/*
 * 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 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package com.sk89q.worldedit.function.generator;

import com.sk89q.worldedit.EditSession;
import com.sk89q.worldedit.WorldEditException;
import com.sk89q.worldedit.function.RegionFunction;
import com.sk89q.worldedit.math.BlockVector3;
import com.sk89q.worldedit.util.TreeGenerator;
import com.sk89q.worldedit.world.block.BlockState;
import com.sk89q.worldedit.world.block.BlockType;
import com.sk89q.worldedit.world.block.BlockTypes;

/**
 * Generates forests by searching for the ground starting from the given upper Y
 * coordinate for every column given.
 */
public class ForestGenerator implements RegionFunction {

    private final TreeGenerator.TreeType treeType;
    private final EditSession editSession;

    /**
     * Create a new instance.
     *
     * @param editSession the edit session
     * @param treeType    a tree generator
     */
    public ForestGenerator(EditSession editSession, TreeGenerator.TreeType treeType) {
        this.editSession = editSession;
        this.treeType = treeType;
    }

    @Override
    public boolean apply(BlockVector3 position) throws WorldEditException {
        BlockState block = editSession.getBlock(position);
        BlockType t = block.getBlockType();

        if (t.getMaterial().isSolid()) {
            return treeType.generate(editSession, position.add(0, 1, 0));
        } else if (t.getMaterial().isReplacedDuringPlacement()) {
            // since the implementation's tree generators generally don't generate in non-air spots,
            // we trick editsession history here in the first call
            editSession.setBlock(position, BlockTypes.AIR.getDefaultState());
            // and then trick the generator here by directly setting into the world
            editSession.getWorld().setBlock(position, BlockTypes.AIR.getDefaultState());
            // so that now the generator can generate the tree
            boolean success = treeType.generate(editSession, position);
            if (!success) {
                editSession.setBlock(position, block); // restore on failure
            }
            return success;
        } else { // Trees won't grow on this!
            return false;
        }
    }

}
