/*
 * WorldEdit, a Minecraft world manipulation toolkit
 * Copyright (C) sk89q <http://www.sk89q.com>
 * Copyright (C) WorldEdit team and contributors
 *
 * This program is free software: you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by the
 * Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License
 * for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

package com.sk89q.worldedit.function.block;

import com.boydti.fawe.util.ReflectionUtils;
import com.sk89q.jnbt.ByteTag;
import com.sk89q.jnbt.CompoundTag;
import com.sk89q.jnbt.Tag;
import com.sk89q.worldedit.Vector;
import com.sk89q.worldedit.WorldEditException;
import com.sk89q.worldedit.blocks.BaseBlock;
import com.sk89q.worldedit.extent.Extent;
import com.sk89q.worldedit.function.RegionFunction;
import com.sk89q.worldedit.internal.helper.MCDirections;
import com.sk89q.worldedit.math.transform.Transform;
import com.sk89q.worldedit.util.Direction;
import com.sk89q.worldedit.util.Direction.Flag;
import java.util.Map;


import static com.google.common.base.Preconditions.checkNotNull;

/**
 * Copies blocks from one extent to another.
 */
public class ExtentBlockCopy implements RegionFunction {

    private final Extent source;
    private final Extent destination;
    private final Vector from;
    private final Vector to;
    private final Transform transform;

    /**
     * Make a new copy.
     *
     * @param source      the source extent
     * @param from        the source offset
     * @param destination the destination extent
     * @param to          the destination offset
     * @param transform   a transform to apply to positions (after source offset, before destination offset)
     */
    public ExtentBlockCopy(Extent source, Vector from, Extent destination, Vector to, Transform transform) {
        checkNotNull(source);
        checkNotNull(from);
        checkNotNull(destination);
        checkNotNull(to);
        checkNotNull(transform);
        this.source = source;
        this.from = from;
        this.destination = destination;
        this.to = to;
        this.transform = transform;
    }

    @Override
    public boolean apply(Vector position) throws WorldEditException {
        BaseBlock block = source.getBlock(position);
        Vector orig = position.subtract(from);
        Vector transformed = transform.apply(orig);

        // Apply transformations to NBT data if necessary
        block = transformNbtData(block);

        return destination.setBlock(transformed.add(to), block);
    }

    /**
     * Transform NBT data in the given block state and return a new instance
     * if the NBT data needs to be transformed.
     *
     * @param state the existing state
     * @return a new state or the existing one
     */
    private BaseBlock transformNbtData(BaseBlock state) {
        CompoundTag tag = state.getNbtData();
        if (tag != null) {
            // Handle blocks which store their rotation in NBT
            if (tag.containsKey("Rot")) {
                int rot = tag.asInt("Rot");

                Direction direction = MCDirections.fromRotation(rot);

                if (direction != null) {
                    Vector applyAbsolute = transform.apply(direction.toVector());
                    Vector applyOrigin = transform.apply(Vector.ZERO);
                    applyAbsolute.mutX(applyAbsolute.getX() - applyOrigin.getX());
                    applyAbsolute.mutY(applyAbsolute.getY() - applyOrigin.getY());
                    applyAbsolute.mutZ(applyAbsolute.getZ() - applyOrigin.getZ());

                    Direction newDirection = Direction.findClosest(applyAbsolute, Flag.CARDINAL | Flag.ORDINAL | Flag.SECONDARY_ORDINAL);

                    if (newDirection != null) {
                        Map<String, Tag> values = ReflectionUtils.getMap(tag.getValue());
                        values.put("Rot", new ByteTag((byte) MCDirections.toRotation(newDirection)));
                    }
                }
            }
        }
        return state;
    }

    public static Class<?> inject() {
        return ExtentBlockCopy.class;
    }

}
