/**
 * 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.activemq.store.jdbc;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import org.apache.activemq.broker.ConnectionContext;
import org.apache.activemq.command.ActiveMQDestination;
import org.apache.activemq.command.Message;
import org.apache.activemq.command.MessageAck;
import org.apache.activemq.command.MessageId;
import org.apache.activemq.command.TransactionId;
import org.apache.activemq.command.XATransactionId;
import org.apache.activemq.store.MessageStore;
import org.apache.activemq.store.ProxyTopicMessageStore;
import org.apache.activemq.store.TopicMessageStore;
import org.apache.activemq.store.TransactionRecoveryListener;
import org.apache.activemq.store.memory.MemoryTransactionStore;
import org.apache.activemq.util.ByteSequence;
import org.apache.activemq.util.DataByteArrayInputStream;

/**
 * respect 2pc prepare
 * uses local transactions to maintain prepared state
 * xid column provides transaction flag for additions and removals
 * a commit clears that context and completes the work
 * a rollback clears the flag and removes the additions
 * Essentially a prepare is an insert &| update transaction
 *  commit|rollback is an update &| remove
 */
public class JdbcMemoryTransactionStore extends MemoryTransactionStore {


    private HashMap<ActiveMQDestination, MessageStore> topicStores = new HashMap<ActiveMQDestination, MessageStore>();

    public JdbcMemoryTransactionStore(JDBCPersistenceAdapter jdbcPersistenceAdapter) {
        super(jdbcPersistenceAdapter);
    }

    @Override
    public void prepare(TransactionId txid) throws IOException {
        Tx tx = inflightTransactions.remove(txid);
        if (tx == null) {
            return;
        }

        ConnectionContext ctx = new ConnectionContext();
        // setting the xid modifies the add/remove to be pending transaction outcome
        ctx.setXid((XATransactionId) txid);
        persistenceAdapter.beginTransaction(ctx);
        try {

            // Do all the message adds.
            for (Iterator<AddMessageCommand> iter = tx.messages.iterator(); iter.hasNext();) {
                AddMessageCommand cmd = iter.next();
                cmd.run(ctx);
            }
            // And removes..
            for (Iterator<RemoveMessageCommand> iter = tx.acks.iterator(); iter.hasNext();) {
                RemoveMessageCommand cmd = iter.next();
                cmd.run(ctx);
            }

        } catch ( IOException e ) {
            persistenceAdapter.rollbackTransaction(ctx);
            throw e;
        }
        persistenceAdapter.commitTransaction(ctx);

        ctx.setXid(null);
        // setup for commit outcome
        ArrayList<AddMessageCommand> updateFromPreparedStateCommands = new ArrayList<AddMessageCommand>();
        for (Iterator<AddMessageCommand> iter = tx.messages.iterator(); iter.hasNext();) {
            final AddMessageCommand addMessageCommand = iter.next();
            updateFromPreparedStateCommands.add(new AddMessageCommand() {
                @Override
                public Message getMessage() {
                    return addMessageCommand.getMessage();
                }

                @Override
                public MessageStore getMessageStore() {
                    return addMessageCommand.getMessageStore();
                }

                @Override
                public void run(ConnectionContext context) throws IOException {
                    JDBCPersistenceAdapter jdbcPersistenceAdapter = (JDBCPersistenceAdapter) persistenceAdapter;
                    Message message = addMessageCommand.getMessage();
                    jdbcPersistenceAdapter.commitAdd(context, message.getMessageId());
                    ((JDBCMessageStore)addMessageCommand.getMessageStore()).onAdd(
                            message.getMessageId(),
                            (Long)message.getMessageId().getDataLocator(),
                            message.getPriority());

                }
            });
        }
        tx.messages = updateFromPreparedStateCommands;
        preparedTransactions.put(txid, tx);

