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

namespace XCEngine {
namespace RHI {

OpenGLDepthStencilView::OpenGLDepthStencilView() 
    : m_texture(0)
    , m_framebuffer(0)
    , m_mipLevel(0)
    , m_width(0)
    , m_height(0)
    , m_type(DepthStencilType::Texture2D)
    , m_format(DepthStencilFormat::D24_UNORM_S8_UINT) {
}

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

bool OpenGLDepthStencilView::Initialize(unsigned int texture, const OpenGLDepthStencilViewDesc& desc) {
    m_texture = texture;
    m_mipLevel = desc.mipLevel;
    m_type = desc.type;

    glGenFramebuffers(1, &m_framebuffer);
    glBindFramebuffer(GL_FRAMEBUFFER, m_framebuffer);

    GLenum depthAttachment = GL_DEPTH_ATTACHMENT;
    GLenum stencilAttachment = GL_STENCIL_ATTACHMENT;

    switch (desc.type) {
        case DepthStencilType::Texture2D:
            glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_2D, texture, desc.mipLevel);
            break;
        case DepthStencilType::Texture2DArray:
            glFramebufferTextureLayer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, texture, desc.mipLevel, desc.baseArraySlice);
            break;
        case DepthStencilType::TextureCube:
            glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_CUBE_MAP_POSITIVE_X + desc.baseArraySlice, texture, desc.mipLevel);
            break;
    }

    if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
        glBindFramebuffer(GL_FRAMEBUFFER, 0);
        return false;
    }

    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    return true;
}

bool OpenGLDepthStencilView::Initialize(unsigned int texture, int mipLevel) {
    OpenGLDepthStencilViewDesc desc;
    desc.mipLevel = mipLevel;
    return Initialize(texture, desc);
}

bool OpenGLDepthStencilView::InitializeCubemap(unsigned int cubemap, int face, int mipLevel) {
    m_texture = cubemap;
    m_mipLevel = mipLevel;
    m_type = DepthStencilType::TextureCube;

    glGenFramebuffers(1, &m_framebuffer);
    glBindFramebuffer(GL_FRAMEBUFFER, m_framebuffer);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_TEXTURE_CUBE_MAP_POSITIVE_X + face, cubemap, mipLevel);

    if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GL_FRAMEBUFFER_COMPLETE) {
        glBindFramebuffer(GL_FRAMEBUFFER, 0);
        return false;
    }

    glBindFramebuffer(GL_FRAMEBUFFER, 0);
    return true;
}

void OpenGLDepthStencilView::Shutdown() {
    if (m_framebuffer) {
        glDeleteFramebuffers(1, &m_framebuffer);
        m_framebuffer = 0;
    }
}

void OpenGLDepthStencilView::Bind() {
    glBindFramebuffer(GL_FRAMEBUFFER, m_framebuffer);
}

void OpenGLDepthStencilView::Unbind() {
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
}

void OpenGLDepthStencilView::ClearDepth(float depth) {
    glBindFramebuffer(GL_FRAMEBUFFER, m_framebuffer);
    glClearDepth(depth);
    glClear(GL_DEPTH_BUFFER_BIT);
}

void OpenGLDepthStencilView::ClearStencil(uint8_t stencil) {
    glBindFramebuffer(GL_FRAMEBUFFER, m_framebuffer);
    glClearStencil(stencil);
    glClear(GL_STENCIL_BUFFER_BIT);
}

void OpenGLDepthStencilView::ClearDepthStencil(float depth, uint8_t stencil) {
    glBindFramebuffer(GL_FRAMEBUFFER, m_framebuffer);
    glClearDepth(depth);
    glClearStencil(stencil);
    glClear(GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
}

void OpenGLDepthStencilView::BindFramebuffer(unsigned int framebuffer) {
    glBindFramebuffer(GL_FRAMEBUFFER, framebuffer);
}

void OpenGLDepthStencilView::UnbindFramebuffer() {
    glBindFramebuffer(GL_FRAMEBUFFER, 0);
}

} // namespace RHI
} // namespace XCEngine