/* JavaScript Strange Attractor generator using Canvas
 * by Jacob Seidelin 2009
 * Somewhat based on code by the magnificent Paul Bourke */


var StrangeGenerator = function() {

function $(id) { return document.getElementById(id); }

var background;

var 	w, h,
	running = false,
	doneCallback,
 	maxIterations,
	maxAttractors = 10000,
	numAttractors = 0,

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

	isChrome = /Chrome/.test(navigator.userAgent), // sorry.

 	sin = Math.sin,
	cos = Math.cos,
	sqrt = Math.sqrt,
	abs = Math.abs,
	log = Math.log,
	pow = Math.pow,

 	RNG = new MersenneTwister19937(),
	seed;

function random() {
	return RNG.genrand_real1();
}

var 	logelement = $("log"),
	loglines = [],
	fadelogTimer;

function printLog(str, newline) {
	if (newline) {
		if (loglines.length > 20) loglines.shift();
		loglines.push(str);
	} else {
		loglines[loglines.length-1] += str;
	}
	logelement.innerHTML = loglines.join("<br>");
}

function fadeoutLog() {
	var logopacity = 1;
	var next = function() {
		logopacity -= 0.05;
		if (logopacity < 0) {
			logopacity = 0;
			fadelogTimer = 0;
			logelement.style.display = "none";
		} else {
			fadelogTimer = setTimeout(next, 1000 / 30);
		}
		logelement.style.opacity = logopacity;
		logelement.style.mozOpacity = logopacity;

	}
	next();
}

function resetLog() {
	if (fadelogTimer) {
		clearTimeout(fadelogTimer)
		fadelogTimer = 0; 
	}

	loglines = [];
	logelement.innerHTML = "";
	logelement.style.display = "block";
	logelement.style.opacity = 1;
	logelement.style.mozOpacity = 1;
}



function nextAttractor(fixedseed) {
	running = true;
	numAttractors++;
	if (numAttractors > maxAttractors) {
		printLog("Attractor limit reached, bailing out");
		running = false;
		return;
	}
	if (numAttractors > 1000)
		$("piece-title").innerHTML = "This is taking a long time, huh?";

	seed = (typeof fixedseed == "number") ? fixedseed : (Math.round(Math.random() * 0xffffffff));
	RNG.init_genrand(seed);

	printLog("Calculating attractor (seed = " + seed + ") ", true);
	setTimeout(function() {
		generateAttractor(typeof fixedseed == "number");
	}, 1);
}

function generateAttractor(fixed) {

	var ax = [];
	var ay = [];
	var drawit;
	var xmin=1e32,xmax=-1e32,ymin=1e32,ymax=-1e32;
	var d0,dd,dx,dy,lyapunov;
	var xe,ye,xenew,yenew;

	for (i=0;i<6;i++) {
		ax[i] = 4 * (random() - 0.5);
		ay[i] = 4 * (random() - 0.5);
	}
	var 	ax0 = ax[0],
		ax1 = ax[1],
		ax2 = ax[2],
		ax3 = ax[3],
		ax4 = ax[4],
		ax5 = ax[5],
		ay0 = ay[0],
		ay1 = ay[1],
		ay2 = ay[2],
		ay3 = ay[3],
		ay4 = ay[4],
		ay5 = ay[5];

	var x = [random() - 0.5];
	var y = [random() - 0.5];
	var hxy = [0];

	lyapunov = 0;
	xmin =  1e32;
	xmax = -1e32;
	ymin =  1e32;
	ymax = -1e32;

	hxy = [];

	drawit = true;
	do {
		xe = x[0] + (random() - 0.5) / 1000.0;
		ye = y[0] + (random() - 0.5) / 1000.0;
		dx = x[0] - xe;
		dy = y[0] - ye;
		d0 = sqrt(dx * dx + dy * dy);
	} while (d0 <= 0);

	var i=1;
	var batchcalc = 2500;

	var calcdone = function(bailout) {
		if (!fixed) {
			/* Classify the series according to lyapunov */
			if (!bailout) {
				if (abs(lyapunov) < 10) {
					printLog("Found neutrally stable, cancelling.", true);
					bailout = true;
				} else if (lyapunov < 0) {
					printLog("Found periodic " + lyapunov + ", cancelling", true);
					bailout = true; 
				} else {
					printLog("Found chaotic " + lyapunov, true); 
				}
			}
		}
	
		if (!bailout || fixed) {
			printLog("Drawing attractor ", true);
			setTimeout(function() {
				draw(x, y, xmin, xmax, ymin, ymax, hxy);
			}, 1);
		} else {
			setTimeout(function() {nextAttractor()}, 1);
		}
	}

	var nextcalc = function() {
		var bailout = false;
		for (j=0;j<batchcalc&&i<maxIterations;i++,j++) {
			var i1 = i-1;
			var x1 = x[i1], y1 = y[i1];
			var xx = x1*x1, yy = y1*y1, xy = x1*y1;

