package rep;

import java.io.IOException;
import java.net.InetSocketAddress;
import java.nio.channels.ClosedChannelException;
import java.nio.channels.SelectionKey;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
import java.util.Set;
import java.util.concurrent.BlockingQueue;
import java.util.concurrent.LinkedBlockingQueue;


import rep.channel.REPServerSocketChannel;
import rep.channel.REPSocketChannel;
import rep.handler.PacketSet;
import rep.handler.REPHandler;
import rep.handler.REPHandlerImpl;
import rep.handler.REPHandlerInMerge;
import rep.channel.REPSelector;
import rep.xml.SessionXMLDecoder;
import rep.xml.SessionXMLEncoder;
import rep.channel.REPSelectionKey;

/*
	+-------+--------+--------+-------+--------+---------+------+
	| cmd   | session| editor | seqid | lineno | textsiz | text |
	|       | id     | id     |       |        |         |      |
	+-------+--------+--------+-------+--------+---------+------+
	o---------- header section (network order) ----------o
	
	int cmd;		kind of command
	int sid;		session ID : uniqu to editing file
	int eid;		editor ID : owner editor ID = 1。Session に対して unique
	                -1 session manager command
	                -2 merge command
	int seqno;		Sequence number : sequence number はエディタごとに管理
	int lineno;		line number
	int textsize;   textsize : bytesize
	byte[] text;
*/

public class SessionManager implements SessionManagerEventListener{
	
	private LinkedList<Session> sessionList;
	private SessionManagerGUI gui;
	private REPSelector<REPCommand> selector;
	private SessionManagerList smList;
	private List<Editor> editorList;
	// editorList は、sessionList に入っているeditorとは別なeditorのlistらしい。
	private String maxHost;
	private List<PacketSet> waitingCommandInMerge;
	REPHandler normalHandler = new REPHandlerImpl(this);
	REPHandler handlerInMerge =new REPHandlerInMerge(this); 
	private BlockingQueue<SessionManagerEvent> waitingEventQueue = new LinkedBlockingQueue<SessionManagerEvent>();;
	private String myHost;
	private static int receive_port;
	private static int parent_port;
	static final int DEFAULT_PORT = 8766;
	
	
	public void openSelector() throws IOException{
		selector = REPSelector.<REPCommand>create();
	}

	public void init(int port, SessionManagerGUI gui) throws IOException, InterruptedException {
		this.gui = gui;
		openSelector();
		init(port);
		mainLoop(); 
	}


	private void init(int port) throws InterruptedException, IOException {
	
		REPServerSocketChannel<REPCommand> ssc = REPServerSocketChannel.<REPCommand>open(new REPCommandPacker());
		ssc.configureBlocking(false);	//reuse address 必須
		ssc.socket().setReuseAddress(true);
		//getAllByNameで取れた全てのアドレスに対してbindする
		ssc.socket().bind(new InetSocketAddress(port));
		ssc.register(selector, SelectionKey.OP_ACCEPT, normalHandler);

		sessionList = new LinkedList<Session>();
		smList = new SessionManagerList();
		editorList = new LinkedList<Editor>();
		waitingCommandInMerge = new LinkedList<PacketSet>();
		

	}
	
	/*
	 * We wrote everything in one thread, but we can assign
	 * one thread for each communication channel and GUI event.
	 */

	public void mainLoop() throws IOException {
		while(true){
			if (checkInputEvent() ||
			    checkWaitingWrite() || 
			    checkWaitingCommandInMerge()) {
				   // try to do fair execution for waiting task
				   if(selector.selectNow() > 0) select();
				   continue;
			}
			// now we can wait for input packet or event
			selector.select();
			select();
		}
	}

	private boolean checkInputEvent() {
		SessionManagerEvent e;
		if((e = waitingEventQueue.poll())!=null){
			e.exec();
			return true;
		}
		return false;
	}

	private boolean checkWaitingWrite() throws IOException {
		for(Session s:sessionList) {
			for(Editor editor: s.getEditorList()) 
				if (editor.doWaitingWrite()) return true;
		}
		return false;
	}

