package rep.handler;

import java.util.Comparator;
import java.util.LinkedList;
import java.util.List;
import java.util.TreeSet;

import rep.REP;
import rep.REPCommand;
import rep.SessionManager;
import rep.channel.REPLogger;
import rep.optimizers.REPCommandOptimizer;

public class Translator {
	public int eid;
	
	public REPCommandOptimizer optimizer;
	private LinkedList<REPCommand> unMergedCmds;
	public LinkedList<REPCommand> sentMergedList;
	boolean mergeAgain;
	public REPLogger logger = SessionManager.logger;
	boolean merge_mode = false;

	public Translator(int _eid,REPCommandOptimizer opt){
		eid = _eid;
		optimizer = opt;
		unMergedCmds = new LinkedList<REPCommand>();
		mergeAgain = false;
		sentMergedList = new LinkedList<REPCommand>();
	}

	/**
	 * New command from an editor
	 * The command is sent to the next editor
	 * @param cmd
	 * @return translated command.
	 */
	public REPCommand transSendCmd(REPCommand cmd){
		assert(cmd.eid==eid);
		unMergedCmds.addLast(cmd);
		
		//マージ中にユーザから割り込みがあった場合
		if(isMerging()){
			mergeAgain = true;
		}
		
		return cmd;
	}
	
	/**
	 * My command is returned from the session ring, and START_MERGE_ACK
	 * is returned.　At this
	 * stage my writeQueue is empty, our editor is waiting for me.
	 * Start merge process.
	 * @param cmd
	 */
	public boolean catchOwnCommand(REPNode editor, int eid){
		logger.writeLog("beforeMerge:"+unMergedCmds);
		LinkedList<REPCommand> output = new LinkedList<REPCommand>();
		TreeSet<REPCommand> cmds = new TreeSet<REPCommand>(new REPCommandComparator(eid));
		// merge queue上にあるコマンドを全部undoコマンドするのと同時に
		// sort したコマンド列を生成する
		for( REPCommand cmd0 : unMergedCmds) {
			output.add( createUndo(cmd0) );
		}
		for( REPCommand cmd0 : editor.getSentList()) {
			if (cmd0.cmd==REP.REPCMD_INSERT || cmd0.cmd==REP.REPCMD_DELETE)
				cmds.add(cmd0);
		}
		output.addAll(cmds);
		// ACKが来たものは必ず先頭
		
		// unMerged command のdeleteのundo string は、この時点で使えない。
		// Editor 側から送り返して来たものを使う必要がある。
		unMergedCmds.clear();
		logger.writeLog("outputMerge:"+output);
		return optimizedSend(editor,output);
	}

	/**
	 * Sent optimized merged command list
	 * @param editor 
	 * @param output
	 * @return if any sent commands output 
	 */
	public boolean optimizedSend(REPNode editor, LinkedList<REPCommand> output) {
		List<REPCommand> output1 = optimizer.optimize(output);
		if (output1.size()==0) {
			merge_mode = false;
			return false;
		}
		assert(sentMergedList.size()==0);
		for(REPCommand c:output1) {
			REPCommand m = new REPCommand(c);
			m.setEID(REP.MERGE_EID.id);
			m.setSEQID(editor.seq());
			sentMergedList.add(m);
			editor.send(m);
		}				
		merge_mode = true;
		return true;
	}
	
	private REPCommand createUndo(REPCommand cmd){
		REPCommand retCmd = new REPCommand(cmd);
		if (cmd.cmd==REP.REPCMD_INSERT) retCmd.cmd=REP.REPCMD_DELETE;
		else if (cmd.cmd==REP.REPCMD_DELETE) retCmd.cmd=REP.REPCMD_INSERT;
		return retCmd;
	}

	class REPCommandComparator implements Comparator<REPCommand>{
		int base;
		REPCommandComparator(int base) {
			this.base = base;
		}
		public int compare(REPCommand o1, REPCommand o2) {
			int eid1 = o1.eid-base; if (eid1<0) eid1 += Integer.MAX_VALUE;
			int eid2 = o2.eid-base; if (eid2<0) eid2 += Integer.MAX_VALUE;
			if ( eid1<eid2 ) return -1;
			if ( eid1>eid2 ) return 1;
			if ( o1.seq<o2.seq ) return -1;
			if ( o1.seq>o2.seq ) return 1;
			assert(false);
			return 0;
		}
	}
	
	/**
	 * Translate Command cmd that was received from SeMa.
	 * @param cmd the command to be translated.
	 * @return translated commannd.
	 */
	public void transReceiveCmd(REPNode nextEditor,REPCommand cmd){
		assert (cmd.eid != eid);
		unMergedCmds.addFirst(cmd);
	}

	public void setEid(int _eid){
		eid = _eid;
	}

	public boolean checkMergeConflict(REPCommand command) {
		unMergedCmds.addFirst(command);
		REPCommand prev = sentMergedList.remove();
		assert (prev.seq==command.seq);
		
		if (mergeAgain) {
			return true;
		}
		if(sentMergedList.size()==0) {
			merge_mode=false;
		}
		return false;
	}

	public void getMergeAgain(REPNode editor) {
		LinkedList<REPCommand> returnCommand = new LinkedList<REPCommand>();
		LinkedList<REPCommand> merge = new LinkedList<REPCommand>();
		LinkedList<REPCommand> conflict = new LinkedList<REPCommand>();
		for(REPCommand command : unMergedCmds) {
			returnCommand.add(createUndo(command));
		}
		for(REPCommand command : unMergedCmds) {
			if(command.eid == REP.MERGE_EID.id){
				merge.addLast(command);
			}
		}
		for(REPCommand command : unMergedCmds){
			if(command.eid == eid){
				command.eid = REP.MERGE_EID.id;
				conflict.addLast(command);
			}
		}
		unMergedCmds.clear();
		returnCommand.addAll(merge);
		returnCommand.addAll(conflict);
//		int count = 0;
//		for(REPCommand command: returnCommand) {
//			switch(command.cmd) {
//			case REPCMD_INSERT: count++; break;
//			case REPCMD_DELETE: count--; break;
//			default: assert false;
//			}
//		}
		logger.writeLog("MergeAgain ret="+returnCommand.size());
//				+" increment="+count);
		mergeAgain = false;
		optimizedSend(editor, returnCommand);
	}

	public boolean isFinished() {
		if(unMergedCmds.size() > 0) return false;
		if(sentMergedList.size() > 0) return false;
		return true;
	}

	public boolean isMerging() {
		return merge_mode;
	}

	public void startMerge(REPCommand cmd) {
		logger.writeLog("START MERGE command ="+cmd+" and top of unMergedCmds = "+ unMergedCmds.getLast());
		merge_mode = true;
	}

	public void mergeAck() {
	}



}