			if (options.formula == 0) { // Quadratic
				var xi = ax0 + ax1*x1 + ax2*xx + ax3*xy + ax4*y1 + ax5*yy;
				var yi = ay0 + ay1*x1 + ay2*xx + ay3*xy + ay4*y1 + ay5*yy;
			} else if (options.formula == 1) { // Trig
				var xi = ax0 * sin(ax1*y1) + ax2 * cos(ax3*x1);
				var yi = ay0 * sin(ay1*x1) + ay2 * cos(ay4*y1);
			} else if (options.formula == 2) { // Henon
				var xi = y1 + 1 - 1.4 * xx;
				var yi = 0.3 * x1;
			} else if (options.formula == 3) { // de Jong
				/* ax1 = 1.40; ax2 = 1.56; ay0 = 1.40; ax0 = -6.56; */
				var xi = ax0 * sin(ax1*y1) - cos(ax2*x1);
				var yi = ay0 * sin(ax1*x1) - cos(ax2*y1);
			}

			x[i] = xi;
			y[i] = yi;

			/* Update the bounds */
			if (xi < xmin) xmin = xi;
			if (yi < ymin) ymin = yi;
			if (xi > xmax) xmax = xi;
			if (yi > ymax) ymax = yi;

			if (options.compositing) {
				dx = (xi - x1) / (xmax - xmin);
				dy = (yi - y1) / (ymax - ymin);
				hxy[i] = dx*dx + dy*dy;
			}

			if (!fixed) {
				/* Does the series tend to infinity */
				if (xmin < -1e10 || ymin < -1e10 || xmax > 1e10 || ymax > 1e10) {
					//printLog("(Wow, infinity is huge!)", false);
					bailout = true;
					break;
				}

				var xexe = xe*xe, xeye = xe*ye, yeye = ye*ye;

				if (options.formula == 0) {
					xenew = ax0 + ax1*xe + ax2*xexe + ax3*xeye + ax4*ye + ax5*yeye;
					yenew = ay0 + ay1*xe + ay2*xexe + ay3*xeye + ay4*ye + ay5*yeye;
				} else if (options.formula == 1) {
					xenew = ax0 * sin(ax1*ye) + ax2 * cos(ax3*xe);
					yenew = ay0 * sin(ay1*xe) + ay2 * cos(ay4*ye);
				} else if (options.formula == 2) {
					var xenew = y1 + 1 - 1.4 * xexe;
					var yenew = 0.3 * xe;
				} else if (options.formula == 3) {
					var xenew = ax0 * sin(ax1*ye) - cos(ax2*xe);
					var yenew = ay0 * sin(ax1*xe) - cos(ax2*ye);
				}

				/* Does the series tend to a point */
				dx = x[i] - x[i-1];
				dy = y[i] - y[i-1];
				var absdx = dx < 0 ? -dx : dx;
				var absdy = dy < 0 ? -dy : dy;
				if (absdx < 1e-10 && absdy < 1e-10) {
					//printLog("(A point, that's no good)", false);
					bailout = true;
					break;
				}
	
				/* Calculate the lyapunov exponents */
				if (i > 1000) {
					dx = x[i] - xenew;
					dy = y[i] - yenew;
					dd = sqrt(dx * dx + dy * dy);
					var absddd0 = dd / d0;
					if (absddd0 < 0) absddd0 = -absddd0;
					lyapunov += log(absddd0);
					xe = x[i] + d0 * dx / dd;
					ye = y[i] + d0 * dy / dd;
				}
			}
		}
		if (i<maxIterations && !bailout) {
			printLog(".");
			setTimeout(nextcalc, 1);
		} else {
			calcdone(bailout);
		}
	}

	nextcalc();


}

var titleTimer;

// generate a name and start the silly animated text under the image
function createTitle() {
	if (options.formula == 2) {
		var name = "Hénon";
	} else {
		var 	names = StrangeGenerator.names,
			RNG = new MersenneTwister19937();
		RNG.init_genrand(seed);
		var twopart = (RNG.genrand_real1() < 0.5),
		    l = names.length;
		if (twopart) {
			var n1 = (l * RNG.genrand_real1()) >> 0,
			    n2 = (l * RNG.genrand_real1()) >> 0;
			name = names[n1] + " " + names[n2];
		} else {
			var n1 = (l * RNG.genrand_real1()) >> 0;
			name = names[n1];
		}
	}

	var 	seedstr = seed+"",
		lastdigit = (seedstr)[seedstr.length-1];

	switch (lastdigit) {
		case "1" :
			seedstr += "<sup>st</sup>";
			break;
		case "2" : 
			seedstr += "<sup>nd</sup>";
			break;
		case "3" :
			seedstr += "<sup>rd</sup>";
			break;
		default :
			seedstr += "<sup>th</sup>";
	}

	if (options.formula != 2) {
		var text = [
			"We have found your attractor",
			"It is strange and we have named it...",
			name + " (" + seed + ")",
			"There are many other attractors",
			"But this, the " + seedstr + ", is yours",
			name + " (" + seed + ")"
		];
	} else {
		var text = [
			"We have found your attractor",
			"It is strange and we have named it...",
			name
		]
	}

	var showtitle = function() {
		$("piece-title").innerHTML = text[0]
		text.shift();
		if (text.length)
			titleTimer = setTimeout(showtitle, 3000);
		else
			titleTimer = 0;
	}
	showtitle();
}

function resetTitle() {
	if (titleTimer) {
		clearTimeout(titleTimer);
		titleTimer = 0;
	}
	$("piece-title").innerHTML = "It is a mystery";
}

function draw(x, y, xmin, xmax, ymin, ymax, hxy) {
	//ctx.fillStyle = options.compositing ? background : "rgb(20,29,39)";
	ctx.fillStyle = options.compositing ? background : "rgb(21,29,41)";
	ctx.fillRect(0,0,w,h);

