#include "opengl.h"
#include "globals.h"
#include "fifo.h"
#include "report.h"

GLuint createTexture(SDL_Surface *surface) {
  GLuint texture;
  GLenum format;
  GLint colors = surface->format->BytesPerPixel;
  if (colors == 4) { // with alpha
    if (surface->format->Rmask == 0x000000ff) {
      format = GL_RGBA;
    } else {
      format = GL_BGRA;
    }   
  } else if (colors == 3) {
    if (surface->format->Rmask == 0x000000ff) {
      format = GL_RGB;
    } else {
      format = GL_BGR;
    }
  } else {
    // non truecolor, handle error or convert
  }
  // generate texture handle
  glGenTextures(1, &texture);
  // bind the texture object
  glBindTexture(GL_TEXTURE_2D, texture);
  // set stretching properties
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);

  // mipmap, I guess
  //glGenerateMipmap(GL_TEXTURE_2D);
  // get the appropriate endianness for data packing
  int num = 1;
  int pack_type = ( (*(char*)&num == 1) ? GL_UNSIGNED_BYTE : GL_UNSIGNED_INT_8_8_8_8_REV); // unsigned char vs reversed uint? Doesn't seem right...
  // copy it over! :)
  glTexImage2D(GL_TEXTURE_2D, 0, colors, surface->w, surface->h, 0, format, pack_type, surface->pixels);
  return texture;
}

GLuint create1dTexture(SDL_Surface *surface) {
  GLenum format;
  GLint colors = surface->format->BytesPerPixel;
  if (colors == 4) { // with alpha
    if (surface->format->Rmask == 0x000000ff) {
      format = GL_RGBA;
    } else {
      format = GL_BGRA;
    }   
  } else if (colors == 3) {
    if (surface->format->Rmask == 0x000000ff) {
      format = GL_RGB;
    } else {
      format = GL_BGR;
    }
  } else {
    // non truecolor, handle error or convert
  }
  GLuint texture;
  // generate texture handle
  glGenTextures(1, &texture);
  // bind 1D texture object
  glBindTexture(GL_TEXTURE_1D, texture);
  // set stretching properties
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
  glTexParameteri(GL_TEXTURE_1D, GL_TEXTURE_WRAP_S, GL_REPEAT);
  // get endianness for data packing
  int num = 1;
  int pack_type = ( (*(char*)&num == 1) ? GL_UNSIGNED_BYTE : GL_UNSIGNED_INT_8_8_8_8_REV); // unsigned char vs reversed uint? Doesn't seem right...
  // copy image over
  glTexImage1D(GL_TEXTURE_1D, 0, colors, surface->w, 0, format, pack_type, surface->pixels);
  return texture;
}

// this should not go here, but it's the most accessible
int reinitDisplay() {
  SDL_SetWindowSize(g_window, g_v_width, g_v_height);
  SDL_GL_SetSwapInterval(g_v_vsync);
  reinitGl();
}

int reinitGl() {
  glViewport(0, 0, g_v_width, g_v_height);
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  glOrtho(0.0f, g_v_width * g_v_zoom, g_v_height * g_v_zoom, 1.0f, -1.0f, 1.0f);

  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  return 0;
}

/*int loadShader(const char *filename, GLchar **shader) {
  int ret;
  if ((ret = fileToBuffer(shader, filename)) < -1) {
    report(ERROR, "loadShader", "fileToBuffer returned %d", ret);
    free(*shader);
    *shader = NULL;
    return -1;
  }
  return 0;
}

int unloadShader(GLchar **shader) {
  if (shader != NULL) {
    free(*shader);
  }
  *shader = NULL;
  return 0;
}
// compile fragment shader
GLuint compileFShader(GLchar *shader_source) {
  // create shader
  GLuint shader = glCreateShader(GL_FRAGMENT_SHADER);
  // load source into shader
  glShaderSource(shader, 1, &shader_source, NULL);
  // compile shader
  glCompileShader(shader);
  // check results
  GLint status;
  glGetShaderiv(shader, GL_COMPILE_STATUS, &status);
  if (status == 0) {
    GLint length;
    char *info;

    glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &length);
    info = SDL_stack_alloc(char, length+1);
    glGetShaderInfoLog(shader, length, NULL, info);
    report(ERROR, "compileFShader", "failed to compile:\n%s", info);
    SDL_stack_free(info);
    return 0;
  } else {
  }
  // return shader!
  return shader;
}
int deleteShader(GLuint shader) {
  glDeleteShader(shader);
  return 0;
}

GLuint shaderToProgram(GLuint shader) {
  GLuint program = glCreateProgram();
  glAttachShader(program, shader);
  glLinkProgram(program);
  GLint status;
  glGetProgramiv(program, GL_LINK_STATUS, &status);
  if (status == 0) {
    report(ERROR, "shaderToProgram", "failed to link program: %d", status);
    return 0;
  }
  return program;
}
int deleteProgram(GLuint program) {
  glDeleteProgram(program);
  return 0;
}*/