namespace BlockParty;

/// <summary>
/// Smile block — fades invisible on impact. Phase 1 toggles visible/invisible each impact.
/// Phase 2 stays invisible but briefly fades back in on each impact, then goes invisible
/// again during the eye-cycle pause so it's always invisible before it moves off. While
/// invisible it keeps moving and is still dangerous; its speed-lines still show as a tell.
/// Port of the original BlockSmile (the staggered greyscale fade is realised as an alpha fade).
/// </summary>
public sealed class BlockSmile : Block
{
	const float FADE_TIME = 0.2f;

	bool _invisible;
	bool _briefReveal;
	float _alpha = 1f, _alphaTarget = 1f;

	public override void Impact( Block otherBlock )
	{
		ImpactEffects( otherBlock );
		if ( IsDead ) return;

		if ( Phase == 1 )
		{
			if ( !_invisible ) GoInvisible(); else GoVisible();
		}
		else if ( Phase == 2 )
		{
			if ( !_invisible ) GoInvisible();
			else { GoVisible(); _briefReveal = true; } // re-hidden in OnEyesClosed (before it moves)
		}

		CloseEyesAndPickNewDirection();
	}

	// Eyes have shut and the new direction is chosen — re-hide now so the phase-2 "peek" is
	// always over before the block opens its eyes and moves off.
	protected override void OnEyesClosed()
	{
		if ( _briefReveal )
		{
			_briefReveal = false;
			GoInvisible();
		}
	}

	public override void Tick( float dt )
	{
		base.Tick( dt );

		if ( _alpha != _alphaTarget )
		{
			float step = dt / FADE_TIME;
			_alpha = _alpha < _alphaTarget ? MathF.Min( _alphaTarget, _alpha + step ) : MathF.Max( _alphaTarget, _alpha - step );
			SetLayersAlpha( _alpha );
		}
	}

	void GoInvisible()
	{
		if ( _invisible ) return;
		_invisible = true;
		_alphaTarget = 0f;
		Audio.PlaySfx( SfxType.TurnInvisible, Position );
	}

	void GoVisible()
	{
		if ( !_invisible ) return;
		_invisible = false;
		_alphaTarget = 1f;
		Audio.PlaySfx( SfxType.TurnVisible, Position );
	}

	protected override void NextPhase()
	{
		base.NextPhase();
		_briefReveal = false;
		if ( _invisible ) GoVisible();
	}

	public override void PlayerHasDied()
	{
		_briefReveal = false;
		GoVisible();
	}

	public override void Die()
	{
		base.Die();
		_briefReveal = false;
		GoVisible();
	}
}