	/**
	 * Check waiting command in merge
	 * @return true if there is a processed waiting command
	 * @throws IOException
	 */
	private boolean checkWaitingCommandInMerge() throws IOException {
		for(Iterator<PacketSet> it = waitingCommandInMerge.iterator(); it.hasNext();){
			PacketSet p = it.next();
			if(p.getEditor().isMerging()) { // still merging do nothing
				continue;
			}else{
				// process one command and return true
				manage(p.channel, p.command);
				it.remove();
				return true;
			}
		}
		return false;
	}

	private void select() throws IOException {
		
		Set<REPSelectionKey<REPCommand>> keys = selector.selectedKeys1();
		for(REPSelectionKey<REPCommand> key : keys){
			if(key.isAcceptable()){
				REPSocketChannel<REPCommand> channel = key.accept(new REPCommandPacker());
				System.out.println("SessionManager.select() : key.isAcceptable : channel = " + channel);
				registerChannel (channel, SelectionKey.OP_READ);
				channel = null;

			}else if(key.isReadable()){
				REPHandler handler = (REPHandler)(key.attachment());
				try {
					handler.handle(key);
				} catch (ClosedChannelException x) {
					key.cancel();
					handler.cancel(key.channel1());
				} catch (IOException x) {
					key.cancel();
					handler.cancel( key.channel1());
				}
			}
		}
	}
	
	private void registerChannel(REPSocketChannel<REPCommand> channel, int ops) throws IOException {
		if(channel == null) {
			return;
		}
		channel.configureBlocking(false);
		REPHandler handler = normalHandler;
		channel.register(selector, ops, handler);
	}

	public void manage(REPSocketChannel<REPCommand> channel, REPCommand receivedCommand) throws IOException {
		if(receivedCommand == null) return;
		//Session session;
		REPCommand sendCommand = new REPCommand(receivedCommand);
		REPSocketChannel<REPCommand> send = channel;

		switch(receivedCommand.cmd){

		case SMCMD_JOIN:
		{
			//どのSessionにも属さないエディタをリストに追加
			//エディタとchannelは1対1
			//エディタが新しくputする場合は新しくソケットを作る
			Editor editor = new Editor(editorList.size(), channel);
			editor.setHost(myHost);
			editorList.add(editor);

			updateGUI();

		}

		break;

		case SMCMD_JOIN_ACK:
			assert (false);
			break;

		case SMCMD_PUT:
		{
			//エディタのリストに追加
			Editor editor = new Editor(editorList.size(), channel);
			//editorList.add(editor);

			//Sessionを生成
			int sid = sessionList.size();
			editor = new Editor(0, channel);
			editor.setHost(myHost);
			Session session = new Session(sid, receivedCommand.string, editor);
			session.hasOwner(true);
			sessionList.add(session);

			updateGUI();

			//エディタにAckを送信
			sendCommand.setCMD(REP.SMCMD_PUT_ACK);
			sendCommand.setEID(editor.getEID());
			sendCommand.setSID(session.getSID());
			editor.send(sendCommand);

			//他のSessionManagerへSessionの追加を報告
			//親に送って、親から子へ
			SessionXMLEncoder sessionEncoder = new SessionXMLEncoder(session);
			REPCommand command = new REPCommand();
			command.setSID(session.getSID());
			command.setString(sessionEncoder.sessionListToXML());
			command.setCMD(REP.SMCMD_UPDATE);
			smList.sendExcept(channel, command);

		}

		break;

		case SMCMD_SELECT:
		{
			//他のSessionManagerをエディタとしてSessionに追加
			Editor editor = new Editor(channel);
			Session session = getSession(receivedCommand.sid);
			session.addEditor(editor);

			if(session.hasOwner()){
				//このSessionManagerがオーナーを持っている場合、Sessionにエディタを追加し、エディタへAckを返す
				sendCommand.setCMD(REP.SMCMD_SELECT_ACK);
				sendCommand.setEID(editor.getEID());
				editor.send(sendCommand);
			}else{
				//オーナーを持ってない場合は、オーナーを持っているSessionManagerへSELECTコマンドを中継する
				Editor owner = session.getOwner();
				owner.send(receivedCommand);
			}
		}

		break;

		case SMCMD_SELECT_ACK:
		{
			String hostport = receivedCommand.string;
			Editor editor = getEditor(hostport);

			if(editor != null) {
				//host, port を見て、このコマンドが自分が送信したSelectコマンドのAckかどうかを判断する
				REPCommand command = new REPCommand();
				command.setCMD(REP.SMCMD_JOIN_ACK);
				command.setSID(receivedCommand.sid);
				command.setEID(receivedCommand.eid);
				editor.send(command);

