/* nt3d - Javascript library for doing some 3D stuff.
 * Copyright (C) 2012  Scott Worley <ScottWorley@ScottWorley.com>
 *
 *  This program is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Affero General Public License as
 *  published by the Free Software Foundation, either version 3 of the
 *  License, or (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Affero General Public License for more details.
 *
 *  You should have received a copy of the GNU Affero General Public License
 *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

nt3d = {
	triangle: function(a, b, c) {
		return [a, b, c];
	},
	quad: function(a, b, c, d) {
		return this.triangle(a, b, c).concat(
		       this.triangle(c, d, a));
	},
	trianglefan: function(fan) {
		var result = [];
		for (var i = 2; i < fan.length; i++) {
			result.push(fan[0], fan[i-1], fan[i]);
		}
		return result;
	},
	quadstrip: function(strip) {
		if (strip.length % 2 != 0) {
			alert("quadstrip length not divisble by 2!");
		}
		var result = [];
		for (var i = 2; i < strip.length; i += 2) {
			result = result.concat(nt3d.quad(strip[i-2], strip[i-1], strip[i+1], strip[i]));
		}
		return result;
	},
	closed_quadstrip: function(strip) {
		return nt3d.quadstrip(strip).concat(nt3d.quad(strip[strip.length-2], strip[strip.length-1], strip[1], strip[0]));
	},
	sub: function(a, b) {
		return [a[0] - b[0],
		        a[1] - b[1],
		        a[2] - b[2]];
	},
	cross: function(a, b) {
		return [a[1]*b[2] - a[2]*b[1],
		        a[2]*b[0] - a[0]*b[2],
		        a[0]*b[1] - a[1]*b[0]];
	},
	normal: function(a, b, c) {
		return this.cross(this.sub(a, b), this.sub(b, c));
	},
	go: function() {
		// Get params from form
		var params = [];
		for (var i = 0; i < this.user_params.length; i++) {
			params[i] = this.form.elements["param"+i].value;
		}

		// Run user_function
		this.points = this.user_function.apply(null, params);
		if (this.points.length % 3 != 0) {
			alert("Points list length not divisble by 3!");
		}
		var n = this.points.length / 3;

		// Make STL
		this.stl = "solid " + this.user_function.name + "\n";
		for (var i = 0; i < n; i++) {
			var a = this.points[i*3+0];
			var b = this.points[i*3+1];
			var c = this.points[i*3+2];
			var normal = this.normal(a, b, c);
			this.stl += "facet normal " + normal[0] + " " + normal[1] + " " + normal[2] + "\n" +
				"outer loop\n" +
				"vertex " + a[0] + " " + a[1] + " " + a[2] + "\n"+
				"vertex " + b[0] + " " + b[1] + " " + b[2] + "\n"+
				"vertex " + c[0] + " " + c[1] + " " + c[2] + "\n"+
				"endloop\n" +
				"endfacet\n";
		}
		this.stl += "endsolid " + this.user_function.name + "\n";

		// Remove any previous download links
		var old_download_link = document.getElementById("nt3d_download");
		if (old_download_link) {
			old_download_link.parentNode.removeChild(old_download_link);
		}

		// Offer result as download
		var download_link = document.createElement("a");
		download_link.appendChild(document.createTextNode("Download!"));
		download_link.setAttribute("id", "nt3d_download");
		download_link.setAttribute("style", "background-color: blue");
		download_link.setAttribute("download", this.user_function.name + ".stl");
		download_link.setAttribute("href", "data:application/sla," + encodeURIComponent(this.stl));
		this.ui.appendChild(download_link);
		setTimeout(function() { download_link.setAttribute("style", "-webkit-transition: background-color 0.4s; -moz-transition: background-color 0.4s; -o-transition: background-color 0.4s; -ms-transition: background-color 0.4s; transition: background-color 0.4s; background-color: inherit"); }, 0);
	},
	framework: function (f, params) {
		this.user_function = f;
		this.user_params = params;

		// Make the UI
		this.ui = document.getElementById("nt3dui");
		if (!this.ui) {
			this.ui = document.createElement("div");
			this.ui.setAttribute("id", "nt3dui");
			document.body.appendChild(this.ui);
		}
		this.form = document.createElement("form");
		this.form.setAttribute("onsubmit", "nt3d.go(); return false");
		this.ui.appendChild(this.form);
		var table = document.createElement("table");
		this.form.appendChild(table);
		var tr = document.createElement("tr");
		table.appendChild(tr);
		var th = document.createElement("th");
		th.appendChild(document.createTextNode("Variable"));
		tr.appendChild(th);
		th = document.createElement("th");
		th.appendChild(document.createTextNode("Value"));
		tr.appendChild(th);
		for (var i = 0; i < params.length; i++) {
			tr = document.createElement("tr");
			table.appendChild(tr);
			var td = document.createElement("td");
			td.appendChild(document.createTextNode(params[i][0]));
			tr.appendChild(td);
			td = document.createElement("td");
			var input = document.createElement("input");
			input.setAttribute("name", "param" + i);
			input.setAttribute("value", params[i][1]);
			td.appendChild(input);
			tr.appendChild(td);
		}
		var go = document.createElement("input");
		go.setAttribute("type", "button");
		go.setAttribute("value", "Go!");
		go.setAttribute("onclick", "nt3d.go()");
		this.form.appendChild(go);
	}
};