/*! FileSaver.js demo script

 *  2012-01-23

 *

 *  By Eli Grey, http://eligrey.com

 *  License: X11/MIT

 *    See LICENSE.md

 */

/*! @source http://purl.eligrey.com/github/FileSaver.js/blob/master/demo/demo.js */

/*jshint laxbreak: true, laxcomma: true, smarttabs: true*/

/*global saveAs, self*/

(function(view) {

"use strict";

// The canvas drawing portion of the demo is based off the demo at

// http://www.williammalone.com/articles/create-html5-canvas-javascript-drawing-app/

var

	  document = view.document

	, $ = function(id) {

		return document.getElementById(id);

	}

	, session = view.sessionStorage

	// only get URL when necessary in case Blob.js hasn't defined it yet

	, get_blob = function() {

		return view.Blob;

	}

	, canvas = $("canvas")

	, canvas_options_form = $("canvas-options")

	, canvas_filename = $("canvas-filename")

	, canvas_clear_button = $("canvas-clear")

	, text = $("text")

	, text_options_form = $("text-options")

	, text_filename = $("text-filename")

	, html = $("html")

	, html_options_form = $("html-options")

	, html_filename = $("html-filename")

	, ctx = canvas.getContext("2d")

	, drawing = false

	, x_points = session.x_points || []

	, y_points = session.y_points || []

	, drag_points = session.drag_points || []

	, add_point = function(x, y, dragging) {

		x_points.push(x);

		y_points.push(y);

		drag_points.push(dragging);

	}

	, draw = function(){

		canvas.width = canvas.width;

		ctx.lineWidth = 6;

		ctx.lineJoin = "round";

		ctx.strokeStyle = "#000000";

		var

			  i = 0

			, len = x_points.length

		;

		for(; i < len; i++) {

			ctx.beginPath();

			if (i && drag_points[i]) {

				ctx.moveTo(x_points[i-1], y_points[i-1]);

			} else {

				ctx.moveTo(x_points[i]-1, y_points[i]);

			}

			ctx.lineTo(x_points[i], y_points[i]);

			ctx.closePath();

			ctx.stroke();

		}

	}

	, stop_drawing = function() {

		drawing = false;

	}

	// Title guesser and document creator available at https://gist.github.com/1059648

	, guess_title = function(doc) {

		var

			  h = "h6 h5 h4 h3 h2 h1".split(" ")

			, i = h.length

			, headers

			, header_text

		;

		while (i--) {

			headers = doc.getElementsByTagName(h[i]);

			for (var j = 0, len = headers.length; j < len; j++) {

				header_text = headers[j].textContent.trim();

				if (header_text) {

					return header_text;

				}

			}

		}

	}

	, doc_impl = document.implementation

	, create_html_doc = function(html) {

		var

			  dt = doc_impl.createDocumentType('html', null, null)

			, doc = doc_impl.createDocument("http://www.w3.org/1999/xhtml", "html", dt)

			, doc_el = doc.documentElement

			, head = doc_el.appendChild(doc.createElement("head"))

			, charset_meta = head.appendChild(doc.createElement("meta"))

			, title = head.appendChild(doc.createElement("title"))

			, body = doc_el.appendChild(doc.createElement("body"))

			, i = 0

			, len = html.childNodes.length

		;

		charset_meta.setAttribute("charset", html.ownerDocument.characterSet);

		for (; i < len; i++) {

			body.appendChild(doc.importNode(html.childNodes.item(i), true));

		}

		var title_text = guess_title(doc);

		if (title_text) {

			title.appendChild(doc.createTextNode(title_text));

		}

		return doc;

	}

;

canvas.width = 500;

canvas.height = 300;

  if (typeof x_points === "string") {

	x_points = JSON.parse(x_points);

} if (typeof y_points === "string") {

	y_points = JSON.parse(y_points);

} if (typeof drag_points === "string") {

	drag_points = JSON.parse(drag_points);

} if (session.canvas_filename) {

	canvas_filename.value = session.canvas_filename;

} if (session.text) {

	text.value = session.text;

} if (session.text_filename) {

	text_filename.value = session.text_filename;

} if (session.html) {

	html.innerHTML = session.html;

} if (session.html_filename) {

	html_filename.value = session.html_filename;

}

drawing = true;

draw();

drawing = false;

canvas_clear_button.addEventListener("click", function() {

	canvas.width = canvas.width;

	x_points.length =

	y_points.length =

	drag_points.length =

		0;

}, false);

canvas.addEventListener("mousedown", function(event) {

	event.preventDefault();

	drawing = true;

	add_point(event.pageX - canvas.offsetLeft, event.pageY - canvas.offsetTop, false);

	draw();

}, false);

canvas.addEventListener("mousemove", function(event) {

	if (drawing) {

		add_point(event.pageX - canvas.offsetLeft, event.pageY - canvas.offsetTop, true);

		draw();

	}

}, false);

canvas.addEventListener("mouseup", stop_drawing, false);

canvas.addEventListener("mouseout", stop_drawing, false);

canvas_options_form.addEventListener("submit", function(event) {

	event.preventDefault();

	canvas.toBlob(function(blob) {

		saveAs(

			  blob

			, (canvas_filename.value || canvas_filename.placeholder) + ".png"

		);

	}, "image/png");

}, false);

text_options_form.addEventListener("submit", function(event) {

	event.preventDefault();

	var BB = get_blob();

	saveAs(

		  new BB(

			  [text.value || text.placeholder]

			, {type: "text/plain;charset=" + document.characterSet}

		)

		, (text_filename.value || text_filename.placeholder) + ".txt"

	);

}, false);

html_options_form.addEventListener("submit", function(event) {

	event.preventDefault();

	var

		  BB = get_blob()

		, xml_serializer = new XMLSerializer()

		, doc = create_html_doc(html)

	;

	saveAs(

		  new BB(

			  [xml_serializer.serializeToString(doc)]

			, {type: "application/xhtml+xml;charset=" + document.characterSet}

		)

		, (html_filename.value || html_filename.placeholder) + ".xhtml"

	);

}, false);

view.addEventListener("unload", function() {

	session.x_points = JSON.stringify(x_points);

	session.y_points = JSON.stringify(y_points);

	session.drag_points = JSON.stringify(drag_points);

	session.canvas_filename = canvas_filename.value;

	session.text = text.value;

	session.text_filename = text_filename.value;

	session.html = html.innerHTML;

	session.html_filename = html_filename.value;

}, false);

}(self));