// Copyright 2007 Google, Inc.
// This sample code is under the Apache2 license, see
// http://www.apache.org/licenses/LICENSE-2.0 for license details.

/**
 * @fileoverview Wrapper for Time Tracking
 */

/**
 * @class Time Tracking component.
 *     This class encapsulates all logic for time tracking on a particular
 *     page. Time tracking could be for any object within a page or the page
 *     itself.
 *
 * @param {Array.<Number>} arg1 Optional array that represents the bucket
 * @constructor
 */
var TimeTracker = function(opt_bucket) {
	if (opt_bucket) {
		this.bucket_ = opt_bucket.sort(this.sortNumber); 
	} else {
		this.bucket_ = TimeTracker.DEFAULT_BUCKET;
	}
};

TimeTracker.prototype.startTime_;
TimeTracker.prototype.stopTime_;
TimeTracker.prototype.bucket_;
TimeTracker.DEFAULT_BUCKET = [100, 500, 1500, 2500, 5000];

/**
 * Calculates time difference between start and stop
 * @return {Number} The time difference between start and stop
 */
TimeTracker.prototype._getTimeDiff = function() {
	return (this.stopTime_ - this.startTime_);
};

/**
 * Helper function to sort an Array of numbers
 * @param {Number} arg1 The first number
 * @param {Number} arg2 The second number
 * @return {Number} The difference used to sort
 */
TimeTracker.prototype.sortNumber = function(a, b) {
	return (a - b);
}

/**
 * Records the start time
 * @param {Number} arg1 Optional start time specified by user
 */
TimeTracker.prototype._recordStartTime = function(opt_time) {
	if (opt_time != undefined) {
		this.startTime_ = opt_time;
	} else {
		this.startTime_ = (new Date()).getTime();
	}
};

/**
 * Records the stop time
 * @param {Number} arg1 Optional stop time specified by user
 */
TimeTracker.prototype._recordEndTime = function(opt_time) {
	if (opt_time != undefined) {
		this.stopTime_ = opt_time;
	} else {
		this.stopTime_ = (new Date()).getTime();
	}
};

/**
 * Tracks the event. Calculates time and sends information to
 * the event tracker passed
 * @param {Object} arg1 GA tracker created by user
 * @param {String} arg2 Optional event category
 * @param {String} arg3 Optional event label
 */
TimeTracker.prototype._track = function(tracker,
										opt_event_category,
                                        opt_event_label) {

	var i;
	var bucketString;
	var category;
	var page;
	
	if (opt_event_category != undefined && opt_event_category.length != 0) {
		category = opt_event_category;
	} else {
		category = 'TimeTracker';
	}
	
	if (opt_event_label != undefined && opt_event_label.length != 0) {
		page = opt_event_label;
	} else {
		page = 'Page';
	}
	
	for(i = 0; i < this.bucket_.length; i++) {
		if ((this._getTimeDiff()) < this.bucket_[i]) {
			if (i == 0) {
				bucketString = "0-" + (this.bucket_[0]);
				break;
			} else {
				bucketString = this.bucket_[i - 1] + "-" + (this.bucket_[i] - 1);
				break;
			}
		}
	}
	if (!bucketString) {
		bucketString = this.bucket_[i - 1] + "+";
	}
	
	try {
		tracker._trackEvent(category, bucketString, opt_event_label, this._getTimeDiff());
	} catch (e) {}
};

/**
 * Sets the bucket for histogram generation in GA
 * @param {Array.<Number>} The bucket array
 */
TimeTracker.prototype._setHistogramBuckets = function(buckets_array) {
	this.bucket_ = buckets_array.sort(this.sortNumber);
};