#include <windows.h>

#include "BsApplication.h"
#include "BsImporter.h"
#include "BsGpuProgramImportOptions.h"
#include "BsTextureImportOptions.h"
#include "BsMaterial.h"
#include "BsShader.h"
#include "BsTechnique.h"
#include "BsPass.h"
#include "BsCoreThreadAccessor.h"
#include "BsApplication.h"
#include "BsVirtualInput.h"
#include "BsCamera.h"
#include "BsRenderable.h"
#include "BsGUIWidget.h"
#include "BsGUIArea.h"
#include "BsGUILayoutX.h"
#include "BsGUILayoutY.h"
#include "BsGUISpace.h"
#include "BsGUILabel.h"
#include "BsGUIButton.h"
#include "BsGUIListBox.h"
#include "BsBuiltinResources.h"
#include "BsRTTIType.h"
#include "BsHString.h"
#include "BsRenderWindow.h"
#include "BsSceneObject.h"
#include "BsCoreThread.h"
#include "BsProfilerOverlay.h"
#include "BsRenderer.h"

#include "CameraFlyer.h"

namespace BansheeEngine
{
    /**
     * Imports all of ours assets and prepares GameObject that handle the example logic.
     */
    void setUpExample();

    /**
     * Toggles the primary window between full-screen and windowed mode.
     */
    void toggleFullscreen();

    /**
     * Triggered whenever a virtual button is released.
     */
    void buttonUp(const VirtualButton& button, UINT32 deviceIdx);
}

using namespace BansheeEngine;

/**
 * Main entry point into the application.
 */
int CALLBACK WinMain(
    _In_  HINSTANCE hInstance,
    _In_  HINSTANCE hPrevInstance,
    _In_  LPSTR lpCmdLine,
    _In_  int nCmdShow
    )
{
    // Descriptor used for initializing the primary application window.
    RENDER_WINDOW_DESC renderWindowDesc;
    renderWindowDesc.videoMode = VideoMode(resolutionWidth, resolutionHeight);
    renderWindowDesc.title = "Banshee Example App";
    renderWindowDesc.fullscreen = false;

    // Initializes the application with primary window defined as above and DirectX 11 render system.
    // You may use other render systems than DirectX 11, however this example for simplicity only uses DirectX 11.
    // If you wanted other render systems you would need to create separate shaders for them and import them above
    // along with (or replace) the DX11 ones.
    Application::startUp(renderWindowDesc, RenderSystemPlugin::DX11);

    // Imports all of ours assets and prepares GameObject that handle the example logic.
    setUpExample();

    // Runs the main loop that does most of the work. This method will exit when user closes the main
    // window or exits in some other way.
    Application::instance().runMainLoop();

    // Perform cleanup
    Application::shutDown();

    return 0;
}

namespace BansheeEngine
{
    Path exampleModelPath = "..\\..\\..\\..\\Data\\Examples\\Pyromancer.fbx";
    Path exampleTexturePath = "..\\..\\..\\..\\Data\\Examples\\Pyromancer.psd";
    Path exampleFragmentShaderPath = "..\\..\\..\\..\\Data\\Examples\\example_fs.gpuprog";
    Path exampleVertexShaderPath = "..\\..\\..\\..\\Data\\Examples\\example_vs.gpuprog";

    GUIButton* toggleFullscreenButton = nullptr;
    UINT32 resolutionWidth = 1280;
    UINT32 resolutionHeight = 720;
    bool fullscreen = false;
    const VideoMode* videoMode = nullptr;

    HMesh exampleModel;
    HTexture exampleTexture;
    HGpuProgram exampleFragmentGPUProg;
    HGpuProgram exampleVertexGPUProg;

    HCamera sceneCamera;
    HProfilerOverlay profilerOverlay;

    VirtualButton toggleCPUProfilerBtn;
    VirtualButton toggleGPUProfilerBtn;

    bool cpuProfilerActive = false;
    bool gpuProfilerActive = false;

    void setUpExample()
    {
        /************************************************************************/
        /*                              IMPORT ASSETS                           */
        /************************************************************************/
        // Import mesh, texture and shader from the disk. In a normal application you would want to save the imported assets
        // so next time the application is ran you can just load them directly. This can be done with Resources::save/load.

