/*
 * This file is part of libdom.
 * Licensed under the MIT License,
 *                http://www.opensource.org/licenses/mit-license.php
 * Copyright 2009 Bo Yang <struggleyb.nku@gmail.com>
 */

#include <assert.h>
#include <stdlib.h>

#include "events/event.h"
#include "events/event_listener.h"
#include "events/event_target.h"

#include "core/document.h"
#include "core/node.h"
#include "core/string.h"

#include "utils/utils.h"
#include "utils/validate.h"

static void event_target_destroy_listeners(struct listener_entry *list)
{
	struct listener_entry *next = NULL;

	for (; list != next; list = next) {
		next = (struct listener_entry *) list->list.next;

		list_del(&list->list);
		dom_event_listener_unref(list->listener);
		dom_string_unref(list->type);
		free(list);
	}
}

/* Initialise this EventTarget */
dom_exception _dom_event_target_internal_initialise(
		dom_event_target_internal *eti)
{
	eti->listeners = NULL;

	return DOM_NO_ERR;
}

/* Finalise this EventTarget */
void _dom_event_target_internal_finalise(dom_event_target_internal *eti)
{
	if (eti->listeners != NULL)
		event_target_destroy_listeners(eti->listeners);
}

/*-------------------------------------------------------------------------*/
/* The public API */

/**
 * Add an EventListener to the EventTarget
 *
 * \param et        The EventTarget object
 * \param type      The event type which this event listener listens for
 * \param listener  The event listener object
 * \param capture   Whether add this listener in the capturing phase
 * \return DOM_NO_ERR on success, appropriate dom_exception on failure.
 */
dom_exception _dom_event_target_add_event_listener(
		dom_event_target_internal *eti,
		dom_string *type, struct dom_event_listener *listener, 
		bool capture)
{
	struct listener_entry *le = NULL;

	le = malloc(sizeof(struct listener_entry));
	if (le == NULL)
		return DOM_NO_MEM_ERR;
	
	/* Initialise the listener_entry */
	list_init(&le->list);
	le->type = dom_string_ref(type);
	le->listener = listener;
	dom_event_listener_ref(listener);
	le->capture = capture;

	if (eti->listeners == NULL) {
		eti->listeners = le;
	} else {
		list_append(&eti->listeners->list, &le->list);
	}

	return DOM_NO_ERR;
}

/**
 * Remove an EventListener from the EventTarget
 *
 * \param et        The EventTarget object
 * \param type      The event type this listener is registered for 
 * \param listener  The listener object
 * \param capture   Whether the listener is registered at the capturing phase
 * \return DOM_NO_ERR on success, appropriate dom_exception on failure.
 */
dom_exception _dom_event_target_remove_event_listener(
		dom_event_target_internal *eti,
		dom_string *type, struct dom_event_listener *listener, 
		bool capture)
{
	if (eti->listeners != NULL) {
		struct listener_entry *le = eti->listeners;

		do {
			if (dom_string_isequal(le->type, type) &&
					le->listener == listener &&
					le->capture == capture) {
				list_del(&le->list);
				dom_event_listener_unref(le->listener);
				dom_string_unref(le->type);
				free(le);
				break;
			}

			le = (struct listener_entry *) le->list.next;
		} while (le != eti->listeners);
	}

	return DOM_NO_ERR;
}

/**
 * Add an EventListener
 *
 * \param et         The EventTarget object
 * \param namespace  The namespace of this listener
 * \param type       The event type which this event listener listens for
 * \param listener   The event listener object
 * \param capture    Whether add this listener in the capturing phase
 * \return DOM_NO_ERR on success, appropriate dom_exception on failure.
 *
 * We don't support this API now, so it always return DOM_NOT_SUPPORTED_ERR.
 */
dom_exception _dom_event_target_add_event_listener_ns(
		dom_event_target_internal *eti,
		dom_string *namespace, dom_string *type, 
		struct dom_event_listener *listener, bool capture)
{
	UNUSED(eti);
	UNUSED(namespace);
	UNUSED(type);
	UNUSED(listener);
	UNUSED(capture);

	return DOM_NOT_SUPPORTED_ERR;
}

/**
 * Remove an EventListener
 *
 * \param et         The EventTarget object
 * \param namespace  The namespace of this listener
 * \param type       The event type which this event listener listens for
 * \param listener   The event listener object
 * \param capture    Whether add this listener in the capturing phase
 * \return DOM_NO_ERR on success, appropriate dom_exception on failure.
 *
 * We don't support this API now, so it always return DOM_NOT_SUPPORTED_ERR.
 */
dom_exception _dom_event_target_remove_event_listener_ns(
		dom_event_target_internal *eti,
		dom_string *namespace, dom_string *type, 
		struct dom_event_listener *listener, bool capture)
{
	UNUSED(eti);
	UNUSED(namespace);
	UNUSED(type);
	UNUSED(listener);
	UNUSED(capture);

	return DOM_NOT_SUPPORTED_ERR;
}

/*-------------------------------------------------------------------------*/

/**
 * Dispatch an event on certain EventTarget
 *
 * \param et       The EventTarget object
 * \param eti      Internal EventTarget object
 * \param evt      The event object
 * \param success  Indicates whether any of the listeners which handled the 
 *                 event called Event.preventDefault(). If 
 *                 Event.preventDefault() was called the returned value is 
 *                 false, else it is true.
 * \return DOM_NO_ERR on success, appropriate dom_exception on failure.
 */
dom_exception _dom_event_target_dispatch(dom_event_target *et,
		dom_event_target_internal *eti, 
		struct dom_event *evt, dom_event_flow_phase phase,
		bool *success)
{
	if (eti->listeners != NULL) {
		struct listener_entry *le = eti->listeners;

		evt->current = et;

		do {
			if (dom_string_isequal(le->type, evt->type)) {
				assert(le->listener->handler != NULL);

				if ((le->capture && 
						phase == DOM_CAPTURING_PHASE) ||
				    (le->capture == false && 
						phase == DOM_BUBBLING_PHASE) ||
				    (evt->target == evt->current && 
						phase == DOM_AT_TARGET)) {
					le->listener->handler(evt, 
							le->listener->pw);
					/* If the handler called
					 * stopImmediatePropagation, we should
					 * break */
					if (evt->stop_now == true)
						break;
				}
			}

			le = (struct listener_entry *) le->list.next;
		} while (le != eti->listeners);
	}

	if (evt->prevent_default == true)
		*success = false;

	return DOM_NO_ERR;
}