package rep.handler;

import java.io.IOException;
import java.util.LinkedList;
import java.util.List;

import rep.PacketSet;
import rep.REP;
import rep.REPCommand;
import rep.ServerMainLoop;
import rep.SessionManager;
import rep.channel.REPSelectionKey;
import rep.channel.REPSocketChannel;
import rep.optimizers.*;

public class Editor extends Forwarder {

	private Translator translator;
	// REPCommands we are going to send to the next editor
	private List<REPCommand> sentList = new LinkedList<REPCommand>();
	private REPCommand quit2=null;
	private boolean merging;
	private REPCommand preMergeCommand;
	public static boolean noMergeMode=false;
	static final boolean doOptimize = true;

	public Editor(SessionManager manager,int editorNo){
		// no translator case
		super(manager, null);
	}

	public Editor(int editorNo, SessionManager manager,REPSocketChannel<REPCommand> channel){
		super(editorNo,manager,channel);
		eid = editorNo;
		REPCommandOptimizer optimizer;
		if (doOptimize) optimizer = new DeleteInsertOptimizer(); //タカノがつくったおぷてぃまいざ
		else            optimizer = new NullOptimizer();         //なにもしないけどOptimizer.
		translator = new Translator(eid,optimizer);
	}
	

	public void translate(REPCommand command){
		if (command.eid == eid){
			//エディタからの新たな編集コマンド
			if (next==this) return; // singleton case
			translator.transSendCmd(command);
			sentList.add(new REPCommand(command));
			assert(sentList.size()<limit);
			next.send(command);
			return;
		} else if (command.eid == REP.MERGE_EID.id){
			//マージコマンドが返ってきた
			if(translator.checkMergeConflict(command)){
				//マージ中にエディタからの割り込みがあった場合
				translator.getMergeAgain(this);
			}
			checkEndMerge();
		} else if (command.eid == next.getEID()){
			// 次のEditorで一周するコマンドが来た
			if (next==this) return; // singleton case
			// これは、distributed case では、うまくいかないので、送り先のforwarder で処理する。
			if (next.isDirect())
				((Editor) next).checkReturnedCommand(command);
			else
				next.send(command);
		} else {
			//他のエディタからの編集コマンド
			if (manager.hasWaitingCommand(channel)) {
				// We cannot do this operation before watingCommandQueue.
				manager.addWaitingCommand(new PacketSet(channel, this, command));
			} else if (isMerging()) { 
				manager.addWaitingCommand(new PacketSet(getChannel(), this, new REPCommand(command)));
			} else {
				switch(command.cmd) {
				case REPCMD_INSERT_ACK:
				case REPCMD_DELETE_ACK:
					startMerge(command);
					break;
				default:
					translator.transReceiveCmd(next,command);
				}
			}
		}
		return;
	}

	boolean merge(REPCommand command) {
		//マージして送信
		return translator.catchOwnCommand(this);
	}

	/**
	 * 一周して来たcommandの処理。
	 * @param command
	 */
	void checkReturnedCommand(REPCommand command) {
		REPCommand prev = sentList.remove(0);
		if (prev==null || prev.seq != command.seq || prev.eid!=command.eid) {
			String err = "Editor.checkReturnedCommand() : command = " + command + " prev=";
			err += prev==null?"null":prev.toString();
			ServerMainLoop.logger.writeLog(err);
			assert(false);
		}
		switch (command.cmd) {
		case REPCMD_INSERT_ACK:
		case REPCMD_DELETE_ACK:
			// Second Phase が終わって同期が終了。
			return;
		case REPCMD_INSERT:
			command.cmd = REP.REPCMD_INSERT_ACK;
			break;
		case REPCMD_DELETE:
			command.cmd = REP.REPCMD_DELETE_ACK;
			break;
		}
		startMerge(command);
		return;
	}

	private void startMerge(REPCommand command) {
		preMergeCommand = command;
		// merge は必須だが、EditorのCommand実装をテストするには邪魔なので、off に出来るようにする。
		if (noMergeMode) {
			endMerge();
			return;
		}
		// START_MERGE を送る
		//    送らないで良い場合もある?
		REPCommand cmd = new REPCommand(REP.SMCMD_START_MERGE,command.sid,REP.SM_EID.id,seq(),0,"");
		send(cmd);
		merging = true;
		// Session Manager 側で、このeditorへの他のeditorからの
		// 入力を止めて、merge にそなえる。merge は、eidtor 側から
		// ACKが来てから始まる。
		translator.startMerge(cmd);
	}

