/*
 * Copyright (c) 2019-2020 GeyserMC. http://geysermc.org
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 *
 * @author GeyserMC
 * @link https://github.com/GeyserMC/Geyser
 */

package org.geysermc.connector.network.session.cache;

import com.github.steveice10.mc.protocol.data.game.chunk.Chunk;
import com.github.steveice10.mc.protocol.data.game.chunk.Column;
import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
import org.geysermc.connector.bootstrap.GeyserBootstrap;
import org.geysermc.connector.network.session.GeyserSession;
import org.geysermc.connector.network.translators.world.block.BlockTranslator;
import org.geysermc.connector.utils.MathUtils;

public class ChunkCache {

    private final boolean cache;

    private final Long2ObjectMap<Column> chunks = new Long2ObjectOpenHashMap<>();

    public ChunkCache(GeyserSession session) {
        if (session.getConnector().getWorldManager().getClass() == GeyserBootstrap.DEFAULT_CHUNK_MANAGER.getClass()) {
            this.cache = session.getConnector().getConfig().isCacheChunks();
        } else {
            this.cache = false; // To prevent Spigot from initializing
        }
    }

    public Column addToCache(Column chunk) {
        if (!cache) {
            return chunk;
        }

        long chunkPosition = MathUtils.chunkPositionToLong(chunk.getX(), chunk.getZ());
        Column existingChunk;
        if (chunk.getBiomeData() == null // Only consider merging columns if the new chunk isn't a full chunk
            && (existingChunk = chunks.getOrDefault(chunkPosition, null)) != null) { // Column is already present in cache, we can merge with existing
            boolean changed = false;
            for (int i = 0; i < chunk.getChunks().length; i++) { // The chunks member is final, so chunk.getChunks() will probably be inlined and then completely optimized away
                if (chunk.getChunks()[i] != null) {
                    existingChunk.getChunks()[i] = chunk.getChunks()[i];
                    changed = true;
                }
            }
            return changed ? existingChunk : null;
        } else {
            chunks.put(chunkPosition, chunk);
            return chunk;
        }
    }

    public Column getChunk(int chunkX, int chunkZ)  {
        long chunkPosition = MathUtils.chunkPositionToLong(chunkX, chunkZ);
        return chunks.getOrDefault(chunkPosition, null);
    }

    public void updateBlock(int x, int y, int z, int block) {
        if (!cache) {
            return;
        }

        Column column = this.getChunk(x >> 4, z >> 4);
        if (column == null) {
            return;
        }

        Chunk chunk = column.getChunks()[y >> 4];
        if (chunk != null) {
            chunk.set(x & 0xF, y & 0xF, z & 0xF, block);
        }
    }

    public int getBlockAt(int x, int y, int z) {
        if (!cache) {
            return BlockTranslator.AIR;
        }

        Column column = this.getChunk(x >> 4, z >> 4);
        if (column == null) {
            return BlockTranslator.AIR;
        }

        Chunk chunk = column.getChunks()[y >> 4];
        if (chunk != null) {
            return chunk.get(x & 0xF, y & 0xF, z & 0xF);
        }

        return BlockTranslator.AIR;
    }

    public void removeChunk(int chunkX, int chunkZ) {
        if (!cache) {
            return;
        }

        long chunkPosition = MathUtils.chunkPositionToLong(chunkX, chunkZ);
        chunks.remove(chunkPosition);
    }
}