        // Import an FBX mesh.
        exampleModel = static_resource_cast<Mesh>(Importer::instance().import(exampleModelPath));

        // When importing you may specify optional import options that control how is the asset imported.
        ImportOptionsPtr textureImportOptions = Importer::instance().createImportOptions(exampleTexturePath);

        // rtti_is_of_type checks if the import options are of valid type, in case the provided path is pointing to a non-texture resource.
        // This is similar to dynamic_cast but uses Banshee internal RTTI system for type checking.
        if (rtti_is_of_type<TextureImportOptions>(textureImportOptions))
        {
            TextureImportOptions* importOptions = static_cast<TextureImportOptions*>(textureImportOptions.get());

            // We want the texture to be compressed, just a basic non-alpha format
            importOptions->setFormat(PF_BC1);

            // We want maximum number of mipmaps to be generated
            importOptions->setGenerateMipmaps(true);
        }

        // Import texture with specified import options
        exampleTexture = static_resource_cast<Texture>(Importer::instance().import(exampleTexturePath, textureImportOptions));

        // Create import options for fragment GPU program
        ImportOptionsPtr gpuProgImportOptions = Importer::instance().createImportOptions(exampleFragmentShaderPath);
        if (rtti_is_of_type<GpuProgramImportOptions>(gpuProgImportOptions))
        {
            GpuProgramImportOptions* importOptions = static_cast<GpuProgramImportOptions*>(gpuProgImportOptions.get());

            // Name of the entry function in the GPU program
            importOptions->setEntryPoint("ps_main");

            // Language the GPU program is written in. Can only be hlsl for DX11
            importOptions->setLanguage("hlsl");

            // GPU program profile specifying what feature-set the shader code uses.
            importOptions->setProfile(GPP_PS_4_0);

            // Type of the shader.
            importOptions->setType(GPT_FRAGMENT_PROGRAM);
        }

        // Import fragment GPU program
        exampleFragmentGPUProg = static_resource_cast<GpuProgram>(Importer::instance().import(exampleFragmentShaderPath, gpuProgImportOptions));

        // Create import options for vertex GPU program. Similar as above.
        gpuProgImportOptions = Importer::instance().createImportOptions(exampleVertexShaderPath);
        if (rtti_is_of_type<GpuProgramImportOptions>(gpuProgImportOptions))
        {
            GpuProgramImportOptions* importOptions = static_cast<GpuProgramImportOptions*>(gpuProgImportOptions.get());

            importOptions->setEntryPoint("vs_main");
            importOptions->setLanguage("hlsl");
            importOptions->setProfile(GPP_VS_4_0);
            importOptions->setType(GPT_VERTEX_PROGRAM);
        }

        // Import vertex GPU program
        exampleVertexGPUProg = static_resource_cast<GpuProgram>(Importer::instance().import(exampleVertexShaderPath, gpuProgImportOptions));

        /************************************************************************/
        /*                          CREATE SHADER                               */
        /************************************************************************/
        // Create a shader that references our vertex and fragment GPU programs, and set
        // up shader input parameters.
        ShaderPtr exampleShader = Shader::create("ExampleShader");

        // Set up shader parameters and renderer semantics.
        // Renderer semantics allow our renderer to automatically populate certain shader parameters (e.g. a world view projection matrix).
        // These semantics are purely optional and depend on the renderer used. Certain renderers expect certain semantics to be set up
        // otherwise they will not render the objects. You always have the option to populate all the parameters manually, but in this example
        // we go with the semantics route as it allows for a "set up and forget" approach.