    }


    @Override
    public void rollback(TransactionId txid) throws IOException {

        Tx tx = inflightTransactions.remove(txid);
        if (tx == null) {
            tx = preparedTransactions.remove(txid);
            if (tx != null) {
                // undo prepare work
                ConnectionContext ctx = new ConnectionContext();
                persistenceAdapter.beginTransaction(ctx);
                try {

                    for (Iterator<AddMessageCommand> iter = tx.messages.iterator(); iter.hasNext(); ) {
                        final Message message = iter.next().getMessage();
                        // need to delete the row
                        ((JDBCPersistenceAdapter) persistenceAdapter).commitRemove(ctx, new MessageAck(message, MessageAck.STANDARD_ACK_TYPE, 1));
                    }

                    for (Iterator<RemoveMessageCommand> iter = tx.acks.iterator(); iter.hasNext(); ) {
                        RemoveMessageCommand removeMessageCommand = iter.next();
                        if (removeMessageCommand instanceof LastAckCommand ) {
                            ((LastAckCommand)removeMessageCommand).rollback(ctx);
                        } else {
                            // need to unset the txid flag on the existing row
                            ((JDBCPersistenceAdapter) persistenceAdapter).commitAdd(ctx,
                                    removeMessageCommand.getMessageAck().getLastMessageId());
                        }
                    }
                } catch (IOException e) {
                    persistenceAdapter.rollbackTransaction(ctx);
                    throw e;
                }
                persistenceAdapter.commitTransaction(ctx);
            }
        }
    }

    @Override
    public void recover(TransactionRecoveryListener listener) throws IOException {
        ((JDBCPersistenceAdapter)persistenceAdapter).recover(this);
        super.recover(listener);
    }

    public void recoverAdd(long id, byte[] messageBytes) throws IOException {
        final Message message = (Message) ((JDBCPersistenceAdapter)persistenceAdapter).getWireFormat().unmarshal(new ByteSequence(messageBytes));
        message.getMessageId().setDataLocator(id);
        Tx tx = getPreparedTx(message.getTransactionId());
        tx.add(new AddMessageCommand() {
            @Override
            public Message getMessage() {
                return message;
            }

            @Override
            public MessageStore getMessageStore() {
                return null;
            }

            @Override
            public void run(ConnectionContext context) throws IOException {
                ((JDBCPersistenceAdapter)persistenceAdapter).commitAdd(null, message.getMessageId());
            }

        });
    }

    public void recoverAck(long id, byte[] xid, byte[] message) throws IOException {
        Message msg = (Message) ((JDBCPersistenceAdapter)persistenceAdapter).getWireFormat().unmarshal(new ByteSequence(message));
        msg.getMessageId().setDataLocator(id);
        Tx tx = getPreparedTx(new XATransactionId(xid));
        final MessageAck ack = new MessageAck(msg, MessageAck.STANDARD_ACK_TYPE, 1);
        tx.add(new RemoveMessageCommand() {
            @Override
            public MessageAck getMessageAck() {
                return ack;
            }

            @Override
            public void run(ConnectionContext context) throws IOException {
                ((JDBCPersistenceAdapter)persistenceAdapter).commitRemove(context, ack);
            }

            @Override
            public MessageStore getMessageStore() {
                return null;
            }

        });

    }

    interface LastAckCommand extends RemoveMessageCommand {
        void rollback(ConnectionContext context) throws IOException;

        String getClientId();

        String getSubName();

        long getSequence();

        byte getPriority();

        void setMessageStore(JDBCTopicMessageStore jdbcTopicMessageStore);
    }

    public void recoverLastAck(byte[] encodedXid, final ActiveMQDestination destination, final String subName, final String clientId) throws IOException {
        Tx tx = getPreparedTx(new XATransactionId(encodedXid));
        DataByteArrayInputStream inputStream = new DataByteArrayInputStream(encodedXid);
        inputStream.skipBytes(1); // +|-
        final long lastAck = inputStream.readLong();
        final byte priority = inputStream.readByte();
        final MessageAck ack = new MessageAck();
        ack.setDestination(destination);
        tx.add(new LastAckCommand() {
            JDBCTopicMessageStore jdbcTopicMessageStore;

            @Override
            public MessageAck getMessageAck() {
                return ack;
            }

            @Override
            public MessageStore getMessageStore() {
                return jdbcTopicMessageStore;
            }

