This wiki page is no longer kept up to date with the project progress. Up to date documentation on CiviRules can be found at http://redmine.civicoop.org/projects/civirules/wiki

interface CRM_Rules_Interface_EventDefinition {
 
    /**
     * Returns a system name of this event
     * e.g. post_contact
     *
     * @return string
     */
	public function getName();
 
	/**
     * Returns a human and translatable label of the event
     * E.g. 'Before a contact is changed'
     * 
     * @return string
     */
	public function getLabel();
 
    /**
     * Returns the name of the entity e.g. 'Contact', 'Contribution'
     *
     * @return string
     */
	public function getEntity();
 
	/**
     * Returns whether the given event parameters are valid. 
     * If they are not valid the whole rule would probably not be executed
     *
     * @param array $event_parameters
     * @return bool
     */
	public function validateEventParameters($event_parameters);
 
	/**
     * Returns an array which replacement patterns this event provides
     *
     * E.g. a post contribution event provides the Contact and the Contribution contact
     * So the return array looks like:
     * array (
     *  new CRM_Rules_Model_ReplacementPattern('contact', 'CRM_Contact_DAO_Contact'),
     *  new CRM_Rules_Model_ReplacementPattern('soft_credit', 'CRM_Contact_DAO_Contact'),
     *  new CRM_Rules_Model_ReplacementPattern('contribution', 'CRM_Contribution_DAO_Contribution'),
     * )
     * 
     * @return array
     */
	public function getReplacementPatterns();
 
}

interface CRM_Rules_Interface_ActionDefinition {
 
	public function getName();
 
	public function getLabel();
 
	public function getEntity();
 
}

function rules_civicrm_rules_event_definition() {
	$events['post_contact'] = new CRM_Rules_Events_PostContact();
	return $events;
}
 
/*
 * To trigger on this event we add this event to post hook
 */
function rules_civicrm_post($op, $objectName, $objectId, $objectRef) {
	$api = civicrm_api3('Rules', 'InvokeEvent', array(
		'event' => 'post_'.$objectName,
        'event_parameters' => array(
           'operation' => $op,
           'entity_id' => $objectId,
           'entity' => $objectName,
           'entity_data'  => $objectRef,
        );
	));
}
 
/*
 * Below is an example of the CRM_Rules_Events_PostContact class
 */
class CRM_Rules_Events_PostContact {
 
	public function getName() {
		return 'post_contact';
	}
 
	public function getLabel() {
		return ts('After updating a contact');
	}
 
	public function getEntity() {
		return 'Contact';
	}
 
	public function validateEventParameters($event_parameters) {
		if ($event_parameters['objectName'] == 'Contact') {
			return true;
		} else {
			return false;
		}
	}
}

function rules_civicrm_rules_action_definition() {
	$actions['set_data_value'] = new CRM_Rules_Actions_SetDataValue();
	$actions['send_email'] = new CRM_Rules_Actions_SendEmail();
	return $actions;
}

function hook_civicrm_rules_alter_dataselectors($dao, &$current_data_selectors) {
	if ($dao == 'CRM_Contact_DAO_Contact') {
		$current_data_selectors['total_contribution_amount_this_year'] = new CRM_Rules_Model_DataSelector(); //the model for data selector is not yet defined.
	}
}

function my_civicrm_post($op, $objectName, $objectId, $objectRef) {
	$api = civicrm_api3('Rules', 'InvokeEvent', array(
		'event' => 'post_'.$objectName,
        'event_parameters' => array(
           'operation' => $op,
           'entity_id' => $objectId,
           'entity' => $objectName,
           'entity_data'  => $objectRef,
        );
	));
}

class CRM_Rules_Model_Rule {
 
	protected $event_name; //loaded from database
 
	protected $conditions; //loaded from database
 
	protected $actions; //loaded from database
 
	protected $event_parameters; //set on triggerEvent
 
	public function setEvent($event_name) {
		$this->event_name = $event;
	}
 
	public function getEvent() {
		return $this->event_name;
	}
 
	...
 
	/**
     * Trigger the event and check the conditions and eventually execute the actions
     *
     * @return void
     */
	public function triggerEvent($event_name, $event_parameters) {
		if ($event_name != $this->event_name) {
			//not a valid event
			return;
		}
 
		$this->event_parameters = $event_parameters;
		if ($this->checkConditions()) {
			$this->doActions();
		}
	}
	
	/**	
	 * Returns true when all condition criteria are met
	 * returns false when one of the condition criteria is not met
     * 
     * @return bool
     */
	protected function checkConditions() {
		//functionality to test conditions
		//returns true when all conditions are met
		//returns false when one condition fails
		foreach($this->conditions as $condition) {
			if ($condition->check($this->event_name, $this->event_parameters, $this) != false) {
				return false;
			}
		}
		return true;
	}
	
	/**
	 * Execute the actions immediatly or schedule them for future execution
     *
     * @return void
     */
	protected function doActions() {
		//execute the actions are schedule them
		foreach($this->actions as $action) {
			//add the action to the action queue of civicrm core
			CRM_Rules_Queue::addToQueue($action, $this->event_name, $this->event_parameters, $this);
		}
	}
 
	/**
     * Returns the data what can be used for the replacement patterns
     * We don't know yet how this is going to work or to look like
     * but we do know we have to have a method for retrieving and storing this data for future action execution
     *
     * @return array|mixed
     */
	public function getDataForReplacementPatterns() {
		//return something...
	}
 
}

class CRM_Rules_Model_ReplacementPattern {
 
	protected $dataselector;
 
    protected $dao;
 
    public function __construct($dataselector, $dao) {
		$this->dataselector = $dataselector;
        $this->dao = $dao;
    }
 
	public function getDataSelector() {
		return $this->dataselector;
	}
 
	public function getDao() {
		return $this->dao;
	}
 
	/**
     * Returns an array with sub dataselectors for this dataselector
     * E.g. if this data selector is on Contribution DAO then this will return all contribution dao fields
     * but the selection could also be altered by a hook
     *
     * @return array
     */
	public function getAvailableDataSelectors() {
		//code to return the available sub data selectors
	}
 
}