			}else{
				//自分が送信したコマンドでなければ、次のSessionManagerへ中継する
				smList.sendExcept(channel, receivedCommand);
			}
		}

		break;

		case SMCMD_SM_JOIN:

		{
			//SessionManagerのリストへ追加
			smList.add(channel);

			//XMLからSessionListオブジェクトを生成する。
			SessionXMLDecoder decoder = new SessionXMLDecoder();
			SessionList receivedSessionList = decoder.decode(receivedCommand.string);

			//myHost を設定。
			//立ち上げ時にやるとlocalhostしか取れない
			if(myHost == null) setMyHostName(getLocalHostName(channel));

			//maxHost を設定。
			if(setMaxHost(channel, receivedSessionList.getMaxHost())){
				sendCommand = new REPCommand();
				sendCommand.setCMD(REP.SMCMD_CH_MASTER);
				sendCommand.setString(maxHost);
				smList.sendExcept(channel, sendCommand);
			}

			//SessionListからXMLを生成。
			//joinしてきたSessionManagerに対してACKを送信。
			SessionXMLEncoder sessionlistEncoder = new SessionXMLEncoder(sessionList);
			sendCommand = new REPCommand();
			sendCommand.setCMD(REP.SMCMD_SM_JOIN_ACK);
			sendCommand.setString(sessionlistEncoder.sessionListToXML());
			send.write(sendCommand);

			//その他の SessionManager に対して SMCMD_UPDATEを 送信。
			sendCommand = new REPCommand();
			sendCommand.setCMD(REP.SMCMD_UPDATE);
			sendCommand.setString(receivedCommand.string);
			smList.sendExcept(channel, sendCommand);

		}
		break;

		case SMCMD_SM_JOIN_ACK:

			//XMLからSessionListオブジェクトを生成。
			SessionXMLDecoder decoder2 = new SessionXMLDecoder();
			SessionList receivedSessionList2 = decoder2.decode(receivedCommand.string);

			//maxHostを決定。
			if(setMaxHost(channel, receivedSessionList2.getMaxHost())){
				sendCommand = new REPCommand();
				sendCommand.setCMD(REP.SMCMD_CH_MASTER);
				sendCommand.setString(maxHost);
				smList.sendExcept(channel, sendCommand);
			}

			break;

		case SMCMD_UPDATE:
		{
			SessionXMLDecoder decoder3 = new SessionXMLDecoder();
			SessionList receivedSessionList3 = decoder3.decode(receivedCommand.string);

			//UPDATEコマンドにより送られてきたSessionの情報を追加する
			LinkedList<Session> list = receivedSessionList3.getList();
			for(Session session : list){
				session.getEditorList().get(0).setChannel(channel);
				sessionList.add(session);
			}

			//他のSessionManagerへ中継する
			smList.sendExcept(channel, receivedCommand);

			//リストのコピーをGUIに渡す
			LinkedList<Session> sList = new LinkedList<Session>(sessionList);
			LinkedList<Editor> eList = new LinkedList<Editor>(editorList);
			//GUIに反映
			Runnable doRun = new DoGUIUpdate(sList, eList, gui);
			gui.invokeLater(doRun);
		}
			break;

		case SMCMD_UPDATE_ACK:
		{
			if(receivedCommand.sid > sessionList.size()){
				Editor editor = new Editor(channel);
				editor.setName(receivedCommand.string);

				Session session = new Session(editor);
				session.addEditor(editor);

				sessionList.add(session);
				