            @Override
            public void run(ConnectionContext context) throws IOException {
                ((JDBCPersistenceAdapter)persistenceAdapter).commitLastAck(context, lastAck, priority, destination, subName, clientId);
                jdbcTopicMessageStore.complete(clientId, subName);
            }

            @Override
            public void rollback(ConnectionContext context) throws IOException {
                ((JDBCPersistenceAdapter)persistenceAdapter).rollbackLastAck(context, priority, jdbcTopicMessageStore.getDestination(), subName, clientId);
                jdbcTopicMessageStore.complete(clientId, subName);
            }

            @Override
            public String getClientId() {
                return clientId;
            }

            @Override
            public String getSubName() {
                return subName;
            }

            @Override
            public long getSequence() {
                return lastAck;
            }

            @Override
            public byte getPriority() {
                return priority;
            }

            @Override
            public void setMessageStore(JDBCTopicMessageStore jdbcTopicMessageStore) {
                this.jdbcTopicMessageStore = jdbcTopicMessageStore;
            }
        });

    }

    @Override
    protected void onProxyTopicStore(ProxyTopicMessageStore proxyTopicMessageStore) {
        topicStores.put(proxyTopicMessageStore.getDestination(), proxyTopicMessageStore.getDelegate());
    }

    @Override
    protected void onRecovered(Tx tx) {
        for (RemoveMessageCommand removeMessageCommand: tx.acks) {
            if (removeMessageCommand instanceof LastAckCommand) {
                LastAckCommand lastAckCommand = (LastAckCommand) removeMessageCommand;
                JDBCTopicMessageStore jdbcTopicMessageStore = (JDBCTopicMessageStore) topicStores.get(lastAckCommand.getMessageAck().getDestination());
                jdbcTopicMessageStore.pendingCompletion(lastAckCommand.getClientId(), lastAckCommand.getSubName(), lastAckCommand.getSequence(), lastAckCommand.getPriority());
                lastAckCommand.setMessageStore(jdbcTopicMessageStore);
            } else {
                // when reading the store we ignore messages with non null XIDs but should include those with XIDS starting in - (pending acks in an xa transaction),
                // but the sql is non portable to match BLOB with LIKE etc
                // so we make up for it when we recover the ack
                ((JDBCPersistenceAdapter)persistenceAdapter).getBrokerService().getRegionBroker().getDestinationMap().get(removeMessageCommand.getMessageAck().getDestination()).getDestinationStatistics().getMessages().increment();
            }
        }
    }

    @Override
    public void acknowledge(final TopicMessageStore topicMessageStore, final String clientId, final String subscriptionName,
                           final MessageId messageId, final MessageAck ack) throws IOException {

        if (ack.isInTransaction()) {
            Tx tx = getTx(ack.getTransactionId());
            tx.add(new LastAckCommand() {
                public MessageAck getMessageAck() {
                    return ack;
                }

                public void run(ConnectionContext ctx) throws IOException {
                    topicMessageStore.acknowledge(ctx, clientId, subscriptionName, messageId, ack);
                }

                @Override
                public MessageStore getMessageStore() {
                    return topicMessageStore;
                }

                @Override
                public void rollback(ConnectionContext context) throws IOException {
                    JDBCTopicMessageStore jdbcTopicMessageStore = (JDBCTopicMessageStore)topicMessageStore;
                    ((JDBCPersistenceAdapter)persistenceAdapter).rollbackLastAck(context,
                            jdbcTopicMessageStore,
                            ack,
                            subscriptionName, clientId);
                    jdbcTopicMessageStore.complete(clientId, subscriptionName);
                }


                @Override
                public String getClientId() {
                    return clientId;
                }

                @Override
                public String getSubName() {
                    return subscriptionName;
                }

                @Override
                public long getSequence() {
                    throw new IllegalStateException("Sequence id must be inferred from ack");
                }

                @Override
                public byte getPriority() {
                    throw new IllegalStateException("Priority must be inferred from ack or row");
                }

                @Override
                public void setMessageStore(JDBCTopicMessageStore jdbcTopicMessageStore) {
                    throw new IllegalStateException("message store already known!");
                }
            });
        } else {
            topicMessageStore.acknowledge(null, clientId, subscriptionName, messageId, ack);
        }
    }

}
