package org.onlab.onos.store.cluster.impl;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertTrue;
import static org.onlab.onos.net.MastershipRole.*;

import java.util.Map;
import java.util.Set;
import java.util.concurrent.CountDownLatch;
import java.util.concurrent.TimeUnit;

import org.junit.After;
import org.junit.AfterClass;
import org.junit.Before;
import org.junit.BeforeClass;
import org.junit.Ignore;
import org.junit.Test;
import org.onlab.onos.cluster.ClusterEventListener;
import org.onlab.onos.cluster.ClusterService;
import org.onlab.onos.cluster.ControllerNode;
import org.onlab.onos.cluster.ControllerNode.State;
import org.onlab.onos.cluster.DefaultControllerNode;
import org.onlab.onos.cluster.NodeId;
import org.onlab.onos.net.DeviceId;
import org.onlab.onos.net.device.DeviceMastershipEvent;
import org.onlab.onos.net.device.DeviceMastershipStoreDelegate;
import org.onlab.onos.net.device.DeviceMastershipTerm;
import org.onlab.onos.net.device.DeviceMastershipEvent.Type;
import org.onlab.onos.store.common.StoreManager;
import org.onlab.onos.store.common.StoreService;
import org.onlab.onos.store.common.TestStoreManager;
import org.onlab.onos.store.serializers.KryoSerializer;
import org.onlab.packet.IpPrefix;

import com.google.common.collect.Sets;
import com.hazelcast.config.Config;
import com.hazelcast.core.Hazelcast;

/**
 * Test of the Hazelcast-based distributed MastershipStore implementation.
 */
public class DistributedDeviceMastershipStoreTest {

    private static final DeviceId DID1 = DeviceId.deviceId("of:01");
    private static final DeviceId DID2 = DeviceId.deviceId("of:02");
    private static final DeviceId DID3 = DeviceId.deviceId("of:03");

    private static final IpPrefix IP = IpPrefix.valueOf("127.0.0.1");

    private static final NodeId N1 = new NodeId("node1");
    private static final NodeId N2 = new NodeId("node2");

    private static final ControllerNode CN1 = new DefaultControllerNode(N1, IP);
    private static final ControllerNode CN2 = new DefaultControllerNode(N2, IP);

    private DistributedDeviceMastershipStore dms;
    private TestDistributedDeviceMastershipStore testStore;
    private KryoSerializer serializationMgr;
    private StoreManager storeMgr;

    @BeforeClass
    public static void setUpBeforeClass() throws Exception {
    }

    @AfterClass
    public static void tearDownAfterClass() throws Exception {
    }

    @Before
    public void setUp() throws Exception {
        // TODO should find a way to clean Hazelcast instance without shutdown.
        Config config = TestStoreManager.getTestConfig();

        storeMgr = new TestStoreManager(Hazelcast.newHazelcastInstance(config));
        storeMgr.activate();

        serializationMgr = new KryoSerializer();

        dms = new TestDistributedDeviceMastershipStore(storeMgr, serializationMgr);
        dms.clusterService = new TestClusterService();
        dms.activate();

        testStore = (TestDistributedDeviceMastershipStore) dms;
    }

    @After
    public void tearDown() throws Exception {
        dms.deactivate();

        storeMgr.deactivate();
    }

    @Test
    public void getRole() {
        assertEquals("wrong role:", NONE, dms.getRole(N1, DID1));
        testStore.put(DID1, N1, true, false, true);
        assertEquals("wrong role:", MASTER, dms.getRole(N1, DID1));
        assertEquals("wrong role:", STANDBY, dms.getRole(N2, DID1));
    }

    @Test
    public void getMaster() {
        assertTrue("wrong store state:", dms.masters.isEmpty());

        testStore.put(DID1, N1, true, false, false);
        assertEquals("wrong master:", N1, dms.getMaster(DID1));
        assertNull("wrong master:", dms.getMaster(DID2));
    }

