/*
	Copyright (c) 2004-2005, The Dojo Foundation
	All Rights Reserved.

	Licensed under the Academic Free License version 2.1 or above OR the
	modified BSD license. For more information on Dojo licensing, see:

		http://dojotoolkit.org/community/licensing.shtml
*/

dojo.provide("dojo.graphics.color");
dojo.require("dojo.lang");
dojo.require("dojo.string");
dojo.require("dojo.math");

// TODO: rewrite the "x2y" methods to take advantage of the parsing
//       abilities of the Color object. Also, beef up the Color
//       object (as possible) to parse most common formats

// takes an r, g, b, a(lpha) value, [r, g, b, a] array, "rgb(...)" string, hex string (#aaa, #aaaaaa, aaaaaaa)
dojo.graphics.color.Color = function(r, g, b, a) {
	// dojo.debug("r:", r[0], "g:", r[1], "b:", r[2]);
	if(dojo.lang.isArray(r)) {
		this.r = r[0];
		this.g = r[1];
		this.b = r[2];
		this.a = r[3]||1.0;
	} else if(dojo.lang.isString(r)) {
		var rgb = dojo.graphics.color.extractRGB(r);
		this.r = rgb[0];
		this.g = rgb[1];
		this.b = rgb[2];
		this.a = g||1.0;
	} else if(r instanceof dojo.graphics.color.Color) {
		this.r = r.r;
		this.b = r.b;
		this.g = r.g;
		this.a = r.a;
	} else {
		this.r = r;
		this.g = g;
		this.b = b;
		this.a = a;
	}
}

dojo.lang.extend(dojo.graphics.color.Color, {
	toRgb: function(includeAlpha) {
		if(includeAlpha) {
			return this.toRgba();
		} else {
			return [this.r, this.g, this.b];
		}
	},

	toRgba: function() {
		return [this.r, this.g, this.b, this.a];
	},

	toHex: function() {
		return dojo.graphics.color.rgb2hex(this.toRgb());
	},

	toCss: function() {
		return "rgb(" + this.toRgb().join() + ")";
	},

	toString: function() {
		return this.toHex(); // decent default?
	},

	toHsv: function() {
		return dojo.graphics.color.rgb2hsv(this.toRgb());
	},

	toHsl: function() {
		return dojo.graphics.color.rgb2hsl(this.toRgb());
	},

	blend: function(color, weight) {
		return dojo.graphics.color.blend(this.toRgb(), new Color(color).toRgb(), weight);
	}
});

dojo.graphics.color.named = {
	white:      [255,255,255],
	black:      [0,0,0],
	red:        [255,0,0],
	green:	    [0,255,0],
	blue:       [0,0,255],
	navy:       [0,0,128],
	gray:       [128,128,128],
	silver:     [192,192,192]
};

// blend colors a and b (both as RGB array or hex strings) with weight from -1 to +1, 0 being a 50/50 blend
dojo.graphics.color.blend = function(a, b, weight) {
	if(typeof a == "string") { return dojo.graphics.color.blendHex(a, b, weight); }
	if(!weight) { weight = 0; }
	else if(weight > 1) { weight = 1; }
	else if(weight < -1) { weight = -1; }
	var c = new Array(3);
	for(var i = 0; i < 3; i++) {
		var half = Math.abs(a[i] - b[i])/2;
		c[i] = Math.floor(Math.min(a[i], b[i]) + half + (half * weight));
	}
	return c;
}

// very convenient blend that takes and returns hex values
// (will get called automatically by blend when blend gets strings)
dojo.graphics.color.blendHex = function(a, b, weight) {
	return dojo.graphics.color.rgb2hex(dojo.graphics.color.blend(dojo.graphics.color.hex2rgb(a), dojo.graphics.color.hex2rgb(b), weight));
}

