class HeadsUpDisplay
{
  int [] colorQueue;
  int queueSpeed;
  int timeUntilNextColor;
  float blackSpeed;
  float blackForce;
  float gameTimer;
  
  void Initialize()
  {     
    int i;
    colorQueue = new int[10];   
    for( i = 0; i < 10; ++i )
    {
      GetNewColorIndex( i );
    }
    
    Reset();
  }
  
  void Reset()
  {
    blackSpeed = .5f;
    blackForce = 0.f;
    gameTimer = GAME_TIMER_LENGTH;
    
    queueSpeed = 120;
    timeUntilNextColor = queueSpeed;
  }
  
  void Update()
  {
    //update color queue
    --timeUntilNextColor;
    if( timeUntilNextColor <= 0 )
    {
      timeUntilNextColor = queueSpeed;
      
      int i;
      //shift all colors down the line
      for( i = 1; i < 10; ++i )
      {
        colorQueue[i-1] = colorQueue[i];
      }
      
      //add a new color at the end of the line
      GetNewColorIndex( 9 );
    }
    
    //update game timer
    gameTimer -= blackSpeed;
    gameTimer += blackForce;
    if( gameTimer < 0 )
    {
      RESET();
    }
    else if( gameTimer > GAME_TIMER_LENGTH )
    {
      blackForce = 0.f;
      gameTimer = GAME_TIMER_LENGTH;
    }
    
    //decay black force applied to game timer
    blackForce *= .9f;
    if( blackForce < .05f )
    {
      blackForce = 0.f;
    }  
  }
  
  void Draw()
  {
    float halfWidth = SCREEN_WIDTH * .5f;
    
    //draw border
    stroke( 0 );
    fill( 0, 0, 0 );          
    rect( 0.f, 0.f, SCREEN_WIDTH, 40.f );  
    rect( 0.f, SCREEN_HEIGHT - 40.f, SCREEN_WIDTH, 40.f );    
    rect( 0.f, 0.f, 40.f, SCREEN_HEIGHT );    
    rect( SCREEN_WIDTH - 40.f, 0.f, 40.f, SCREEN_HEIGHT );      
  
    //draw beam
    float currentColorRatio = 1.f - (float)timeUntilNextColor / (float)queueSpeed;
    float currentColorPosX = halfWidth - (currentColorRatio*200.f);

    stroke( GAME_COLORS[ colorQueue[3] ] );   fill( GAME_COLORS[ colorQueue[3] ] );
    rect( currentColorPosX - 400.f, SCREEN_HEIGHT - 35.f, 200.f, 20.f );   
    stroke( GAME_COLORS[ colorQueue[4] ] );   fill( GAME_COLORS[ colorQueue[4] ] );
    rect( currentColorPosX - 200.f, SCREEN_HEIGHT - 35.f, 200.f, 20.f );    
    stroke( GAME_COLORS[ colorQueue[5] ] );   fill( GAME_COLORS[ colorQueue[5] ] );
    rect( currentColorPosX, SCREEN_HEIGHT - 35.f, 200.f, 20.f );
    stroke( GAME_COLORS[ colorQueue[6] ] );   fill( GAME_COLORS[ colorQueue[6] ] );
    rect( currentColorPosX + 200.f, SCREEN_HEIGHT - 35.f, 200.f, 20.f ); 
    stroke( GAME_COLORS[ colorQueue[7] ] );   fill( GAME_COLORS[ colorQueue[7] ] );
    rect( currentColorPosX + 400.f, SCREEN_HEIGHT - 35.f, 200.f, 20.f );
    
    //draw beam locks
    float beamLockWidth = 10.f;
    float beamLockHeight = 10.f;    
    stroke( GAME_COLORS[ colorQueue[3] ] );   fill( GAME_COLORS[ colorQueue[3] ] );
    rect( currentColorPosX - 200.f, SCREEN_HEIGHT - 30.f, beamLockWidth, beamLockHeight );    
    stroke( GAME_COLORS[ colorQueue[4] ] );   fill( GAME_COLORS[ colorQueue[4] ] );
    rect( currentColorPosX - 210.f, SCREEN_HEIGHT - 30.f, beamLockWidth, beamLockHeight );  
    rect( currentColorPosX + 0.f, SCREEN_HEIGHT - 30.f, beamLockWidth, beamLockHeight );    
    stroke( GAME_COLORS[ colorQueue[5] ] );   fill( GAME_COLORS[ colorQueue[5] ] );
    rect( currentColorPosX - 10.f, SCREEN_HEIGHT - 30.f, beamLockWidth, beamLockHeight );    
    rect( currentColorPosX + 200.f, SCREEN_HEIGHT - 30.f, beamLockWidth, beamLockHeight );   
    stroke( GAME_COLORS[ colorQueue[6] ] );   fill( GAME_COLORS[ colorQueue[6] ] );
    rect( currentColorPosX + 190.f, SCREEN_HEIGHT - 30.f, beamLockWidth, beamLockHeight );    
    rect( currentColorPosX + 400.f, SCREEN_HEIGHT - 30.f, beamLockWidth, beamLockHeight );    
    stroke( GAME_COLORS[ colorQueue[7] ] );   fill( GAME_COLORS[ colorQueue[7] ] );
    rect( currentColorPosX + 390.f, SCREEN_HEIGHT - 30.f, beamLockWidth, beamLockHeight ); 
    
    //draw triangle
    stroke( 100 );
    fill( 100 );    
    triangle( halfWidth - 30.f, SCREEN_HEIGHT - 5.f, 
              halfWidth + 30.f, SCREEN_HEIGHT - 5.f, 
              halfWidth       , SCREEN_HEIGHT - 55.f );
              
    stroke( GAME_COLORS[ colorQueue[5] ] );
    fill( GAME_COLORS[ colorQueue[5] ] );              
    triangle( halfWidth - 21.5f, SCREEN_HEIGHT - 9.f, 
              halfWidth + 21.5f, SCREEN_HEIGHT - 9.f, 
              halfWidth       , SCREEN_HEIGHT - 45.f );              
  }  
  
  void GetNewColorIndex( int queueIndex )
  {
    if( queueIndex == 0 )
    {
      int newIndex = int( random( 3, 7 ) );
      while( newIndex == 4 || newIndex == 7 )
      {
        newIndex = int( random( 3, 7 ) );
      }      
      
      colorQueue[0] = newIndex;
    }
    else
    {
      int newIndex = int( random( 3, 7 ) );
      while( newIndex == 4 || newIndex == 7 || newIndex == colorQueue[queueIndex-1] )
      {
        newIndex = int( random( 3, 7 ) );
      }      
      
      colorQueue[queueIndex] = newIndex;
    }    
  }
  
  void AddForce( float Force )
  {
    blackForce = Force;
  }
}