#ifdef HAVE_CONFIG_H
#  include "config.h"
#endif

#ifdef HAVE_GL_GL_H
#  include <GL/gl.h>
#elif HAVE_OPENGL_GL_H
#  include <OpenGL/gl.h>
#endif
#ifdef HAVE_GL_GLU_H
#  include <GL/glu.h>
#elif HAVE_OPENGL_GLU_H
#  include <OpenGL/glu.h>
#endif
#include <SDL.h>
#include "camera.h"
#include "events.h"
#include "globals.h"
#include "height_quantity.h"

/* Called for each SDL_KEYDOWN or SDL_KEYUP event. Returns 1 if we're not stopping, else 0. */
static int handleInput(const SDL_Event *event){
  int more = 1;
  if(event->type == SDL_KEYDOWN)
    if(event->key.keysym.mod & KMOD_ALT)
      switch(event->key.keysym.sym){
      case SDLK_UP: anugavis.keys[KEY_FORWARD] = 1; break;
      case SDLK_DOWN: anugavis.keys[KEY_BACKWARD] = 1; break;
      case SDLK_LEFT: anugavis.keys[KEY_STRAFE_LEFT] = 1; break;
      case SDLK_RIGHT: anugavis.keys[KEY_STRAFE_RIGHT] = 1; break;
      default: break;
      }
    else if(event->key.keysym.mod & KMOD_SHIFT) switch(event->key.keysym.sym){
      case SDLK_UP: anugavis.keys[KEY_ZOOM_IN] = 1; break;
      case SDLK_DOWN: anugavis.keys[KEY_ZOOM_OUT] = 1; break;
      default: break;
      }
    else switch(event->key.keysym.sym){
      case SDLK_z:
	anugavis.current_frame = MAX(anugavis.current_frame - 10, 0);
	break;
      case SDLK_x:
	if(anugavis.current_frame > 0) anugavis.current_frame--;
	break;
      case SDLK_c:
      case SDLK_SPACE: anugavis.paused = !anugavis.paused; break;
      case SDLK_v:
	if(anugavis.current_frame <
	   (signed int)anugavis.number_of_timesteps - 1)
	  anugavis.current_frame++;
	break;
      case SDLK_b:
	anugavis.current_frame = MIN(anugavis.current_frame + 10,
				     (signed int)anugavis.number_of_timesteps
				     - 1);
	break;
      case SDLK_h: camera_home(); break;
      case SDLK_ESCAPE: more = 0; break;
      case SDLK_UP: anugavis.keys[KEY_PITCH_UP] = 1; break;
      case SDLK_DOWN: anugavis.keys[KEY_PITCH_DOWN] = 1; break;
      case SDLK_LEFT: anugavis.keys[KEY_ROTATE_LEFT] = 1; break;
      case SDLK_RIGHT: anugavis.keys[KEY_ROTATE_RIGHT] = 1; break;
      default: break;
      }
  else if(event->type == SDL_KEYUP) switch(event->key.keysym.sym){
    case SDLK_UP:
      anugavis.keys[KEY_FORWARD] = 0;
      anugavis.keys[KEY_PITCH_UP] = 0;
      anugavis.keys[KEY_ZOOM_IN] = 0;
      break;
    case SDLK_DOWN:
      anugavis.keys[KEY_BACKWARD] = 0;
      anugavis.keys[KEY_PITCH_DOWN] = 0;
      anugavis.keys[KEY_ZOOM_OUT] = 0;
      break;
    case SDLK_LEFT:
      anugavis.keys[KEY_STRAFE_LEFT] = 0;
      anugavis.keys[KEY_ROTATE_LEFT] = 0;
      break;
    case SDLK_RIGHT:
      anugavis.keys[KEY_STRAFE_RIGHT] = 0;
      anugavis.keys[KEY_ROTATE_RIGHT] = 0;
      break;
    default: break;
    }
  return more;
}

int AnugaVis_Step(void){
  static Uint32 ticks = 0;
  static Uint32 lastframe;
  GLfloat lightpos[4];
  int i;
  SDL_Event event;
  int more = 1;
  struct height_quantity_simple *height;

  /* Animation. */
  if(ticks == 0) lastframe = ticks = SDL_GetTicks();
  else ticks = SDL_GetTicks();
  if(ticks - lastframe < TARGET_FRAME_RATE) return more;

  lastframe = ticks;
  if(anugavis.current_frame < (signed int)anugavis.number_of_timesteps - 1){
    if(!anugavis.paused) anugavis.current_frame++;
  }else
    anugavis.paused = 1;

  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  if(anugavis.keys[KEY_ROTATE_LEFT]) camera_yaw(-CAMERA_YAW_STEP);
  if(anugavis.keys[KEY_ROTATE_RIGHT]) camera_yaw(CAMERA_YAW_STEP);
  if(anugavis.keys[KEY_PITCH_UP]) camera_pitch(CAMERA_PITCH_STEP);
  if(anugavis.keys[KEY_PITCH_DOWN]) camera_pitch(-CAMERA_PITCH_STEP);
  if(anugavis.keys[KEY_FORWARD]) camera_track(-CAMERA_TRACK_STEP *
					      anugavis.diagonal);
  if(anugavis.keys[KEY_BACKWARD]) camera_track(CAMERA_TRACK_STEP * 
					       anugavis.diagonal);
  if(anugavis.keys[KEY_STRAFE_LEFT]) camera_strafe(CAMERA_STRAFE_STEP *
						   anugavis.diagonal);
  if(anugavis.keys[KEY_STRAFE_RIGHT]) camera_strafe(-CAMERA_STRAFE_STEP *
						    anugavis.diagonal);
  if(anugavis.keys[KEY_ZOOM_IN]) camera_zoom(CAMERA_ZOOM_STEP *
					     anugavis.diagonal);
  if(anugavis.keys[KEY_ZOOM_OUT]) camera_zoom(-CAMERA_ZOOM_STEP *
					      anugavis.diagonal);
  gluLookAt(anugavis.eye[0], anugavis.eye[1], anugavis.eye[2],
	    anugavis.focus[0], anugavis.focus[1], anugavis.focus[2],
	    0, 0, 1);
  for(i = 0 ; i < 3 ; i++) lightpos[i] = anugavis.eye[i];
  lightpos[3] = 1.0;
  glLightfv(GL_LIGHT0, GL_POSITION, lightpos);
  for(height = anugavis.heights ; height != NULL ; height = height->next)
    AnugaVis_DrawHeightQuantity(height);
  SDL_GL_SwapBuffers();

  while(SDL_PollEvent(&event))
    if(event.type == SDL_QUIT) more = 0;
    else if((event.type == SDL_KEYDOWN) || (event.type == SDL_KEYUP)) more = handleInput(&event);
  return more;
}

void AnugaVis_Run(void){
  while(AnugaVis_Step());
}