defineSuite([
        'Renderer/ComputeCommand',
        'Core/BoundingRectangle',
        'Core/PixelFormat',
        'Renderer/Buffer',
        'Renderer/BufferUsage',
        'Renderer/ShaderProgram',
        'Renderer/Texture',
        'Renderer/VertexArray',
        'Scene/Material',
        'Scene/ViewportQuad',
        'Specs/createScene'
    ], function(
        ComputeCommand,
        BoundingRectangle,
        PixelFormat,
        Buffer,
        BufferUsage,
        ShaderProgram,
        Texture,
        VertexArray,
        Material,
        ViewportQuad,
        createScene) {
    'use strict';

    var scene;
    var context;

    beforeAll(function() {
        scene = createScene();
        context = scene.context;
    });

    afterAll(function() {
        scene.destroyForSpecs();
    });

    afterEach(function() {
       scene.primitives.removeAll();
    });

    function CommandMockPrimitive(command) {
        this.update = function(frameState) {
            frameState.commandList.push(command);
        };
        this.destroy = function() {
        };
    }

    it('throws if no shader is provided', function() {
        var outputTexture = new Texture({
            context : context,
            width : 1,
            height : 1,
            pixelFormat : PixelFormat.RGBA
        });
        var computeCommand = new ComputeCommand({
            outputTexture : outputTexture
        });
        scene.primitives.add(new CommandMockPrimitive(computeCommand));

        expect(function() {
            scene.renderForSpecs();
        }).toThrowDeveloperError();
    });

    it('throws if no output texture is provided', function() {
        var computeCommand = new ComputeCommand({
            fragmentShaderSource : 'void main() { gl_FragColor = vec4(1.0); }'
        });
        scene.primitives.add(new CommandMockPrimitive(computeCommand));

        expect(function() {
            scene.renderForSpecs();
        }).toThrowDeveloperError();
    });

    it('renderer resources are preserved or destroyed based on the persists flag', function() {
        var vertexShader = 'attribute vec4 position; void main() { gl_PointSize = 1.0; gl_Position = position; }';
        var fragmentShader = 'void main() { gl_FragColor = vec4(1.0); }';
        var shaderProgram = ShaderProgram.fromCache({
            context : context,
            vertexShaderSource : vertexShader,
            fragmentShaderSource : fragmentShader,
            attributeLocations : {
                position : 0
            }
        });

        var vertexArray = new VertexArray({
            context : context,
            attributes : [{
                index : 0,
                vertexBuffer : Buffer.createVertexBuffer({
                    context : context,
                    typedArray : new Float32Array([0, 0, 0, 1]),
                    usage : BufferUsage.STATIC_DRAW
                }),
                componentsPerAttribute : 4
            }]
        });

        var outputTexture = new Texture({
            context : context,
            width : 1,
            height : 1,
            pixelFormat : PixelFormat.RGBA
        });

        var computeCommand = new ComputeCommand({
            vertexArray : vertexArray,
            shaderProgram : shaderProgram,
            outputTexture : outputTexture
        });

        // check that resources are preserved when persists is true
        computeCommand.persists = true;
        scene.primitives.add(new CommandMockPrimitive(computeCommand));
        scene.renderForSpecs();
        context.shaderCache.destroyReleasedShaderPrograms();
        scene.primitives.removeAll();

        expect(shaderProgram.isDestroyed()).toEqual(false);
        expect(vertexArray.isDestroyed()).toEqual(false);
        expect(outputTexture.isDestroyed()).toEqual(false);

        // check that resources are destroyed when persists is false, except
        // outputTexture which is always preserved
        computeCommand.persists = false;
        scene.primitives.add(new CommandMockPrimitive(computeCommand));
        scene.renderForSpecs();
        context.shaderCache.destroyReleasedShaderPrograms();
        scene.primitives.removeAll();

        expect(shaderProgram.isDestroyed()).toEqual(true);
        expect(vertexArray.isDestroyed()).toEqual(true);
        expect(outputTexture.isDestroyed()).toEqual(false);
    });

    it('renders to a texture and draws that texture to the screen', function() {
        var outputTexture = new Texture({
            context : context,
            width : 1,
            height : 1,
            pixelFormat : PixelFormat.RGBA
        });
        var computeCommand = new ComputeCommand({
            fragmentShaderSource : 'void main() { gl_FragColor = vec4(1.0); }',
            outputTexture : outputTexture
        });

        var viewportQuad = new ViewportQuad();
        viewportQuad.rectangle = new BoundingRectangle(0, 0, 1, 1);
        viewportQuad.material = Material.fromType(Material.ImageType);
        viewportQuad.material.uniforms.image = outputTexture;

        expect(scene).toRender([0, 0, 0, 255]);
        scene.primitives.add(new CommandMockPrimitive(computeCommand));
        scene.primitives.add(viewportQuad);
        expect(scene).notToRender([0, 0, 0, 255]);
    });
}, 'WebGL');