var global_pending_events = 0;

function display_element(e, args) {
	var elem = document.getElementById(args.id);

	if (elem)
		elem.style.display = args.style;
}

function set_html(e, args) {
	var elem = document.getElementById(args.id);

	if (elem)
		elem.innerHTML = args.html;
}

function set_focus(e, args) {
	if (args.check_focused && focused)
		return;
	for (var i in args.id) {
		var id = args.id[i];

		if (args.sel_id)
			id += this.getAttribute("sel_id");

		var element = document.getElementById(id);
		if (element && element.offsetWidth) {
			if (!args.only_if_empty || !element.value || element.value.length == 0)
				element.focus();
			break;
		}
	}
}

function show_by_feature(e, args) {
	var id = args.id;
	var feat = args.feat;
	var klfun = args.klfun;
	var style = args.style;

	var elem = document.getElementById(id);
	if (!elem)
		return;

	if (!feat)
		feat = id;
	if (!klfun)
		klfun = form_key_lookup;
	if (!style)
		style = '';
	
	var f = split_setting(get_settings(feat, klfun, category_features));
	if (f && f.show > 0) {
		elem.style.display = style;
	} else {
		elem.style.display = 'none';
	}
}

/*
 * Registers all events to objects
 * (uses root so that object searching can be narrower)
 */
function register_events(events, root) {
	for (var event_id in events) {
		var current_event = events[event_id];
		var elements = [];

		/* Get all involved elements */
		if (current_event.id) {
			var element = root.getElementById(current_event.id);
			if (element)
				elements = [element];
		} else if (current_event.name) {
			elements = root.getElementsByName(current_event.name);
		} else if (current_event.array_name) {
			var element;
			var i = 0;
			while (element = root.getElementsByName(current_event.array_name + '[' + i + ']')[0]) {
				elements[i++] = element;
			}	
		} else if (current_event.array_id) {
			var element;
			var i = 0;
			while (element = root.getElementById(current_event.array_id + i)) {
				elements[i++] = element;
			}	
		}

		/* Check if object exists to attach event to */
		for (var element_index = 0; element_index < elements.length; element_index++) { 
			var element = elements[element_index];

			/* Init event id array */
			if (!element.event_ids)
				element.event_ids = [];

			/* Check if current event already have been attached to the object */
			if (isInArray(event_id, element.event_ids))
				continue;

			/* Store current event id */
			element.event_ids[element.event_ids.length] = event_id;

			/* Hijack the element, create an event array */
			if (!element.events)
				element.events = [];

			/* Create array for each event trigger (Support for multiple events each event) */
			if (!element.events[current_event.trigger])
				element.events[current_event.trigger] = [];

			/* Store the event in the objects event array */
			element.events[current_event.trigger][element.events[current_event.trigger].length] = current_event;

			/* Load events */
			if (current_event.trigger == 'init') {
				call_event_timeout(element, 'init', 0);
			} else if (element.attachEvent) {
				/* Add an event listener to the object */
				element.attachEvent("on" +  current_event.trigger, /* The event trigger name */
						call_event /* Event callback */
						);
			} else {
				element.addEventListener(current_event.trigger, /* The event trigger name */
						call_event, /* Event callback */
						true); /* Event bubbling */
			}
		}
	}
}

/*
 * Event call back handler
 */
function call_event(e) {
	/* This element */
	var element = this;
	var type = e.type;

	/* TODO srcElement is not necessarily the element we registered to. */
	if (window.event)
		element = window.event.srcElement;

	if (element.asyncs > 0) {
		/* Already running, reschedule ourselves. */
		call_event_timeout(element, type, 50);
		return;
	}

	global_pending_events++;
	element.asyncs = 1;

	/* Go through all events linked to the element event type */
	for (var ep in element.events[type]) {
		var current_event = element.events[type][ep];

		if (!current_event.bubble) {
			/* Don't do events below this object*/
			if (window.event) {
				window.event.cancelBubble = true;
			} else if (e && e.stopPropagation) {
				e.stopPropagation();
			}
		}

		/* Execute all actions in the current event */
		for (var function_index in current_event.action) {
			var function_conf = current_event.action[function_index];
			var f = eval(function_conf.name);
			var args = function_conf.args;

			/* 
			 * (element, f, args) need local binding within the higher order function. To bind them, we need to
			 * create a higher higher order function and evalutate it to force the binding.
			 */
			var run_me = (function (element, f, args) {
					return (function () {
						/* Get function reference */
						/* Execute function as if it was called by THIS, and send the event argument */
						f.call(element, [element, type], args);
					});
				})(element, f, args);

			if (function_conf.async) {
				global_pending_events++;
				element.asyncs++;
				run_me();
			} else
				queue_document_change([element, type], run_me);
			run_me = null;
		}
	}

	global_pending_events--;
	if (--element.asyncs == 0) {
		run_document_changes(element);
	}
}

function queue_document_change(e, f) {
	var element = e[0];

	if (!element.document_changes || element.document_changes === "")
		element.document_changes = [];
	element.document_changes[element.document_changes.length] = f;
}

function event_async_done(e) {
	var element = e[0];
	var type = e[1];

	global_pending_events--;
	element.asyncs--;

	if (element.asyncs == 0) {
		run_document_changes(element);
	}
}

function run_document_changes(element) {
	while (element.document_changes) {
		var to_run = element.document_changes;
		element.document_changes = "";

		/* LIFO */
		for (var i = to_run.length - 1; i >= 0; i--) {
			var f = to_run[i];

			f();
		}
	}
}

function call_event_timeout(element, type, time) {
	setTimeout(function() { call_event.call(element, {'type' : type}) }, time);
}