/**
* @file
* @brief JS implementation of the ChangeSink.
* @note Uncomment lines commented like //t to enable spent time counting
* in the mutation event collector.
*/

if (!window.SkypeToolbars)
{
window.SkypeToolbars = {};
}

/**
* @brief Creates new ChangeSink object.
* @param doc Parent document.
*/
SkypeToolbars.CreateChangeSink = function(doc)
{
return new SkypeToolbars.ChangeSink(doc);
}

/**
* @brief Constructor.
* @param doc Parent document.
*/
SkypeToolbars.ChangeSink = function(doc)
{
this.NOTIFICATION_TIMER_DELAY = 200; // Timeout between handling mutation event and sending notification to C++.
this.MAX_DELAYED_EVENTS = 100; // Amount of mutation events to collect before explicitly sending notification to C++.

this.m_doc = doc; // Parent document.
this.m_injection = false; // True after BeginInjection was called and flase after EndInjection was called.
this.m_injectionNode = null // Node marked as 'being modified' in BeginInjection.
this.m_textNode = null; // Temporary variable to store node for DOMCharacterDataModified event during injection.
this.m_timerId = null; // ID of the timer.
this.m_modifiedNodes = new Array(); // List of modified nodes
//t this.tcounter = 0.0; // spent time in miliseconds during mutation event collecting.

var self = this;
this.on_event = function(e){self.EventHandler(e)};
this.on_timer = function(){self.SendNotification()};
}

/**
* @brief Adds or removes event listener (m_impl) to m_docEvents for events: DOMNodeInserted, DOMCharacterDataModified, DOMNodeRemoved.
* @param [in] add Adds event listener
* @return True if everything is OK, otherwise false.
*/
SkypeToolbars.ChangeSink.prototype.AddRemoveListener = function(add)
{
try
{
var el = this.m_doc.body;
if (!el)
{
el = this.m_doc;
}

var events = [ "DOMNodeInserted",
"DOMCharacterDataModified"];

for(var i = 0, length = events.length; i < length; i++) { if (add) el.addEventListener (events[i], this.on_event, true) else el.removeEventListener(events[i], this.on_event, true) } } catch (e) { console.log("error: " + e); } } /** * Stops receiving update events for specific range. Call this method before do any manipulations * with DOM if you don't want receive events for this changes. This method will call * range->PrepareForInjection if range isn't null.
* @param [in] node Domain html node for changes. May be null.
* @return SST_OK if successful, or an error value otherwise.
*/
SkypeToolbars.ChangeSink.prototype.BeginInjection = function(node)
{
this.m_injection = true;
this.m_injectionNode = node;
}

/**
* Starts receiving update events for specific range. Call this method after manipulations
* with DOM done to start receiving events. This method will call range->RestoreAfterInjection
* if range isn't null.
* @param [in] node Domain html node for changes. May be null.
* @return SST_OK if successful, or an error value otherwise.
*/
SkypeToolbars.ChangeSink.prototype.EndInjection = function()
{
this.m_injection = false;
this.m_injectionNode = null;
}

/// True, if BeginInjection was called and EndInjection wasn't.
SkypeToolbars.ChangeSink.prototype.IsInjecting = function()
{
return this.m_injection;
}


SkypeToolbars.ChangeSink.prototype.EventHandler = function(event)
{
try
{
var newNode = event.target;

if (this.m_injection)
{
// BeginInjection was called, so we should skip all children of the m_injectionNode
if (!this.m_injectionNode)
{
return;
}

var compare = this.m_injectionNode.compareDocumentPosition(newNode);
if (compare & SkypeToolbars.Node.DOCUMENT_POSITION_CONTAINED_BY)
{
// new node inside m_injectionNode
// do nothing with new node
return;
}
}

//t var start_time = (new Date).getTime() - 1.0; // round to upper integer value

// join nodes if JS makes multiple changes in DOM
if (this.m_modifiedNodes.length > 0)
{
var lastNode = this.m_modifiedNodes[this.m_modifiedNodes.length - 1];
var compare = lastNode.compareDocumentPosition(newNode);

if (compare & SkypeToolbars.Node.DOCUMENT_POSITION_CONTAINED_BY)
{
// new node inside last one
// do nothing with new node
return;
}
if (compare & SkypeToolbars.Node.DOCUMENT_POSITION_CONTAINS)
{
// new node contains last one
// use new node instead of last one
this.m_modifiedNodes[this.m_modifiedNodes.length - 1] = newNode;
return;
}
if (compare & SkypeToolbars.Node.DOCUMENT_POSITION_FOLLOWING)
{
if (newNode.isSameNode(lastNode.nextSibling))
{
// new node is the next sibling of the last node
// use parent instead of last node
this.m_modifiedNodes[this.m_modifiedNodes.length - 1] = lastNode.parentNode;
return;
}
}
if (compare & SkypeToolbars.Node.DOCUMENT_POSITION_PRECEDING)
{
if (newNode.isSameNode(lastNode.previousSibling))
{
// new node is the previous sibling of the last node
// use parent instead of last node
this.m_modifiedNodes[this.m_modifiedNodes.length - 1] = lastNode.parentNode;
return;
}
}
}

this.m_modifiedNodes.push(event.target);

if (this.m_modifiedNodes.length == 1)
{
// start timer on first node
clearTimeout(this.m_timerId);
this.m_timerId = setTimeout(this.on_timer, this.NOTIFICATION_TIMER_DELAY);
}
else if (this.m_modifiedNodes.length == this.MAX_DELAYED_EVENTS)
{
// immediately send notification to the C++ part of the plugin
// if we got enough delayed events
clearTimeout(this.m_timerId);
this.SendNotification();
}
}
catch (e)
{
console.log("error: " + e);
}
finally
{
//t this.tcounter += (new Date).getTime() - start_time;
}
}

/// Sends notification to the C++ part of the plugin
SkypeToolbars.ChangeSink.prototype.SendNotification = function()
{
var e = document.createEvent("Event");
e.initEvent("SkypeToolbars_ChangeSink", false, true);
e.modifiedNodes = this.m_modifiedNodes;
this.m_modifiedNodes = new Array();
//t e.tcounter = this.tcounter;
//t console.log("time: " + this.tcounter.toString());
//t this.tcounter = 0;
document.dispatchEvent(e);
}

// create META to inform contentscript.js that this file is ready
document.head.appendChild(document.createElement('meta')).name = "change_sink.js";