/*
This is the core logic for the main page.
It implements most page transitions by showing and hiding DIV elements
in the page with javascript+jquery
*/

/* Convert a JSON string to an object, or null if unparseable */
function j2o(json) { try { return JSON.parse(json); } catch(e) { return null; } }

/* Convert an object to a JSON string (just easier to type than "JSON.stringify" */
function o2j(obj) { return JSON.stringify(obj); }

function showHome(matches, cb) {
	cb("home");
}

// go to the page that lists the schools
function showSchools(matches, cb) {
	ProtoDiv.reset("PROTO_school");
	$.get("/schools", { cache: false }, function(response) {
		var schools = [];
		if(typeof response == 'object') {
			schools = response.schools;
		}
		ProtoDiv.replicate("PROTO_school", schools);
		cb("schools");
	});
}

// go to the page that lists the courses for a specific school
function showCourses(matches, cb) {
	var schoolId = matches[1];
	ProtoDiv.reset("PROTO_course");
	$.get("/school/"+schoolId, { cache: false }, function(response) {
		var courses = [];
		if(typeof response == 'object') {
			var school = response.school;
			$("#school_name").html(school.name);
			courses = school.courses;
		}
		ProtoDiv.replicate("PROTO_course", courses);
		cb("courses");
	});
}

// go to the page that lists the lectures for a specific course
function showLectures(matches, cb) {
	var courseId = matches[1];
	ProtoDiv.reset("PROTO_lecture");
	$.get("/course/"+courseId, { cache: false }, function(response) {
		ProtoDiv.reset("PROTO_lectures_head");
		ProtoDiv.reset("PROTO_lectures_instructor");
		ProtoDiv.reset("PROTO_lecture");
		if(typeof response == 'object') {
			var course = response.course;
			if(course)
				ProtoDiv.replicate("PROTO_lectures_head", [course]);
			var instructor = response.instructor;
			if(instructor)
				ProtoDiv.replicate("PROTO_lectures_instructor", [instructor]);
			var lectures = response.lectures;
			if(lectures)
				ProtoDiv.replicate("PROTO_lecture", lectures);
		}
		cb("lectures");
	});
}

// go to the page that lists the note taking sessions for a specific lecture
function showNotes(matches, cb) {
	var lectureId = matches[1];
	ProtoDiv.reset("PROTO_note");
	$.get("/lecture/"+lectureId, { cache: false }, function(response) {
		if(typeof response == 'object') {
			var course = response.course;
			//if(course)
			//	ProtoDiv.replicate("PROTO_lectures_head", [course])
			var instructor = response.instructor;
			//if(instructor)
			//	ProtoDiv.replicate("PROTO_lectures_instructor", [instructor])
			var lecture = response.lecture;
			//if(lecture)
			//	ProtoDiv.replicate("PROTO_lecture", lectures);
			var notes = response.notes;
			if(notes)
				ProtoDiv.replicate("PROTO_note", notes);
		}
		cb("notes");
	});
}

// go to the page that lists the archived subject names
function showArchiveSubjects(matches, cb) {
	ProtoDiv.reset("PROTO_archive_subject");
	$.get("/archive", { cache: false }, function(response) {
		var subjects = response.subjects;
		ProtoDiv.replicate("PROTO_archive_subject", subjects);
	})
	cb("archive_subjects");
}

function showArchiveCourses(matches, cb) {
	var subjectId = parseInt(matches[1]);
	ProtoDiv.reset("PROTO_archive_course");
	$.get("/archive/subject/"+subjectId, { cache: false }, function(response) {
		var courses = response.courses;
		ProtoDiv.replicate("PROTO_archive_course", courses);
	})
	cb("archive_courses");
}

function showArchiveNotes(matches, cb) {
	var courseId = parseInt(matches[1]);
	ProtoDiv.reset("PROTO_archive_note");
	$.get("/archive/course/"+courseId, { cache: false }, function(response) {
		var notes = response.notes;
		$.each(notes, function(i, note) {
			if(!note.topic)
				note.topic = note.text.substr(0, 15)+" ...";
		})
		ProtoDiv.replicate("PROTO_archive_note", notes);
	})
	cb("archive_notes");
}