				//リストのコピーをGUIに渡す
				LinkedList<Session> sList = new LinkedList<Session>(sessionList);
				LinkedList<Editor> eList = new LinkedList<Editor>(editorList);
				//GUIに反映
				Runnable doRun = new DoGUIUpdate(sList, eList, gui);
				gui.invokeLater(doRun);
			}
			smList.sendToSlave(receivedCommand);
		}
			break;

		case SMCMD_CH_MASTER:
		{
			//maxHost を設定。
			if(setMaxHost(channel, receivedCommand.string)){
				sendCommand = new REPCommand();
				sendCommand.setCMD(REP.SMCMD_CH_MASTER);
				sendCommand.setString(maxHost);
				smList.sendExcept(channel, sendCommand);
			}
		}
			break;

		case REPCMD_DELETE:
		case REPCMD_INSERT:
		case REPCMD_NOP:
		{
			// sid から Session を取得
			Session session = getSession(receivedCommand.sid);
			if (session==null) throw new IOException();
			// 次のエディタへコマンドを送信する処理
			Editor editor = session.getEditor(channel);
			boolean old = editor.isMerging();
			session.translate(channel, receivedCommand);
			if(editor.isMerging()!=old){
				assert(old==false);
				REPCommand mergeEnd = new REPCommand(REP.SMCMD_END_MERGE,receivedCommand.sid,editor.getEID(),editor.seq(),0,"");
				editor.send(mergeEnd);
				Editor prevEditor = session.getPrevEditor(editor);
				setNormalState(prevEditor.getChannel(), session.getSID());
			}
			break;
		}
		case SMCMD_START_MERGE_ACK:
		{
			// sid から Session を取得
			Session session = getSession(receivedCommand.sid);
			if (session==null) throw new IOException();
			// マージの処理と次のエディタへコマンドを送信する処理
			Editor editor = session.getEditor(channel);
			if (editor.merge(receivedCommand)) {
				//マージ中のエディタはコマンドを受け取らない
				Editor prevEditor = session.getPrevEditor(editor);
				setMergeState(prevEditor.getChannel(), session.getSID());
			}
			break;
		}
		case SMCMD_QUIT:
		{
			Session session = getSession(receivedCommand.sid);
			if (session==null) throw new IOException();
			session.sendToNextEditor(channel,receivedCommand);
			break;
		}
		case SMCMD_QUIT_2:
		{
			Session session = getSession(receivedCommand.sid);
			if (session==null) throw new IOException();
			Editor editor = session.getEditor(channel);
			editor.setQuit2(receivedCommand);
			break;
		}
		default:
			assert(false);
			break;
			
		}
	}

	private void updateGUI() {
		//リストのコピーをGUIに渡す
		LinkedList<Session> sList = new LinkedList<Session>(sessionList);
		LinkedList<Editor> eList = new LinkedList<Editor>(editorList);
		//GUIに反映
		Runnable doRun = new DoGUIUpdate(sList, eList, gui);
		gui.invokeLater(doRun);
	}

	private void setNormalState(REPSocketChannel<REPCommand> channel, int sid) {
		SelectionKey key = channel.keyFor(selector);
		key.attach(normalHandler);
	}

	private void setMergeState(REPSocketChannel<REPCommand> channel, int sid) {
		SelectionKey key = channel.keyFor(selector);
		key.attach(handlerInMerge);
	}

	private Editor getEditor(String hostport) {
		for(Editor editor : editorList){
			if(editor.getHost() == hostport){
				return editor;
			}
		}
		return null;
	}
	
	public Session getSession(int sid) {
		for(Session session : sessionList){
			if(session.getSID() == sid) return session;
		}
		return null;
	}

	private boolean setMaxHost(REPSocketChannel<REPCommand> channel, String maxHost2) {
		if(maxHost.compareTo(maxHost2) > 0){
			return false;
		}else{
			maxHost = maxHost2;
			return true;
		}
	}

	private void setMyHostName(String localHostName) {
		myHost = localHostName + receive_port;
		if(maxHost == null) {
			maxHost = myHost;
		}
		setHostToEditor(myHost);
	}

	private void setHostToEditor(String myHost2) {
		for(Editor editor : editorList){
			editor.setHost(myHost2);
		}
	}

	public static void main(String[] args) throws InterruptedException, IOException {
		
		int port = DEFAULT_PORT;
		int port_s = DEFAULT_PORT;
		//System.setProperty("file.encoding", "UTF-8");
		if(args.length > 0){
			port = Integer.parseInt(args[0]);
			port_s = Integer.parseInt(args[1]);
		}
		receive_port = port;
		parent_port = port_s;
		SessionManager sm = new SessionManager();
		sm.init(port,new SessionManagerGUIimpl(sm));
		

