#include "Graphics.h"
#include "dxerr.h"
#include <sstream>
#include <d3dcompiler.h>
#include <DirectXMath.h>
#include "GraphicsThrowMacros.h"

namespace wrl = Microsoft::WRL;
namespace dx = DirectX;

#pragma comment(lib,"d3d11.lib")
#pragma comment(lib,"D3DCompiler.lib")

Graphics::Graphics( HWND hWnd )
{
	// 交换链的参数定义
	DXGI_SWAP_CHAIN_DESC sd = {};
	sd.BufferDesc.Width = 0;
	sd.BufferDesc.Height = 0;
	sd.BufferDesc.Format = DXGI_FORMAT_B8G8R8A8_UNORM;
	sd.BufferDesc.RefreshRate.Numerator = 0;
	sd.BufferDesc.RefreshRate.Denominator = 0;
	sd.BufferDesc.Scaling = DXGI_MODE_SCALING_UNSPECIFIED;
	sd.BufferDesc.ScanlineOrdering = DXGI_MODE_SCANLINE_ORDER_UNSPECIFIED;
	sd.SampleDesc.Count = 1;
	sd.SampleDesc.Quality = 0;
	sd.BufferUsage = DXGI_USAGE_RENDER_TARGET_OUTPUT;
	sd.BufferCount = 1;
	sd.OutputWindow = hWnd;
	sd.Windowed = TRUE;
	sd.SwapEffect = DXGI_SWAP_EFFECT_DISCARD;
	sd.Flags = 0;

	UINT swapCreateFlags = 0u;
	#ifndef NDEBUG
	swapCreateFlags |= D3D11_CREATE_DEVICE_DEBUG;
	#endif

	// for checking results of d3d functions
	HRESULT hr;

	// create device and front/back buffers, and swap chain and rendering context
	// 创建Device，SwapChain和Context
	GFX_THROW_INFO(D3D11CreateDeviceAndSwapChain(
		nullptr,
		D3D_DRIVER_TYPE_HARDWARE,
		nullptr,
		swapCreateFlags,
		nullptr,
		0,
		D3D11_SDK_VERSION,
		&sd,
		&pSwap,
		&pDevice,
		nullptr,
		&pContext
	));

	// gain access to texture subresource in swap chain (back buffer)
	wrl::ComPtr<ID3D11Resource> pBackBuffer;
	GFX_THROW_INFO(pSwap->GetBuffer(0, __uuidof(ID3D11Resource), &pBackBuffer));
	GFX_THROW_INFO(pDevice->CreateRenderTargetView(pBackBuffer.Get(), nullptr, &pTarget));

	// Create depth stencil state
	D3D11_DEPTH_STENCIL_DESC depthStencilDesc = {};
	depthStencilDesc.DepthEnable = TRUE;
	depthStencilDesc.DepthWriteMask = D3D11_DEPTH_WRITE_MASK_ALL;
	depthStencilDesc.DepthFunc = D3D11_COMPARISON_LESS;
	wrl::ComPtr<ID3D11DepthStencilState> pDepthStencilState;
	// Create depth stencil state
	GFX_THROW_INFO(pDevice->CreateDepthStencilState(&depthStencilDesc, &pDepthStencilState));

	// bind depth state
	pContext->OMSetDepthStencilState(pDepthStencilState.Get(), 1u);

	// Create the depth stencil texture
	wrl::ComPtr<ID3D11Texture2D> depthStencilTexture;
	D3D11_TEXTURE2D_DESC depthStencilTextureDesc = {};
	depthStencilTextureDesc.Width = 800;
	depthStencilTextureDesc.Height = 600;
	depthStencilTextureDesc.MipLevels = 1u;
	depthStencilTextureDesc.ArraySize = 1u;
	depthStencilTextureDesc.Format = DXGI_FORMAT_D32_FLOAT;
	depthStencilTextureDesc.SampleDesc.Count = 1u;
	depthStencilTextureDesc.SampleDesc.Quality = 0u;
	depthStencilTextureDesc.Usage = D3D11_USAGE_DEFAULT;
	depthStencilTextureDesc.BindFlags = D3D11_BIND_DEPTH_STENCIL;
	GFX_THROW_INFO(pDevice->CreateTexture2D(&depthStencilTextureDesc, nullptr, &depthStencilTexture));

	// Create the depth stencil view
	D3D11_DEPTH_STENCIL_VIEW_DESC depthStencilViewDesc = {};
	depthStencilViewDesc.Format = DXGI_FORMAT_D32_FLOAT;
	depthStencilViewDesc.ViewDimension = D3D11_DSV_DIMENSION_TEXTURE2D;
	depthStencilViewDesc.Texture2D.MipSlice = 0u;
	GFX_THROW_INFO(pDevice->CreateDepthStencilView(depthStencilTexture.Get(), &depthStencilViewDesc, &pDSView));

