/*
 * Copyright (c) 2014 Cisco Systems, Inc. and others.  All rights reserved.
 *
 * This program and the accompanying materials are made available under the
 * terms of the Eclipse Public License v1.0 which accompanies this distribution,
 * and is available at http://www.eclipse.org/legal/epl-v10.html
 */
package org.opendaylight.controller.cluster.raft.behaviors;

import akka.actor.ActorRef;
import akka.actor.Props;
import akka.testkit.JavaTestKit;
import java.util.HashMap;
import java.util.Map;
import org.junit.Test;
import org.opendaylight.controller.cluster.raft.MockRaftActorContext;
import org.opendaylight.controller.cluster.raft.RaftActorContext;
import org.opendaylight.controller.cluster.raft.RaftState;
import org.opendaylight.controller.cluster.raft.messages.AppendEntriesReply;
import org.opendaylight.controller.cluster.raft.utils.DoNothingActor;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;

public class IsolatedLeaderTest  extends AbstractRaftActorBehaviorTest {

    private ActorRef leaderActor =
        getSystem().actorOf(Props.create(DoNothingActor.class));

    private ActorRef senderActor =
        getSystem().actorOf(Props.create(DoNothingActor.class));

    @Override
    protected RaftActorBehavior createBehavior(
        RaftActorContext actorContext) {
        return new Leader(actorContext);
    }

    @Override
    protected RaftActorContext createActorContext() {
        return createActorContext(leaderActor);
    }


    @Test
    public void testHandleMessageWithThreeMembers() {
        new JavaTestKit(getSystem()) {{
            String followerAddress1 = "akka://test/user/$a";
            String followerAddress2 = "akka://test/user/$b";

            MockRaftActorContext leaderActorContext = (MockRaftActorContext) createActorContext();
            Map<String, String> peerAddresses = new HashMap<>();
            peerAddresses.put("follower-1", followerAddress1);
            peerAddresses.put("follower-2", followerAddress2);
            leaderActorContext.setPeerAddresses(peerAddresses);

            IsolatedLeader isolatedLeader = new IsolatedLeader(leaderActorContext);
            assertTrue(isolatedLeader.state() == RaftState.IsolatedLeader);

            // in a 3 node cluster, even if 1 follower is returns a reply, the isolatedLeader is not isolated
            RaftActorBehavior behavior = isolatedLeader.handleMessage(senderActor,
                new AppendEntriesReply("follower-1", isolatedLeader.lastTerm() - 1, true,
                    isolatedLeader.lastIndex() - 1, isolatedLeader.lastTerm() - 1));

            assertEquals(RaftState.Leader, behavior.state());

            behavior = isolatedLeader.handleMessage(senderActor,
                new AppendEntriesReply("follower-2", isolatedLeader.lastTerm() - 1, true,
                    isolatedLeader.lastIndex() -1, isolatedLeader.lastTerm() -1 ));

            assertEquals(RaftState.Leader, behavior.state());
        }};
    }

    @Test
    public void testHandleMessageWithFiveMembers() {
        new JavaTestKit(getSystem()) {{

            String followerAddress1 = "akka://test/user/$a";
            String followerAddress2 = "akka://test/user/$b";
            String followerAddress3 = "akka://test/user/$c";
            String followerAddress4 = "akka://test/user/$d";

            MockRaftActorContext leaderActorContext = (MockRaftActorContext) createActorContext();
            Map<String, String> peerAddresses = new HashMap<>();
            peerAddresses.put("follower-1", followerAddress1);
            peerAddresses.put("follower-2", followerAddress2);
            peerAddresses.put("follower-3", followerAddress3);
            peerAddresses.put("follower-4", followerAddress4);
            leaderActorContext.setPeerAddresses(peerAddresses);

            IsolatedLeader isolatedLeader = new IsolatedLeader(leaderActorContext);
            assertEquals(RaftState.IsolatedLeader, isolatedLeader.state());

            // in a 5 member cluster, atleast 2 followers need to be active and return a reply
            RaftActorBehavior behavior = isolatedLeader.handleMessage(senderActor,
                new AppendEntriesReply("follower-1", isolatedLeader.lastTerm() - 1, true,
                    isolatedLeader.lastIndex() -1, isolatedLeader.lastTerm() -1 ));

            assertEquals(RaftState.IsolatedLeader, behavior.state());

            behavior = isolatedLeader.handleMessage(senderActor,
                new AppendEntriesReply("follower-2", isolatedLeader.lastTerm() - 1, true,
                    isolatedLeader.lastIndex() -1, isolatedLeader.lastTerm() -1 ));

            assertEquals(RaftState.Leader, behavior.state());

            behavior = isolatedLeader.handleMessage(senderActor,
                new AppendEntriesReply("follower-3", isolatedLeader.lastTerm() - 1, true,
                    isolatedLeader.lastIndex() -1, isolatedLeader.lastTerm() -1 ));

            assertEquals(RaftState.Leader, behavior.state());
        }};
    }

    @Test
    public void testHandleMessageFromAnotherLeader() {
        new JavaTestKit(getSystem()) {{
            String followerAddress1 = "akka://test/user/$a";
            String followerAddress2 = "akka://test/user/$b";

            MockRaftActorContext leaderActorContext = (MockRaftActorContext) createActorContext();
            Map<String, String> peerAddresses = new HashMap<>();
            peerAddresses.put("follower-1", followerAddress1);
            peerAddresses.put("follower-2", followerAddress2);
            leaderActorContext.setPeerAddresses(peerAddresses);

            IsolatedLeader isolatedLeader = new IsolatedLeader(leaderActorContext);
            assertTrue(isolatedLeader.state() == RaftState.IsolatedLeader);

            // if an append-entries reply is received by the isolated-leader, and that reply
            // has a term  > than its own term, then IsolatedLeader switches to Follower
            // bowing itself to another leader in the cluster
            RaftActorBehavior behavior = isolatedLeader.handleMessage(senderActor,
                new AppendEntriesReply("follower-1", isolatedLeader.lastTerm() + 1, true,
                    isolatedLeader.lastIndex() + 1, isolatedLeader.lastTerm() + 1));

            assertEquals(RaftState.Follower, behavior.state());
        }};

    }
}