AlttdGriefPrevention/src/me/ryanhamshire/GriefPrevention/AutoExtendClaimTask.java

package me.ryanhamshire.GriefPrevention;

import java.util.ArrayList;

import org.bukkit.Bukkit;
import org.bukkit.ChunkSnapshot;
import org.bukkit.World.Environment;
import org.bukkit.block.Biome;

//automatically extends a claim downward based on block types detected
class AutoExtendClaimTask implements Runnable
{
    private Claim claim;
    private ArrayList<ChunkSnapshot> chunks;
    private Environment worldType;

    public AutoExtendClaimTask(Claim claim, ArrayList<ChunkSnapshot> chunks, Environment worldType)
    {
        this.claim = claim;
        this.chunks = chunks;
        this.worldType = worldType;
    }

    @Override
    public void run()
    {
        int newY = this.getLowestBuiltY();
        if(newY < this.claim.getLesserBoundaryCorner().getBlockY())
        {
            Bukkit.getScheduler().runTask(GriefPrevention.instance, new ExecuteExtendClaimTask(claim, newY));
        }
    }

    @SuppressWarnings("deprecation")
    private int getLowestBuiltY()
    {
        int y = this.claim.getLesserBoundaryCorner().getBlockY();
        
        if(this.yTooSmall(y)) return y;
        
        for(ChunkSnapshot chunk : this.chunks)
        {
            Biome biome = chunk.getBiome(0,  0);
            ArrayList<Integer> playerBlockIDs = RestoreNatureProcessingTask.getPlayerBlocks(this.worldType, biome);
            
            boolean ychanged = true;
            while(!this.yTooSmall(y) && ychanged)
            {
                ychanged = false;
                for(int x = 0; x < 16; x++)
                {
                    for(int z = 0; z < 16; z++)
                    {
                        int blockType = chunk.getBlockTypeId(x, y, z);
                        while(!this.yTooSmall(y) && playerBlockIDs.contains(blockType))
                        {
                            ychanged = true;
                            blockType = chunk.getBlockTypeId(x, --y, z);
                        }
                        
                        if(this.yTooSmall(y)) return y;
                    }
                }
            }
            
            if(this.yTooSmall(y)) return y;
        }
        
        return y;
    }

    private boolean yTooSmall(int y)
    {
        return y == 0 || y <= GriefPrevention.instance.config_claims_maxDepth;
    }
    
    //runs in the main execution thread, where it can safely change claims and save those changes
    private class ExecuteExtendClaimTask implements Runnable
    {
        private Claim claim;
        private int newY;

        public ExecuteExtendClaimTask(Claim claim, int newY)
        {
            this.claim = claim;
            this.newY = newY;
        }

        @Override
        public void run()
        {
            GriefPrevention.instance.dataStore.extendClaim(claim, newY);
        }
    }

}