path: root/src/Blocks/BlockSponge.h

#pragma once

#include "BlockHandler.h"





class cBlockSpongeHandler :
	public cBlockHandler
{
	using super = cBlockHandler;

public:

	cBlockSpongeHandler(BLOCKTYPE a_BlockType):
		super(a_BlockType)
	{
	}





	virtual void Check(
		cChunkInterface & a_ChunkInterface, cBlockPluginInterface & a_PluginInterface,
		Vector3i a_RelPos,
		cChunk & a_Chunk
	) override
	{
		if (GetSoaked(a_RelPos, a_Chunk))
		{
			return;
		}
		super::Check(a_ChunkInterface, a_PluginInterface, a_RelPos, a_Chunk);
	}





	/** Check blocks around the sponge to see if they are water.
	If a dry sponge is touching water, soak up up to 65 blocks of water,
	with a taxicab distance of 7, and turn the sponge into a wet sponge.
	Returns TRUE if the block was changed. */
	bool GetSoaked(Vector3i a_Rel, cChunk & a_Chunk)
	{
		static const std::array<Vector3i, 6> WaterCheck
		{
			{
				{ 1,  0,  0},
				{-1,  0,  0},
				{ 0,  0,  1},
				{ 0,  0, -1},
				{ 0,  1,  0},
				{ 0, -1,  0},
			}
		};
		struct sSeed
		{
			sSeed(Vector3i pos, int d)
			{
				m_Pos = pos;
				m_Depth = d;
			}
			Vector3i m_Pos;
			int m_Depth;
		};


		// Check if this is a dry sponge next to a water block.
		NIBBLETYPE TargetMeta = a_Chunk.GetMeta(a_Rel.x, a_Rel.y, a_Rel.z);
		if (TargetMeta != E_META_SPONGE_DRY)
		{
			return false;
		}

		bool ShouldSoak = std::any_of(WaterCheck.cbegin(), WaterCheck.cend(), [a_Rel, & a_Chunk](Vector3i a_Offset)
			{
				return IsWet(a_Rel + a_Offset, a_Chunk);
			}
		);

		// Early return if the sponge isn't touching any water.
		if (! ShouldSoak)
		{
			return false;
		}


		// Use a queue to hold blocks that we want to check, so our search is breadth-first.
		std::queue<sSeed> Seeds;
		int count = 0;
		// Only go 7 blocks away from the center block.
		const int maxDepth = 7;
		// Start with the 6 blocks around the sponge.
		for (unsigned int i = 0; i < 6; i++)
		{
			Seeds.emplace(a_Rel + WaterCheck[i], maxDepth - 1);
		}


		// Keep checking blocks that are touching water blocks, or until 65 have been soaked up.
		while (!Seeds.empty() && count < 65)
		{
			sSeed seed = Seeds.front();
			Vector3i checkRel = seed.m_Pos;
			if (IsWet(checkRel, a_Chunk))
			{
				count++;
				DryUp(checkRel, a_Chunk);
				if (seed.m_Depth > 0)
				{
					// If this block was water, and we haven't yet gone too far away,
					// add its neighbors to the queue to check.
					for (unsigned int i = 0; i < 6; i++)
					{
						Seeds.emplace(checkRel + WaterCheck[i], seed.m_Depth - 1);
					}
				}
			}
			Seeds.pop();
		}
		a_Chunk.SetBlock(a_Rel, E_BLOCK_SPONGE, E_META_SPONGE_WET);
		return true;
	}





	static void DryUp(Vector3i a_Rel, cChunk & a_Chunk)
	{
		// TODO: support evaporating waterlogged blocks.
		a_Chunk.UnboundedRelSetBlock(a_Rel.x, a_Rel.y, a_Rel.z, E_BLOCK_AIR, 0);
	}





	static bool IsWet(Vector3i a_Rel, cChunk & a_Chunk)
	{
		// TODO: support detecting waterlogged blocks.
		BLOCKTYPE Type;
		return(a_Chunk.UnboundedRelGetBlockType(a_Rel.x, a_Rel.y, a_Rel.z, Type) && IsBlockWater(Type));
	}





	virtual ColourID GetMapBaseColourID(NIBBLETYPE a_Meta) override
	{
		UNUSED(a_Meta);
		return 18;
	}





};