<?php

/* 2DO
 - Module die conditional block visibility doet
 - Disablen conditions werkend maken
 - Keuze of condition TRUE is bij geen, een of alle requirements OK
 */
 
define('CONDITION_ANY',		1);
define('CONDITION_ALL',		2);
define('CONDITION_NONE',	3);

/**
* Implementation of hook_menu().
*/
function condition_menu() {
	$items['admin/settings/condition'] = array(
		'title' => 'Conditions',
		'description' => 'Configure conditions other modules use to trigger actions.',
		'page callback' => 'drupal_get_form',
		'page arguments' => array('condition_list_form'),
		'access arguments' => array('administer conditions'),
		'file' => 'condition.admin.inc',
	);
	$items['admin/settings/condition/list'] = array(
    'title' => t('List'),
    'weight' => -10,
    'type' => MENU_DEFAULT_LOCAL_TASK,
  );
	$items['admin/settings/condition/add'] = array(
    'title' => t('Add'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('condition_edit_form'),
    'type' => MENU_LOCAL_TASK,
    'file' => 'condition.admin.inc',
  );
	$items['admin/settings/condition/%condition/edit'] = array(
    'title' => t('Edit'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('condition_edit_form', 3),
    'type' => MENU_CALLBACK,
    'file' => 'condition.admin.inc',
  );
	$items['admin/settings/condition/%condition/delete'] = array(
    'title' => t('Delete'),
    'page callback' => 'drupal_get_form',
    'page arguments' => array('condition_delete_form', 3),
    'type' => MENU_CALLBACK,
    'file' => 'condition.admin.inc',
  );

  return $items;
}

/**
* Implementation of hook_perm().
*/
function condition_perm() {
  return array('administer conditions');
}

/**
* Implementation of hook_theme().
*/
function condition_theme() {
  return array(
    'condition_edit_form' => array('arguments' => array('form' => NULL)),
    'condition_list_form' => array('arguments' => array('form' => NULL)),
  );
}

/**
* Implementation of hook_help().
*/
function condition_help($path, $arg) {
  switch ($path) {
    case 'admin/settings/condition':
      return '<p>'.t('Conditions are sets of requirements that make the condition met (<em>TRUE</em>) or not (<em>FALSE</em>). Other modules can provide requirements (e.g. requested path is <em>admin/*</em>) or use the Condition API to trigger some kind of action (e.g. switch theme to <em>Garland</em>) in case a condition is met. Start by !adding a condition.', array('!adding' => l(t('adding'), 'admin/settings/condition/add'))).'</p>';
  }
}

/**
* Loading one, more or all conditions.
*/
function condition_load($cid = NULL) {
	static $conditions;
	
	if (!is_array($conditions)) {
	
		if (is_numeric($cid)) {
			$condition = db_fetch_object(db_query("SELECT * FROM {conditions} WHERE cid = %d", $cid));
			$condition->parameters = (array) unserialize($condition->parameters);
			return $condition;
			
		} else {
			$result	= db_query("SELECT * FROM {conditions} ORDER BY weight ASC");
			$conditions	= array();
			
			while ($condition = db_fetch_object($result)) {
				$condition->parameters = (array) unserialize($condition->parameters);
				$conditions[$condition->cid] = $condition;
			}
		}
	}
		
	if (is_array($conditions)) {
		
		if (is_numeric($cid)) {
			return $conditions[$cid];
			
		} elseif (is_array($cid)) {
			return array_intersect_key($conditions, array_flip($cid));
			
		} else {		
			return $conditions;
		}		
	}
}

/**
* Saving one or more conditions.
*/
function condition_save($condition) {
	
	if (is_array($condition)) {
		
		foreach (array_keys($condition) as $key) {
			$condition[$key]->saved = condition_save($condition[$key]);
		}
		
		return $condition;
	}
	
	if ($condition->parameters) {
		$condition->parameters = serialize((array) $condition->parameters);
	}

	return drupal_write_record('conditions', $condition, $condition->cid ? 'cid' : array());
}