// get RGB array from css-style color declarations
dojo.graphics.color.extractRGB = function(color) {
	var hex = "0123456789abcdef";
	color = color.toLowerCase();
	if( color.indexOf("rgb") == 0 ) {
		var matches = color.match(/rgba*\((\d+), *(\d+), *(\d+)/i);
		var ret = matches.splice(1, 3);
		return ret;
	} else {
		var colors = dojo.graphics.color.hex2rgb(color);
		if(colors) {
			return colors;
		} else {
			// named color (how many do we support?)
			return dojo.graphics.color.named[color] || [255, 255, 255];
		}
	}
}

dojo.graphics.color.hex2rgb = function(hex) {
	var hexNum = "0123456789ABCDEF";
	var rgb = new Array(3);
	if( hex.indexOf("#") == 0 ) { hex = hex.substring(1); }
	hex = hex.toUpperCase();
	if(hex.replace(new RegExp("["+hexNum+"]", "g"), "") != "") {
		return null;
	}
	if( hex.length == 3 ) {
		rgb[0] = hex.charAt(0) + hex.charAt(0)
		rgb[1] = hex.charAt(1) + hex.charAt(1)
		rgb[2] = hex.charAt(2) + hex.charAt(2);
	} else {
		rgb[0] = hex.substring(0, 2);
		rgb[1] = hex.substring(2, 4);
		rgb[2] = hex.substring(4);
	}
	for(var i = 0; i < rgb.length; i++) {
		rgb[i] = hexNum.indexOf(rgb[i].charAt(0)) * 16 + hexNum.indexOf(rgb[i].charAt(1));
	}
	return rgb;
}

dojo.graphics.color.rgb2hex = function(r, g, b) {
	if(dojo.lang.isArray(r)) {
		g = r[1] || 0;
		b = r[2] || 0;
		r = r[0] || 0;
	}
	return ["#",
		dojo.string.pad(r.toString(16), 2),
		dojo.string.pad(g.toString(16), 2),
		dojo.string.pad(b.toString(16), 2)].join("");
}

dojo.graphics.color.rgb2hsv = function(r, g, b){

	if (dojo.lang.isArray(r)) {
		b = r[2] || 0;
		g = r[1] || 0;
		r = r[0] || 0;
	}

	// r,g,b, each 0 to 255, to HSV.
	// h = 0.0 to 360.0 (corresponding to 0..360.0 degrees around hexcone)
	// s = 0.0 (shade of gray) to 1.0 (pure color)
	// v = 0.0 (black) to 1.0 {white)
	//
	// Based on C Code in "Computer Graphics -- Principles and Practice,"
	// Foley et al, 1996, p. 592. 
	//
	// our calculatuions are based on 'regular' values (0-360, 0-1, 0-1) 
	// but we return bytes values (0-255, 0-255, 0-255)

	var h = null;
	var s = null;
	var v = null;

	var min = Math.min(r, g, b);
	v = Math.max(r, g, b);

	var delta = v - min;

	// calculate saturation (0 if r, g and b are all 0)

	s = (v == 0) ? 0 : delta/v;

	if (s == 0){
		// achromatic: when saturation is, hue is undefined
		h = 0;
	}else{
		// chromatic
		if (r == v){
			// between yellow and magenta
			h = 60 * (g - b) / delta;
		}else{
			if (g == v){
				// between cyan and yellow
				h = 120 + 60 * (b - r) / delta;
			}else{
				if (b == v){
					// between magenta and cyan
					h = 240 + 60 * (r - g) / delta;
				}
			}
		}
		if (h < 0){
			h += 360;
		}
	}


	h = (h == 0) ? 360 : Math.ceil((h / 360) * 255);
	s = Math.ceil(s * 255);

	return [h, s, v];
}

dojo.graphics.color.hsv2rgb = function(h, s, v){
 
	if (dojo.lang.isArray(h)) {
		v = h[2] || 0;
		s = h[1] || 0;
		h = h[0] || 0;
	}

	h = (h / 255) * 360;
	if (h == 360){ h = 0;}

	s = s / 255;
	v = v / 255;

