//
// "Block Attack!" scrolling blocks game using the Fast Light Tool Kit (FLTK).
//
// Copyright © 2006-2021 by Michael Sweet.
//
// This library is free software. Distribution and use rights are outlined in
// the file "COPYING" which should have been included with this file.  If this
// file is missing or damaged, see the license at:
//
//     https://www.fltk.org/COPYING.php
//
// Please see the following page on how to report bugs and issues:
//
//     https://www.fltk.org/bugs.php
//

#include <FL/Fl.H>
#include <FL/Fl_Double_Window.H>
#include <FL/Fl_Button.H>
#include <FL/Fl_Preferences.H>
#include <FL/Fl_XPM_Image.H>
#include <FL/Fl_XBM_Image.H>
#include <FL/Fl_Tiled_Image.H>
#include <FL/fl_draw.H>
#include <FL/platform.H>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <time.h>
#include <math.h>

// Audio headers...
#include <config.h>

#ifndef _WIN32
#  include <unistd.h>
#  include <sys/time.h> // gettimeofday()
#endif // !_WIN32

#ifdef HAVE_ALSA_ASOUNDLIB_H
#  define ALSA_PCM_NEW_HW_PARAMS_API
#  include <alsa/asoundlib.h>
#endif // HAVE_ALSA_ASOUNDLIB_H
#ifdef __APPLE__
#  include <CoreAudio/AudioHardware.h>
#endif // __APPLE__
#ifdef _WIN32
#  include <mmsystem.h>
#endif // _WIN32

#define BLOCK_COLS      25
#define BLOCK_ROWS      15
#define BLOCK_SIZE      32
#define BLOCK_BLAST     100

// These factors are used to fine-tune the game when these events
// occur by multiplying the timer interval with the given factor:
//
// (a) enter the next game level
// (b) click on a "normal block", destroy this one and adjacent blocks
// (c) click on a "bomb", destroy all blocks of the same color

#define LEVEL_FACTOR    0.900f    // was: 0.95
#define NORMAL_FACTOR   0.999f
#define BOMB_FACTOR     0.995f

// Set this to 1 to debug the timer callback (should be 0)
#define DEBUG_TIMER     0

#include "pixmaps/blast.xpm"
Fl_Pixmap blast_pixmap(blast_xpm);

#include "pixmaps/red.xpm"
Fl_Pixmap red_pixmap(red_xpm);
#include "pixmaps/red_bomb.xpm"
Fl_Pixmap red_bomb_pixmap(red_bomb_xpm);

#include "pixmaps/green.xpm"
Fl_Pixmap green_pixmap(green_xpm);
#include "pixmaps/green_bomb.xpm"
Fl_Pixmap green_bomb_pixmap(green_bomb_xpm);

#include "pixmaps/blue.xpm"
Fl_Pixmap blue_pixmap(blue_xpm);
#include "pixmaps/blue_bomb.xpm"
Fl_Pixmap blue_bomb_pixmap(blue_bomb_xpm);

#include "pixmaps/yellow.xpm"
Fl_Pixmap yellow_pixmap(yellow_xpm);
#include "pixmaps/yellow_bomb.xpm"
Fl_Pixmap yellow_bomb_pixmap(yellow_bomb_xpm);

#include "pixmaps/cyan.xpm"
Fl_Pixmap cyan_pixmap(cyan_xpm);
#include "pixmaps/cyan_bomb.xpm"
Fl_Pixmap cyan_bomb_pixmap(cyan_bomb_xpm);

#include "pixmaps/magenta.xpm"
Fl_Pixmap magenta_pixmap(magenta_xpm);
#include "pixmaps/magenta_bomb.xpm"
Fl_Pixmap magenta_bomb_pixmap(magenta_bomb_xpm);

#include "pixmaps/gray.xpm"
Fl_Pixmap gray_pixmap(gray_xpm);
#include "pixmaps/gray_bomb.xpm"
Fl_Pixmap gray_bomb_pixmap(gray_bomb_xpm);

