var utils = require('../../utils');

/**
 * Builds a polygon to draw
 *
 * @private
 * @param graphicsData {PIXI.WebGLGraphicsData} The graphics object containing all the necessary properties
 * @param webGLData {object} an object containing all the webGL-specific information to create this shape
 */
var buildPoly = function (graphicsData, webGLData)
{
    var points = graphicsData.points;

    if (points.length < 6)
    {
        return;
    }

    // get first and last point.. figure out the middle!
    var verts = webGLData.points;
    var indices = webGLData.indices;

    var length = points.length / 2;

    // sort color
    var color = utils.hex2rgb(graphicsData.fillColor);
    var alpha = graphicsData.fillAlpha;
    var r = color[0] * alpha;
    var g = color[1] * alpha;
    var b = color[2] * alpha;

    var triangles = earcut(points, null, 2);

    if (!triangles) {
        return false;
    }

    var vertPos = verts.length / 6;

    var i = 0;

    for (i = 0; i < triangles.length; i+=3)
    {
        indices.push(triangles[i] + vertPos);
        indices.push(triangles[i] + vertPos);
        indices.push(triangles[i+1] + vertPos);
        indices.push(triangles[i+2] +vertPos);
        indices.push(triangles[i+2] + vertPos);
    }

    for (i = 0; i < length; i++)
    {
        verts.push(points[i * 2], points[i * 2 + 1],
                   r, g, b, alpha);
    }

    return true;
};


module.exports = buildPoly;