PhysicalConnectivity/src/main/kotlin/net/shadowfacts/phycon/block/FaceDeviceBlock.kt

package net.shadowfacts.phycon.block

import net.minecraft.block.Block
import net.minecraft.block.BlockState
import net.minecraft.block.ShapeContext
import net.minecraft.item.ItemPlacementContext
import net.minecraft.state.StateManager
import net.minecraft.state.property.EnumProperty
import net.minecraft.state.property.Properties
import net.minecraft.util.StringIdentifiable
import net.minecraft.util.math.BlockPos
import net.minecraft.util.math.Direction
import net.minecraft.util.shape.VoxelShape
import net.minecraft.util.shape.VoxelShapes
import net.minecraft.world.BlockView
import net.minecraft.world.World
import net.minecraft.world.WorldAccess
import net.shadowfacts.phycon.api.Interface
import net.shadowfacts.phycon.api.NetworkComponentBlock
import net.shadowfacts.phycon.block.cable.CableBlock
import java.util.*


/**
 * @author shadowfacts
 */
abstract class FaceDeviceBlock<T: DeviceBlockEntity>(settings: Settings): DeviceBlock<T>(settings) {
	companion object {
		val FACING = Properties.FACING
		val CABLE_CONNECTION = EnumProperty.of("cable_connection", FaceCableConnection::class.java)
	}

	enum class FaceCableConnection : StringIdentifiable {
		NONE, DOWN, UP, NORTH, SOUTH, WEST, EAST;

		companion object {
			fun from(dir: Direction?) = when (dir) {
				null -> NONE
				Direction.DOWN -> DOWN
				Direction.UP -> UP
				Direction.NORTH -> NORTH
				Direction.SOUTH -> SOUTH
				Direction.WEST -> WEST
				Direction.EAST -> EAST
			}
		}

		val direction: Direction?
			get() = when (this) {
				NONE -> null
				DOWN -> Direction.DOWN
				UP -> Direction.UP
				NORTH -> Direction.NORTH
				SOUTH -> Direction.SOUTH
				WEST -> Direction.WEST
				EAST -> Direction.EAST
			}

		override fun asString() = name.toLowerCase()
	}

	protected abstract val faceThickness: Double
	protected abstract val faceShapes: Map<Direction, VoxelShape>
	private val centerShapes: Map<Direction, VoxelShape> by lazy {
		mapOf(
			Direction.DOWN to createCuboidShape(6.0, faceThickness, 6.0, 10.0, 10.0, 10.0),
			Direction.UP to createCuboidShape(6.0, 6.0, 6.0, 10.0, 16.0 - faceThickness, 10.0),
			Direction.NORTH to createCuboidShape(6.0, 6.0, faceThickness, 10.0, 10.0, 10.0),
			Direction.SOUTH to createCuboidShape(6.0, 6.0, 6.0, 10.0, 10.0, 16.0 - faceThickness),
			Direction.WEST to createCuboidShape(faceThickness, 6.0, 6.0, 10.0, 10.0, 10.0),
			Direction.EAST to createCuboidShape(6.0, 6.0, 6.0, 16.0 - faceThickness, 10.0, 10.0)
		)
	}
	private val shapeCache = mutableMapOf<Pair<Direction, FaceCableConnection>, VoxelShape>()

	private fun getShape(facing: Direction, cableConnection: FaceCableConnection): VoxelShape {
		return shapeCache.getOrPut(facing to cableConnection) {
			if (cableConnection == FaceCableConnection.NONE) {
				VoxelShapes.union(faceShapes[facing], centerShapes[facing])
			} else {
				VoxelShapes.union(faceShapes[facing], centerShapes[facing], CableBlock.SIDE_SHAPES[cableConnection.direction])
			}
		}
	}

	override fun getNetworkConnectedSides(state: BlockState, world: WorldAccess, pos: BlockPos): Collection<Direction> {
		val direction = state[CABLE_CONNECTION].direction
		return if (direction != null) EnumSet.of(direction) else setOf()
	}

	override fun getNetworkInterfaceForSide(side: Direction, state: BlockState, world: WorldAccess, pos: BlockPos): Interface? {
		return if (side == state[FACING]) {
			null
		} else {
			getBlockEntity(world, pos)
		}
	}

	override fun appendProperties(builder: StateManager.Builder<Block, BlockState>) {
		super.appendProperties(builder)
		builder.add(FACING)
		builder.add(CABLE_CONNECTION)
	}

	override fun getPlacementState(context: ItemPlacementContext): BlockState {
		val facing = if (context.player?.isSneaking == true) context.side.opposite else context.playerLookDirection.opposite
		val cableConnection = FaceCableConnection.from(getCableConnectedSide(context.world, context.blockPos, facing))
		return defaultState
			.with(FACING, facing)
			.with(CABLE_CONNECTION, cableConnection)
	}

	private fun getCableConnectedSide(world: WorldAccess, pos: BlockPos, facing: Direction): Direction? {
		for (side in Direction.values()) {
			if (side == facing) {
				continue
			}
			val offsetPos = pos.offset(side)
			val state = world.getBlockState(offsetPos)
			val block = state.block
			if (block is NetworkComponentBlock && block.getNetworkConnectedSides(state, world, offsetPos).contains(side.opposite)) {
				return side
			}
		}
		return null
	}

	override fun getStateForNeighborUpdate(state: BlockState, side: Direction, neighborState: BlockState, world: WorldAccess, pos: BlockPos, neighborPos: BlockPos): BlockState {
		val current = state[CABLE_CONNECTION]
		var newConnection = current

		if (current == FaceCableConnection.NONE) {
			if (neighborState.block is NetworkComponentBlock) {
				newConnection = FaceCableConnection.from(side)
			}
		} else {
			val currentConnectedPos = pos.offset(current.direction)
			if (neighborPos == currentConnectedPos && neighborState.block !is NetworkComponentBlock) {
				// the old cable connection is no longer correct, try to find another
				newConnection = FaceCableConnection.from(getCableConnectedSide(world, pos, state[FACING]))
			}
		}
		return state.with(CABLE_CONNECTION, newConnection)
	}

	override fun getOutlineShape(state: BlockState, world: BlockView, pos: BlockPos, context: ShapeContext): VoxelShape {
		return getShape(state[FACING], state[CABLE_CONNECTION])
	}
}