Fl_Pixmap *normal_pixmaps[] = {
  &red_pixmap,
  &green_pixmap,
  &blue_pixmap,
  &yellow_pixmap,
  &cyan_pixmap,
  &magenta_pixmap,
  &gray_pixmap
};
Fl_Pixmap *bomb_pixmaps[] = {
  &red_bomb_pixmap,
  &green_bomb_pixmap,
  &blue_bomb_pixmap,
  &yellow_bomb_pixmap,
  &cyan_bomb_pixmap,
  &magenta_bomb_pixmap,
  &gray_bomb_pixmap
};

const unsigned char screen_bits[] = {
  0xff, 0x55, 0xff, 0xaa, 0xff, 0x55, 0xff, 0xaa
};
Fl_Bitmap screen_bitmap(screen_bits, 8, 8);
Fl_Tiled_Image screen_tile(&screen_bitmap);


// Sound class...
//
// There are MANY ways to implement sound in a FLTK application.
// The approach we are using here is to conditionally compile OS-
// specific code into the application - CoreAudio for MacOS X, the
// standard Win32 API stuff for Windows, ALSA or X11 for Linux, and
// X11 for all others.  We have to support ALSA on Linux because the
// current Xorg releases no longer support XBell() or the PC speaker.
//
// There are several good cross-platform audio libraries we could also
// use, such as OpenAL, PortAudio, and SDL, however they were not chosen
// for this application because of our limited use of sound.
//
// Many thanks to Ian MacArthur who provided sample code that led to
// the CoreAudio implementation you see here!
class BlockSound {
  // Private, OS-specific data...
#ifdef __APPLE__
  AudioDeviceID device;
#ifndef MAC_OS_X_VERSION_10_5
#define MAC_OS_X_VERSION_10_5 1050
#endif
#  if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5
  AudioDeviceIOProcID audio_proc_id;
#  endif
  AudioStreamBasicDescription format;
  short *data;
  int remaining;

  static OSStatus audio_cb(AudioDeviceID device,
                           const AudioTimeStamp *current_time,
                           const AudioBufferList *data_in,
                           const AudioTimeStamp *time_in,
                           AudioBufferList *data_out,
                           const AudioTimeStamp *time_out,
                           void *client_data);
#elif defined(_WIN32)
  HWAVEOUT      device;
  HGLOBAL       header_handle;
  LPWAVEHDR     header_ptr;
  HGLOBAL       data_handle;
  LPSTR         data_ptr;

#else
#  ifdef HAVE_ALSA_ASOUNDLIB_H
  snd_pcm_t *handle;
#  endif // HAVE_ALSA_ASOUNDLIB_H
#endif // __APPLE__

  public:

  // Common data...
  static short *sample_data;
  static int sample_size;

  BlockSound();
  ~BlockSound();

  void  play_explosion(float duration);
};

// Sound class globals...
short *BlockSound::sample_data = NULL;
int BlockSound::sample_size = 0;


// Initialize the BlockSound class
BlockSound::BlockSound() {
  sample_size = 0;

#ifdef __APPLE__
  remaining = 0;

  UInt32 size = sizeof(device);

  if (AudioHardwareGetProperty(kAudioHardwarePropertyDefaultOutputDevice,
                               &size, (void *)&device) != noErr) return;

  size = sizeof(format);
  if (AudioDeviceGetProperty(device, 0, false, kAudioDevicePropertyStreamFormat,
                             &size, &format) != noErr) return;

  // Set up a format we like...
  format.mSampleRate       = 44100.0;   // 44.1kHz
  format.mChannelsPerFrame = 2;         // stereo

  if (AudioDeviceSetProperty(device, NULL, 0, false,
                             kAudioDevicePropertyStreamFormat,
                             sizeof(format), &format) != noErr) return;

  // Check we got linear pcm - what to do if we did not ???
  if (format.mFormatID != kAudioFormatLinearPCM) return;

  // Attach the callback and start the device
#  if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5
  if (AudioDeviceCreateIOProcID(device, audio_cb, (void *)this, &audio_proc_id) != noErr) return;
  AudioDeviceStart(device, audio_proc_id);
#  else
  if (AudioDeviceAddIOProc(device, audio_cb, (void *)this) != noErr) return;
  AudioDeviceStart(device, audio_cb);
#  endif

  sample_size = (int)format.mSampleRate;

