/******
  SDL opengl renderer
******/
#include <SDL/SDL_opengl.h>
#include "../ui/elements.h"
#include "r_gl.h"
#include "interface.h"
#include "../globals.h"

void r_gl_Init() {
  SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);

  if ((screen = SDL_SetVideoMode(g_video_width, g_video_height, 32, SDL_HWSURFACE|SDL_OPENGL|SDL_RESIZABLE|g_video_fullscreen)) == NULL) 
    return; // TODO: handle error

  glEnable( GL_TEXTURE_2D );
   
  glClearColor( 0.0f, 0.0f, 0.0f, 0.0f );
   
  glViewport( 0, 0, g_video_width, g_video_height);
   
  glClear( GL_COLOR_BUFFER_BIT );
   
  glMatrixMode( GL_PROJECTION );
  glLoadIdentity();
   
  glOrtho(0.0f, g_video_width, g_video_height, 1.0f, -1.0f, 1.0f);
  //glOrtho(0.0f, g_video_width, 0, g_video_height, -1.0f, 1.0f);
   
  glMatrixMode( GL_MODELVIEW );
  glLoadIdentity();

  /* enable transparency */
  glEnable(GL_BLEND);
  glBlendFunc(GL_SRC_ALPHA,GL_ONE_MINUS_SRC_ALPHA);

  /* spritesheets */
  r_gl_createTexture(&(spritesheet_ui->texture), spritesheet_ui->surface);
  r_gl_createTexture(&((struct Spritesheet*)menu_bg)->texture, ((struct Spritesheet*)menu_bg)->surface);
}

void r_gl_Reinit() {

}

void r_gl_Close() {
  printf("closing gl\n");
}

void r_gl_clearScreen() {
  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
}

void r_gl_renderScreen() {
  SDL_GL_SwapBuffers();
}

void r_gl_renderElements(struct ElementList *list) {
  if (list == NULL)
    return;
  struct Element *current = list->first;
  while(current != NULL) {
    struct Element *next = current->next;
    r_gl_renderElement(current);
    current = next;
  }
}

void r_gl_renderElement(struct Element *element) {
  if (element == NULL)
    return;
  if (element->flags & E_FLAG_HIDE)
    return;
  if (element->flags & E_FLAG_UPDATE) {
    int x_start = element->sx*(g_video_width/3);
    int y_start = element->sy*(g_video_height/3);
    int x_offset = 0;
    int sprite_id = 0;
    switch (element->type) {
      case E_TYPE_TEXT:
        //r_gl_renderText(element->font, ((struct TextElement*)element->data)->string, element->dimen.x, element->dimen.y);
        r_gl_renderText(element->font, ((struct TextElement*)element->data)->string, element->dimen.x+x_start, element->dimen.y+y_start);
        break;
      case E_TYPE_BUTTON:
        switch (element->state) {
          case E_STATE_NORMAL:
            break;
          case E_STATE_ACTIVE:
            sprite_id += spritesheet_ui->columns;
            break;
        }
        //r_gl_renderSprite(spritesheet_ui, 0, element->dimen.x, element->dimen.y);
        r_gl_renderSprite(spritesheet_ui, NULL, sprite_id, element->dimen.x+x_start, element->dimen.y+y_start);
        x_offset += spritesheet_ui->s_width;
        int width;
        for (width = (element->dimen.w/spritesheet_ui->s_width)-2; width > 0; width-=2) {
          r_gl_renderSprite(spritesheet_ui, NULL, sprite_id+1, element->dimen.x+x_start+x_offset, element->dimen.y+y_start);
          x_offset += spritesheet_ui->s_width;
        }
        r_gl_renderSprite(spritesheet_ui, NULL, sprite_id+2, element->dimen.x+x_start+x_offset, element->dimen.y+y_start);
        //r_gl_renderText(element->font, ((struct TextElement*)element->data)->string, element->dimen.x, element->dimen.y);
        //r_gl_renderText(element->font, ((struct TextElement*)element->data)->string, element->dimen.x+x_start+(6*spritesheet_ui->scale_x), element->dimen.y+y_start+(14*spritesheet_ui->scale_y));
        r_gl_renderText(element->font, ((struct TextElement*)element->data)->string, element->dimen.x+x_start+( (element->dimen.w/2) - (((struct Font*)element->font)->s_width * ((struct TextElement*)element->data)->length)/2 ), element->dimen.y+y_start+(14*spritesheet_ui->scale_y));
        // render the shortkey fancy-like
        if (element->key != '\0') {
          // TODO: renderChar
          //r_gl_renderText(element->font, ((struct TextElement*)element->data)->string[element->key_pos], element->dimen.x+x_start+( (element->dimen.w/2) - (((struct Font*)element->font)->s_width * ((struct TextElement*)element->data)->length)/2 )+4, element->dimen.y+y_start+(14*spritesheet_ui->scale_y));
        }
        break;
      default:
        break;
    }
  }
}

void r_gl_renderText(struct Font *font, const char *string, int x, int y) {
  if (font == NULL) { 
    printf("font is null\n");
    return;
  }
  if (font->texture == 0) {
    r_gl_createTexture(&font->texture, font->surface);
  }
  int i = 0;
  int x_offset, y_offset;
  int x_render = 0;
  int y_render = 0;

