/*
    This file is part of LibSCORM 2004.

    LibSCORM 2004 is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 2 of the License, or
    (at your option) any later version.

    LibSCORM 2004 is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with LibSCORM 2004; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

*/


//////////////////////////////////////////////////////////////////////////////
// This library finds the DOM object API_1484_11 and wraps its API, throwing
// clear, detailed exceptions upon any error. This saves you from having to
// both constantly check for error codes and translate them when they appear.
//////////////////////////////////////////////////////////////////////////////

function LMS(win) {
	this._api  = this._getAPI(win);
	this._time = 0;
	this._terminated = false;
	
	if(this._api == null) {
		throw new LibScormException(
			-1, "LMS::LMS",
			"The SCORM API is not available.",
			"This SCO might not be running within an LMS environment.");
	}
	this._wrap("Initialize", true, "");

	this.PauseSessionTimer();
	var self = this;
	setInterval(function(){ if(!self._isTimePaused) self._time++; }, 1000);
}

LMS.prototype.Terminate = function() {
	this._terminated = true;
	this._wrap("Terminate", true, "");
}

LMS.prototype.IsTerminated = function() {
	return this._terminated;
}

LMS.prototype.GetValue = function(name) {
	return this._wrap("GetValue", false, name);
}

LMS.prototype.SetValue = function(name, value) {
	this._wrap("SetValue", true, name, value);
}

LMS.prototype.Commit = function() {
	this._wrap("Commit", true, "");
}

LMS.prototype.StartSessionTimer = function() {
	this._isTimePaused = false;
}

LMS.prototype.PauseSessionTimer = function() {
	this._isTimePaused = true;
}

LMS.prototype.RecordSessionTime = function() {
	this.SetValue("cmi.session_time", this._secondsToDuration(this._time));
}

//////////////////////////////////////////////////////////////////////////////
//                              DISCOURAGED STUFF
// You won't need these error info methods. Rely on exception handling in
// JavaScript SCOs. The methods are included only for Flash SCOs (which
// can't catch exceptions).
//////////////////////////////////////////////////////////////////////////////

LMS.prototype.GetLastError = function() {
	return this._api.GetLastError();
}

LMS.prototype.GetDiagnostic = function(errorCode) {
	return this._api.GetDiagnostic(errorCode);
}

LMS.prototype.GetErrorString = function(errorCode) {
	return this._api.GetErrorString(errorCode);
}

//////////////////////////////////////////////////////////////////////////////
//////////////////////////////// PRIVATE STUFF ///////////////////////////////
//////////////////////////////////////////////////////////////////////////////

LMS.prototype._api;
LMS.prototype._time;
LMS.prototype._isTimePaused;
LMS.prototype._terminated;

// _wrap passes along any extra arguments
LMS.prototype._wrap = function(func, isBoolean) {
	var args = new Array();
	for(var i = 2; i < arguments.length; i++) {
		// These arguments will appear in an eval, so we MUST
		// escape them since we're wrapping them in another layer
		// of quotes. (QuoteString comes from SerializeJS.js)
		args.push((typeof arguments[i] == 'string')
		          ? '"' + QuoteString(arguments[i]) + '"'
		          : arguments[i]);
	}
	// You may wonder, "Why not simply use this._api[func].apply(...)?"
	// Certainly we wouldn't have to mess with quoting the arguments, etc.
	// The answer is that LiveConnect does not offer us a real object
	// with function members, e.g. typeof this._api["Initialize"] == undefined
	var result = eval("this._api." + func + "(" + args.join(",") + ");");

	// boolean functions afford us an optimization: if the function returns
	// true then we needn't GetLastError (another costly call to the LMS)
	if(!isBoolean || result != "true") {
		var err = this._api.GetLastError();
		if(err != 0) {
			throw new LibScormException(
				err,
				"LMS::" + func + "(" + args.join(",") + ")",
				this._api.GetErrorString(err),
				this._api.GetDiagnostic(err)
			);
		}
	}
	return result;
}

// _getAPI and _scanForAPI functions adapted from
// http://www.ostyn.com/standards/scorm/samples/api_discovery_ff_issue.htm

LMS.prototype._getAPI = function(win) {
	try {
		var ret = this._scanParentsForAPI(win);
		return ret ? ret : this._scanParentsForAPI(win.opener);
	} catch(e) {
		return null;
	}
}

LMS.prototype._scanParentsForAPI = function(win) {
	var api;
	do {
		api = win.API_1484_11;
		if (win.parent == null || win.parent == win) {
			break;
		}
		win = win.parent;
	} while (!api);
	return api;
}

LMS.prototype._secondsToDuration = function(time) {
	var result;
	if(time == 0) {
		result = "PT0H0M0S";
	} else {
		result = "P";
		var tmp = time;
		var years = Math.floor(tmp / 31536000);
		tmp -= years * 31536000;
		var months = Math.floor(tmp / 2592000);
		tmp -= months * 2592000;
		var days = Math.floor(tmp / 86400);
		tmp -= days * 86400;
		var hours = Math.floor(tmp / 3600);
		tmp -= hours * 3600;
		var minutes = Math.floor(tmp / 60);
		tmp -= minutes * 60;
		var seconds = Math.floor(tmp);
		tmp -= seconds;
		//Now we are dealing with some fraction of seconds
		//We need to round it to 100ths
		var centisecs = Math.round(tmp * 100);

		if(years > 0) {
			result += years + "Y";
		}
		if(months > 0) {
			result += months + "M";
		}
		if(days > 0) {
			result += days + "D";
		}
		result += "T";
		result += hours + "H";
		result += minutes + "M";
		result += seconds + (centisecs > 0? "." + centisecs: "") + "S";
	}
	return result;
}