#elif defined(_WIN32)
  WAVEFORMATEX  format;

  memset(&format, 0, sizeof(format));
  format.cbSize          = sizeof(format);
  format.wFormatTag      = WAVE_FORMAT_PCM;
  format.nChannels       = 2;
  format.nSamplesPerSec  = 44100;
  format.nAvgBytesPerSec = 44100 * 4;
  format.nBlockAlign     = 4;
  format.wBitsPerSample  = 16;

  data_handle = GlobalAlloc(GMEM_MOVEABLE | GMEM_SHARE, format.nSamplesPerSec * 4);
  if (!data_handle) return;

  data_ptr = (LPSTR)GlobalLock(data_handle);

  header_handle = GlobalAlloc(GMEM_MOVEABLE | GMEM_SHARE, sizeof(WAVEHDR));
  if (!header_handle) return;

  header_ptr = (WAVEHDR *)GlobalLock(header_handle);

  header_ptr->lpData  = data_ptr;
  header_ptr->dwFlags = 0;
  header_ptr->dwLoops = 0;

  if (waveOutOpen(&device, WAVE_MAPPER, &format, 0, 0, WAVE_ALLOWSYNC)
          != MMSYSERR_NOERROR) return;

  sample_size = format.nSamplesPerSec;

#else
#  ifdef HAVE_ALSA_ASOUNDLIB_H
  handle = NULL;

  if (snd_pcm_open(&handle, "default", SND_PCM_STREAM_PLAYBACK, 0) >= 0) {
    // Initialize PCM sound stuff...
    snd_pcm_hw_params_t *params;

    snd_pcm_hw_params_alloca(&params);
    snd_pcm_hw_params_any(handle, params);
    snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
    snd_pcm_hw_params_set_format(handle, params, SND_PCM_FORMAT_S16);
    snd_pcm_hw_params_set_channels(handle, params, 2);
    unsigned rate = 44100;
    int dir;
    snd_pcm_hw_params_set_rate_near(handle, params, &rate, &dir);
    snd_pcm_uframes_t period = (int)rate;
    snd_pcm_hw_params_set_period_size_near(handle, params, &period, &dir);

    sample_size = rate;

    if (snd_pcm_hw_params(handle, params) < 0) {
      sample_size = 0;
      snd_pcm_close(handle);
      handle = NULL;
    }
  }
#  endif // HAVE_ALSA_ASOUNDLIB_H
#endif // __APPLE__

  if (sample_size) {
    // Make an explosion sound by passing white noise through a low pass
    // filter with a decreasing frequency...
    sample_data = new short[2 * sample_size];

    short *sample_ptr = sample_data;
    int max_sample = 2 * sample_size - 2;

    *sample_ptr++ = 0;
    *sample_ptr++ = 0;

    for (int j = max_sample; j > 0; j --, sample_ptr ++) {
      float freq = (float)j / (float)max_sample;
      float volume = float(32767.0 * (0.5 * sqrt(freq) + 0.5));
      float sample = float(0.0001 * ((rand() % 20001) - 10000));

      *sample_ptr = (int)(volume * freq * sample +
                          (1.0 - freq) * sample_ptr[-2]);
    }
  }
}


// Cleanup the BlockSound class
BlockSound::~BlockSound() {
#ifdef __APPLE__
  if (sample_size) {
#  if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_5
    AudioDeviceStop(device, audio_proc_id);
    AudioDeviceDestroyIOProcID(device, audio_proc_id);
#  else
    AudioDeviceStop(device, audio_cb);
    AudioDeviceRemoveIOProc(device, audio_cb);
#  endif
  }

#elif defined(_WIN32)
  if (sample_size) {
    waveOutClose(device);

    GlobalUnlock(header_handle);
    GlobalFree(header_handle);

    GlobalUnlock(data_handle);
    GlobalFree(data_handle);
  }

#else
#  ifdef HAVE_ALSA_ASOUNDLIB_H
  if (handle) {
    snd_pcm_drain(handle);
    snd_pcm_close(handle);
  }
#  endif // HAVE_ALSA_ASOUNDLIB_H
#endif // __APPLE__

  if (sample_size) {
    delete[] sample_data;
  }
}


#ifdef __APPLE__
// Callback function for writing audio data...
OSStatus BlockSound::audio_cb(AudioDeviceID device,
                              const AudioTimeStamp *current_time,
                              const AudioBufferList *data_in,
                              const AudioTimeStamp *time_in,
                              AudioBufferList *data_out,
                              const AudioTimeStamp *time_out,
                              void *client_data) {
  BlockSound *ss = (BlockSound *)client_data;
  int count;
  float *buffer;