        // Add a world view projection matrix parameter, which will be populated by the renderer.
        // We map our shader parameter name to the actual GPU program variable, both being "matWorldViewProj" in this case.
        exampleShader->addParameter("matWorldViewProj", "matWorldViewProj", GPDT_MATRIX_4X4, RPS_WorldViewProjTfrm);

        // Add a sampler and a texture semantic that we will populate manually.
        exampleShader->addParameter("samp", "samp", GPOT_SAMPLER2D);
        exampleShader->addParameter("tex", "tex", GPOT_TEXTURE2D);

        // Our GPU programs use parameter blocks (constant buffers in DX11 lingo). Here we notify the renderer
        // that this particular parameter block contains object-specific data (like the world view projection parameter
        // we defined above).
        exampleShader->setParamBlockAttribs("PerObject", true, GPBU_DYNAMIC, RBS_PerObject);

        /************************************************************************/
        /*                          CREATE MATERIAL                             */
        /************************************************************************/

        // Create a shader technique. Shader can have many different techniques and the renderer will automatically
        // use the most appropriate technique depending on the active renderer and render system. e.g. you can have different
        // techniques using HLSL9, HLSL11 and GLSL GPU programs for DirectX 9, DirectX 11 and OpenGL render systems respectively.
        TechniquePtr technique = exampleShader->addTechnique(RenderSystemDX11, RendererDefault);

        // Add a new pass to the technique. Each technique can have multiple passes that allow you to render the same
        // object multiple times using different shaders.
        PassPtr pass = technique->addPass();
        pass->setVertexProgram(exampleVertexGPUProg);
        pass->setFragmentProgram(exampleFragmentGPUProg);

        // And finally create a material with the newly created shader
        HMaterial exampleMaterial = Material::create(exampleShader);

        // And set the texture to be used by the "tex" shader parameter. We leave the "samp"
        // parameter at its defaults.
        exampleMaterial->setTexture("tex", exampleTexture);

        /************************************************************************/
        /*                              SCENE OBJECT                            */
        /************************************************************************/

        // Now we create a scene object that has a position, orientation, scale and optionally
        // components to govern its logic. In this particular case we are creating a SceneObject
        // with a Renderable component which will render a mesh at the position of the scene object
        // with the provided material.

        // Create new scene object at (0, 0, 0)
        HSceneObject pyromancerSO = SceneObject::create("Pyromancer");

        // Attach the Renderable component and hook up the mesh we imported earlier,
        // and the material we created in the previous section.
        HRenderable renderable = pyromancerSO->addComponent<Renderable>();
        renderable->setMesh(exampleModel);
        renderable->setMaterial(exampleMaterial);

        /************************************************************************/
        /*                                  CAMERA                              */
        /************************************************************************/

        // In order something to render on screen we need at least one camera.

        // Like before, we create a new scene object at (0, 0, 0).
        HSceneObject sceneCameraSO = SceneObject::create("SceneCamera");

        // We retrieve the primary render window and add a Camera component that
        // will output whatever it sees into that window (You could also use a render texture
        // or another window you created).
        RenderWindowPtr window = gApplication().getPrimaryWindow();
        sceneCamera = sceneCameraSO->addComponent<Camera>(window);

        // Set up camera component properties

        // Priority determines in what order are cameras rendered in case multiple cameras render to the same render target.
        // We raise the priority slightly because later in code we have defined a GUI camera that we want to render second.
        sceneCamera->setPriority(1);

        // Set closest distance that is visible. Anything below that is clipped.
        sceneCamera->setNearClipDistance(5);

        // Set aspect ratio depending on the current resolution
        sceneCamera->setAspectRatio(resolutionWidth / (float)resolutionHeight);

        // Add a CameraFlyer component that allows us to move the camera. See CameraFlyer for more information.
        sceneCameraSO->addComponent<CameraFlyer>();

