remote.js

// primitive encryption functions. this'll get 'em!

String.prototype.rot13 = function (){
	return this.replace(/[a-zA-Z]/g, function(c){
		return String.fromCharCode((c <= "Z" ? 90 : 122) >= (c = c.charCodeAt(0) + 13) ? c : c - 26);
	});
};

String.prototype.b64enc = function () {
	return Base64.encode(this);
};

String.prototype.b64dec = function () {
	return Base64.decode(this);
}

String.prototype.encrypt = function () {
	return this.b64enc().rot13();
};

String.prototype.decrypt = function () {
	return this.rot13().b64dec();
}

/**
 * A queue of XHRs
 * @namespace
 */
Queuer = (function () {

	/** @constructor */
	function Queuer() {
		this.queue = [];
	};

	/**
	 * Adds an XHR to the queue
	 * @param {XMLHttpRequest} xhr - the request to add
	 * @returns the Queuer
	 * @namespace Queuer
	 */
	Queuer.prototype.addRequest = function (xhr) {
		this.queue.push(xhr);
		return this;
	};

	/**
	 * Aborts all of the XHRs in the queue
	 * @returns the Queuer
	 * @namespace Queuer
	 */
	Queuer.prototype.abortAll = function () {
		while (this.queue.length) {
			this.queue[0].abort();
			this.queue.splice(0, 1);
		}
		return this;
	};

	return Queuer;
})();

/** @type Queuer */
var XHR_Queue = new Queuer();

/**
 * Logs an error to the console
 * @param {XMLHttpRequest} jqXHR - the request that threw the error
 * @param {string} textStatus - the type of error thrown
 * @param {string} errorThrown - a description of the error
 */
function default_error_handler(jqXHR, textStatus, errorThrown) {
	console.error(jqXHR, textStatus, errorThrown)
}

/**
 * Manages the time of the last update
 * @namespace
 */
var Updater = {

	/**
	 * Saves the current time to localStorage as the last updated time
	 */
	set_updated: function () {
		localStorage.setItem("lastupdated", (new Date()).getTime());
	},

	/**
	 * Gets the relative time of the last update based on localStorage
	 * @returns {string} relative time of the last update
	 */
	get_update_text: function () {
		return moment(parseInt(localStorage["lastupdated"])).fromNow();
	}
};

/**
 * Generates useful links for the user
 */
var Ad = {
	host: "https://hacaccess.herokuapp.com",

	/**
	 * Creates the most relevant link
	 * @returns {Element} a link to append to the marking period grades table
	 */
	generate_ad: function () {
		// update from server if necessary
		var curr_time = +new Date;
		var get_time = parseInt(localStorage["ad_updatetime"]);
		if (isNaN(get_time) || (curr_time - get_time > 24 * 60 * 60 * 1000))
			Ad.fetch_ad();

		// create the ad
		var ad = localStorage["ad_" + localStorage["ad"]];
		if (ad == "no") return document.createDocumentFragment();
		else {
			try {
				ad_json = JSON.parse(ad);
			} catch (e) {
				return document.createDocumentFragment();
			}
			return Ad.generate_ad_inner(ad_json.text, ad_json.url, ad_json.id);
		}
	},

	/**
	 * Generates a formatted link
	 * @param {string} text - the text of the link
	 * @param {string} url - the destination of the link
	 * @param {string} id - a unique identifier to send to Google Analytics when
	 * the link is clicked
	 */
	generate_ad_inner: function (text, url, id) {
		var wrapper = document.createElement("div");
		wrapper.setAttribute("id", "ad_wrapper");

		// create main ad
		var ad;
		if (url == "") {
			ad = document.createElement("span");
			$(ad).attr("id", "ad").html(text);
		} else {
			ad = document.createElement("a");
			$(ad).attr("id", "ad").data("label", id)
				.click(function () {
					chrome.tabs.create({"url": url});
					var label = $(this).data("label");
					if (label != "")
						_gaq.push(['_trackEvent', 'Ad', 'Follow ' + label]);
				})
				.html(text);
		}
		wrapper.appendChild(ad);

		// create link to hide ad
		var hideAd = document.createElement("a");
		$(hideAd).attr({"id": "hide_ad", "href": "#"}).data("label", id)
			.html("&times;").click(function () {
				var label = $(this).data("label");
				if (label != "")
					_gaq.push(['_trackEvent', 'Ad', 'Hide ' + label]);
				$("#ad_wrapper").remove();
				localStorage.setItem("ad_" + label, "no");
			});
		wrapper.appendChild(hideAd);

		return wrapper;
	},

	/**
	 * Fetches ad content from the qHAC server and caches it
	 */
	fetch_ad: function() {
		$.get(Ad.host + "/api/ad/latest", function(data) {
			var ad = JSON.parse(data);
			if (localStorage["ad_" + ad.id] == "no") return;
			localStorage["ad"] = ad.id;
			localStorage["ad_" + ad.id] = data;
			localStorage["ad_updatetime"] = +new Date;
		});
	}
};

/**
 * Interfaces with the Round Rock ISD Home Access Center
 * @namespace
 */
var RRISD_HAC = {