  if (!ss->remaining) return noErr;

  for (count = data_out->mBuffers[0].mDataByteSize / sizeof(float),
          buffer = (float*) data_out->mBuffers[0].mData;
       ss->remaining > 0 && count > 0;
       count --, ss->data ++, ss->remaining --) {
    *buffer++ = *(ss->data) / 32767.0;
  }

  while (count > 0) {
    *buffer++ = 0.0;
    count --;
  }

  return noErr;
}
#endif // __APPLE__


// Play a note for the given amount of time...
void BlockSound::play_explosion(float duration) {
  Fl::check();

  if (duration <= 0.0)
    return;

#if defined(__APPLE__) || defined(_WIN32) || defined(HAVE_ALSA_ASOUNDLIB_H)
  if (duration > 1.0)
    duration = 1.0;

  int samples = (int)(duration * sample_size);
  short *sample_ptr = sample_data + 2 * (sample_size - samples);
#endif // __APPLE__ || _WIN32 || HAVE_ALSA_ASOUNDLIB_H

#ifdef __APPLE__
  // Point to the next note...
  data      = sample_ptr;
  remaining = samples * 2;

#elif defined(_WIN32)
  if (sample_size) {
    memcpy(data_ptr, sample_ptr, samples * 4);

    header_ptr->dwBufferLength = samples * 4;
    waveOutPrepareHeader(device, header_ptr, sizeof(WAVEHDR));

    waveOutWrite(device, header_ptr, sizeof(WAVEHDR));
  } else
    Beep(440, (int)(1000.0 * duration));

#elif defined(HAVE_ALSA_ASOUNDLIB_H)
  if (handle) {
    // Use ALSA to play the sound...
    if (snd_pcm_writei(handle, sample_ptr, samples) < 0) {
      snd_pcm_prepare(handle);
      snd_pcm_writei(handle, sample_ptr, samples);
    }
    return;
  }
#endif // __APPLE__
}


class BlockWindow : public Fl_Double_Window {
  public:

  struct Block {
    int         color;
    bool        bomb;
    float       y;
  };

  struct Column {
    int         num_blocks;
    Block       blocks[BLOCK_ROWS];
    float       x;
  };

  private:

  int           frames_,
                frames_per_second_;
  time_t        frame_time_;
  bool          show_fps_;

  Fl_Button     *help_button_,
                *play_button_;

  int           num_columns_;
  Column        columns_[BLOCK_COLS];
  int           count_;
  bool          help_;
  int           high_score_;
  float         interval_;
  int           level_;
  int           num_colors_;
  int           opened_columns_;
  bool          paused_;
  static Fl_Preferences prefs_;
  int           score_;
  BlockSound    *sound_;
  char          title_[255];
  int           title_y_;

  void          _BlockWindow();
  int           bomb(int color);
  int           click(int col, int row);
  static void   help_cb(Fl_Widget *wi, BlockWindow *bw);
  void          init();
  static void   play_cb(Fl_Widget *wi, BlockWindow *bw);
  static void   timeout_cb(BlockWindow *bw);

  public:

  BlockWindow(int X, int Y, int W, int H, const char *L = 0);
  BlockWindow(int W, int H, const char *L = 0);
  ~BlockWindow();

  void          draw();
  int           handle(int event);
  void          new_game();
  int           score() { return (score_); }
  void          up_level();
};


Fl_Preferences  BlockWindow::prefs_(Fl_Preferences::USER_L, "fltk.org", "blocks");


int main(int argc, char *argv[]) {
  Fl::scheme("plastic");
  Fl::visible_focus(0);

  BlockWindow   *bw = new BlockWindow(BLOCK_COLS * BLOCK_SIZE,
                                      BLOCK_ROWS * BLOCK_SIZE + 20,
                                      "Block Attack!");

  bw->show(argc, argv);

  return (Fl::run());
}


// Create a block window at the specified position
BlockWindow::BlockWindow(int X, int Y, int W, int H, const char *L)
    : Fl_Double_Window(X, Y, W, H, L) {
  _BlockWindow();
}


// Create a block window
BlockWindow::BlockWindow(int W, int H, const char *L)
    : Fl_Double_Window(W, H, L) {
  _BlockWindow();
}


