Plex/src/main/java/dev/plex/world/CustomWorld.java

package dev.plex.world;

import dev.plex.Plex;
import java.io.File;
import java.util.Objects;
import net.kyori.adventure.text.Component;
import org.bukkit.Material;
import org.bukkit.World;
import org.bukkit.WorldCreator;
import org.bukkit.block.Block;
import org.bukkit.block.BlockState;
import org.bukkit.block.Sign;
import org.bukkit.generator.ChunkGenerator;

public class CustomWorld extends WorldCreator
{
    private static final Plex plugin = Plex.get();

    private final CustomChunkGenerator chunks;

    public CustomWorld(String name, CustomChunkGenerator generator)
    {
        super(name);
        this.chunks = generator;
        this.generator(this.chunks);
    }

    public static World generateConfigFlatWorld(String name)
    {
        if (!plugin.config.contains("worlds." + name))
        {
            return null;
        }
        CustomWorld customWorld = new CustomWorld(name, new ConfigurationChunkGenerator(name))
        {
            @Override
            public World generate()
            {
                boolean existed = new File(name).exists();
                World world = super.generate();
                if (!existed)
                {
                    Block block = world.getBlockAt(0, world.getHighestBlockYAt(0, 0) + 1, 0);
                    block.setType(Material.OAK_SIGN);
                    BlockState state = block.getState();
                    if (state instanceof Sign)
                    {
                        Sign sign = (Sign)state;
                        sign.line(1, Component.text(
                                Objects.requireNonNull(plugin.config.getString("worlds." + name + ".name"))));
                        sign.line(2, Component.text("- 0, 0 -"));
                        sign.update();
                    }
                }
                return world;
            }
        };
        return customWorld.generate();
    }

    @Override
    public ChunkGenerator generator()
    {
        return chunks;
    }

    public World generate()
    {
        return this.createWorld();
    }
}