	/**
	 * Requests a session ID from Home Access by logging in
	 * @param {string} login - username
	 * @param {string} pass - password
	 * @param {string} id - 6-digit district-provided student ID
	 * @param {function} callback - a function to call if the request succeeds
	 * @param {function} on_error  a funciton to call if the request fails
	 */
	get_session: function (login, pass, id, callback, on_error) {
		GradeRetriever.login(
			Districts.roundrock,
			login,
			pass,
			function (doc, $dom, choices, state) {
				window.session_id = true;
				
				if (choices == null)
					callback(doc);
				else
					GradeRetriever.disambiguate(
						Districts.roundrock,
						id,
						state,
						callback)
			},
			on_error
		);
	},

	load_session: function (callback) {
		if (window.session_id == true || typeof localStorage["url"] != "undefined")
			callback();
		else
			RRISD_HAC.get_session(
				localStorage["login"].decrypt().decrypt(),
				localStorage["rrisd_password"].decrypt().decrypt(),
				localStorage["studentid"].decrypt().decrypt(),
				callback);
	},

	/**
	 * Retrieves grades from RRISD
	 * @param {string} url - the unique student URL that accesses grades
	 * @param {function} callback - a function to call when the request succeeds
	 * @param {function} on_error - a function to call when the request fails
	 */
	get_gradesHTML: function (url, callback, on_error) {
		if (typeof url == "undefined")
			GradeRetriever.getAverages(Districts.roundrock, function(doc) {
				window.doc = doc;
				callback(doc);
			}, on_error);
		else {
			var jqXHR = $.ajax({
				url: "https://gradebook.roundrockisd.org/pc/displaygrades.aspx?studentid=" + url,
				type: "GET"
				// dataType: "text gjson"
			}).done(callback).fail(on_error || default_error_handler);
			XHR_Queue.abortAll().addRequest(jqXHR);
		}
	},

	/**
	 * Retrieves class grades from RRISD
	 * @param {string} sID - the unique student URL that accesses grades
	 * @param {string} data - the class and marking period identifier
	 * @param {function} callback - a function to call when the request succeeds
	 * @param {function} on_error - a function to call when the request fails
	 */
	get_classGradeHTML: function (sID, data, callback, on_error) {

		if (typeof sID == "undefined")
			// overall grades need to be loaded first; load those if haven't already
			if (typeof window.doc == "undefined")
				RRISD_HAC.get_gradesHTML(undefined, function() {
					RRISD_HAC.get_classGradeHTML(sID, data, callback, on_error);
				}, on_error);
			else
				GradeRetriever.getClassGrades(Districts.roundrock, decodeURIComponent(data), window.doc, callback);
		else {
			var jqXHR = $.ajax({
					url: "https://gradebook.roundrockisd.org/pc/displaygrades.aspx?data=" + data + "&studentid=" + sID,
					type: "GET"
					// dataType: "text cjson",
					// data: {
					// 	"data": data,
					// 	"studentid": sID
					// }
				}).done(function (doc) {
					if (doc == "Could not decode student id.") {
						console.log("Error while fetching class grades (could not decode student ID)");
						on_error(new Error("Unable to decode student ID"));
						return false;
					}
					callback(doc);
				}).fail(on_error || default_error_handler);
			XHR_Queue.abortAll().addRequest(jqXHR);
		}
	}
};

/**
 * Interfaces with the Austin ISD Gradespeed (Home Access Center)
 */
var AISD_HAC = {

	/**
	* Requests a session ID from Home Access by logging in
	* @param {string} login - username
	* @param {string} pass - password
	* @param {string} id - 6-digit district-provided student ID
	* @param {function} callback - a function to call if the request succeeds
	* @param {function} on_error  a funciton to call if the request fails
	*/
	get_session: function (login, pass, id, callback, on_error) {
		GradeRetriever.login(
			Districts.austin,
			login,
			pass,
			function (doc, $dom, choices, state) {
				window.session_id = true;

				if (choices == null)
					callback(doc);
				else
					GradeRetriever.disambiguate(
						Districts.austin,
						id,
						state,
						callback)
			},
			on_error
		);
	},
	/**
	 * Calls a function, ensuring that window.session_id has been set to an
	 * AISD session ID.
	 * @param {function} callback - the function to call once the session
	 * has been loaded
	 */
	load_session: function (callback) {
		if (window.session_id == true)
			callback();
		else
			AISD_HAC.get_session(
				localStorage["login"].decrypt().decrypt(),
				localStorage["aisd_password"].decrypt().decrypt(),
				localStorage["studentid"].decrypt().decrypt(),
				callback);
	},

	/**
	 * Retrieves grades from AISD
	 * @param {string} id - a valid AISD session ID
	 * @param {function} callback - a function to call when the request succeeds
	 */
	get_gradesHTML: function (id, studentid, callback, on_error) {
		GradeRetriever.getAverages(Districts.austin, callback, on_error);
	},

	/**
	 * Retrieves class grades from AISD
	 * @param {string} id - a valid AISD session ID
	 * @param {string} studentid - the 7-digit district-assigned student ID
	 * @param {string} data - the class and marking period identifier
	 * @param {function} callback - a function to call when the request succeeds
	 */
	get_classGradeHTML: function (id, studentid, data, callback, on_error) {
		GradeRetriever.getClassGrades(Districts.austin, decodeURIComponent(data), undefined, callback, on_error);
	}
};