// Delete a block window
BlockWindow::~BlockWindow() {
  Fl::remove_timeout((Fl_Timeout_Handler)timeout_cb, (void *)this);
}


// Initialize a block window...
void BlockWindow::_BlockWindow() {
  init();

  help_button_ = new Fl_Button(0, 0, 20, 20, "?");
  help_button_->callback((Fl_Callback *)help_cb, this);
  help_button_->shortcut('?');

  play_button_ = new Fl_Button(80, (h() - 80) / 2, 80, 80, "@>");
  play_button_->callback((Fl_Callback *)play_cb, this);
  play_button_->labelsize(44);
  play_button_->shortcut(' ');

  sound_ = new BlockSound();

  prefs_.get("high_score", high_score_, 0);

  Fl::add_timeout(0.01666666, (Fl_Timeout_Handler)timeout_cb, (void *)this);
}


// Bomb all blocks of a given color and return the number of affected blocks
int BlockWindow::bomb(int color) {
  int           j, k;
  int           count;
  Block         *b;
  Column        *c;


  if (color >= BLOCK_BLAST) return (0);

  for (j = num_columns_, c = columns_, count = 1; j > 0; j --, c ++)
    for (k = c->num_blocks, b = c->blocks; k > 0; k --, b ++)
      if (b->color == color) {
        b->color = -color;
        count ++;
      }

  return (count);
}


// Tag all blocks connected to the clicked block and return the number
// of affected blocks
int BlockWindow::click(int col, int row) {
  Block         *b;
  Column        *c;
  int           count, color;


  c     = columns_ + col;
  b     = c->blocks + row;
  color = b->color;

  if (color < 0 || color >= BLOCK_BLAST) return (0);

  // Find the bottom block...
  while (row > 0 && b[-1].color == color) {
    row --;
    b --;
  }

  count = 0;

  while (row < c->num_blocks && b->color == color) {
    b->color = -color;

    if (col > 0 && row < c[-1].num_blocks &&
        c[-1].blocks[row].color == color) {
      count += click(col - 1, row);
    }

    if (col < (num_columns_ - 1) && row < c[1].num_blocks &&
        c[1].blocks[row].color == color) {
      count += click(col + 1, row);
    }

    count ++;
    row ++;
    b ++;
  }

  return (count);
}


// Draw the block window...
void BlockWindow::draw() {
  int           j, k, xx, yy;
  Block         *b;
  Column        *c;


  // Draw the blocks...
  fl_color(FL_BLACK);
  fl_rectf(0, 0, w(), h());

  // Draw the blocks...
  for (j = num_columns_, c = columns_; j > 0; j --, c ++)
    for (k = c->num_blocks, b = c->blocks; k > 0; k --, b ++) {
      xx = w() - (int)c->x;
      yy = h() - BLOCK_SIZE - (int)b->y;

      if (b->color >= BLOCK_BLAST) {
        b->color ++;
        blast_pixmap.draw(xx, yy);
      } else if (b->color < 0) {
        if (b->bomb) bomb_pixmaps[-b->color - 1]->draw(xx, yy);
        else normal_pixmaps[-b->color - 1]->draw(xx, yy);
      } else {
        if (b->bomb) bomb_pixmaps[b->color - 1]->draw(xx, yy);
        else normal_pixmaps[b->color - 1]->draw(xx, yy);
      }
    }

  if (interval_ < 0.0 || paused_) {
    fl_color(FL_BLACK);
    screen_tile.draw(0, 0, w(), h(), 0, 0);
  }

  // Redraw the widgets...
  play_button_->redraw();
  help_button_->redraw();
  draw_children();

  // Draw any paused/game over/new game message...
  if ((paused_ || interval_ < 0.0) && play_button_->w() == 80) {
    const char *s;

    if (help_) {
      s = "Click on adjacent blocks of the same color. Clear all blocks "
          "before they reach the left side.";

      fl_font(FL_HELVETICA_BOLD, 24);
      fl_color(FL_BLACK);
      fl_draw(s, 171, 3, w() - 250, h() - 6,
              (Fl_Align)(FL_ALIGN_WRAP | FL_ALIGN_LEFT));

