define([
        './BoundingSphere',
        './Cartesian2',
        './Cartesian3',
        './ComponentDatatype',
        './CylinderGeometryLibrary',
        './defaultValue',
        './defined',
        './DeveloperError',
        './Geometry',
        './GeometryAttribute',
        './GeometryAttributes',
        './IndexDatatype',
        './Math',
        './PrimitiveType',
        './VertexFormat'
    ], function(
        BoundingSphere,
        Cartesian2,
        Cartesian3,
        ComponentDatatype,
        CylinderGeometryLibrary,
        defaultValue,
        defined,
        DeveloperError,
        Geometry,
        GeometryAttribute,
        GeometryAttributes,
        IndexDatatype,
        CesiumMath,
        PrimitiveType,
        VertexFormat) {
    'use strict';

    var radiusScratch = new Cartesian2();
    var normalScratch = new Cartesian3();
    var bitangentScratch = new Cartesian3();
    var tangentScratch = new Cartesian3();
    var positionScratch = new Cartesian3();


    /**
     * A description of a cylinder.
     *
     * @alias CylinderGeometry
     * @constructor
     *
     * @param {Object} options Object with the following properties:
     * @param {Number} options.length The length of the cylinder.
     * @param {Number} options.topRadius The radius of the top of the cylinder.
     * @param {Number} options.bottomRadius The radius of the bottom of the cylinder.
     * @param {Number} [options.slices=128] The number of edges around the perimeter of the cylinder.
     * @param {VertexFormat} [options.vertexFormat=VertexFormat.DEFAULT] The vertex attributes to be computed.
     *
     * @exception {DeveloperError} options.length must be greater than 0.
     * @exception {DeveloperError} options.topRadius must be greater than 0.
     * @exception {DeveloperError} options.bottomRadius must be greater than 0.
     * @exception {DeveloperError} bottomRadius and topRadius cannot both equal 0.
     * @exception {DeveloperError} options.slices must be greater than or equal to 3.
     *
     * @see CylinderGeometry.createGeometry
     *
     * @example
     * // create cylinder geometry
     * var cylinder = new Cesium.CylinderGeometry({
     *     length: 200000,
     *     topRadius: 80000,
     *     bottomRadius: 200000,
     * });
     * var geometry = Cesium.CylinderGeometry.createGeometry(cylinder);
     */
    function CylinderGeometry(options) {
        options = defaultValue(options, defaultValue.EMPTY_OBJECT);

        var length = options.length;
        var topRadius = options.topRadius;
        var bottomRadius = options.bottomRadius;
        var vertexFormat = defaultValue(options.vertexFormat, VertexFormat.DEFAULT);
        var slices = defaultValue(options.slices, 128);

        //>>includeStart('debug', pragmas.debug);
        if (!defined(length)) {
            throw new DeveloperError('options.length must be defined.');
        }
        if (!defined(topRadius)) {
            throw new DeveloperError('options.topRadius must be defined.');
        }
        if (!defined(bottomRadius)) {
            throw new DeveloperError('options.bottomRadius must be defined.');
        }
        if (slices < 3) {
            throw new DeveloperError('options.slices must be greater than or equal to 3.');
        }
        //>>includeEnd('debug');

        this._length = length;
        this._topRadius = topRadius;
        this._bottomRadius = bottomRadius;
        this._vertexFormat = VertexFormat.clone(vertexFormat);
        this._slices = slices;
        this._workerName = 'createCylinderGeometry';
    }

    /**
     * The number of elements used to pack the object into an array.
     * @type {Number}
     */
    CylinderGeometry.packedLength = VertexFormat.packedLength + 4;

    /**
     * Stores the provided instance into the provided array.
     *
     * @param {CylinderGeometry} value The value to pack.
     * @param {Number[]} array The array to pack into.
     * @param {Number} [startingIndex=0] The index into the array at which to start packing the elements.
     *
     * @returns {Number[]} The array that was packed into
     */
    CylinderGeometry.pack = function(value, array, startingIndex) {
        //>>includeStart('debug', pragmas.debug);
        if (!defined(value)) {
            throw new DeveloperError('value is required');
        }
        if (!defined(array)) {
            throw new DeveloperError('array is required');
        }
        //>>includeEnd('debug');

        startingIndex = defaultValue(startingIndex, 0);

        VertexFormat.pack(value._vertexFormat, array, startingIndex);
        startingIndex += VertexFormat.packedLength;

        array[startingIndex++] = value._length;
        array[startingIndex++] = value._topRadius;
        array[startingIndex++] = value._bottomRadius;
        array[startingIndex]   = value._slices;

        return array;
    };

    var scratchVertexFormat = new VertexFormat();
    var scratchOptions = {
        vertexFormat : scratchVertexFormat,
        length : undefined,
        topRadius : undefined,
        bottomRadius : undefined,
        slices : undefined
    };