        // Position and orient the camera scene object
        sceneCameraSO->setPosition(Vector3(40.0f, 30.0f, 230.0f));
        sceneCameraSO->lookAt(Vector3(0, 0, 0));

        /************************************************************************/
        /*                                  INPUT                               */
        /************************************************************************/

        // Register input configuration
        // Banshee allows you to use VirtualInput system which will map input device buttons
        // and axes to arbitrary names, which allows you to change input buttons without affecting
        // the code that uses it, since the code is only aware of the virtual names.
        // If you want more direct input, see Input class.
        auto inputConfig = VirtualInput::instance().getConfiguration();

        // Camera controls for buttons (digital 0-1 input, e.g. keyboard or gamepad button)
        inputConfig->registerButton("Forward", BC_W);
        inputConfig->registerButton("Back", BC_S);
        inputConfig->registerButton("Left", BC_A);
        inputConfig->registerButton("Right", BC_D);
        inputConfig->registerButton("Forward", BC_UP);
        inputConfig->registerButton("Back", BC_BACK);
        inputConfig->registerButton("Left", BC_LEFT);
        inputConfig->registerButton("Right", BC_RIGHT);
        inputConfig->registerButton("FastMove", BC_LSHIFT);
        inputConfig->registerButton("RotateCam", BC_MOUSE_RIGHT);

        // Camera controls for axes (analog input, e.g. mouse or gamepad thumbstick)
        // These return values in [-1.0, 1.0] range.
        inputConfig->registerAxis("Horizontal", VIRTUAL_AXIS_DESC((UINT32)InputAxis::MouseX));
        inputConfig->registerAxis("Vertical", VIRTUAL_AXIS_DESC((UINT32)InputAxis::MouseY));

        // Controls that toggle the profiler overlays
        inputConfig->registerButton("CPUProfilerOverlay", BC_F1);
        inputConfig->registerButton("GPUProfilerOverlay", BC_F2);

        // Cache the profiler overlay buttons so when a button is pressed we can quickly
        // use these to determine its the one we want
        toggleCPUProfilerBtn = VirtualButton("CPUProfilerOverlay");
        toggleGPUProfilerBtn = VirtualButton("GPUProfilerOverlay");

        // Hook up a callback that gets triggered whenever a virtual button is released
        VirtualInput::instance().onButtonUp.connect(&buttonUp);

        /************************************************************************/
        /*                                  GUI                                 */
        /************************************************************************/

        // Create a scene object that will contain GUI components
        HSceneObject guiSO = SceneObject::create("Example");

        // First we want another camera that is responsible for rendering GUI
        HCamera guiCamera = guiSO->addComponent<Camera>(window);

        // Set up GUI camera properties.
        // We don't care about aspect ratio for GUI camera.
        guiCamera->setAspectRatio(1.0f);

        // This camera should ignore any Renderable objects in the scene
        guiCamera->setIgnoreSceneRenderables(true);

        // Don't clear this camera as that would clear anything the main camera has rendered.
        guiCamera->getViewport()->setRequiresClear(false, false, false);

        // Add a GUIWidget, the top-level GUI component, parent to all GUI elements. GUI widgets
        // require you to specify a viewport that they will output rendered GUI elements to.
        HGUIWidget gui = guiSO->addComponent<GUIWidget>(guiCamera->getViewport().get());

        // Depth allows you to control how is a GUI widget rendered in relation to other widgets
        // Lower depth means the widget will be rendered in front of those with higher. In this case we just
        // make the depth mid-range as there are no other widgets.
        gui->setDepth(128);

        // GUI skin defines how are all child elements of the GUI widget renderer. It contains all their styles
        // and default layout properties. We use the default skin that comes built into Banshee.
        gui->setSkin(BuiltinResources::instance().getGUISkin());

        // Create a GUI area that is used for displaying messages about buttons for toggling profiler overlays.
        // This area will stretch the entire surface of its parent widget, even if the widget is resized.
        GUIArea* topArea = GUIArea::createStretchedXY(*gui, 0, 0, 0, 0);

