#include <cigui/core/App.hpp>

#include <iostream>
#include <LLGL/Utils/VertexFormat.h>


#include <cigui/core/Memory.hpp>
namespace cig
{
	App::App() : m_WindowListener(std::make_shared<WindowListener>(*this))
	{
		// Rectangle
		m_Vertices.emplace_back(Vertex{ { 0.5f, -0.5f }, {    0, 255,   0, 255 } });
		m_Vertices.emplace_back(Vertex{ { -0.5f, -0.5f }, { 255,   0,   0, 255 } });
		m_Vertices.emplace_back(Vertex{ { -0.5f,  0.5f }, {   0,   0, 255, 255 } });
		m_Vertices.emplace_back(Vertex{ { 0.5f,  0.5f }, {  255,   0,   0, 255 } });
		m_Vertices.emplace_back(Vertex{ { -0.5f, -0.5f }, {   0, 255,   0, 255 } });
		m_Vertices.emplace_back(Vertex{ { -0.5f,  0.5f }, {   0,   0, 255, 255 } });

		for (const char* module : { "Direct3D12", "Direct3D11", "Vulkan", "OpenGL" }) {
			LLGL::Report report;
			m_RenderSystem = LLGL::RenderSystem::Load(module, &report);
			if (m_RenderSystem == nullptr) {
				LLGL::Log::Errorf("%s", report.GetText());
			}
		}
		if (m_RenderSystem == nullptr) {
			std::cout << "No renderer found!" << std::endl;
			return;
		}

		LLGL::SwapChainDescriptor swapChainDesc;
		swapChainDesc.resizable			= true;
		swapChainDesc.debugName			= "SwapChain";
		swapChainDesc.swapBuffers		= 2;
		swapChainDesc.resolution.width	= 800;
		swapChainDesc.resolution.height	= 600;				// Framebuffer resolution of 800x600 pixels
		swapChainDesc.fullscreen		= false;			// No fullscreen, use windowed mode
		swapChainDesc.samples			= 8;				// 8 samples for anti-aliasing
		m_SwapChain = m_RenderSystem->CreateSwapChain(swapChainDesc);

		LLGL::VertexFormat vertexFormat;
		vertexFormat.AppendAttribute({ "position", LLGL::Format::RG32Float  });
		vertexFormat.AppendAttribute({ "color",    LLGL::Format::RGBA8UNorm });

		LLGL::BufferDescriptor VBufferDesc;
		VBufferDesc.size          = sizeof(Vertex) * m_Vertices.size();	// Size (in bytes) of the buffer
		VBufferDesc.bindFlags     = LLGL::BindFlags::VertexBuffer;		// Use for vertex buffer binding
		VBufferDesc.vertexAttribs = vertexFormat.attributes;			// Vertex buffer attributes
		m_VertexBuffer = m_RenderSystem->CreateBuffer(VBufferDesc, m_Vertices.data());

		LLGL::ShaderDescriptor VSDesc, FSDesc;
		if (ShaderLanguageIsSupported(LLGL::ShadingLanguage::HLSL)) {
			VSDesc = { LLGL::ShaderType::Vertex,   "shader/MyShader.hlsl", "VMain", "vs_4_0" };
			FSDesc = { LLGL::ShaderType::Fragment, "shader/MyShader.hlsl", "PMain", "ps_4_0" };
		} else if (ShaderLanguageIsSupported(LLGL::ShadingLanguage::GLSL)) {
			VSDesc = { LLGL::ShaderType::Vertex,   "shader/MyShader.vert" };
			FSDesc = { LLGL::ShaderType::Fragment, "shader/MyShader.frag" };
		} else {
			std::cout << "Shading language not supported!" << std::endl;
			return;
		}
		VSDesc.vertex.inputAttribs = vertexFormat.attributes;

		m_ShaderPack.first  = m_RenderSystem->CreateShader(VSDesc);
		m_ShaderPack.second = m_RenderSystem->CreateShader(FSDesc);

		for (LLGL::Shader* shader : { m_ShaderPack.first, m_ShaderPack.second }) {
			if (const LLGL::Report* report = shader->GetReport()) {
				if (report->HasErrors()) {
					LLGL::Log::Errorf("Shader compile errors:\n%s", report->GetText());
				} else {
					LLGL::Log::Printf("Shader compile warnings:\n%s", report->GetText());
				}
			}
		}