  /* get the width and height of each sprite in gl texture terms */
  double sx = 1.0f/(font->surface->w / font->width);
  double sy = 1.0f/(font->surface->h / font->height);
  glBindTexture(GL_TEXTURE_2D, font->texture);
  while(string[i] != '\0') {
    switch(string[i]) {
      case '\n':
        y_render += font->height*font->scale_y;
        x_render = 0;
        break;
      default:
        y_offset = string[i] / 16;
        x_offset = string[i] - (y_offset*16);
        /* get the texture offsets for the target sprite */
        double tx = (x_offset == 0 ? 0.0f : 1.0f/((float)(16.0f/x_offset)));
        double ty = (y_offset == 0 ? 0.0f : 1.0f/(8.0f/y_offset));
        /* reset view */
        glLoadIdentity();
        /* draw a clipped portion of our font texture to a quad*/
        glTranslated(x+x_render, y+y_render, 1.0f);
        //glTranslated(font->width, y_render, 0.0f);
        /* draw that quad !*/
        glBegin(GL_QUADS);
          // tl
          //glTexCoord2d(tx,ty+sy); glVertex2f(0,0);
          glTexCoord2d(tx,ty); glVertex2f(0,0);
          // tr
          //glTexCoord2d(tx+sx,ty+sy); glVertex2f(font->width, 0);
          glTexCoord2d(tx+sx,ty); glVertex2f(font->width*font->scale_x, 0);
          // br
          //glTexCoord2d(tx+sx,ty); glVertex2f(font->width, font->height);
          glTexCoord2d(tx+sx,ty+sy); glVertex2f(font->width*font->scale_x, font->height*font->scale_y);
          // bl
          //glTexCoord2d(tx,ty); glVertex2f(0,font->height);
          glTexCoord2d(tx,ty+sy); glVertex2f(0,font->height*font->scale_y);
        glEnd();
        x_render += font->width*font->scale_x;
        break;
    }
    i++;
  }
  glLoadIdentity();
}

void r_gl_renderSprite(struct Spritesheet *sheet, void *surface, int id, int x, int y) {
  /* get the width and height of each sprite in gl texture terms */
  float sx = 1.0f/(sheet->surface->w / sheet->width);
  float sy = 1.0f/(sheet->surface->h / sheet->height);

  int y_offset = id / sheet->columns;
  int x_offset = id - (y_offset*sheet->columns);
  /* get the texture offsets for the target sprite */
  float tx = (x_offset == 0 ? 0.0f : 1.0f/((float)((float)sheet->columns/(float)x_offset)));
  float ty = (y_offset == 0 ? 0.0f : 1.0f/((float)(((float)sheet->surface->h/(float)sheet->height)/(float)y_offset)));
  /* reset view */
  glLoadIdentity();
  /* bind our texture */
  glBindTexture(GL_TEXTURE_2D, sheet->texture);
  /* draw a clipped portion of our sheet texture to a quad*/
  glTranslated(x, y, 0.0f);
  /* draw that quad !*/
  glBegin(GL_QUADS);
    // tl
    glTexCoord2d(tx,ty); glVertex2f(0,0);
    // tr
    glTexCoord2d(tx+sx,ty); glVertex2f(sheet->width*sheet->scale_x, 0);
    // br
    glTexCoord2d(tx+sx,ty+sy); glVertex2f(sheet->width*sheet->scale_x, sheet->height*sheet->scale_y);
    // bl
    glTexCoord2d(tx,ty+sy); glVertex2f(0,sheet->height*sheet->scale_y);
  glEnd();

  //glLoadIdentity();

}

GLuint r_gl_createTexture(GLuint *texture, 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
  }
  // 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_NEAREST);
  glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
  // 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;
}

void r_gl_setupElement(struct Element *element) {
  // set default font
  setElementFont(element, g_font_medium);
  // set our element's free/clean event function
  setElementEvent(element, E_EVENT_FREE, &r_gl_cleanElement);
  setElementEvent(element, E_EVENT_CHANGE, &genElementDimensions);
}

int r_gl_loadSpritesheet(struct Spritesheet *spritesheet, char *file_name, int width, int height, int columns) {
  int ret;
  if ((ret = loadSpritesheetFromFile(spritesheet, file_name, width, height, columns)) == 0) {
    r_gl_createTexture(&spritesheet->texture, spritesheet->surface);
  }
  return ret;
}

void r_gl_cleanElement(struct Element *element) {
  printf("cleaning element in opengl\n");
}

void r_gl_changeElement(struct Element *element) {
}