	@Override
	public void setQuit2(REPCommand cmd) {
		quit2 = cmd;
		checkQuit();
		// do not send quit2 until we received all pending
		// command
	}

	@Override
	public void setEID(int eid) {
		this.eid = eid;
		if (translator!=null)
			translator.setEid(eid);
	}
	
	public String toString(){
		return ("Editor eid="+eid+" sid="+sid+" " + host  + ":" + file);
	}

	public boolean isMerging() {
		return translator.isMerging();
	}

	

	void checkEndMerge() {
		if (merging) {
			if(translator.isMerging()) return;
			endMerge();
			merging = false;
		}
		if (quit2!=null) checkQuit();
	}

	private void endMerge() {
		REPCommand mergeEnd = new REPCommand(REP.SMCMD_END_MERGE,sid,eid,seq(),0,"");
		send(mergeEnd);
		// send INSERT_ACK/DELETE_ACK as next editor's merge trigger
		sentList.add(new REPCommand(preMergeCommand));
		next.send(preMergeCommand);
	}

	private boolean checkQuit() {
		if (sentList.size()==0&&!isMerging()) {
			send(quit2);
			quit2 = null;
			return true;
		}
		return false;
	}

	@Override
	public boolean manage(REPCommand command) {
		
		
		switch(command.cmd){
		// Editor Command

		case REPCMD_DELETE:
		case REPCMD_INSERT:
		case REPCMD_DELETE_ACK:
		case REPCMD_INSERT_ACK:
		case REPCMD_NOP:
		{
			translate(command);
			break;
		}

		case SMCMD_START_MERGE_ACK:
		{
			// 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
			translator.mergeAck();
			if (!merge(command)) {
				// nothing to do, send END_MERGE
				checkEndMerge();
			}
			break;
		}
		
		case SMCMD_SYNC:
			if (isMaster()) 
				send(command);
			else
				next.send(command);
			
		case SMCMD_QUIT:
		{
			next.send(command);
			break;
		}
		case SMCMD_QUIT_2:
		{
			// QUIT_2 is returned.
			if (command.eid!=eid) {
				// stop this editor unless this is the start, starter will stopped
				// by QUIT_2_ACK
				manager.remove(this);
			}
			// don't send quit_2 directly to the editor until all pending
			// merge is processed.
			//   this does not work in distributed case.
			if (next.isDirect())
				next.setQuit2(command);
			else
				next.send(command);
			break;
		}
		case SMCMD_QUIT_2_ACK:
		{
			manager.remove(this);
			break;
		}
		default:
			assert false;
			return false;
		}
		return true;
	}
	

	@Override
	public void handle(REPCommand command, REPSelectionKey<REPCommand> key) throws IOException {
		ServerMainLoop.logger.writeLog("Manager "+manager.getId()+"read : command = " + command 
				+" from "+manager.editorList.editorByChannel(channel));
		if (command.cmd==REP.SMCMD_JOIN||command.cmd==REP.SMCMD_PUT) {
			assert false;
			// 若干問題があるらしい
			next = new Forwarder(manager,next.channel);
			REPNode first = new FirstConnector(manager,channel);
			first.handle(command, key);
			key.attach(new Dispatcher(manager,channel));
			return;
		}
		if (manager.sessionManage(this, command)) return;
		manage(command);
	}

	@Override
	public void cancel(REPSocketChannel<REPCommand> socketChannel) {
		manager.remove(socketChannel);
	}

	public boolean isMaster() {
		return mode==REP.SMCMD_PUT;
	}

	
	/* Handle special case first, usually these cases
	 * are handled in the next Editor in a session manager, but 
	 * it is forwarded here.
	 */
	public void forwardedCommandManage(REPCommand command) {
		if (command.cmd==REP.SMCMD_QUIT_2) {
			// we have to wait next editor's finishing before sending this.
			// this is odd, but the editor itself does not know it's merging
			// state. Only this session manager knows it.
			setQuit2(command);
		} else if (command.eid==eid) {
			// if we handle in editor.manage(), this editor cannot distinguish this
			// and user input command from the editor.
			switch(command.cmd) {
			case REPCMD_DELETE:
			case REPCMD_INSERT:
			case REPCMD_NOP:
				checkReturnedCommand(command);
				return;
			}
		} 
		send(command);
	}

}