// Package Definition //
var Package = {
	NAME: 'Profiler',
	VERSION: 0.1,
	DEFAULT: ['addProfiling', 'removeProfiling', 'profileReport'],
	EXPORT: [ ],
	EXPORT_OK: ['_start','_stop','_init'],
	EXPORT_TAGS: { }
};

// Private Variables //
var _fnlist = {};

/**
 * Create a tracking object for a new function
 * to be profiled.
 * @function
 */
function _init(fname, fn, scope) {
	console.log("Adding " + fname + ": ");
	if (typeof _fnlist[fname] == 'undefined') {
		_fnlist[fname] = {
			fn: fn,			// save original function
			scope: scope,	// object owner of function (context)
			ncalls: 0,		// number of calls made
			calls: {}		// individual call profiling
		};
	}
	else
		throw new Error(fname + " is already being profiled");
}

/**
 * Start timing this function, run prior to the
 * actual function's execution.
 * @function
 */
function _start(fname, fn, args) {
	_fnlist[fname].ncalls++;
	var start = new Date().getTime();
	var id = start + "_" + _fnlist[fname].ncalls;
	_fnlist[fname].calls[id] = {
		start: start,
		stop: null,
		args: args,
		total: 0
	};
	return id;	// unique id for *this* call
}

/**
 * Stop timing a function and calculate total
 * elapsed time (milliseconds)
 * @function
 */
function _stop(fname, id) {
	var ref = _fnlist[fname].calls[id];
	ref.stop = new Date().getTime();
	ref.total = ref.stop - ref.start;
}

/**
 * Add profiling for a given function, identified
 * by the given label. Returns the newly modified
 * function to be assigned to the old function.
 * @example addProfiling('func');
 * @example addProfiling('func', window);
 * @function
 */
function addProfiling(fname, scope) {
	var scope = scope || window;
	_init(fname, scope[fname], scope);
	var tmpfn = scope[fname];
	scope[fname] = function() {
		var id = _start(fname, tmpfn, arguments);
		var rv = tmpfn.apply(tmpfn, arguments);
		_stop(fname, id);
		return rv;	// return result of original function
	}
}

/**
 * Remove a function identified by the lable
 * from being profiled. Returns original function
 * to be reassigned.
 * @example removeProfiling('func');
 * @function
 */
function removeProfiling(fname) {
	_fnlist[fname]['scope'][fname] = _fnlist[fname].fn;
	delete _fnlist[fname];
}

/**
 * Report our profiling information via the console.
 * @function
 */
function profileReport() {
	for (fn in _fnlist) {
		var obj = _fnlist[fn];
		console.log("Function: " + fn + ":");
		console.dir(obj);
		console.log("\tTotal Calls: " + obj['ncalls']);
		var totaltime = 0;
		for (call in obj['calls']) {
			totaltime += obj['calls'][call].total;
		}
		console.log("\tTotal Time (sec): " + (totaltime/1000).toFixed(5));
	}
}