	// canvas used for compositing effects
	var 	blur = document.createElement("canvas"),
		blurctx = blur.getContext("2d");

	blur.width = w;
	blur.height = h;
	blurctx.fillStyle = background;
	blurctx.fillRect(0,0,w,h);

	var fx, fy, ix, iy;

	var finish = function() {
		printLog("All done!", true)
		setTimeout(fadeoutLog, 500);
		running = false;
		if (doneCallback)
			doneCallback();
	};

	var composite = function() {
		printLog("(1/3)", false)

		setTimeout(function() {
			var blur1 = Pixastic.process(canvas, "blurfast", {amount : 1, leaveDOM : true});
			var res = Pixastic.process(canvas, "blend", {image : blur1, mode : "normal", amount : 0.2, leaveDOM : true});
			ctx.drawImage(res, 0, 0);

			printLog("Compositing...(2/3)", true)

			setTimeout(function() {

				var blur2 = Pixastic.process(blur, "blurfast", {amount : 2, leaveDOM : true})
				var res = Pixastic.process(canvas, "blend", {image : blur2, mode : "lineardodge", leaveDOM : true, amount : 0.4});
				ctx.drawImage(res, 0, 0, w, h);

				printLog("Compositing...(3/3)", true)
		
				setTimeout(function() {
					var glow = Pixastic.process(canvas, "glow", {amount : 0.4, radius : 0.3, leaveDOM : true})
					ctx.drawImage(glow, 0, 0, w, h);

					finish();
				},50);
			},50);
		},50);
	};

	var drawdone = function() {
		ctx.putImageData(data, 0, 0);
		if (options.compositing) {
			printLog("Compositing...", true)
			setTimeout(composite, 100);
		} else {
			finish();
		}
	};


	var 	xrange = (xmax - xmin) / 0.8,
		yrange = (ymax - ymin) / 0.8;

	if (!options.stretch) {
		if (yrange > xrange) {
			xmin -= (yrange - xrange) / 2;
			xmax -= (yrange - xrange) / 2;
			xrange = yrange;
		} else if (xrange > yrange) {
			ymin -= (xrange - yrange) / 2;
			ymax -= (xrange - yrange) / 2;
			yrange = xrange;
		}
	}


	blurctx.beginPath();
	var hue = ((random() * 360 * 4)) % 360 >> 0;
	blurctx.fillStyle = "hsla(" + hue + ",100%,60%,0.05)";

	createTitle();

	var data = ctx.getImageData(0,0,w,h),
	    batchcalc = 2000,
	    dc = 0,
	    i = 0;

	var nextdraw = function() {
		var 	c = 1.5 / options.quality,
			bc = (10 * options.quality)>>0;
		dc++;
		for (j=0;j<batchcalc&&i<maxIterations;i++,j++) {
			fx = (x[i] - xmin) / xrange + 0.1;
			fy = (y[i] - ymin) / yrange + 0.1;
			ix = (fx * w) >> 0;
			iy = (fy * h) >> 0;
			if (i > 100) {
				var p = (w*iy + ix) * 4;

				var 	r = data.data[p] + c,
					g = data.data[p+1] + c,
					b = data.data[p+2] + c;
				if (r > 255) r = 255;
				if (g > 255) g = 255;
				if (b > 255) b = 255;

				data.data[p] = r;
				data.data[p+1] = g;
				data.data[p+2] = b;

				if (options.compositing) {
					if (i < batchcalc*25) {
						var bhue = ((hue + hxy[i] * 120) % 360) >> 0;

						blurctx.fillStyle = "hsla(" + bhue + ",100%,60%,0.075)";

						var 	off = 5,
							bx = (ix - off)>>0,
							by = (iy - off)>>0;
						blurctx.fillRect(bx, by, 10, 10);
					}
				}
			}
		}

		if ((dc % 5) == 0)
			ctx.putImageData(data, 0, 0);

		if (i<maxIterations) {
			printLog(".");
			setTimeout(nextdraw, 1);
		} else {
			blurctx.fill();
			drawdone();
		}
	}

	nextdraw();
}


return {
	isRunning : function() {
		return running;
	},
	makeAttractor : function(seed, opt, callback) {
		options = opt;
		w = options.width;
		h = options.height;
		canvas.width = w;
		canvas.height = h;
		//background = "rgb(10,15,20)";
		background = "rgb(11,15,21)";
		maxIterations = 2000000 * options.quality;
		numAttractors = 0;

		resetLog();
		resetTitle();

		doneCallback = callback;

		nextAttractor(seed);
	}
}

};