// Some silly experimentation with colour effects.

function PixelGrid(root, width, height) {
    this.root = root;
    this.width = width;
    this.height = height;
    this.pixels = null;
    this.create();
};

PixelGrid.prototype = {
    create: function() {
        var pixels = [], root = this.root, width = this.width, height = this.height;
        for (var j = 0; j < height; j++) {
    		var row = document.createElement("tr"), inner = [];
    		for (var i = 0; i < width; i++) {
    			var cell = document.createElement("td");
    			inner.push([cell.style, [0, 0, 0], {}]);
    			row.appendChild(cell);
    		}
    		root.appendChild(row);
    		pixels.push(inner);
    	}
    	this.pixels = pixels;
    },
    
    fillRandom: function(base, variance) {
        
        var width = this.width,
            height = this.height;
        
        var base_h = base[0] - variance[0],
            base_s = base[1] - variance[1],
            base_v = base[2] - variance[2];
    	
    	var var_h = variance[0] * 2,
    	    var_s = variance[1] * 2,
    	    var_v = variance[2] * 2;
    	
    	var out = [null, null, null];

    	for (var j = 0; j < height; j++) {
    		for (var i = 0; i < width; i++) {
    			var h = base_h + Math.random() * var_h;
    			var s = base_s + Math.random() * var_s;
    			var v = base_v + Math.random() * var_v;
    			this._hsv2rgb(h, s, v, out);
    			this.set(i, j, out[0], out[1], out[2]);
    		}
    	}
        
    },
    
    // gets r,g,b triple at grid x,y
    get: function(x, y) {
        var a = this.pixels[y][x][1]
        return [a[0], a[1], a[2]];
    },
    
    // returns the "extra" data for grid x,y
    extra: function(x, y) {
        return this.pixels[y][x][2];
    },
    
    set: function(x, y, r, g, b) {
        var ele = this.pixels[y][x];
    	ele[0].backgroundColor = 'rgb(' + r + ',' + g + ',' + b + ')';
    	ele[1][0] = r;
    	ele[1][1] = g;
    	ele[1][2] = b;
    },
    
    // Convert an HSV triple to RGB
    // Algorithm from Wikipedia...
    // http://en.wikipedia.org/wiki/HSV_color_space
    _hsv2rgb: function (h, s, v, out) {
    	var r, i, f, p, q, t;
    	i = Math.floor(h / 60) % 6;
    	f = (h / 60) - i;
    	p = v * (1 - s);
    	q = v * (1 - f * s);
    	t = v * (1 - (1 - f) * s);
    	switch (i) {
    		case 0: 
    			out[0] = Math.floor(v * 255);
    			out[1] = Math.floor(t * 255);
    			out[2] = Math.floor(p * 255);
    			return;
    		case 1:
    			out[0] = Math.floor(q * 255);
    			out[1] = Math.floor(v * 255);
    			out[2] = Math.floor(p * 255);
    			return;
    		case 2:
    			out[0] = Math.floor(p * 255);
    			out[1] = Math.floor(v * 255);
    			out[2] = Math.floor(t * 255);
    			return;
    		case 3:
    			out[0] = Math.floor(p * 255);
    			out[1] = Math.floor(q * 255);
    			out[2] = Math.floor(v * 255);
    			return;
    		case 4:
    			out[0] = Math.floor(t * 255);
    			out[1] = Math.floor(p * 255);
    			out[2] = Math.floor(v * 255);
    			return;
    		case 5:
    			out[0] = Math.floor(v * 255);
    			out[1] = Math.floor(p * 255);
    			out[2] = Math.floor(q * 255);
    			return;
    	}
    }
    
};

PixelGrid.Glimmer = function(pixels, count) {
    var tweens = [];
    for (var i = 0; i < count; i++) {
        tweens.push({ delay: i * 7, max_delay: 70, completed: true });
    }
    
    setInterval(function() {
        for (var i = 0; i < count; i++) {
            var t = tweens[i];
            if (t.completed) {
                if (t.delay > 0) {
                    t.delay -= 1;
                } else {
                    var x;
                    do {
                        t.x = Math.floor(Math.random() * pixels.width);
                        t.y = Math.floor(Math.random() * pixels.height);
                        x = pixels.extra(t.x, t.y);
                    } while (x.animating);
                    x.animating = true;
                    t.to = pixels.get(t.x, t.y);
                    t.from = [235, 255, 183];
                    t.delta = [t.to[0] - t.from[0], t.to[1] - t.from[1], t.to[2] - t.from[2]];
                    t.progress = 0;
                    t.completed = false;
                }
            } else {
                pixels.set(t.x, t.y, Math.floor(t.from[0] + t.delta[0] * t.progress),
                                     Math.floor(t.from[1] + t.delta[1] * t.progress),
                                     Math.floor(t.from[2] + t.delta[2] * t.progress));
                t.progress += 0.04;
                if (t.progress >= 1) {
                    t.delay = t.max_delay;
                    t.completed = true;
                    pixels.set(t.x, t.y, t.to[0], t.to[1], t.to[2]);
                    pixels.extra(t.x, t.y).animating = false;
                }
            }
        }
    }, 40);
};