#include <Rendering\StaticMeshComponent.h>
#include <RHI\D3D12\D3D12RHI.h>
#include <RHI\D3D12\D3D12Resources.h>
#include <cstdio>

namespace XCEngine {
namespace RHI {

StaticMeshComponent::StaticMeshComponent() {
}

StaticMeshComponent::~StaticMeshComponent() {
    if (m_vertexBuffer) {
        delete m_vertexBuffer;
    }
    for (auto& pair : m_subMeshes) {
        delete pair.second;
    }
}

bool StaticMeshComponent::Initialize(ICommandList* commandList, const char* filePath) {
    D3D12CommandList* d3d12CmdList = static_cast<D3D12CommandList*>(commandList);
    D3D12Device* device = d3d12CmdList->GetDevice();
    
    FILE* file = nullptr;
    if (fopen_s(&file, filePath, "rb") != 0) {
        return false;
    }
    
    int vertexCount = 0;
    fread(&vertexCount, 4, 1, file);
    m_vertexCount = vertexCount;
    
    MeshVertex* vertices = new MeshVertex[vertexCount];
    fread(vertices, sizeof(MeshVertex), vertexCount, file);
    
    CreateVertexBuffer(device, commandList, vertices, sizeof(MeshVertex) * vertexCount, sizeof(MeshVertex), &m_vertexBuffer);
    
    delete[] vertices;
    
    while (!feof(file)) {
        int nameLength = 0;
        fread(&nameLength, 4, 1, file);
        if (feof(file)) break;
        
        char name[256] = {0};
        fread(name, 1, nameLength, file);
        
        int indexCount = 0;
        fread(&indexCount, 4, 1, file);
        
        uint32_t* indices = new uint32_t[indexCount];
        fread(indices, sizeof(uint32_t), indexCount, file);
        
        IIndexBuffer* indexBuffer = nullptr;
        CreateIndexBuffer(device, commandList, indices, sizeof(uint32_t) * indexCount, &indexBuffer);
        
        delete[] indices;
        
        SubMesh* submesh = new SubMesh();
        submesh->indexBuffer = indexBuffer;
        submesh->indexCount = indexCount;
        m_subMeshes[std::string(name)] = submesh;
    }
    
    fclose(file);
    return true;
}

void StaticMeshComponent::Render(ICommandList* commandList) {
    if (!m_vertexBuffer) return;
    
    commandList->SetVertexBuffer(0, m_vertexBuffer, 0, sizeof(MeshVertex));
    
    if (m_subMeshes.empty()) {
        commandList->DrawInstanced(m_vertexCount, 1, 0, 0);
    }
    else {
        for (auto& pair : m_subMeshes) {
            SubMesh* submesh = pair.second;
            commandList->SetIndexBuffer(submesh->indexBuffer, 0);
            commandList->DrawIndexedInstanced(submesh->indexCount, 1, 0, 0, 0);
        }
    }
}

} // namespace RHI
} // namespace XCEngine