        // Add a vertical layout that will automatically position any child elements top to bottom.
        GUILayout& topLayout = topArea->getLayout().addLayoutY();

        // Add a couple of labels to the layout with the needed messages. Labels expect a HString object that
        // maps into a string table and allows for easily localization.
        topLayout.addElement(GUILabel::create(HString(L"Press F1 to toggle CPU profiler overlay")));
        topLayout.addElement(GUILabel::create(HString(L"Press F2 to toggle GPU profiler overlay")));

        // Add a flexible space that fills up any remaining area in the area, making the two labels above be aligned
        // to the top of the GUI widget (and the screen).
        topLayout.addFlexibleSpace();

        // Create a GUI area that is used for displaying resolution and fullscreen options.
        GUIArea* rightArea = GUIArea::createStretchedXY(*gui, 0, 0, 0, 0);

        // We want all the GUI elements be right aligned, so we add a flexible space first.
        rightArea->getLayout().addFlexibleSpace();

        // And we want the elements to be vertically placed, top to bottom
        GUILayout& rightLayout = rightArea->getLayout().addLayoutY();

        // Add an empty space of 50 pixels
        rightLayout.addSpace(50);

        // Add a button that will trigger a callback when clicked
        toggleFullscreenButton = GUIButton::create(HString(L"Toggle fullscreen"));
        toggleFullscreenButton->onClick.connect(&toggleFullscreen);
        rightLayout.addElement(toggleFullscreenButton);

        // Add a profiler overlay object that is resposible for displaying CPU and GPU profiling GUI
        profilerOverlay = guiSO->addComponent<ProfilerOverlay>(guiCamera->getViewport());
    }

    void toggleFullscreen()
    {
        RenderWindowPtr window = gApplication().getPrimaryWindow();

        // In order to toggle between full-screen and windowed mode we need to use a CoreAccessor.
        // Banshee is a multi-threaded engine and when you need to communicate between simulation and
        // core thread you will use a CoreAccessor. Calling a core accessor method will essentially
        // queue the method to be executed later. Since RenderWindow is a core object you need to use
        // CoreAccessor to modify and access it from simulation thread, except where noted otherwise.

        // Classes where it is not clear if they are to be used on the core or simulation thread have
        // it noted in their documentation. e.g. RenderWindow::setWindowed method is marked as "Core only".
        // Additional asserts are normally in place for debug builds which make it harder for you to accidentally
        // call something from the wrong thread.
        if (fullscreen)
        {
            gCoreAccessor().setWindowed(window, resolutionWidth, resolutionHeight);
        }
        else
        {
            gCoreAccessor().setFullscreen(window, 1920, 1200);
        }

        fullscreen = !fullscreen;
    }

    void buttonUp(const VirtualButton& button, UINT32 deviceIdx)
    {
        // Check if the pressed button is one of the either buttons we defined
        // in "setUpExample", and toggle profiler overlays accordingly.
        // Device index is ignored for now, as it is assumed the user is using a single keyboard,
        // but if you wanted support for multiple gamepads you would check deviceIdx.
        if (button == toggleCPUProfilerBtn)
        {
            if (cpuProfilerActive)
            {
                profilerOverlay->hide();
                cpuProfilerActive = false;
            }
            else
            {
                profilerOverlay->show(ProfilerOverlayType::CPUSamples);
                cpuProfilerActive = true;
                gpuProfilerActive = false;
            }
        }
        else if (button == toggleGPUProfilerBtn)
        {
            if (gpuProfilerActive)
            {
                profilerOverlay->hide();
                gpuProfilerActive = false;
            }
            else
            {
                profilerOverlay->show(ProfilerOverlayType::GPUSamples);
                gpuProfilerActive = true;
                cpuProfilerActive = false;
            }
        }
    }
}