/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */
package org.apache.tuscany.sca.guardian;

import java.util.LinkedList;
import java.util.List;
import java.util.Queue;
import java.util.Stack;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.osoa.sca.annotations.Init;
import org.osoa.sca.annotations.Reference;
import org.osoa.sca.annotations.Scope;
import org.osoa.sca.annotations.Destroy;
import org.osoa.sca.annotations.Service;

@Service(GuardianMember.class)
@Scope("COMPOSITE")
public class GuardianMemberImpl implements GuardianMember {

    private int participantState;
    private Stack<Context> contextList;
    private BlockingInterface service;
    private Queue<GlobalException> exceptionQueue;
    @Reference(name = "guardian_group", required = true)
    public GuardianGroup guardianGroup;
    private int id;

    public GuardianMemberImpl() {
        contextList = new Stack<Context>();
        contextList.add(Context.INIT_CONTEXT);
        exceptionQueue = new LinkedList<GlobalException>();
        participantState = GuardianGroup.NORMAL_PARTICIPANT_STATE;
    }

    @Init
    public void init() {
        guardianGroup.addGuardianMember(this);
    }

    @Destroy
    public void destroy() {
        guardianGroup.removeGuardianMember(this);
    }

    public void addException(GlobalException ex) {
        exceptionQueue.add(ex);
    }

    public void setService(BlockingInterface service) {
        this.service = service;
    }

    public Context getCurrentContext() {
        return contextList.peek();
    }

    public BlockingInterface getService() {
        return service;
    }

    public void enableContext(Context context) {
        //Update the context list with the related set of exceptions
        contextList.push(context);

        if (contextList.size() == 2) {
            JoinException ex = new JoinException();
            ex.setSignalingContext(context);
            ex.setSignalingParticipant(getParticipantIdentifier());
            gthrow(ex, null);
        }

    }

    public void removeContext() {
        if (!contextList.isEmpty()) {
            contextList.pop();
        }
    }

    //Adapt to allow a regular expression
    //If participantList is null then signal to ALL participants
    public void gthrow(GlobalExceptionInterface ex, List<String> participantList) {
        //1)Block the participant until raise an exception

        if (!(ex instanceof SuspendException)) {
            //Set the exception's parameters
            ex.setSignalingContext(getCurrentContext());
            ex.setSignalingParticipant(getParticipantIdentifier());

            guardianGroup.gthrow(ex, participantList);
        } else {
            /*if (service instanceof BlockingInterface && !service.isBlocked()) {
                service.block();
            }*/
            participantState = GuardianGroup.SUSPENDED_PARTICIPANT_STATE;
        }

        //*Is here the best place to receive such kind of msg?
        //
        //2B)When receive exception_msg from GuardianGroup do
        //   if participant is not suspended then suspend it
        //      if participant supports interrupts then
        //          interrupt it, add SuspendException in the exception_queue, and invoke checkExceptionStatus
        //      else invoke checkExceptionStatus periodically
        //
        //4)Once ALL required participants are SUSPENDED (suspended point), invoke the defined Recovery Rules
        //  4.1) recovery_rules < signaled exceptions + context_list of all participant > target context + exception to raise
        //  4.2) raise the resolved exception in each participant -> it goes to the exception_queue

    }

    public boolean propagate(GlobalExceptionInterface ex) {
        //1)Compares the current context with the exception's target context
        return !getCurrentContext().equals(ex.getTargetContext());
    }

    public void checkExceptionStatus() throws GlobalException {
        //1)Chek the exception queue
        //  1.1) if exception_queue is empty then return
        //       else if first element on the exception_queue is SuspendException then
        //          the method blocks until the next exception is received. The method raises the first non-SuspendException in the queue

        //Blocks until the state be diferent the SUSPENDED_STATE
        while (participantState == GuardianGroup.SUSPENDED_PARTICIPANT_STATE) {
            try {
                Thread.sleep(5000);                
            } catch (InterruptedException ex) {
                Logger.getLogger(GuardianMemberImpl.class.getName()).log(Level.SEVERE, null, ex);
            }
        }

        GlobalException exc;

        if ((exc = exceptionQueue.peek()) == null) {
            System.out.println(getParticipantIdentifier() + "#No exception on exception queue");
            return;
        }

        //Check if ex.targetContext() matches the participant id
        //Eg. ex.targetContext(): Main and participant id: Init.Main.Backup -> should thrown the exception
        //Test if the exception should be thrown in the target context
        for (Context c : contextList) {
            if (exc.getTargetContext().equals(c) && (c.equals(Context.INIT_CONTEXT) || c.getExceptionList().contains(exc.getClass()))) {
                System.out.println(getParticipantIdentifier() + "#Returning an exception");
                exceptionQueue.poll();
                throw exc;
            }
        }

        return;
    }

    public String getParticipantIdentifier() {
        //1) Return the participant identifier -> context list dot separated
        StringBuffer participantIdentifier = new StringBuffer();
        //id.append(this.id + "." + Context.INIT_CONTEXT.getName());
        participantIdentifier.append(this.id);
        for (int i = 0; i < contextList.size(); i++) {
            participantIdentifier.append("." + contextList.get(i).getName());
        }
        return participantIdentifier.toString();
    }

    public void setUniqueParticipantID(int id) {
        this.id = id;
    }

    public void removeService() {
        this.service = null;
    }

    public int getParticipantState() {
        return participantState;
    }

    public void setParticipantState(int state) {
        this.participantState = state;
    }
}