    @Test
    public void getDevices() {
        assertTrue("wrong store state:", dms.masters.isEmpty());

        testStore.put(DID1, N1, true, false, false);
        testStore.put(DID2, N1, true, false, false);
        testStore.put(DID3, N2, true, false, false);

        assertEquals("wrong devices",
                Sets.newHashSet(DID1, DID2), dms.getDevices(N1));
    }

    @Test
    public void requestRoleAndTerm() {
        //CN1 is "local"
        testStore.setCurrent(CN1);

        //if already MASTER, nothing should happen
        testStore.put(DID2, N1, true, false, false);
        assertEquals("wrong role for MASTER:", MASTER, dms.requestRole(DID2));

        //populate maps with DID1, N1 thru NONE case
        assertEquals("wrong role for NONE:", MASTER, dms.requestRole(DID1));
        assertTrue("wrong state for store:", !dms.terms.isEmpty());
        assertEquals("wrong term",
                DeviceMastershipTerm.of(N1, 0), dms.getTermFor(DID1));

        //CN2 now local. DID2 has N1 as MASTER so N2 is STANDBY
        testStore.setCurrent(CN2);
        assertEquals("wrong role for STANDBY:", STANDBY, dms.requestRole(DID2));
        assertEquals("wrong number of entries:", 2, dms.terms.size());

        //change term and requestRole() again; should persist
        testStore.increment(DID2);
        assertEquals("wrong role for STANDBY:", STANDBY, dms.requestRole(DID2));
        assertEquals("wrong term", DeviceMastershipTerm.of(N1, 1), dms.getTermFor(DID2));
    }

    @Test
    public void setMaster() {
        //populate maps with DID1, N1 as MASTER thru NONE case
        testStore.setCurrent(CN1);
        assertEquals("wrong role for NONE:", MASTER, dms.requestRole(DID1));
        assertNull("wrong event:", dms.setMaster(N1, DID1));

        //switch over to N2
        assertEquals("wrong event:", Type.MASTER_CHANGED, dms.setMaster(N2, DID1).type());
        assertEquals("wrong term", DeviceMastershipTerm.of(N2, 1), dms.getTermFor(DID1));

        //orphan switch - should be rare case
        assertEquals("wrong event:", Type.MASTER_CHANGED, dms.setMaster(N2, DID2).type());
        assertEquals("wrong term", DeviceMastershipTerm.of(N2, 0), dms.getTermFor(DID2));
        //disconnect and reconnect - sign of failing re-election or single-instance channel
        testStore.reset(true, false, false);
        dms.setMaster(N2, DID2);
        assertEquals("wrong term", DeviceMastershipTerm.of(N2, 1), dms.getTermFor(DID2));
    }

    @Test
    public void relinquishRole() {
        //populate maps with DID1, N1 as MASTER thru NONE case
        testStore.setCurrent(CN1);
        assertEquals("wrong role for NONE:", MASTER, dms.requestRole(DID1));
        //no backup, no new MASTER/event
        assertNull("wrong event:", dms.relinquishRole(N1, DID1));

        dms.requestRole(DID1);

        //add backup CN2, get it elected MASTER by relinquishing
        testStore.setCurrent(CN2);
        assertEquals("wrong role for NONE:", STANDBY, dms.requestRole(DID1));
        assertEquals("wrong event:", Type.MASTER_CHANGED, dms.relinquishRole(N1, DID1).type());
        assertEquals("wrong master", N2, dms.getMaster(DID1));

        //STANDBY - nothing here, either
        assertNull("wrong event:", dms.relinquishRole(N1, DID1));
        assertEquals("wrong role for node:", STANDBY, dms.getRole(N1, DID1));

        //all nodes "give up" on device, which goes back to NONE.
        assertNull("wrong event:", dms.relinquishRole(N2, DID1));
        assertEquals("wrong role for node:", NONE, dms.getRole(N2, DID1));
        assertEquals("wrong role for node:", NONE, dms.getRole(N1, DID1));

        assertEquals("wrong number of retired nodes", 2, dms.unusable.size());

