/* -- Object for colors -- */

function Couleurs() {	

	switch (arguments.length) {

	case 1:

		if ("number"==typeof(arguments[0])) {

			if (10==arguments[0]) {

				this.get = d3.scale.category10();

			}

			else if (20==arguments[0]) {

				this.get = d3.scale.category20();

			}

			else {

				var domain = [], quantity = 0, colors = colorbrewer, 

					setID, colorID, color;

				var sets = ["BrBG", "PiYG", "PRGn", "PuOr", "RdBu", "RdYlBu", "RdYlGn"];

				while (quantity < arguments[0]) {

					setID = 	Math.floor(Math.random()*7);

					colorID = Math.floor(Math.random()*11);

					color = Couleurs.fn.d3Color(

							colors[sets[setID]][11][colorID]);

					var available = true;

					for (var i = 0; i < quantity; i++) {

						if (Math.abs(Couleurs.fn.hue(domain[i])

								- Couleurs.fn.hue(color)) < 0.1) {

							available = false;

						}

					}

					if (Couleurs.fn.brightness(color) < 0.9 && available) {

						domain.push(color);

						++quantity;

					}

				}

				// Transform into hexadecimal colors

				for (var index in domain) {

					domain[index] = domain[index].toString();

				}

				this.get = d3.scale.ordinal().range(domain);

			}

		}

		else if (Array==arguments[0].constructor) {

			var inputs = [];

			for (var i in arguments[0]) {

				inputs.push(i);

			}

			this.get = d3.scale.ordinal()

				.domain(inputs)

				.range(arguments[0]);

		}

		else {

			throw "Wrong arguments";

		}

		break;

	case 3:

		this.range = d3.interpolateRgb(arguments[0], arguments[1]);

		this.levels = arguments[2];

		this.get = this.getFromInterpolation;

		break;

	default:

		throw "Wrong number of arguments";

	}

}

Couleurs.fn = Couleurs.prototype = {

	constructor: Couleurs,

	d3Color: function(rgbString) {

		return d3.rgb(rgbString);

	},

	brightness: function(color) {

		return (color.r + color.r + color.b + color.g + color.g + color.g)/(6*255);

	},

	hue: function(color) {

		return Math.sqrt(3) * (color.g - color.b)

			/(color.r + color.r - color.g - color.b);

	},

	getFromInterpolation: function(index) {

		if (index<1) {

			return this.range(index);

		}

		else {

			index = (0==index%this.levels)? this.levels: index%this.levels; 

			return this.range((index - 1)/(this.levels - 1));

		}

	}

};