		if (empty($states)) {
			return [];
		}

		$bindvars = [$this->transitionType];
		$query = "SELECT `transitionId`, `preserve`, `name`, `from`, `to`, `guards` FROM `tiki_transitions` WHERE `type` = ? AND " .
						$db->in('from', $states, $bindvars) . ' AND NOT (' .
						$db->in('to', $states, $bindvars) . ')';

		$result = $db->fetchAll($query, $bindvars);

		return array_map([$this, 'expandGuards'], $result);
	}

	/**
	 * @param $transitionId
	 * @return mixed
	 */
	function getTransition($transitionId)
	{
		$db = TikiDb::get();

		$bindvars = [$this->transitionType, $transitionId];
		$query = "SELECT `transitionId`, `preserve`, `name`, `from`, `to`, `guards` FROM" .
							" `tiki_transitions` WHERE `type` = ? AND `transitionId` = ?";
		$result = $db->fetchAll($query, $bindvars);

		return $this->expandGuards(reset($result));
	}

	/**
	 * @param $transition
	 * @return mixed
	 */
	private function expandGuards($transition)
	{
		$transition['guards'] = json_decode($transition['guards'], true);
		if (! $transition['guards']) {
			$transition['guards'] = [];
		}

		return $transition;
	}

	// The following functions vary depending on the transition type

	/**
	 * @param $object
	 * @param $type
	 * @return array
	 */
	private function getCurrentStates($object, $type)
	{
		switch ($this->transitionType) {
			case 'group':
				$userlib = TikiLib::lib('user');
				return $userlib->get_user_groups($object);
			case 'category':
				$categlib = TikiLib::lib('categ');
				return $categlib->get_object_categories($type, $object);
		}
	}

	/**
	 * @param $state
	 * @param $object
	 * @param $type
	 */
	private function addState($state, $object, $type)
	{
		global $prefs;

		switch ($this->transitionType) {
			case 'group':
				$userlib = TikiLib::lib('user');
				$userlib->assign_user_to_group($object, $state);
				if ($prefs['default_group_transitions'] === 'y') {
					$userlib->set_default_group($object, $state);
				}
				return;
			case 'category':
				$categlib = TikiLib::lib('categ');
				$categlib->categorize_any($type, $object, $state);
				return;
		}
	}

	/**
	 * @param $state
	 * @param $object
	 * @param $type
	 */
	private function removeState($state, $object, $type)
	{
		switch ($this->transitionType) {
			case 'group':
				$userlib = TikiLib::lib('user');
				$userlib->remove_user_from_group($object, $state);
				return;
			case 'category':
				$categlib = TikiLib::lib('categ');
				if ($catobj = $categlib->is_categorized($type, $object)) {
					$categlib->uncategorize($catobj, $state);
				}
				return;
		}
	}
}