#include "../../../include/RenderBackend/OpenGL/DeviceMemory.hpp"
#include "../../../include/RenderBackend/OpenGL/opengl.hpp"
#include <cassert>

namespace amalgine
{
    u32 getOpenglStorageType(DeviceMemory::StorageType storageType)
    {
        switch(storageType)
        {
            case DeviceMemory::StorageType::STATIC:     return GL_STATIC_DRAW;
            case DeviceMemory::StorageType::DYNAMIC:    return GL_DYNAMIC_DRAW;
            case DeviceMemory::StorageType::STREAM:     return GL_STREAM_DRAW;
            default: assert(false); return -1;
        }
    }
    
    u32 getOpenglPrimitiveType(DeviceMemory::PrimitiveType primitiveType)
    {
        switch(primitiveType)
        {
            case DeviceMemory::PrimitiveType::TRIANGLE:     return GL_TRIANGLES;
            default: assert(false); return -1;
        }
    }
    
    u32 getPrimitiveTypePointsPerVertices(DeviceMemory::PrimitiveType primitiveType)
    {
        switch(primitiveType)
        {
            case DeviceMemory::PrimitiveType::TRIANGLE:     return 3;
            default: assert(false); return -1;
        }
    }
    
    DeviceMemory::DeviceMemory() : primitiveType(0), numVertices(0), type(DeviceMemoryType::NONE)
    {
        glGenBuffers(1, &vertexBufferObjectId);
    }
    
    DeviceMemory::~DeviceMemory()
    {
        glDeleteBuffers(1, &vertexBufferObjectId);
    }
    
    void DeviceMemory::use() const
    {
        // TODO: Bind vao here?
        glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObjectId);
    }
    /*
    void DeviceMemory::copy(const DataView<f32> &data, StorageType storageType, PrimitiveType primitiveType)
    {
        glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObjectId);
        glBufferData(GL_ARRAY_BUFFER, data.getByteSize(), data.data, getOpenglStorageType(storageType));
        this->primitiveType = getOpenglPrimitiveType(primitiveType);
        numVertices = getPrimitiveTypePointsPerVertices(primitiveType);
    }
    */
    void DeviceMemory::copy(const DataView<Triangle2D> &triangles, StorageType storageType)
    {
        glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObjectId);
        glBufferData(GL_ARRAY_BUFFER, triangles.getByteSize(), triangles.data, getOpenglStorageType(storageType));
        primitiveType = GL_TRIANGLES;
        numVertices = triangles.size * 3;
        type = DeviceMemoryType::VEC2;
    }

    void DeviceMemory::copy(const DataView<Triangle3D> &triangles, StorageType storageType)
    {
        glBindBuffer(GL_ARRAY_BUFFER, vertexBufferObjectId);
        glBufferData(GL_ARRAY_BUFFER, triangles.getByteSize(), triangles.data, getOpenglStorageType(storageType));
        primitiveType = GL_TRIANGLES;
        numVertices = triangles.size * 3;
        type = DeviceMemoryType::VEC3;
    }
    
    void DeviceMemory::draw()
    {
        glDrawArrays(primitiveType, 0, numVertices);
    }
}