/**
* Deleting one or more conditions.
*/
function condition_delete($condition) {
	
	if (is_array($condition)) {
		
		foreach (array_keys($condition) as $key) {
			$condition[$key]->deleted = condition_delete($condition[$key]);
		}
		
		return $condition;
	}
	
	if (!is_object($condition)) {
		$condition = condition_load($condition);
	}
	
	return db_query("DELETE FROM {conditions} WHERE cid = %d", $condition->cid);
}

/**
* Validating a condition.
*/
function condition_validate($condition) {
	static $validations;
	
	if (is_array($condition)) {
		
		foreach (array_keys($condition) as $key) {
			$condition[$key]->valid = condition_validate($condition[$key]);
		}
		
		return $condition;
	}

	if (is_array($validations) && isset($validations[$condition->cid])) {
		$condition->valid = $validations[$condition->cid];
		return $condition;
	}
	
	if (!$condition->status) {
		return $validations[$condition->cid] = FALSE;
	}
		
	$requirements	= module_invoke_all('requirement_info');
	$valid				= TRUE;
	
	if (is_array($requirements) && count($requirements)) {
		
		foreach ($requirements as $requirement => $info) {

			if ($condition->parameters[$requirement]) {

				if ($requirement($condition, $condition->parameters[$requirement]) === FALSE) {
					$valid = FALSE;
					break;
				}
			}
		}
	}
	
	return $validations[$condition->cid] = $valid;
}

/*
* Selecting conditions for some other module.
*/
function condition_selection_form(&$form_state) {	
	$conditions = condition_load();
	
	// We might get just the values instead of the form_state.
	if ($form_state['conditions']) {
		$form_state['values'] = $form_state;
	}	
	
	if (count($conditions)) {
		$form['conditions'] = array(
			'#type' => 'fieldset', 
			'#title' => t('Conditions'),
			'#description' => t('Restrict to situations where any, all or none of the following conditions are met.'),
			'#collapsible' => TRUE,
			'#collapsed' => FALSE,
			'#tree' => TRUE,
		);
		$form['conditions']['operator'] = array(
			'#type' => 'select',
			'#title' => 'Situation',
			'#options' => array(
				'' => t("(skip conditions)"),
				CONDITION_ANY => t('Any condition'),
				CONDITION_ALL => t('All conditions'),
				CONDITION_NONE => t('No condition'),
			),
			'#default_value' => $form_state['values']['conditions']['operator'],
		);
		$form['conditions']['selection'] = array(
			'#type' => 'checkboxes',
			'#title' => t('Conditions'),
			'#options' => array(),
			'#default_value' => (array) $form_state['values']['conditions']['selection'],
		);
		
		foreach ($conditions as $condition) {
			$form['conditions']['selection']['#options'][$condition->cid] = $condition->name.' ('.l(t('edit'), 'admin/settings/condition/'.$condition->cid.'/edit').')';
		}
	}
	
	return $form;
}

/*
* Submit: Selecting conditions for some other module.
*/
function condition_selection_form_submit($form, $form_state) {
  return array('conditions' => $form_state['values']['conditions']);
}

/*
* Validating a selection of conditions for some other module.
*/
function condition_selection_validate($parameters) {
  
	// We might get all form values instead of just ours.
	if ($parameters['conditions']) {
		$parameters = $parameters['conditions'];
	}
	
	// No operator means we don't use conditions, so that would be a TRUE in order to keep things going.
	if (!$parameters['operator']) {
		return TRUE;
	}

	$values = array_values($parameters['selection']);
	sort($values);
	
	// We might get the condition ids as values or as keys with the value telling if they are selected.
	if (array_pop($values) > 1 || array_key_exists(0, $parameters['selection'])) {
		$parameters['selection'] = array_flip(array_filter($parameters['selection']));
	}
	
	$conditions	= condition_load($parameters['selection']);

	// If no (existing) conditions were selected our reponse is only TRUE if the operator is NONE.
	if (!is_array($conditions) || count($conditions) == 0) {
		return ($parameters['operator'] == CONDITION_NONE);
	}
	
	$valid = 0;
	
	foreach ($conditions as $condition) {
		
		if (condition_validate($condition)) {
			$valid++;
		}
	}

	// If we need all to be valid we check if all existing (not selected, some might be deleted) conditions are valid.
	if ($parameters['operator'] == CONDITION_ALL) {
		return (count($conditions) == $valid);
		
	// If we need just one, that's what we will check here.
	} else {
		return ($valid > 0);
	}
}

?>