	// Bind depth stencil view to out put merger
	pContext->OMSetRenderTargets(1u, pTarget.GetAddressOf(), pDSView.Get());

	// configure viewport
	D3D11_VIEWPORT vp;
	vp.Width = 800.0f;
	vp.Height = 600.0f;
	vp.MinDepth = 0.0f;
	vp.MaxDepth = 1.0f;
	vp.TopLeftX = 0.0f;
	vp.TopLeftY = 0.0f;
	pContext->RSSetViewports(1u, &vp);
}

void Graphics::EndFrame()
{
	// flipping，使用SwapChain将back buffer的内容展现到屏幕
	HRESULT hr;
	#ifndef NDEBUG
	infoManager.Set();
	#endif
	if (FAILED(hr = pSwap->Present(1u, 0u))) // 同步频率1，代表屏幕每刷新一次，就进行图形刷新。
	{
		if (hr == DXGI_ERROR_DEVICE_REMOVED)
		{
			throw GFX_DEVICE_REMOVED_EXCEPT(pDevice->GetDeviceRemovedReason());
		}
		else
		{
			throw GFX_EXCEPT(hr);
		}
	}
}

void Graphics::ClearBuffer(float red, float green, float blue) noexcept
{
	const float color[] = { red,green,blue,1.0f };
	pContext->ClearRenderTargetView(pTarget.Get(), color);
	pContext->ClearDepthStencilView(pDSView.Get(), D3D11_CLEAR_DEPTH, 1.0f, 0u);
}

void Graphics::DrawIndexed(UINT count) noexcept(!IS_DEBUG)
{
    GFX_THROW_INFO_ONLY( pContext->DrawIndexed( count,0u,0u ) );
}

void Graphics::SetProjection( DirectX::FXMMATRIX proj ) noexcept
{
    projection = proj;
}

DirectX::XMMATRIX Graphics::GetProjection() const noexcept
{
	return projection;
}

// Graphics exception stuff
Graphics::HrException::HrException(int line, const char* file, HRESULT hr, std::vector<std::string> infoMsgs) noexcept
	:
	Exception(line, file),
	hr(hr)
{
	// join all info messages with newlines into single string
	for (const auto& m : infoMsgs)
	{
		info += m;
		info.push_back('\n');
	}
	// remove final newline if exists
	if (!info.empty())
	{
		info.pop_back();
	}
}

const char* Graphics::HrException::what() const noexcept
{
	std::ostringstream oss;
	oss << GetType() << std::endl
		<< "[Error Code] 0x" << std::hex << std::uppercase << GetErrorCode()
		<< std::dec << " (" << (unsigned long)GetErrorCode() << ")" << std::endl
		<< "[Error String] " << GetErrorString() << std::endl
		<< "[Description] " << GetErrorDescription() << std::endl;
	if (!info.empty())
	{
		oss << "\n[Error Info]\n" << GetErrorInfo() << std::endl << std::endl;
	}
	oss << GetOriginString();
	whatBuffer = oss.str();
	return whatBuffer.c_str();
}

const char* Graphics::HrException::GetType() const noexcept
{
	return "Chili Graphics Exception";
}

HRESULT Graphics::HrException::GetErrorCode() const noexcept
{
	return hr;
}

std::string Graphics::HrException::GetErrorString() const noexcept
{
	return DXGetErrorString(hr);
}

std::string Graphics::HrException::GetErrorDescription() const noexcept
{
	char buf[512];
	DXGetErrorDescription(hr, buf, sizeof(buf));
	return buf;
}

std::string Graphics::HrException::GetErrorInfo() const noexcept
{
	return info;
}

const char* Graphics::DeviceRemovedException::GetType() const noexcept
{
	return "Chili Graphics Exception [Device Removed] (DXGI_ERROR_DEVICE_REMOVED)";
}

Graphics::InfoException::InfoException(int line, const char* file, std::vector<std::string> infoMsgs) noexcept
	:
	Exception(line, file)
{
	// join all info messages with newlines into single string
	for (const auto& m : infoMsgs)
	{
		info += m;
		info.push_back('\n');
	}
	// remove final newline if exists
	if (!info.empty())
	{
		info.pop_back();
	}
}


const char* Graphics::InfoException::what() const noexcept
{
	std::ostringstream oss;
	oss << GetType() << std::endl
		<< "\n[Error Info]\n" << GetErrorInfo() << std::endl << std::endl;
	oss << GetOriginString();
	whatBuffer = oss.str();
	return whatBuffer.c_str();
}

const char* Graphics::InfoException::GetType() const noexcept
{
	return "Chili Graphics Info Exception";
}

std::string Graphics::InfoException::GetErrorInfo() const noexcept
{
	return info;
}