      fl_color(FL_YELLOW);
      fl_draw(s, 168, 0, w() - 250, h(),
              (Fl_Align)(FL_ALIGN_WRAP | FL_ALIGN_LEFT));
    } else {
      if (interval_ < 0.0) {
#ifdef DEBUG
        // Show sample waveform...
        short *sample_ptr;

        for (i = 0; i < 2; i++) {
          fl_color(FL_RED + i);
          fl_begin_line();
          for (j = 0, sample_ptr = sound_->sample_data + i;
               j < sound_->sample_size;
               j ++, sample_ptr += 2)
            fl_vertex(j * w() / sound_->sample_size,
                      *sample_ptr * h() / 4 / 65534 + h() / 2);
          fl_end_line();
        }
#endif // DEBUG

        if (num_columns_ && (time(NULL) & 7) < 4)
          s = "Game Over";
        else
          s = "Block Attack!\nby Michael R Sweet";
      } else
        s = "Paused";

      fl_font(FL_HELVETICA_BOLD, 32);
      fl_color(FL_BLACK);
      fl_draw(s, 6, 6, w() - 6, h() - 6, FL_ALIGN_CENTER);

      fl_color(FL_YELLOW);
      fl_draw(s, 0, 0, w(), h(), FL_ALIGN_CENTER);
    }
  }

  time_t curtime = time(NULL);
  frames_ ++;
  if (curtime > frame_time_) {
    frames_per_second_ = (frames_per_second_ + 3 * frames_ / int(curtime - frame_time_)) / 4;
    frames_            = 0;
    frame_time_        = curtime;
  }

  // Draw the scores and level...
  char s[255];

  snprintf(s, sizeof(s), " Score: %d", score_);
  fl_color(FL_WHITE);
  fl_font(FL_HELVETICA, 14);
  fl_draw(s, 40, 0, w() - 40, 20, FL_ALIGN_LEFT);

  snprintf(s, sizeof(s), "High Score: %d ", high_score_);
  fl_draw(s, 0, 0, w(), 20, FL_ALIGN_RIGHT);

  if (level_ > 1 || title_y_ <= 0) {
    snprintf(s, sizeof(s), "Level: %d ", level_);
    fl_draw(s, 0, 0, w(), 20, FL_ALIGN_CENTER);
  }

  if (show_fps_) {
    snprintf(s, sizeof(s), "FPS: %d ", frames_per_second_);
    fl_draw(s, 0, h() - 20, w(), 20, FL_ALIGN_LEFT);
  }

  if (title_y_ > 0 && interval_ > 0.0) {
    int sz = 14 + title_y_ * 86 / h();

    fl_font(FL_HELVETICA_BOLD, sz);
    fl_color(FL_YELLOW);
    fl_draw(title_, 0, title_y_, w(), sz, FL_ALIGN_CENTER);
  }
}


// Handle mouse clicks, etc.
int BlockWindow::handle(int event) {
  int           j, k, mx, my, count;
  Block         *b;
  Column        *c;


  if (Fl_Double_Window::handle(event)) return (1);
  else if (interval_ < 0.0 || paused_) return (0);

  switch (event) {

    case FL_KEYBOARD:

      // '+': raise level
      if (Fl::event_text() &&
          !Fl::event_state(FL_CTRL | FL_ALT | FL_META) &&
          !strcmp(Fl::event_text(), "+")) {
        up_level();
        return (1);
      }

      // ALT + SHIFT + 'H': clear highscore
      if (Fl::event_text() &&
          (Fl::event_state() & (FL_ALT | FL_SHIFT)) == (FL_ALT | FL_SHIFT) &&
          !strcmp(Fl::event_text(), "H")) {
        high_score_ = score_;
        prefs_.set("high_score", high_score_);
        return (1);
      }
      // 'f': toggle showing frames-per-second
      if (Fl::event_text() && !strcmp(Fl::event_text(), "f")) {
        show_fps_ = !show_fps_;
      }
      break;

    case FL_PUSH:
      mx    = w() - Fl::event_x() + BLOCK_SIZE;
      my    = h() - Fl::event_y();
      count = 0;
      b     = 0;

      for (j = 0, c = columns_; !count && j < num_columns_; j ++, c ++)
        for (k = 0, b = c->blocks; k < c->num_blocks; k ++, b ++)
          if (mx >= c->x && mx < (c->x + BLOCK_SIZE) &&
              my >= b->y && my < (b->y + BLOCK_SIZE)) {
            if (b->bomb) count = bomb(b->color);
            else count = click(j, k);
            break;
          }