    /**
     * Retrieves an instance from a packed array.
     *
     * @param {Number[]} array The packed array.
     * @param {Number} [startingIndex=0] The starting index of the element to be unpacked.
     * @param {CylinderGeometry} [result] The object into which to store the result.
     * @returns {CylinderGeometry} The modified result parameter or a new CylinderGeometry instance if one was not provided.
     */
    CylinderGeometry.unpack = function(array, startingIndex, result) {
        //>>includeStart('debug', pragmas.debug);
        if (!defined(array)) {
            throw new DeveloperError('array is required');
        }
        //>>includeEnd('debug');

        startingIndex = defaultValue(startingIndex, 0);

        var vertexFormat = VertexFormat.unpack(array, startingIndex, scratchVertexFormat);
        startingIndex += VertexFormat.packedLength;

        var length = array[startingIndex++];
        var topRadius = array[startingIndex++];
        var bottomRadius = array[startingIndex++];
        var slices = array[startingIndex];

        if (!defined(result)) {
            scratchOptions.length = length;
            scratchOptions.topRadius = topRadius;
            scratchOptions.bottomRadius = bottomRadius;
            scratchOptions.slices = slices;
            return new CylinderGeometry(scratchOptions);
        }

        result._vertexFormat = VertexFormat.clone(vertexFormat, result._vertexFormat);
        result._length = length;
        result._topRadius = topRadius;
        result._bottomRadius = bottomRadius;
        result._slices = slices;

        return result;
    };

    /**
     * Computes the geometric representation of a cylinder, including its vertices, indices, and a bounding sphere.
     *
     * @param {CylinderGeometry} cylinderGeometry A description of the cylinder.
     * @returns {Geometry|undefined} The computed vertices and indices.
     */
    CylinderGeometry.createGeometry = function(cylinderGeometry) {
        var length = cylinderGeometry._length;
        var topRadius = cylinderGeometry._topRadius;
        var bottomRadius = cylinderGeometry._bottomRadius;
        var vertexFormat = cylinderGeometry._vertexFormat;
        var slices = cylinderGeometry._slices;

        if ((length <= 0) || (topRadius < 0) || (bottomRadius < 0) || ((topRadius === 0) && (bottomRadius === 0))) {
            return;
        }

        var twoSlices = slices + slices;
        var threeSlices = slices + twoSlices;
        var numVertices = twoSlices + twoSlices;

        var positions = CylinderGeometryLibrary.computePositions(length, topRadius, bottomRadius, slices, true);

        var st = (vertexFormat.st) ? new Float32Array(numVertices * 2) : undefined;
        var normals = (vertexFormat.normal) ? new Float32Array(numVertices * 3) : undefined;
        var tangents = (vertexFormat.tangent) ? new Float32Array(numVertices * 3) : undefined;
        var bitangents = (vertexFormat.bitangent) ? new Float32Array(numVertices * 3) : undefined;

        var i;
        var computeNormal = (vertexFormat.normal || vertexFormat.tangent || vertexFormat.bitangent);

        if (computeNormal) {
            var computeTangent = (vertexFormat.tangent || vertexFormat.bitangent);

            var normalIndex = 0;
            var tangentIndex = 0;
            var bitangentIndex = 0;

            var normal = normalScratch;
            normal.z = 0;
            var tangent = tangentScratch;
            var bitangent = bitangentScratch;

            for (i = 0; i < slices; i++) {
                var angle = i / slices * CesiumMath.TWO_PI;
                var x = Math.cos(angle);
                var y = Math.sin(angle);
                if (computeNormal) {
                    normal.x = x;
                    normal.y = y;

                    if (computeTangent) {
                        tangent = Cartesian3.normalize(Cartesian3.cross(Cartesian3.UNIT_Z, normal, tangent), tangent);
                    }

                    if (vertexFormat.normal) {
                        normals[normalIndex++] = x;
                        normals[normalIndex++] = y;
                        normals[normalIndex++] = 0;
                        normals[normalIndex++] = x;
                        normals[normalIndex++] = y;
                        normals[normalIndex++] = 0;
                    }

                    if (vertexFormat.tangent) {
                        tangents[tangentIndex++] = tangent.x;
                        tangents[tangentIndex++] = tangent.y;
                        tangents[tangentIndex++] = tangent.z;
                        tangents[tangentIndex++] = tangent.x;
                        tangents[tangentIndex++] = tangent.y;
                        tangents[tangentIndex++] = tangent.z;
                    }