        //bring nodes back
        assertEquals("wrong role for NONE:", MASTER, dms.requestRole(DID1));
        testStore.setCurrent(CN1);
        assertEquals("wrong role for NONE:", STANDBY, dms.requestRole(DID1));
        assertEquals("wrong number of backup nodes", 1, dms.standbys.size());

        //NONE - nothing happens
        assertNull("wrong event:", dms.relinquishRole(N1, DID2));
        assertEquals("wrong role for node:", NONE, dms.getRole(N1, DID2));

    }

    @Ignore("Ignore until Delegate spec. is clear.")
    @Test
    public void testEvents() throws InterruptedException {
        //shamelessly copy other distributed store tests
        final CountDownLatch addLatch = new CountDownLatch(1);

        DeviceMastershipStoreDelegate checkAdd = new DeviceMastershipStoreDelegate() {
            @Override
            public void notify(DeviceMastershipEvent event) {
                assertEquals("wrong event:", Type.MASTER_CHANGED, event.type());
                assertEquals("wrong subject", DID1, event.subject());
                assertEquals("wrong subject", N1, event.master());
                addLatch.countDown();
            }
        };

        dms.setDelegate(checkAdd);
        dms.setMaster(N1, DID1);
        //this will fail until we do something about single-instance-ness
        assertTrue("Add event fired", addLatch.await(1, TimeUnit.SECONDS));
    }

    private class TestDistributedDeviceMastershipStore extends
            DistributedDeviceMastershipStore {
        public TestDistributedDeviceMastershipStore(StoreService storeService,
                KryoSerializer kryoSerialization) {
            this.storeService = storeService;
            this.serializer = kryoSerialization;
        }

        //helper to populate master/backup structures
        public void put(DeviceId dev, NodeId node,
                boolean master, boolean backup, boolean term) {
            byte [] n = serialize(node);
            byte [] d = serialize(dev);

            if (master) {
                dms.masters.put(d, n);
                dms.unusable.put(d, n);
                dms.standbys.remove(d, n);
            }
            if (backup) {
                dms.standbys.put(d, n);
                dms.masters.remove(d, n);
                dms.unusable.remove(d, n);
            }
            if (term) {
                dms.terms.put(d, 0);
            }
        }

        //a dumb utility function.
        public void dump() {
            System.out.println("standbys");
            for (Map.Entry<byte [], byte []> e : standbys.entrySet()) {
                System.out.println(deserialize(e.getKey()) + ":" + deserialize(e.getValue()));
            }
            System.out.println("unusable");
            for (Map.Entry<byte [], byte []> e : unusable.entrySet()) {
                System.out.println(deserialize(e.getKey()) + ":" + deserialize(e.getValue()));
            }
        }

        //clears structures
        public void reset(boolean store, boolean backup, boolean term) {
            if (store) {
                dms.masters.clear();
                dms.unusable.clear();
            }
            if (backup) {
                dms.standbys.clear();
            }
            if (term) {
                dms.terms.clear();
            }
        }

        //increment term for a device
        public void increment(DeviceId dev) {
            Integer t = dms.terms.get(serialize(dev));
            if (t != null) {
                dms.terms.put(serialize(dev), ++t);
            }
        }

        //sets the "local" node
        public void setCurrent(ControllerNode node) {
            ((TestClusterService) clusterService).current = node;
        }
    }

    private class TestClusterService implements ClusterService {

        protected ControllerNode current;

        @Override
        public ControllerNode getLocalNode() {
            return current;
        }

        @Override
        public Set<ControllerNode> getNodes() {
            return Sets.newHashSet(CN1, CN2);
        }

        @Override
        public ControllerNode getNode(NodeId nodeId) {
            return null;
        }

        @Override
        public State getState(NodeId nodeId) {
            return null;
        }

        @Override
        public void addListener(ClusterEventListener listener) {
        }

        @Override
        public void removeListener(ClusterEventListener listener) {
        }

    }

}