#define GLFW_INCLUDE_NONE
#include "XCEngine/RHI/OpenGL/OpenGLShader.h"
#include <glad/glad.h>
#include <GLFW/glfw3.h>
#include <fstream>
#include <sstream>
#include <iostream>

namespace XCEngine {
namespace RHI {

OpenGLShader::OpenGLShader()
    : m_program(0) {
}

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

bool OpenGLShader::CompileFromFile(const char* vertexPath, const char* fragmentPath) {
    std::string vertexCode, fragmentCode;
    std::ifstream vShaderFile(vertexPath), fShaderFile(fragmentPath);
    
    if (!vShaderFile.is_open() || !fShaderFile.is_open()) {
        return false;
    }
    
    std::stringstream vShaderStream, fShaderStream;
    vShaderStream << vShaderFile.rdbuf();
    fShaderStream << fShaderFile.rdbuf();
    vShaderFile.close();
    fShaderFile.close();
    
    vertexCode = vShaderStream.str();
    fragmentCode = fShaderStream.str();
    
    return Compile(vertexCode.c_str(), fragmentCode.c_str());
}

bool OpenGLShader::CompileFromFile(const char* vertexPath, const char* fragmentPath, const char* geometryPath) {
    std::string vertexCode, fragmentCode, geometryCode;
    std::ifstream vShaderFile(vertexPath), fShaderFile(fragmentPath), gShaderFile(geometryPath);
    
    if (!vShaderFile.is_open() || !fShaderFile.is_open() || !gShaderFile.is_open()) {
        return false;
    }
    
    std::stringstream vShaderStream, fShaderStream, gShaderStream;
    vShaderStream << vShaderFile.rdbuf();
    fShaderStream << fShaderFile.rdbuf();
    gShaderStream << gShaderFile.rdbuf();
    vShaderFile.close();
    fShaderFile.close();
    gShaderFile.close();
    
    vertexCode = vShaderStream.str();
    fragmentCode = fShaderStream.str();
    geometryCode = gShaderStream.str();
    
    return Compile(vertexCode.c_str(), fragmentCode.c_str(), geometryCode.c_str());
}

bool OpenGLShader::Compile(const char* vertexSource, const char* fragmentSource) {
    unsigned int vertex, fragment;
    
    vertex = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertex, 1, &vertexSource, nullptr);
    glCompileShader(vertex);
    if (!CheckCompileErrors(vertex, "VERTEX")) {
        return false;
    }
    
    fragment = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragment, 1, &fragmentSource, nullptr);
    glCompileShader(fragment);
    if (!CheckCompileErrors(fragment, "FRAGMENT")) {
        return false;
    }
    
    m_program = glCreateProgram();
    glAttachShader(m_program, vertex);
    glAttachShader(m_program, fragment);
    glLinkProgram(m_program);
    
    if (!CheckLinkErrors(m_program)) {
        return false;
    }
    
    glDeleteShader(vertex);
    glDeleteShader(fragment);
    
    return true;
}

bool OpenGLShader::Compile(const char* vertexSource, const char* fragmentSource, const char* geometrySource) {
    unsigned int vertex, fragment, geometry;
    
    vertex = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertex, 1, &vertexSource, nullptr);
    glCompileShader(vertex);
    if (!CheckCompileErrors(vertex, "VERTEX")) {
        return false;
    }
    
    fragment = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragment, 1, &fragmentSource, nullptr);
    glCompileShader(fragment);
    if (!CheckCompileErrors(fragment, "FRAGMENT")) {
        return false;
    }
    
    geometry = glCreateShader(GL_GEOMETRY_SHADER);
    glShaderSource(geometry, 1, &geometrySource, nullptr);
    glCompileShader(geometry);
    if (!CheckCompileErrors(geometry, "GEOMETRY")) {
        return false;
    }
    
    m_program = glCreateProgram();
    glAttachShader(m_program, vertex);
    glAttachShader(m_program, fragment);
    glAttachShader(m_program, geometry);
    glLinkProgram(m_program);
    
    if (!CheckLinkErrors(m_program)) {
        return false;
    }
    
    glDeleteShader(vertex);
    glDeleteShader(fragment);
    glDeleteShader(geometry);
    
    return true;
}

bool OpenGLShader::CompileCompute(const char* computeSource) {
    unsigned int compute = glCreateShader(GL_COMPUTE_SHADER);
    glShaderSource(compute, 1, &computeSource, nullptr);
    glCompileShader(compute);
    if (!CheckCompileErrors(compute, "COMPUTE")) {
        return false;
    }
    
    m_program = glCreateProgram();
    glAttachShader(m_program, compute);
    glLinkProgram(m_program);
    
    if (!CheckLinkErrors(m_program)) {
        return false;
    }
    
    glDeleteShader(compute);
    
