#include "glclasses.hpp"

#include <iostream>
#include <vector>
#include <fstream>
#include <sstream>

namespace endofthejedi {
    VAO::VAO() { glGenVertexArrays(1, &m_name); }

    VAO::~VAO() { glDeleteVertexArrays(1, &m_name); }

    void VAO::bind() { glBindVertexArray(m_name); }
    void VAO::unbind() { glBindVertexArray(0); }

    void VAO::fill(GLuint index, GLint size, GLenum type,
            GLboolean normalized, GLsizei stride,
            const GLvoid *pointer)
    {
        glEnableVertexAttribArray(index);
        glVertexAttribPointer(index, size, type, normalized, stride, pointer);
    }

    Shader::Shader() : m_program(0) { }

    Shader::~Shader() {}

    void Shader::init() { m_program = glCreateProgram(); }

    bool Shader::check() {
        GLint len = 0;
        GLint result = 0;

        glGetProgramiv(m_program, GL_LINK_STATUS, &result);
        glGetProgramiv(m_program, GL_INFO_LOG_LENGTH, &len);

        if (result == GL_FALSE) {
            std::cout<<"getting error log:" << std::endl;
            char *error = (char *)malloc(len+1);
            glGetProgramInfoLog(m_program, len, NULL, error);
            std::string str(error);
            std::cout << str << std::endl;
        }
        //std::cout << "checked program" << std::endl;

        return (bool)result;
    }

    bool Shader::checkShader(GLuint shader) {
        GLint len = 0;
        GLint result = 0;

        glGetShaderiv(shader, GL_COMPILE_STATUS, &result);

        if (result == GL_FALSE) {
            glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &len);
            char *error = (char *)malloc(len+1);
            glGetShaderInfoLog(shader, len, NULL, error);
            std::string str(error, error + len);
            std::cout << str << std::endl;
        }

        //std::cout << "checked shader" << std::endl;

        return result != GL_FALSE;
    }

    void Shader::bind()
    {
        if (m_program == 0) {
            std::cerr << "error: invalid to bind invalid program (0)! "
                "use unbind() if that was your purpose!" << std::endl;

            exit(-1);
            return;
        }

        glUseProgram(m_program);
    }

    GLuint Shader::program() { return m_program; }

    void Shader::unbind() { glUseProgram(0); }

    void Shader::load(const std::string &data, GLenum shadertype) {
        if (m_program == 0) {
            std::cout<<"[shader] error: shader program is invalid (0)!" << std::endl;
            exit(-1);
            return;
        }

        GLuint shader = glCreateShader(shadertype);

        const char *shaderdata = data.c_str();
        glShaderSource(shader, 1, &shaderdata, NULL);
        glCompileShader(shader);
        checkShader(shader);

        glAttachShader(m_program, shader);
        glLinkProgram(m_program);
        check();

        glDeleteShader(shader);
    }

  void Shader::loadFile(const std::string &path, GLenum shadertype) {
    std::string content;
    std::ifstream fileStream(path, std::ios::in);

    if(!fileStream.is_open()) {
        std::cerr << "Could not read file " << path << ". File does not exist." << std::endl;
        return;
    }

    std::string line = "";
    while(!fileStream.eof()) {
        std::getline(fileStream, line);
        content.append(line + "\n");
    }

    fileStream.close();
    load(content, shadertype);
  }

    GLuint Shader::location(const std::string &name) {
        return glGetUniformLocation(m_program, name.c_str());
    }
}

void printGlError(GLenum err)
{
    if (err != GL_NO_ERROR) {
        std::cout << "opengl error is: " << stringFromGlError(err) << std::endl;
    }
}

void discardLastGlError(bool print)
{
    GLenum err = glGetError();
    if (print) {
        printGlError(err);
    }
}

// return false if there's an error
bool checkAndPrintGlError()
{
    GLenum err = glGetError();

    printGlError(err);

    return true;
}

const char *stringFromGlError(GLenum err)
{
    switch(err) {
        case GL_INVALID_ENUM:                  return "GL_INVALID_ENUM"; break;
        case GL_INVALID_VALUE:                 return "GL_INVALID_VALUE"; break;
        case GL_INVALID_OPERATION:             return "GL_INVALID_OPERATION"; break;
        case GL_OUT_OF_MEMORY:                 return "GL_OUT_OF_MEMORY"; break;
        case GL_INVALID_FRAMEBUFFER_OPERATION: return "GL_INVALID_FRAMEBUFFER_OPERATION"; break;
        default:                               return "<unknown>"; break;
    }
}