      if (count < 2) {
        for (j = 0, c = columns_; j < num_columns_; j ++, c ++)
          for (k = 0, b = c->blocks; k < c->num_blocks; k ++, b ++)
            if (b->color < 0) b->color = -b->color;
      } else {
        count --;

        if (b->bomb) {
          sound_->play_explosion(float(0.19 + 0.005 * count));

          interval_ *= BOMB_FACTOR;
          score_ += count;
        } else {
          sound_->play_explosion(float(0.09 + 0.005 * count));

          interval_ *= NORMAL_FACTOR;
          score_ += count * count;
        }

        if (score_ > high_score_) {
          high_score_ = score_;
          prefs_.set("high_score", high_score_);
        }

        for (j = 0, c = columns_; j < num_columns_; j ++, c ++)
          for (k = 0, b = c->blocks; k < c->num_blocks; k ++, b ++)
            if (b->color < 0) b->color = BLOCK_BLAST;
      }
      return (1);

    default:
      break;
  }

  return (0);
}


// Toggle the on-line help...
void BlockWindow::help_cb(Fl_Widget *, BlockWindow *bw) {
  bw->paused_ = bw->help_ = !bw->help_;
  bw->play_button_->label("@>");
  bw->redraw();
}


// Initialize the block window...
void BlockWindow::init() {
  frames_            = 0;
  frames_per_second_ = 0;
  frame_time_        = time(NULL);
  show_fps_          = false;
  count_             = 0;
  help_              = false;
  interval_          = -1.0;
  level_             = 1;
  num_colors_        = 3;
  num_columns_       = 0;
  paused_            = false;
  score_             = 0;
  title_[0]          = '\0';
  title_y_           = 0;
}


// Start a new game...
void BlockWindow::new_game() {
  // Seed the random number generator...
  srand((unsigned int)time(NULL));

  init();

  interval_       = 0.01666666666f;
  opened_columns_ = 0;

  strcpy(title_, "Level: 1");
  title_y_ = h();

  redraw();
}


// Play/pause...
void BlockWindow::play_cb(Fl_Widget *wi, BlockWindow *bw) {
  if (bw->interval_ < 0) bw->new_game();
  else bw->paused_ = !bw->paused_;

  if (bw->paused_) wi->label("@>");
  else {
    wi->label("@-2||");
    bw->help_ = false;
  }
}

void BlockWindow::up_level() {
  interval_ *= LEVEL_FACTOR;
  opened_columns_ = 0;
  if (num_colors_ < 7) num_colors_ ++;
  level_ ++;
  snprintf(title_, sizeof(title_), "Level: %d", level_);
  title_y_ = h();
}

// Animate the game...
void BlockWindow::timeout_cb(BlockWindow *bw) {
  int           i, j;
  Block         *b;
  Column        *c;
  float         lastx, lasty;

#if DEBUG_TIMER
  static double lasttime;
  static double delta_sum;
  static double interval;
  double curtime;
  static int ntime = 0;
  static int level = 0;

#if !defined(_WIN32)
  {
    struct timeval atime;
    gettimeofday(&atime, NULL);
    curtime = atime.tv_sec % 60 + 0.000001 * atime.tv_usec;
  }
#else // (_WIN32)
  {
    SYSTEMTIME atime;
    GetLocalTime(&atime);
    curtime = atime.wSecond + 0.001 * atime.wMilliseconds;
  }
#endif // (_WIN32)

  // platform independent part of timer debugging code
  if (bw->interval_ > 0) { // game is active
    if (bw->level_ != level) {
      if (ntime > 0) {
        printf("*** average delta time = %9.6f, n =%4d, level %d, interval %f\n",
               delta_sum / ntime, ntime, level, interval);
        fflush(stdout);
      }
      delta_sum = 0; // reset average
      ntime = 0;
      interval = bw->interval_;
    }

    double delta = curtime - lasttime;
    if (delta < 0)
      delta += 60;

    printf("%9.6f (%+f - %f = %9.6f), level: %d\n",
           curtime, delta, interval, delta - interval, level);
    fflush(stdout);

    interval = bw->interval_;
    level = bw->level_;
    delta = delta - interval;
    delta_sum += delta > 0 ? delta : -delta; // abs(delta)
    ntime++;
  } else { // waiting ...
    // printf("[OFF] %6.2f\n", curtime);
    // fflush(stdout);
  }
  lasttime = curtime;
#endif // DEBUG_TIMER