		LLGL::GraphicsPipelineDescriptor pipelineDesc;
		pipelineDesc.vertexShader					= m_ShaderPack.first;
		pipelineDesc.fragmentShader					= m_ShaderPack.second;
		pipelineDesc.primitiveTopology				= LLGL::PrimitiveTopology::TriangleList;
		pipelineDesc.rasterizer.multiSampleEnabled	= swapChainDesc.samples > 1;

		m_Pipeline = m_RenderSystem->CreatePipelineState(pipelineDesc);

		m_CmdBuffer = m_RenderSystem->CreateCommandBuffer(LLGL::CommandBufferFlags::ImmediateSubmit);
	}

	App::~App()
	{
	}


	App::WindowListener::WindowListener(App& app) : m_App(app) {}

	void App::WindowListener::OnResize(LLGL::Window& sender, const LLGL::Extent2D& clientAreaSize)
	{
		EventListener::OnResize(sender, clientAreaSize);
		m_App.m_SwapChain->ResizeBuffers(clientAreaSize);
		m_App.resized({clientAreaSize.width, clientAreaSize.height});
		m_App.update(true);
		m_App.render();
	}


	void App::WindowListener::OnQuit(LLGL::Window& sender, bool& veto)
	{
		EventListener::OnQuit(sender, veto);
		veto = !m_App.save() || veto;
		std::cout << "App: Quit" << std::endl;
	}

	void App::WindowListener::OnLostFocus(LLGL::Window& sender)
	{
		EventListener::OnLostFocus(sender);
		std::cout << "App: Lost focus" << std::endl;
	}

	void App::WindowListener::OnGetFocus(LLGL::Window& sender)
	{
		EventListener::OnGetFocus(sender);
		std::cout << "App: Got focus" << std::endl;
	}


	bool App::ShaderLanguageIsSupported(LLGL::ShadingLanguage lang) const
	{
		const auto& supportedLangs = m_RenderSystem->GetRenderingCaps().shadingLanguages;
		return std::find(supportedLangs.begin(), supportedLangs.end(), lang) != supportedLangs.end();
	}

	void App::resized(vec2u size)
	{
		m_WindowSize = size;
	}

	void App::Initialize(int argc, char** argv)
	{

	}

	void App::update(bool force)
	{

	}

	void App::render() const
	{
		static LLGL::ClearValue clear_value(.1f,.1f,.1f,1.f);

		m_CmdBuffer->Begin();
		{
			m_CmdBuffer->SetVertexBuffer(*m_VertexBuffer);

			m_CmdBuffer->BeginRenderPass(*m_SwapChain);
			{
				m_CmdBuffer->SetViewport(m_SwapChain->GetResolution());

				m_CmdBuffer->Clear(LLGL::ClearFlags::Color, clear_value);

				m_CmdBuffer->SetPipelineState(*m_Pipeline);

				{
					m_CmdBuffer->Draw(static_cast<uint32_t>(m_Vertices.size()), 0);
				}
			}
			m_CmdBuffer->EndRenderPass();
		}
		m_CmdBuffer->End();

		m_SwapChain->Present();
	}

	bool App::save() const
	{
		return true;
	}

	int App::Run()
	{
		if (!m_RenderSystem)
			return -1;

		m_Window = &LLGL::CastTo<LLGL::Window>(m_SwapChain->GetSurface());

		m_Window->AddEventListener(m_WindowListener);

		m_Window->SetTitle("Common Interface GUI");
		m_Window->Show();

		while (LLGL::Surface::ProcessEvents() && !m_Window->HasQuit()) {
			update();
			render();
		}
		return 0;
	}
}