using System;

namespace ClassicalSharp {
	
	/// <summary> Stores various properties about the blocks in Minecraft Classic. </summary>
	public partial class BlockInfo {
		
		bool[] hidden = new bool[BlocksCount * BlocksCount * TileSide.Sides];

		internal void SetupCullingCache() {
			for( int tileI = 1; tileI < BlocksCount; tileI++ ) {
				for( int neighbourI = 1; neighbourI < BlocksCount; neighbourI++ ) {
					byte tile = (byte)tileI, neighbour = (byte)neighbourI;
					bool hidden = IsHidden( tile, neighbour );
					if( tile == neighbour && !CullWithNeighbours[tile] )
						hidden = false;
					
					SetHidden( tile, neighbour, TileSide.Left, hidden );
					SetHidden( tile, neighbour, TileSide.Right, hidden );
					SetHidden( tile, neighbour, TileSide.Front, hidden );
					SetHidden( tile, neighbour, TileSide.Back, hidden );
					SetHidden( tile, neighbour, TileSide.Top, hidden && Height[tile] == 1 );
					SetHidden( tile, neighbour, TileSide.Bottom, hidden && Height[neighbour] == 1 );
				}
			}
		}
		
		bool IsHidden( byte tile, byte block ) {
			return
				((tile == block || (IsOpaque[block] && !IsLiquid[block])) && !IsSprite[tile]) ||
				((tile == (byte)Block.Water || tile == (byte)Block.StillWater) && block == (byte)Block.Ice);
		}
		
		void SetHidden( byte tile, byte block, int tileSide, bool value ) {
			hidden[( tile * BlocksCount + block ) * TileSide.Sides + tileSide] = value;
		}
		
		/// <summary> Returns whether the face at the given face of the tile 
		/// should be drawn with the neighbour 'block' present on the other side of the face. </summary>
		public bool IsFaceHidden( byte tile, byte block, int tileSide ) {
			return hidden[( tile * BlocksCount + block ) * TileSide.Sides + tileSide];
		}
	}
}