                    if (vertexFormat.bitangent) {
                        bitangent = Cartesian3.normalize(Cartesian3.cross(normal, tangent, bitangent), bitangent);
                        bitangents[bitangentIndex++] = bitangent.x;
                        bitangents[bitangentIndex++] = bitangent.y;
                        bitangents[bitangentIndex++] = bitangent.z;
                        bitangents[bitangentIndex++] = bitangent.x;
                        bitangents[bitangentIndex++] = bitangent.y;
                        bitangents[bitangentIndex++] = bitangent.z;
                    }
                }
            }

            for (i = 0; i < slices; i++) {
                if (vertexFormat.normal) {
                    normals[normalIndex++] = 0;
                    normals[normalIndex++] = 0;
                    normals[normalIndex++] = -1;
                }
                if (vertexFormat.tangent) {
                    tangents[tangentIndex++] = 1;
                    tangents[tangentIndex++] = 0;
                    tangents[tangentIndex++] = 0;
                }
                if (vertexFormat.bitangent) {
                    bitangents[bitangentIndex++] = 0;
                    bitangents[bitangentIndex++] = -1;
                    bitangents[bitangentIndex++] = 0;
                }
            }

            for (i = 0; i < slices; i++) {
                if (vertexFormat.normal) {
                    normals[normalIndex++] = 0;
                    normals[normalIndex++] = 0;
                    normals[normalIndex++] = 1;
                }
                if (vertexFormat.tangent) {
                    tangents[tangentIndex++] = 1;
                    tangents[tangentIndex++] = 0;
                    tangents[tangentIndex++] = 0;
                }
                if (vertexFormat.bitangent) {
                    bitangents[bitangentIndex++] = 0;
                    bitangents[bitangentIndex++] = 1;
                    bitangents[bitangentIndex++] = 0;
                }
            }
        }

        var numIndices = 12 * slices - 12;
        var indices = IndexDatatype.createTypedArray(numVertices, numIndices);
        var index = 0;
        var j = 0;
        for (i = 0; i < slices - 1; i++) {
            indices[index++] = j;
            indices[index++] = j + 2;
            indices[index++] = j + 3;

            indices[index++] = j;
            indices[index++] = j + 3;
            indices[index++] = j + 1;

            j += 2;
        }

        indices[index++] = twoSlices - 2;
        indices[index++] = 0;
        indices[index++] = 1;
        indices[index++] = twoSlices - 2;
        indices[index++] = 1;
        indices[index++] = twoSlices - 1;

        for (i = 1; i < slices - 1; i++) {
            indices[index++] = twoSlices + i + 1;
            indices[index++] = twoSlices + i;
            indices[index++] = twoSlices;
        }

        for (i = 1; i < slices - 1; i++) {
            indices[index++] = threeSlices;
            indices[index++] = threeSlices + i;
            indices[index++] = threeSlices + i + 1;
        }

        var textureCoordIndex = 0;
        if (vertexFormat.st) {
            var rad = Math.max(topRadius, bottomRadius);
            for (i = 0; i < numVertices; i++) {
                var position = Cartesian3.fromArray(positions, i * 3, positionScratch);
                st[textureCoordIndex++] = (position.x + rad) / (2.0 * rad);
                st[textureCoordIndex++] = (position.y + rad) / (2.0 * rad);
            }
        }

        var attributes = new GeometryAttributes();
        if (vertexFormat.position) {
            attributes.position = new GeometryAttribute({
                componentDatatype: ComponentDatatype.DOUBLE,
                componentsPerAttribute: 3,
                values: positions
            });
        }

        if (vertexFormat.normal) {
            attributes.normal = new GeometryAttribute({
                componentDatatype : ComponentDatatype.FLOAT,
                componentsPerAttribute : 3,
                values : normals
            });
        }

        if (vertexFormat.tangent) {
            attributes.tangent = new GeometryAttribute({
                componentDatatype : ComponentDatatype.FLOAT,
                componentsPerAttribute : 3,
                values : tangents
            });
        }

        if (vertexFormat.bitangent) {
            attributes.bitangent = new GeometryAttribute({
                componentDatatype : ComponentDatatype.FLOAT,
                componentsPerAttribute : 3,
                values : bitangents
            });
        }

        if (vertexFormat.st) {
            attributes.st = new GeometryAttribute({
                componentDatatype : ComponentDatatype.FLOAT,
                componentsPerAttribute : 2,
                values : st
            });
        }

        radiusScratch.x = length * 0.5;
        radiusScratch.y = Math.max(bottomRadius, topRadius);

        var boundingSphere = new BoundingSphere(Cartesian3.ZERO, Cartesian2.magnitude(radiusScratch));

        return new Geometry({
            attributes : attributes,
            indices : indices,
            primitiveType : PrimitiveType.TRIANGLES,
            boundingSphere : boundingSphere
        });
    };

    return CylinderGeometry;
});
