EnergonRelics/src/main/java/com/thebrokenrail/energonrelics/structure/StructurePart.java

package com.thebrokenrail.energonrelics.structure;

import com.thebrokenrail.energonrelics.util.MissingCaseException;
import net.minecraft.block.BlockState;
import net.minecraft.block.Blocks;
import net.minecraft.util.BlockRotation;
import net.minecraft.util.math.BlockPos;
import net.minecraft.util.math.Vec3d;
import net.minecraft.world.World;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

public abstract class StructurePart<T> {
    protected interface Transformation {
        Vec3d transform(Vec3d vec);
        BlockState transform(BlockState state);
    }

    private final T state;

    protected T getState() {
        return state;
    }

    public StructurePart(T state, List<Transformation> list) {
        this.state = state;
        transformations.addAll(list);
    }

    private final Map<Long, BlockState> blocks = new HashMap<>();

    private final List<Transformation> transformations = new ArrayList<>();

    protected static final Transformation NONE = new Transformation() {
        @Override
        public Vec3d transform(Vec3d vec) {
            return vec;
        }

        @Override
        public BlockState transform(BlockState state) {
            return state;
        }
    };
    protected static final Transformation CLOCKWISE_90 = new Transformation() {
        @Override
        public Vec3d transform(Vec3d vec) {
            return new Vec3d(-vec.getZ(), vec.getY(), vec.getX());
        }

        @Override
        public BlockState transform(BlockState state) {
            return state.rotate(BlockRotation.CLOCKWISE_90);
        }
    };
    protected static final Transformation CLOCKWISE_180 = new Transformation() {
        @Override
        public Vec3d transform(Vec3d vec) {
            return new Vec3d(-vec.getX(), vec.getY(), -vec.getZ());
        }

        @Override
        public BlockState transform(BlockState state) {
            return state.rotate(BlockRotation.CLOCKWISE_180);
        }
    };
    protected static final Transformation COUNTERCLOCKWISE_90 = new Transformation() {
        @Override
        public Vec3d transform(Vec3d vec) {
            return new Vec3d(vec.getZ(), vec.getY(), -vec.getX());
        }

        @Override
        public BlockState transform(BlockState state) {
            return state.rotate(BlockRotation.COUNTERCLOCKWISE_90);
        }
    };

    protected abstract int getHeight();
    protected abstract int getWidth();
    protected abstract int getDepth();

    protected abstract void build(StructureContext context);

    private Vec3d getOffset() {
        return new Vec3d(getWidth() / 2f, getHeight() / 2f, getDepth() / 2f);
    }

    private Vec3d transform(Vec3d pos) {
        pos = pos.subtract(getOffset());
        for (Transformation transformation : transformations) {
            pos = transformation.transform(pos);
        }
        return pos;
    }

    private BlockState transform(BlockState state) {
        for (Transformation transformation : transformations) {
            state = transformation.transform(state);
        }
        return state;
    }

    protected void set(int x, int y, int z, BlockState state) {
        Vec3d vec = transform(new Vec3d(x, y, z));
        blocks.put(new BlockPos(vec.getX(), vec.getY(), vec.getZ()).asLong(), transform(state));
    }

    protected void rect(int xPos, int yPos, int zPos, int width, int height, int depth, BlockState state) {
        for (int x = 0; x < width; x++) {
            for (int y = 0; y < height; y++) {
                for (int z = 0; z < depth; z++) {
                    set(x + xPos, y + yPos, z + zPos, state);
                }
            }
        }
    }

    protected void repeat(Transformation[] functions, Runnable action) {
        for (Transformation function : functions) {
            transformations.add(function);
            action.run();
            transformations.remove(transformations.size() - 1);
        }
    }

    protected void repeat(Runnable action) {
        repeat(new Transformation[]{NONE, CLOCKWISE_90, CLOCKWISE_180, COUNTERCLOCKWISE_90}, action);
    }

    public void place(World world, BlockPos pos) {
        Vec3d offset = getOffset();
        BlockPos offsetPos = new BlockPos(offset.getX(), offset.getY(), offset.getZ());
        for (Map.Entry<Long, BlockState> entry : blocks.entrySet()) {
            BlockState state = entry.getValue();
            if (state.getBlock() != Blocks.VOID_AIR) {
                BlockPos newPos = pos.add(BlockPos.fromLong(entry.getKey()).add(offsetPos));
                world.removeBlockEntity(newPos);
                world.setBlockState(newPos, state);
                handleBlockPlace(world, newPos, state);
            }
        }
    }

    protected abstract void handleBlockPlace(World world, BlockPos pos, BlockState state);

    public static Transformation getTransformationFromBlockRotation(BlockRotation rotation) {
        switch (rotation) {
            case NONE: {
                return NONE;
            }
            case CLOCKWISE_90: {
                return CLOCKWISE_90;
            }
            case CLOCKWISE_180: {
                return CLOCKWISE_180;
            }
            case COUNTERCLOCKWISE_90: {
                return COUNTERCLOCKWISE_90;
            }
            default: {
                throw new MissingCaseException(rotation);
            }
        }
    }

    protected void part(StructureContext context, int x, int y, int z, StructurePart<?> part) {
        Vec3d vec = transform(new Vec3d(x, y, z));
        context.addPart((int) vec.getX(), (int) vec.getY(), (int) vec.getZ(), part);
    }

    protected List<Transformation> getTransformations() {
        return transformations;
    }
}