#include "XCEngine/RHI/OpenGL/OpenGLVertexArray.h"
#include <glad/glad.h>

namespace XCEngine {
namespace RHI {

static unsigned int ToGLAttributeType(VertexAttributeType type) {
    switch (type) {
        case VertexAttributeType::Float: return GL_FLOAT;
        case VertexAttributeType::Int: return GL_INT;
        case VertexAttributeType::UnsignedInt: return GL_UNSIGNED_INT;
        case VertexAttributeType::Short: return GL_SHORT;
        case VertexAttributeType::UnsignedShort: return GL_UNSIGNED_SHORT;
        case VertexAttributeType::Byte: return GL_BYTE;
        case VertexAttributeType::UnsignedByte: return GL_UNSIGNED_BYTE;
        case VertexAttributeType::Double: return GL_DOUBLE;
        case VertexAttributeType::HalfFloat: return GL_HALF_FLOAT;
        case VertexAttributeType::Fixed: return GL_FIXED;
        case VertexAttributeType::Int2101010Rev: return GL_INT_2_10_10_10_REV;
        case VertexAttributeType::UnsignedInt2101010Rev: return GL_UNSIGNED_INT_2_10_10_10_REV;
        case VertexAttributeType::UnsignedInt10F11F11FRev: return GL_UNSIGNED_INT_10F_11F_11F_REV;
        default: return GL_FLOAT;
    }
}

OpenGLVertexArray::OpenGLVertexArray()
    : m_vao(0)
    , m_indexBuffer(0)
    , m_indexCount(0)
    , m_vertexBufferCount(0) {
}

OpenGLVertexArray::~OpenGLVertexArray() {
    Shutdown();
}

bool OpenGLVertexArray::Initialize() {
    glGenVertexArrays(1, &m_vao);
    return true;
}

void OpenGLVertexArray::AddVertexBuffer(unsigned int buffer, const VertexAttribute& attribute) {
    glBindVertexArray(m_vao);
    glBindBuffer(GL_ARRAY_BUFFER, buffer);
    glEnableVertexAttribArray(attribute.index);
    glVertexAttribPointer(attribute.index, attribute.count, 
        ToGLAttributeType(attribute.type),
        attribute.normalized == VertexAttributeNormalized::True ? GL_TRUE : GL_FALSE, 
        attribute.stride, (void*)attribute.offset);
    glBindBuffer(GL_ARRAY_BUFFER, 0);
    glBindVertexArray(0);
    m_vertexBufferCount++;
}

void OpenGLVertexArray::SetIndexBuffer(unsigned int buffer, unsigned int type) {
    glBindVertexArray(m_vao);
    glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, buffer);
    glBindVertexArray(0);
    m_indexBuffer = buffer;
}

void OpenGLVertexArray::Shutdown() {
    if (m_vao) {
        glDeleteVertexArrays(1, &m_vao);
        m_vao = 0;
    }
}

void OpenGLVertexArray::Bind() const {
    glBindVertexArray(m_vao);
}

void OpenGLVertexArray::Unbind() const {
    glBindVertexArray(0);
}

} // namespace RHI
} // namespace XCEngine