#define GLFW_INCLUDE_NONE
#include "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::Compile(const char* vertexSource, const char* fragmentSource) {
    unsigned int vertex, fragment;
    
    vertex = glCreateShader(GL_VERTEX_SHADER);
    glShaderSource(vertex, 1, &vertexSource, NULL);
    glCompileShader(vertex);
    if (!CheckCompileErrors(vertex, "VERTEX")) {
        return false;
    }
    
    fragment = glCreateShader(GL_FRAGMENT_SHADER);
    glShaderSource(fragment, 1, &fragmentSource, NULL);
    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;
}

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

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

void OpenGLShader::SetInt(const std::string& name, int value) const {
    glUniform1i(glGetUniformLocation(m_program, name.c_str()), value);
}

void OpenGLShader::SetFloat(const std::string& name, float value) const {
    glUniform1f(glGetUniformLocation(m_program, name.c_str()), value);
}

void OpenGLShader::SetVec3(const std::string& name, float x, float y, float z) const {
    glUniform3f(glGetUniformLocation(m_program, name.c_str()), x, y, z);
}

void OpenGLShader::SetVec3(const std::string& name, const float* values) const {
    glUniform3fv(glGetUniformLocation(m_program, name.c_str()), 1, values);
}

void OpenGLShader::SetMat4(const std::string& name, const float* value) const {
    glUniformMatrix4fv(glGetUniformLocation(m_program, name.c_str()), 1, GL_FALSE, value);
}

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, NULL, 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, NULL, infoLog);
        std::cout << "ERROR::PROGRAM_LINKING_ERROR\n" << infoLog << std::endl;
        return false;
    }
    return true;
}

} // namespace RHI
} // namespace XCEngine