if (typeof(require) !== 'undefined') { var tree = require('less/tree') }

tree.functions = {
    rgb: function (r, g, b) {
        return this.rgba(r, g, b, 1.0);
    },
    rgba: function (r, g, b, a) {
        var rgb = [r, g, b].map(function (c) { return number(c) }),
            a = number(a);
        return new(tree.Color)(rgb, a);
    },
    hsl: function (h, s, l) {
        return this.hsla(h, s, l, 1.0);
    },
    hsla: function (h, s, l, a) {
        h = number(h); s = number(s);
        l = number(l); a = number(a);

        var m2 = l <= 0.5 ? l * (s + 1) : l + s - l * s;
        var m1 = l * 2 - m2;

        return this.rgba(hue(h + 1/3), hue(h), hue(h - 1/3), a);

        function hue(h) {
            h = h < 0 ? h + 1 : (h > 1 ? h - 1 : h);
            if      (h * 6 < 1) return m1 + (m2 - m1) * h * 6;
            else if (h * 2 < 1) return m2;
            else if (h * 3 < 2) return m1 + (m2 - m1) * (2/3 - h) * 6;
            else                return m1;
        }
    }
};

function number(n) {
    if (n instanceof tree.Dimension) {
        return parseFloat(n.value);
    } else if (typeof(n) === 'number') {
        return n;
    } else {
        throw {
            error: "RuntimeError",
            message: "color functions take numbers as parameters"
        };
    }
}
