#include "Mesh.h"
#include "Utilities.h"
#include "Vertex.h"
#include <DirectXMath.h>

using namespace DirectX;

UINT Mesh::init(ID3D11Device* pD3DDevice)
{
	UINT error = 0;

	error = createVertexBuffer(pD3DDevice);
	CheckError(error);

	error = createIndexBuffer(pD3DDevice);
	CheckError(error);

	// create world matrix
	XMStoreFloat4x4(&_worldMatrix, XMMatrixIdentity());

	return 0;
}

void Mesh::update(FLOAT dt)
{
	static FLOAT x = 0.0f;
	static FLOAT y = 0.0f;
	static FLOAT z = 0.0f;
	static FLOAT rot = 0.0f;
	rot += 1.0f * dt;

	FLOAT move = 1.0f * dt;

	if ((GetAsyncKeyState(VK_LEFT) & 0x8000) || (GetAsyncKeyState('A') & 0x8000)) x -= move;
	if ((GetAsyncKeyState(VK_RIGHT) & 0x8000) || (GetAsyncKeyState('D') & 0x8000)) x += move;
	if ((GetAsyncKeyState(VK_UP) & 0x8000) || (GetAsyncKeyState('W') & 0x8000)) y += move;
	if ((GetAsyncKeyState(VK_DOWN) & 0x8000) || (GetAsyncKeyState('S') & 0x8000)) y -= move;
	if ((GetAsyncKeyState(VK_ADD) & 0x8000) || (GetAsyncKeyState('Q') & 0x8000)) z -= move;
	if ((GetAsyncKeyState(VK_SUBTRACT) & 0x8000) || (GetAsyncKeyState('E') & 0x8000)) z += move;

	XMMATRIX translation = XMMatrixTranslation(x, y, z);
	XMMATRIX rotation = XMMatrixRotationRollPitchYaw(0.0f, 0.0f, 0.0f);
	XMMATRIX scale = XMMatrixScaling(1.0f, 1.0f, 1.0f);

	XMVECTOR det = XMMatrixDeterminant(translation);

	XMStoreFloat4x4(&_worldMatrix, scale * rotation * translation);
}

void Mesh::render(ID3D11DeviceContext* pD3DDeviceContext)
{
	// set data
	static UINT offset = 0;
	pD3DDeviceContext->IASetVertexBuffers(0, 1, &_pVertexBuffer, &_vertexStride, &offset);
	pD3DDeviceContext->IASetIndexBuffer(_pIndexBuffer, DXGI_FORMAT_R16_UINT, 0);
	pD3DDeviceContext->IASetPrimitiveTopology(D3D11_PRIMITIVE_TOPOLOGY_TRIANGLELIST);

	// draw
	pD3DDeviceContext->DrawIndexed(_indexCount, 0, 0);
}

void Mesh::deInit()
{
	safeRelease(_pIndexBuffer);
	safeRelease(_pVertexBuffer);
}

UINT Mesh::createVertexBuffer(ID3D11Device* pD3DDevice)
{
	// describe vertex buffer content
	// quad with color
	Vertex vertices[] = { Vertex(-0.5f, 0.5f, 0.0f, 255, 0, 0),
	Vertex(0.5f, 0.5f, 0.0f, 0, 255, 0),
	Vertex(0.5f, -0.5f, 0.0f, 255, 0, 255),
	Vertex(-0.5f, -0.5f, 0.0f, 0, 0, 255) };


	// quad with uv & normal
	//Vertex vertices[] = {
	//	Vertex(-0.5f, 0.5f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, 0.0f),
	//	Vertex(0.5f, 0.5f, 0.0f, 0.0f, 0.0f, -1.0f, 1.0f, 0.0f),
	//	Vertex(0.5f, -0.5f, 0.0f, 0.0f, 0.0f, -1.0f, 1.0f, 1.0f),
	//	Vertex(-0.5f, -0.5f, 0.0f, 0.0f, 0.0f, -1.0f, 0.0f, 1.0f)
	//};

	// general data
	_vertexCount = std::size(vertices);
	_vertexStride = sizeof(Vertex);

	// create vertex buffer object
	D3D11_BUFFER_DESC desc = {};
	desc.ByteWidth = _vertexCount * _vertexStride; // size of vertex buffer in bytes
	desc.BindFlags = D3D11_BIND_VERTEX_BUFFER;
	desc.Usage = D3D11_USAGE_IMMUTABLE; // https://learn.microsoft.com/en-us/windows/win32/api/d3d11/ne-d3d11-d3d11_usage

	D3D11_SUBRESOURCE_DATA data = {};
	data.pSysMem = vertices;

	HRESULT hr = pD3DDevice->CreateBuffer(&desc, &data, &_pVertexBuffer);
	CheckFailed(hr, 30);

	return 0;
}

UINT Mesh::createIndexBuffer(ID3D11Device* pD3DDevice)
{
	// describe index buffer content
	WORD indices[] = {
		0,1,2,
		0,2,3
	};

	// general data
	_indexCount = std::size(indices);

	// create index buffer object
	D3D11_BUFFER_DESC desc = {};
	desc.ByteWidth = _indexCount * sizeof(WORD); // size of index buffer in bytes
	desc.BindFlags = D3D11_BIND_INDEX_BUFFER;
	desc.Usage = D3D11_USAGE_IMMUTABLE;

	D3D11_SUBRESOURCE_DATA data = {};
	data.pSysMem = indices;

	HRESULT hr = pD3DDevice->CreateBuffer(&desc, &data, &_pIndexBuffer);
	CheckFailed(hr, 32);

	return 0;
}