package org.spigotmc;

import org.bukkit.command.defaults.TimingsCommand;
import org.bukkit.event.HandlerList;
import org.bukkit.plugin.Plugin;
import org.bukkit.plugin.RegisteredListener;
import org.bukkit.plugin.TimedRegisteredListener;
import java.io.PrintStream;
import java.util.Collection;
import java.util.HashSet;
import java.util.List;
import java.util.Queue;
import java.util.concurrent.ConcurrentLinkedQueue;

import org.bukkit.Bukkit;
import org.bukkit.World;

/**
 * Provides custom timing sections for /timings merged.
 */
public class CustomTimingsHandler
{

    private static Queue<CustomTimingsHandler> HANDLERS = new ConcurrentLinkedQueue<CustomTimingsHandler>();
    /*========================================================================*/
    private final String name;
    private final CustomTimingsHandler parent;
    private long count = 0;
    private long start = 0;
    private long timingDepth = 0;
    private long totalTime = 0;
    private long curTickTotal = 0;
    private long violations = 0;

    public CustomTimingsHandler(String name)
    {
        this( name, null );
    }

    public CustomTimingsHandler(String name, CustomTimingsHandler parent)
    {
        this.name = name;
        this.parent = parent;
        HANDLERS.add( this );
    }

    /**
     * Prints the timings and extra data to the given stream.
     *
     * @param printStream
     */
    public static void printTimings(PrintStream printStream)
    {
        printStream.println( "Minecraft" );
        for ( CustomTimingsHandler timings : HANDLERS )
        {
            long time = timings.totalTime;
            long count = timings.count;
            if ( count == 0 )
            {
                continue;
            }
            long avg = time / count;

            printStream.println( "    " + timings.name + " Time: " + time + " Count: " + count + " Avg: " + avg + " Violations: " + timings.violations );
        }
        printStream.println( "# Version " + Bukkit.getVersion() );
        int entities = 0;
        int livingEntities = 0;
        for ( World world : Bukkit.getWorlds() )
        {
            entities += world.getEntities().size();
            livingEntities += world.getLivingEntities().size();
        }
        printStream.println( "# Entities " + entities );
        printStream.println( "# LivingEntities " + livingEntities );
    }

    /**
     * Resets all timings.
     */
    public static void reload()
    {
        if ( Bukkit.getPluginManager().useTimings() )
        {
            for ( CustomTimingsHandler timings : HANDLERS )
            {
                timings.reset();
            }
        }
        TimingsCommand.timingStart = System.nanoTime();
    }

    /**
     * Ticked every tick by CraftBukkit to count the number of times a timer
     * caused TPS loss.
     */
    public static void tick()
    {
        if ( Bukkit.getPluginManager().useTimings() )
        {
            for ( CustomTimingsHandler timings : HANDLERS )
            {
                if ( timings.curTickTotal > 50000000 )
                {
                    timings.violations += Math.ceil( timings.curTickTotal / 50000000 );
                }
                timings.curTickTotal = 0;
                timings.timingDepth = 0; // incase reset messes this up
            }
        }
    }

    /**
     * Starts timing to track a section of code.
     */
    public void startTiming()
    {
        // If second condtion fails we are already timing
        if ( Bukkit.getPluginManager().useTimings() && ++timingDepth == 1 )
        {
            start = System.nanoTime();
            if ( parent != null && ++parent.timingDepth == 1 )
            {
                parent.start = start;
            }
        }
    }

    /**
     * Stops timing a section of code.
     */
    public void stopTiming()
    {
        if ( Bukkit.getPluginManager().useTimings() )
        {
            if ( --timingDepth != 0 || start == 0 )
            {
                return;
            }
            long diff = System.nanoTime() - start;
            totalTime += diff;
            curTickTotal += diff;
            count++;
            start = 0;
            if ( parent != null )
            {
                parent.stopTiming();
            }
        }
    }

    /**
     * Reset this timer, setting all values to zero.
     */
    public void reset()
    {
        count = 0;
        violations = 0;
        curTickTotal = 0;
        totalTime = 0;
        start = 0;
        timingDepth = 0;
    }
}
