package serverP2P;
import java.util.Vector;
import java.io.File;
import java.io.IOException;
import java.net.InetAddress;
import java.net.SocketException;
import java.nio.file.Paths;
import java.nio.file.Files;
import java.security.MessageDigest;
import java.security.NoSuchAlgorithmException;
import java.net.ServerSocket;
import java.net.Socket;
import protocolP2P.ProtocolP2PPacketTCP;
import protocolP2P.ProtocolP2PPacket;
import protocolP2P.RequestResponseCode;
import protocolP2P.Payload;
import protocolP2P.LoadRequest;
import protocolP2P.FileList;
import protocolP2P.FilePart;
import localException.InternalError;
import localException.ProtocolError;
import localException.SizeError;
import localException.TransmissionError;
import localException.VersionError;
import localException.SocketClosed;
import exception.LocalException;
import java.util.Arrays;
import tools.Logger;
import tools.LogLevel;
import tools.HostItem;
import java.util.HashMap;
import java.util.Map;
import java.net.UnknownHostException;
import protocolP2P.HashAlgorithm;
import protocolP2P.HashRequest;
import protocolP2P.HashResponse;
import protocolP2P.Register;
import protocolP2P.Unregister;
import serverP2P.ServerManagement;
import serverP2P.FileWatcherTCP;


/** Implementation of P2P-JAVA-PROJECT VERSION 1.0 protocol for TCP.
 * @author	Louis Royer
 * @author	Flavien Haas
 * @author	JS Auge
 * @version	1.0
 */
public class ServerManagementTCP extends ServerManagement {

	private ServerSocket socket;

	/** Constructor for TCP implementation, with baseDirectory and TCPPort parameters.
	 * @param baseDirectory	the root directory where files are stored
	 * @param hostName	the server will bind on this address
	 * @param TCPPort	the server will listen on this port
	 * @param logger	Logger item
	 * @param tracker	Tracker
	 */
	public ServerManagementTCP(String baseDirectory, HostItem server, HostItem tracker, Logger logger) {
		super(baseDirectory, server, tracker, logger);
		assert baseDirectory != null : "baseDirectory is null";
		assert server != null : "server is null";
		assert tracker != null : "tracker is null";
		assert logger != null : "logger is null";
		try {
			socket = new ServerSocket(server.getPort(), 10, server.getInetAddress());
		} catch (SocketException e) {
			writeLog("Error: cannot listen on " + server, LogLevel.Error);
			System.exit(-1);
		} catch (IOException e) {
			writeLog("Error: cannot openning socket", LogLevel.Error);
			System.exit(-2);
		}
	}

	
	/** Implementation of runnable. This methods allows to run the server.
	 */
	public void run() {
		writeLog("Server sucessfully started", LogLevel.Info);
		Runtime.getRuntime().addShutdownHook(new Thread() {
			public void run() {
				sendUnregisterRequest();
			}
		});
		fileListWatcher = (FileWatcher)new FileWatcherTCP(logger, 10000, server, tracker, baseDirectory); // checking every 10 seconds
		Thread flwt = new Thread(fileListWatcher);
		flwt.start();
		fileListWatcher.setThread(flwt);
		ratioWatcher = (RatioWatcher)new RatioWatcherTCP(logger, 10000, tracker);
		Thread rwt = new Thread(ratioWatcher);
		rwt.start();
		ratioWatcher.setThread(rwt);
		while(!stop) {
			try {
				Socket s = socket.accept();
				ClientHandler c = new ClientHandler(s);
				(new Thread(c)).start();
			} catch (IOException e) {
				writeLog("Socket has been closed", LogLevel.Info);
			}
		}
		writeLog("Server end of loop", LogLevel.Debug);
	}

	/** Private runnable class allowing to serve one client.
	 */
	private class ClientHandler implements Runnable {
		private HostItem addr;
		/** Constructor with a socket.
		 * @param	s	Socket of this client
		 */
		public ClientHandler(Socket s) {
			addr = new HostItem(s);
		}

		/** Implementation of runnable. This method allow to serve one client.
		 */
		public void run() {

			boolean end = false;
			writeLog("[" + addr + "] New connection", LogLevel.Action);
			do {
				end = handleClientRequest();
			} while(!end);
			writeLog("[" + addr + "] End of connection", LogLevel.Action);
		}

		/** Respond to next request incomming on socket s.
		 * @param s	Socket used to read request and send response
		 * @return	true if cannot expect another request (ie, socket is closed)
		 */
		private boolean handleClientRequest() {
			try {
				ProtocolP2PPacketTCP<?> pd = new ProtocolP2PPacketTCP<>((Object)addr.getTCPSocket());
				handleRequest(pd);
			} catch (IOException e) {
				return true;
			} catch (SocketClosed e) {
				return true;
			}
			catch (LocalException e) {}
			return false;
		}
	}

	/** Implementation of writeLog
	 * @param text	Text to log
	 * @param logLevel	level of logging
	 */
	protected void writeLog(String text, LogLevel logLevel) {
		logger.writeTCP(text, logLevel);
	}

	/** Implementation of writeLog
	 * @param e	exception to log
	 * @param logLevel	level of logging
	 */
	protected void writeLog(Exception e, LogLevel logLevel) {
		logger.writeTCP(e, logLevel);
	}

	/** Create packets
	 * @param payload	Payload
	 */
	protected < T extends Payload > ProtocolP2PPacket<T> createProtocolP2PPacket(T payload) {
		return (ProtocolP2PPacket<T>)new ProtocolP2PPacketTCP<T>(payload);
	}

	/** Getter for tracker socket
	 * @return Tracker's socket
	 * @throws	SocketException
	 * @throws	UnknownHostException
	 * @throws	IOException
	 */
	protected Object getTrackerSocket() throws SocketException, UnknownHostException, IOException {
		return (Object)tracker.tryGetTCPSocket();
	}


	/** Closes socket */
	protected void closeSocket() {
		try {
			socket.close();
		} catch (IOException e) {
			writeLog("Could not close socket", LogLevel.Error);
		}
	}
}