package org.openslx.taskmanager.tasks;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collection;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.Future;
import java.util.concurrent.TimeUnit;

import org.apache.logging.log4j.util.Strings;
import org.openslx.satserver.util.MessageSink;
import org.openslx.satserver.util.Util;
import org.openslx.satserver.util.WakeOnLanExecutor;
import org.openslx.taskmanager.api.AbstractTask;
import org.openslx.taskmanager.tasks.RemoteExec.Output;
import org.openslx.taskmanager.tasks.RemoteExec.Result;
import org.openslx.util.PrioThreadFactory;

import com.google.gson.annotations.Expose;

public class WakeOnLan extends AbstractTask
{

	/**
	 * List of clients to wake up
	 */
	@Expose
	private List<Machine> clients;

	/**
	 * SHH data (key, command) for waking via another host
	 */
	@Expose
	private Map<String, SshData> ssh;

	/**
	 * UDP port to send WOL packets to
	 */
	@Expose
	private int port;

	private StatusObject status;

	@Override
	protected boolean initTask()
	{
		status = new StatusObject();
		this.setStatusObject( status );
		if ( clients == null ) {
			status.addMsg( "Clients null" );
		} else {
			// Clean
			for ( Iterator<Machine> it = this.clients.iterator(); it.hasNext(); ) {
				Machine client = it.next();
				if ( client == null || Util.isEmpty( client.mac ) || Util.isEmpty( client.ip )
						|| client.methods == null || client.methods.isEmpty() ) {
					it.remove();
				}
			}
			if ( clients.isEmpty() ) {
				status.addMsg( "Clients empty" );
			}
		}
		if ( ssh == null ) {
			ssh = new HashMap<>( 1 );
		}
		if ( !Util.isEmpty( status.messages ) )
			return false;
		return true;
	}

	@Override
	protected boolean execute()
	{
		// Loop over clients until they all were handled (i.e. methods is empty)
		ExecutorService tp = Executors.newFixedThreadPool( Math.max( 1, Math.min( 4, ssh.size() ) ),
				new PrioThreadFactory( "WOL" ) );
		Map<String, ArrayList<String>> byMethod;
		int jobIdCounter = 0;
		do {
			byMethod = new HashMap<>();
			// Fetch next method for all clients
			for ( Machine client : clients ) {
				if ( client.methods.isEmpty() )
					continue;
				// Group by method and destination IP address
				String method = client.methods.remove( 0 ) + "//" + client.ip
						+ "//" + ( client.password == null ? "" : client.password );
				ArrayList<String> list = byMethod.get( method );
				if ( list == null ) {
					list = new ArrayList<>();
					byMethod.put( method, list );
				}
				list.add( client.mac );
			}
			if ( byMethod.isEmpty() )
				break;
			status.addMsg( "Starting job distribution..." );
			// Execute
			List<Future<?>> waitList = new ArrayList<>();
			for ( Entry<String, ArrayList<String>> it : byMethod.entrySet() ) {
				final String[] parts = it.getKey().split( "//" );
				final String method = parts[0];
				final List<String> macs = it.getValue(); 
				final String macString = Strings.join( macs.iterator(), ' ' );
				final String broadcastIp = parts[1];
				final String password = parts.length >= 3 ? parts[2] : "";
				final int jobId = ++jobIdCounter;
				if ( method.equalsIgnoreCase( "DIRECT" ) ) {
					// Directly from server
					waitList.add( tp.submit( () -> {
						status.addMsg( jobId + ": Waking directly from server: " + macString );
						WakeOnLanExecutor wol = new WakeOnLanExecutor( password );
						String[] success = wol.execute( status, macs, broadcastIp, this.port );
						markSuccess( Arrays.asList( success ) );
						if ( success.length == macs.size() ) {
							status.addMsg( jobId + ": Done" );
						} else {
							status.addMsg( jobId + ": Some failed" );
						}
					} ) );
				} else if ( this.ssh.containsKey( method ) ) {
					// Via SSH
					waitList.add( tp.submit( () -> {
						SshData sshData = this.ssh.get( method );
						status.addMsg( jobId + ": Waking via SSH from " + sshData.ip + " to " + broadcastIp + ": " + macString );
						String command = sshData.command.replace( "%MACS%", macString )
								.replace( "%IP%", broadcastIp )
								.replace( "%PASSWORD%", password );
						RemoteExec.Client c = new RemoteExec.Client( null, sshData.ip, sshData.port, sshData.username );
						RemoteExec task = new RemoteExec( new RemoteExec.Client[] { c }, sshData.sshkey, sshData.port, command, 5 );
						task.execute();
						Output s = task.getStatusObject();
						if ( s == null ) {
							status.addMsg( jobId + ": Task status is null, considering failed" );
						} else {
							if ( !Util.isEmpty( s.error ) ) {
								status.addMsg( s.error );
							}
							if ( s.result != null && s.result.containsKey( sshData.ip ) && s.result.get( sshData.ip ).exitCode == 0 ) {
								markSuccess( macs );
								status.addMsg( jobId + ": Done" );
							} else {
								if ( s.result != null ) {
   								for ( Result sshClient : s.result.values() ) {
   									if ( sshClient == null )
   										continue;
   									status.addMsg( jobId + ": stdout: " + sshClient.stdout + "\n" 
   											+ jobId + ": stderr: " + sshClient.stderr );
   								}
								}
								status.addMsg( jobId + ": Non-zero exit code, considering failed" );
							}
						}
					} ) );
				} else {
					status.addMsg( "Ignoring unknown SSH method '" + method + "'" );
				}
			}
			// Wait for all jobs
			for ( Future<?> f : waitList ) {
				try {
					f.get();
				} catch ( InterruptedException e ) {
					status.addMsg( "Threadpool got interrupted" );
					Thread.currentThread().interrupt();
					return false;
				} catch ( ExecutionException e ) {
					status.addMsg( "A treadpool job threw an exception" );
					e.printStackTrace();
				}
			}
		} while ( true );
		tp.shutdown();
		try {
			tp.awaitTermination( 10, TimeUnit.SECONDS );
		} catch ( InterruptedException e ) {
			Thread.currentThread().interrupt();
		}
		status.addMsg( "Mainloop done" );
		if ( this.clients.isEmpty() )
			return true;
		status.addMsg( "Failed clients:" );
		for ( Machine c : clients ) {
			status.addMsg( c.ip );
		}
		return false;
	}

	private void markSuccess( Collection<String> macs )
	{
		synchronized ( this.clients ) {
			for ( Iterator<Machine> it = this.clients.iterator(); it.hasNext(); ) {
				Machine client = it.next();
				if ( macs.contains( client.mac ) ) {
					it.remove();
				}
			}
		}
	}

	static class Machine
	{
		/**
		 * Destination IP (for directed broadcast)
		 */
		@Expose
		String ip;
		/**
		 * Destination MAC
		 */
		@Expose
		String mac;
		/**
		 * Desired WOL modes, from most to least preferred. either a key to the top level ssh map,
		 * or "DIRECT" for sending a WOL packet directly from the server
		 */
		@Expose
		List<String> methods;
		/**
		 * WOL password
		 */
		@Expose
		private String password;
	}

	static class SshData
	{
		@Expose
		String username;
		@Expose
		String sshkey;
		@Expose
		String ip;
		@Expose
		int port;
		@Expose
		String command;
	}

	/*
	 * 
	 */

	/**
	 * Return any messages about progress and status
	 */
	static class StatusObject implements MessageSink
	{
		private String messages = "";

		public synchronized void addMsg( String str )
		{
			messages = messages + "\n" + str;
		}
	}

}