	// Based on C Code in "Computer Graphics -- Principles and Practice,"
	// Foley et al, 1996, p. 593.
	//
	// H = 0.0 to 360.0 (corresponding to 0..360 degrees around hexcone) 0 for S = 0
	// S = 0.0 (shade of gray) to 1.0 (pure color)
	// V = 0.0 (black) to 1.0 (white)

	var r = null;
	var g = null;
	var b = null;

	if (s == 0){
		// color is on black-and-white center line
		// achromatic: shades of gray
		r = v;
		g = v;
		b = v;
	}else{
		// chromatic color
		var hTemp = h / 60;		// h is now IN [0,6]
		var i = Math.floor(hTemp);	// largest integer <= h
		var f = hTemp - i;		// fractional part of h

		var p = v * (1 - s);
		var q = v * (1 - (s * f));
		var t = v * (1 - (s * (1 - f)));

		switch(i){
			case 0: r = v; g = t; b = p; break;
			case 1: r = q; g = v; b = p; break;
			case 2: r = p; g = v; b = t; break;
			case 3: r = p; g = q; b = v; break;
			case 4: r = t; g = p; b = v; break;
			case 5: r = v; g = p; b = q; break;
		}
	}

	r = Math.ceil(r * 255);
	g = Math.ceil(g * 255);
	b = Math.ceil(b * 255);

	return [r, g, b];
}

dojo.graphics.color.rgb2hsl = function(r, g, b){

	if (dojo.lang.isArray(r)) {
		b = r[2] || 0;
		g = r[1] || 0;
		r = r[0] || 0;
	}

	r /= 255;
	g /= 255;
	b /= 255;

	//
	// based on C code from http://astronomy.swin.edu.au/~pbourke/colour/hsl/
	//

	var h = null;
	var s = null;
	var l = null;


	var min = Math.min(r, g, b);
	var max = Math.max(r, g, b);
	var delta = max - min;

	l = (min + max) / 2;

	s = 0;

	if ((l > 0) && (l < 1)){
		s = delta / ((l < 0.5) ? (2 * l) : (2 - 2 * l));
	}

	h = 0;

	if (delta > 0) {
		if ((max == r) && (max != g)){
			h += (g - b) / delta;
		}
		if ((max == g) && (max != b)){
			h += (2 + (b - r) / delta);
		}
		if ((max == b) && (max != r)){
			h += (4 + (r - g) / delta);
		}
		h *= 60;
	}

	h = (h == 0) ? 360 : Math.ceil((h / 360) * 255);
	s = Math.ceil(s * 255);
	l = Math.ceil(l * 255);

	return [h, s, l];
}

dojo.graphics.color.hsl2rgb = function(h, s, l){
 
	if (dojo.lang.isArray(h)) {
		l = h[2] || 0;
		s = h[1] || 0;
		h = h[0] || 0;
	}

	h = (h / 255) * 360;
	if (h == 360){ h = 0;}
	s = s / 255;
	l = l / 255;

	//
	// based on C code from http://astronomy.swin.edu.au/~pbourke/colour/hsl/
	//


	while (h < 0){ h += 360; }
	while (h > 360){ h -= 360; }

	if (h < 120){
		r = (120 - h) / 60;
		g = h / 60;
		b = 0;
	}else if (h < 240){
		r = 0;
		g = (240 - h) / 60;
		b = (h - 120) / 60;
	}else{
		r = (h - 240) / 60;
		g = 0;
		b = (360 - h) / 60;
	}

	r = Math.min(r, 1);
	g = Math.min(g, 1);
	b = Math.min(b, 1);

	r = 2 * s * r + (1 - s);
	g = 2 * s * g + (1 - s);
	b = 2 * s * b + (1 - s);

	if (l < 0.5){
		r = l * r;
		g = l * g;
		b = l * b;
	}else{
		r = (1 - l) * r + 2 * l - 1;
		g = (1 - l) * g + 2 * l - 1;
		b = (1 - l) * b + 2 * l - 1;
	}

	r = Math.ceil(r * 255);
	g = Math.ceil(g * 255);
	b = Math.ceil(b * 255);

	return [r, g, b];
}