	}

	public void connectSession(String host) {
		int port = DEFAULT_PORT;
		port = parent_port;
		InetSocketAddress addr = new InetSocketAddress(host, port);
		try {
			REPSocketChannel<REPCommand> sessionchannel = REPSocketChannel.<REPCommand>create(new REPCommandPacker());
			sessionchannel.configureBlocking(true);
			sessionchannel.connect(addr);
			while(!sessionchannel.finishConnect()){
				System.out.print("test afro");
			}
			System.out.println("");
			registerChannel(sessionchannel, SelectionKey.OP_READ);
			
			sm_join(sessionchannel);
			
		}catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	private void sm_join(REPSocketChannel<REPCommand> channel){
		
		//SM_JOINコマンドを生成。
		REPCommand command = new REPCommand();
		command.setCMD(REP.SMCMD_SM_JOIN);
		
		//hostnameをセット。
		setMyHostName(getLocalHostName(channel));
		
		//XMLを生成。送信コマンドにセット。
		SessionXMLEncoder encoder = new SessionXMLEncoder(sessionList);
		String string = encoder.sessionListToXML();
		command.setString(string);
		
		//SM_JOINコマンドを送信。
		channel.write(command);
		//SessionManagerのListに追加。
		smList.add(channel);
	}

	private String getLocalHostName(REPSocketChannel<?> channel) {
		String host = null;
		host = channel.socket().getLocalAddress().getHostName();
		return host;
	}

	public void selectSession(SelectButtonEvent event) {
		REPSocketChannel<REPCommand> channel = event.getEditorChannel();
		int sid = event.getSID();
		int eid = event.getEID();
		Session session = getSession(sid);
		
		Editor editor = editorList.get(eid);
		if(editor == null){
			System.out.println("SessionManager.selectSession():editor = " + editor);
			return;
		}

		session.addEditor(editor);
		
		System.out.println("SessionManager.session.hasOnwer="+session.hasOwner());
		if(session.hasOwner()){
			REPCommand sendCommand = new REPCommand();
			sendCommand.setCMD(REP.SMCMD_JOIN_ACK);
			sendCommand.setEID(editor.getEID());
			sendCommand.setSID(sid);
			sendCommand.string = "";
			channel.write(sendCommand);
		}else {
			sid = event.getSID();
			editor = new Editor(channel);
			editor.setHost(myHost);
			session = getSession(sid);
			session.addEditor(editor);
			
			Editor owner = session.getOwner();
			
			REPCommand command = new REPCommand();
			command.setCMD(REP.SMCMD_SELECT);
			command.setSID(sid);
			command.setString(editor.getHost());
			owner.send(command);
		}
	}

	public void addWaitingCommand(PacketSet set) {
		waitingCommandInMerge.add(set);
	}

	public void buttonPressed(SessionManagerEvent event) {
		try {
			waitingEventQueue.put(event);
		} catch (InterruptedException e) {}
		selector.wakeup();
	}
	
	public void syncExec(SessionManagerEvent event) {
		try {
			waitingEventQueue.put(event);
		} catch (InterruptedException e) {
		}
	}

	public void closeSession(SessionManagerEvent event) {
		Session session = ((CloseButtonEvent) event).getSession();
		session.closeSession();
		sessionList.remove(session);
		updateGUI();
	}

	public void remove(REPSocketChannel<REPCommand> channel) {
		for(Session s:sessionList) {
			if (s.deleteEditor(channel)) {
				return ;
			}
		}
		assert(false);
		// can be other session manager? what should I do?
	}

}