  // Update blocks that have been destroyed...
  for (i = 0, c = bw->columns_; i < bw->num_columns_; i ++, c ++)
    for (j = 0, b = c->blocks; j < c->num_blocks; j ++, b ++)
      if (b->color > (BLOCK_BLAST + 5)) {
        bw->redraw();

        c->num_blocks --;

        if (j < c->num_blocks) {
          memmove(b, b + 1, (c->num_blocks - j) * sizeof(Block));
        }

        j --;
        b --;

        if (!c->num_blocks) {
          bw->num_columns_ --;

          if (i < bw->num_columns_) {
            memmove(c, c + 1, (bw->num_columns_ - i) * sizeof(Column));
          }

          i --;
          c --;
          j = c->num_blocks;
        }
      }

  // Let the rest of the blocks fall and/or move...
  for (i = bw->num_columns_, c = bw->columns_, lastx = c->x; i > 0; i--, c++) {
    if (c->x > lastx) {
      c->x -= 8;
      bw->redraw();
    }

    lastx = c->x + BLOCK_SIZE;

    if (!bw->paused_ && bw->interval_ > 0.0) {
      bw->redraw();
      c->x += 0.25;
    }

    for (j = c->num_blocks, b = c->blocks, lasty = 0; j > 0; j --, b ++) {
      if (b->y > lasty) {
        bw->redraw();
        b->y -= 4;
      }

      lasty = b->y + BLOCK_SIZE;
    }
  }

  // Slide the title text as needed...
  if (bw->title_y_ > 0) {
    bw->redraw();
    bw->title_y_ -= 2;
  }

  // Play the game...
  if (!bw->paused_ && bw->interval_ > 0.0) {
    bw->count_ --;

    if (bw->count_ <= 0) {
      bw->redraw();
      bw->count_ = 4 * BLOCK_SIZE;

      if (bw->num_columns_ == BLOCK_COLS) {
        bw->interval_ = -1.0;
        bw->sound_->play_explosion(0.8f);
        bw->play_button_->label("@>");
      } else {
        bw->opened_columns_ ++;

        if (bw->opened_columns_ > (2 * BLOCK_COLS)) {
          bw->up_level();
        }

        c = bw->columns_;

        if (bw->num_columns_) {
          memmove(c + 1, c, bw->num_columns_ * sizeof(Column));
        }

        bw->num_columns_ ++;
        c->x          = 0;
        c->num_blocks = BLOCK_ROWS;

        for (j = 0, b = c->blocks; j < BLOCK_ROWS; j ++, b ++) {
          b->bomb  = bw->num_colors_ > 3 && (rand() & 127) < bw->num_colors_;
          b->color = 1 + (rand() % bw->num_colors_);
          b->y     = float(j * (BLOCK_SIZE + 8) + 24);
        }
      }
    }
  } else {
    bw->count_ --;

    if (bw->count_ <= 0) {
      bw->count_ = 40;
      bw->redraw();
    }
  }

  // Update the play/pause button as needed...
  if ((bw->paused_ || bw->interval_< 0.0) &&
      bw->play_button_->w() < 80) {
    int s = bw->play_button_->w() + 5;

    bw->play_button_->resize(s, (s - 20) * (bw->h() - s) / 120, s, s);
    bw->play_button_->labelsize(s / 2 + 4);
    bw->redraw();
  } else if ((!bw->paused_ && bw->interval_ > 0.0) &&
             bw->play_button_->w() > 20) {
    int s = bw->play_button_->w() - 2;

    bw->play_button_->resize(s, (s - 20) * (bw->h() - s) / 120, s, s);
    bw->play_button_->labelsize(s / 2 + 4);
    bw->redraw();
  }

  if (bw->interval_ > 0.0) {
    Fl::repeat_timeout(bw->interval_, (Fl_Timeout_Handler)timeout_cb, (void *)bw);
  } else {
    Fl::repeat_timeout(0.1, (Fl_Timeout_Handler)timeout_cb, (void *)bw);
  }
}