function showArchiveNote(matches, cb) {
	var noteId = matches[1];
	ProtoDiv.reset("PROTO_archive_note_display");
	$.get("/archive/note/"+noteId, { cache: false }, function(response) {
		var note = response.note;
//note = { text: "Hi <i>Mom!</i>", topic: "21st Century Greetings" }
//		note.text = note.text || ""
		if(!note.topic)
			note.topic = note.text.substr(0, 15)+" ...";
//		if(note.err) {
//			note.topic = note.message
//			note.err = note.err.stack
//		}
//
		ProtoDiv.replicate("PROTO_archive_note_display", note);
	})
	cb("archive_note_display");
}

// go to the account registration page
function showRegister(matches, cb) {
	// xxx clear fields?
	// xxx change FORM to use AJAX
	cb("register");
}

function showLogin(matches, cb) {
	cb("login");
}

// go to the press articles page
function showPress(matches, cb) {
	cb("press");
}

// go to the "code of conduct" page
function showConduct(matches, cb) {
	cb("conduct");
}

var pageVectors = [
	{ regex: /^\/(index.html)?$/, func: showHome },
	{ regex: /^\/schools/, func: showSchools },
	{ regex: /^\/school\/([a-f0-9]{24})/, func: showCourses },
	{ regex: /^\/course\/([a-f0-9]{24})/, func: showLectures },
	{ regex: /^\/lecture\/([a-f0-9]{24})/, func: showNotes },
	{ regex: /^\/archive\/?$/, func: showArchiveSubjects },
	{ regex: /^\/archive\/subject\/([0-9]+)/, func: showArchiveCourses },
	{ regex: /^\/archive\/course\/([0-9]+)/, func: showArchiveNotes },
	{ regex: /^\/archive\/note\/([a-f0-9]{24})/, func: showArchiveNote },
	{ regex: /^\/login/, func: showLogin },
	{ regex: /^\/register/, func: showRegister },
	{ regex: /^\/press/, func: showPress },
	{ regex: /^\/conduct/, func: showConduct }
];

/* Do and show the appropriate thing, based on the pages current URL */
function showPage(y) {
	var path = document.location.pathname;
	$(".page").hide(); //(100);		// hide all pseudo pages
	for(var i = 0; i < pageVectors.length; i++) {
		var vector = pageVectors[i];
		var matches = path.match(vector.regex);
		if(matches) {
			vector.func(matches, function(pageId) {
				$("#pg_"+pageId).fadeIn(100);
				window.scroll(0, y);
			})
			break;
		}
	}
	if(i == pageVectors.length) {
		$("#pg_notfound").fadeIn(100);
		window.scroll(0, 0);
	}
	// scroll to top of page (as if we'd done a real page fetch)
	/*$('html, body').animate({
		scrollTop: $("#topofcontent").offset().top
	}, 100);*/
}

/* Simulates a page load.
	'path' is something like "/schools", etc.
	A page fetch doesn't really happen.
	Based on what path looks like, an appropriate DIV is shown, and action taken
*/
var topQueue = [0];
function goPage(path) {
	if(history.pushState !== undefined) {
		topQueue.push(window.pageYOffset);
		history.pushState({}, path, path);
		showPage(0);
	}
	else {
		document.location = path;
	}
}

/* Simulates a "back" browser navigation.  */
var popped = false;
function goBack(event) {
	popped = true;
	showPage( topQueue.pop() );
}

$(document).ready(function() {
	// This code executes after the page has been fully loaded
	$(".proto").css("display", "none");		// make all the prototypes invisible
	//$("body").get(0).onunload = function() { }	// fires when leaving the page proper
	ProtoDiv.each = function(e) { $(e).show() };
	window.onpopstate = goBack;
	/*setTimeout(function() {
		if(!popped)
			showPage(0)
	}, 2000);*/
	// xxx older FF browsers don't fire a page load/reload - deal with it somehow.
	// showPage( 0 );		// needed for some older browsers, redundant for chrome
})