package info.arandombukkitbox;

import java.util.HashMap;

import org.bukkit.Server;
import org.bukkit.World;
import org.bukkit.command.Command;
import org.bukkit.command.CommandSender;
import  org.bukkit.event.Event;
import org.bukkit.event.Event.Priority;
import org.bukkit.event.Event.Type;
import org.bukkit.event.world.ChunkLoadEvent;
import org.bukkit.event.world.ChunkUnloadEvent;
import org.bukkit.event.world.WorldListener;
import org.bukkit.plugin.PluginDescriptionFile;
import org.bukkit.plugin.PluginManager;
import org.bukkit.plugin.java.JavaPlugin;

public class ChunkManager extends JavaPlugin
{
  int count;
  int total;
  long maxMem;
  int maxChunnks;
  ChunkListener listener;
  HashMap<CommandSender, Registrant> registrants;

  public ChunkManager()
  {
    this.count = 0;
    this.total = 0;
    this.maxMem = 0L;
    this.maxChunnks = 0;
    this.listener = new ChunkListener();
    this.registrants = new HashMap();
  }

  public void onDisable() {
  }

  public void onEnable() {
    PluginDescriptionFile pdfFile = getDescription();
    System.out.println(pdfFile.getName() + " version " + pdfFile.getVersion() + " is enabled!");
    getServer().getPluginManager().registerEvent(Type.CHUNK_LOAD, this.listener, Event.Priority.Normal, this);
    getServer().getPluginManager().registerEvent(Event.Type.CHUNK_UNLOAD, this.listener, Event.Priority.Normal, this);
    this.maxMem = (long)(Runtime.getRuntime().totalMemory() * 0.9D);
    this.count = (this.total = ((World)getServer().getWorlds().get(0)).getLoadedChunks().length);
  }

  @Override
  public boolean onCommand(CommandSender sender, Command command, String commandLabel, String[] args)
  {
    String commandName = command.getName().toLowerCase();

    if ((commandName.equals("chunk")) &&
      (args.length > 0)) {
      try {
        if (args[0].equals("stats")) {
          sender.sendMessage("" + this.count + " active chunks.");
          sender.sendMessage("" + this.total + " chunks loaded since server start.");
        }
        else if (args[0].equals("getchunks")) {
          sender.sendMessage("Chunk cutoff set to " + this.maxChunnks + " chunks.");
        }
        else if (args[0].equals("getmemory")) {
          sender.sendMessage("Memory cutoff set to " + this.maxMem / 1024L / 1024L + "MB.");
        }
        else if ((args[0].equals("setchunks")) && (args.length > 1)) {
          this.maxChunnks = Integer.parseInt(args[1]);
        }
        else if ((args[0].equals("setmemory")) && (args.length > 1)) {
          this.maxMem = (Long.parseLong(args[1]) * 1024L * 1024L);
        }
        else if ((args[0].equals("register")) && (args.length > 1)) {
          this.registrants.put(sender, new Registrant(Integer.parseInt(args[1]), sender));
          sender.sendMessage("Registered you for chunk updates.");
        }
        else if (args[0].equals("unregister")) {
          this.registrants.remove(sender);
          sender.sendMessage("You will no longer get chunk updates.");
        }
        else {
          sender.sendMessage("Bad syntax");
          return false;
        }
      }
      catch (Exception e) {
        sender.sendMessage("Bad syntax");
      }
      return true;
    }

    return false;
  }

  private class Registrant
  {
    public int count;
    public int frequency;
    public CommandSender sender;

    Registrant(int frequency, CommandSender sender)
    {
      this.frequency = frequency;
      this.sender = sender;
    }
  }

  private class ChunkListener extends WorldListener
  {
    private ChunkListener()
    {
    }

    @Override
    public void onChunkLoad(ChunkLoadEvent event)
    {
      ChunkManager.this.count += 1;
      ChunkManager.this.total += 1;
      for (ChunkManager.Registrant registrant : ChunkManager.this.registrants.values()) {
        registrant.count += 1;
        if (registrant.count % registrant.frequency == 0)
          registrant.sender.sendMessage("Chunks - Current: " + ChunkManager.this.count + ", Total: " + ChunkManager.this.total);
      }
    }

    @Override
    public void onChunkUnload(ChunkUnloadEvent event)
    {
      Runtime runtime = Runtime.getRuntime();
      long mem = runtime.totalMemory() - runtime.freeMemory();
      if ((ChunkManager.this.count < ChunkManager.this.maxChunnks) && (mem < runtime.totalMemory())) {
        event.setCancelled(true);
        return;
      }
      ChunkManager.this.count -= 1;
      for (ChunkManager.Registrant registrant : ChunkManager.this.registrants.values()) {
        registrant.count += 1;
        if (registrant.count % registrant.frequency == 0)
          registrant.sender.sendMessage("Chunks - Current: " + ChunkManager.this.count + ", Total: " + ChunkManager.this.total);
      }
    }
  }
}