    return true;
}

bool OpenGLShader::Compile(const char* source, ShaderType type) {
    unsigned int shader = 0;
    
    switch (type) {
        case ShaderType::Vertex:
            shader = glCreateShader(GL_VERTEX_SHADER);
            break;
        case ShaderType::Fragment:
            shader = glCreateShader(GL_FRAGMENT_SHADER);
            break;
        case ShaderType::Geometry:
            shader = glCreateShader(GL_GEOMETRY_SHADER);
            break;
        case ShaderType::Compute:
            shader = glCreateShader(GL_COMPUTE_SHADER);
            break;
        case ShaderType::TessControl:
            shader = glCreateShader(GL_TESS_CONTROL_SHADER);
            break;
        case ShaderType::TessEvaluation:
            shader = glCreateShader(GL_TESS_EVALUATION_SHADER);
            break;
        default:
            return false;
    }
    
    glShaderSource(shader, 1, &source, nullptr);
    glCompileShader(shader);
    
    const char* typeName[] = { "VERTEX", "FRAGMENT", "GEOMETRY", "COMPUTE", "TESS_CONTROL", "TESS_EVALUATION" };
    if (!CheckCompileErrors(shader, typeName[(int)type])) {
        return false;
    }
    
    if (m_program == 0) {
        m_program = glCreateProgram();
    }
    glAttachShader(m_program, shader);
    glLinkProgram(m_program);
    
    if (!CheckLinkErrors(m_program)) {
        return false;
    }
    
    glDeleteShader(shader);
    return true;
}

void OpenGLShader::Shutdown() {
    if (m_program) {
        glDeleteProgram(m_program);
        m_program = 0;
    }
}

void OpenGLShader::Use() const {
    glUseProgram(m_program);
}

void OpenGLShader::Unbind() {
    glUseProgram(0);
}

void OpenGLShader::SetInt(const char* name, int value) {
    glUniform1i(glGetUniformLocation(m_program, name), value);
}

void OpenGLShader::SetIntArray(const char* name, const int* values, unsigned int count) {
    glUniform1iv(glGetUniformLocation(m_program, name), count, values);
}

void OpenGLShader::SetFloat(const char* name, float value) {
    glUniform1f(glGetUniformLocation(m_program, name), value);
}

void OpenGLShader::SetFloatArray(const char* name, const float* values, unsigned int count) {
    glUniform1fv(glGetUniformLocation(m_program, name), count, values);
}

void OpenGLShader::SetVec3(const char* name, float x, float y, float z) {
    glUniform3f(glGetUniformLocation(m_program, name), x, y, z);
}

void OpenGLShader::SetVec3(const char* name, const float* values) {
    glUniform3fv(glGetUniformLocation(m_program, name), 1, values);
}

void OpenGLShader::SetVec4(const char* name, float x, float y, float z, float w) {
    glUniform4f(glGetUniformLocation(m_program, name), x, y, z, w);
}

void OpenGLShader::SetVec4(const char* name, const float* values) {
    glUniform4fv(glGetUniformLocation(m_program, name), 1, values);
}

void OpenGLShader::SetMat2(const char* name, const float* value) {
    glUniformMatrix2fv(glGetUniformLocation(m_program, name), 1, GL_FALSE, value);
}

void OpenGLShader::SetMat3(const char* name, const float* value) {
    glUniformMatrix3fv(glGetUniformLocation(m_program, name), 1, GL_FALSE, value);
}

void OpenGLShader::SetMat4(const char* name, const float* value) {
    glUniformMatrix4fv(glGetUniformLocation(m_program, name), 1, GL_FALSE, value);
}

void OpenGLShader::SetMat4Array(const char* name, const float* values, unsigned int count) {
    glUniformMatrix4fv(glGetUniformLocation(m_program, name), count, GL_FALSE, values);
}

int OpenGLShader::GetUniformLocation(const char* name) const {
    return glGetUniformLocation(m_program, name);
}

bool OpenGLShader::CheckCompileErrors(unsigned int shader, const char* type) {
    int success;
    char infoLog[1024];
    
    glGetShaderiv(shader, GL_COMPILE_STATUS, &success);
    if (!success) {
        glGetShaderInfoLog(shader, 1024, nullptr, infoLog);
        std::cout << "ERROR::SHADER_COMPILATION_ERROR: " << type << "\n" << infoLog << std::endl;
        return false;
    }
    return true;
}

bool OpenGLShader::CheckLinkErrors(unsigned int program) {
    int success;
    char infoLog[1024];
    
    glGetProgramiv(program, GL_LINK_STATUS, &success);
    if (!success) {
        glGetProgramInfoLog(program, 1024, nullptr, infoLog);
        std::cout << "ERROR::PROGRAM_LINKING_ERROR\n" << infoLog << std::endl;
        return false;
    }
    return true;
}

} // namespace RHI
} // namespace XCEngine