/*
 * Copyright (c) "Neo4j"
 * Neo4j Sweden AB [http://neo4j.com]
 *
 * This file is part of Neo4j.
 *
 * Neo4j is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package org.neo4j.internal.recordstorage;

import static java.lang.reflect.Modifier.isAbstract;
import static java.util.Arrays.asList;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertNull;

import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import org.junit.jupiter.api.Test;
import org.neo4j.internal.recordstorage.Command.NodeCountsCommand;
import org.neo4j.internal.recordstorage.Command.RelationshipCountsCommand;
import org.neo4j.internal.schema.IndexDescriptor;
import org.neo4j.internal.schema.IndexPrototype;
import org.neo4j.internal.schema.SchemaDescriptors;
import org.neo4j.io.fs.ReadPastEndException;
import org.neo4j.kernel.impl.store.record.DynamicRecord;
import org.neo4j.kernel.impl.store.record.LabelTokenRecord;
import org.neo4j.kernel.impl.store.record.MetaDataRecord;
import org.neo4j.kernel.impl.store.record.NeoStoreRecord;
import org.neo4j.kernel.impl.store.record.NodeRecord;
import org.neo4j.kernel.impl.store.record.PropertyKeyTokenRecord;
import org.neo4j.kernel.impl.store.record.PropertyRecord;
import org.neo4j.kernel.impl.store.record.RelationshipRecord;
import org.neo4j.kernel.impl.store.record.RelationshipTypeTokenRecord;
import org.neo4j.kernel.impl.store.record.SchemaRecord;
import org.neo4j.kernel.impl.transaction.log.InMemoryClosableChannel;
import org.neo4j.storageengine.api.RelationshipDirection;
import org.neo4j.storageengine.api.StorageCommand;
import org.neo4j.test.LatestVersions;

/**
 * At any point, a power outage may stop us from writing to the log, which means that, at any point, all our commands
 * need to be able to handle the log ending mid-way through reading it.
 */
class LogTruncationTest {
    private final InMemoryClosableChannel inMemoryChannel = new InMemoryClosableChannel();
    private final LogCommandSerialization serialization =
            RecordStorageCommandReaderFactory.INSTANCE.get(LatestVersions.LATEST_KERNEL_VERSION);
    /** Stores all known commands, and an arbitrary set of different permutations for them */
    private final Map<Class<?>, Command[]> permutations = new HashMap<>();

    {
        NeoStoreRecord after = new NeoStoreRecord();
        after.setNextProp(42);
        permutations.put(Command.NodeCommand.class, new Command[] {
            new Command.NodeCommand(
                    serialization,
                    new NodeRecord(12).initialize(false, 13, false, 13, 0),
                    new NodeRecord(0).initialize(false, 0, false, 0, 0))
        });
        RelationshipRecord relationship = new RelationshipRecord(1);
        relationship.setLinks(2, 3, 4);
        permutations.put(Command.RelationshipCommand.class, new Command[] {
            new Command.RelationshipCommand(serialization, new RelationshipRecord(1), relationship)
        });
        permutations.put(Command.PropertyCommand.class, new Command[] {
            new Command.PropertyCommand(
                    serialization,
                    new PropertyRecord(1, new NodeRecord(12).initialize(false, 13, false, 13, 0)),
                    new PropertyRecord(1, new NodeRecord(12).initialize(false, 13, false, 13, 0)))
        });
        permutations.put(Command.RelationshipGroupCommand.class, new Command[] {
            new Command.LabelTokenCommand(serialization, new LabelTokenRecord(1), createLabelTokenRecord(1))
        });
        IndexDescriptor schemaRule = IndexPrototype.forSchema(SchemaDescriptors.forLabel(3, 4))
                .withName("index_1")
                .materialise(1);
        permutations.put(Command.SchemaRuleCommand.class, new Command[] {
            new Command.SchemaRuleCommand(
                    serialization,
                    new SchemaRecord(1).initialize(true, 41),
                    new SchemaRecord(1).initialize(true, 42),
                    schemaRule),
            new Command.SchemaRuleCommand(
                    serialization, new SchemaRecord(1), new SchemaRecord(1).initialize(true, 42), schemaRule),
            new Command.SchemaRuleCommand(
                    serialization, new SchemaRecord(1).initialize(true, 41), new SchemaRecord(1), null),
            new Command.SchemaRuleCommand(serialization, new SchemaRecord(1), new SchemaRecord(1), null),
        });
        permutations.put(Command.RelationshipTypeTokenCommand.class, new Command[] {
            new Command.RelationshipTypeTokenCommand(
                    serialization, new RelationshipTypeTokenRecord(1), createRelationshipTypeTokenRecord(1))
        });
        permutations.put(Command.PropertyKeyTokenCommand.class, new Command[] {
            new Command.PropertyKeyTokenCommand(
                    serialization, new PropertyKeyTokenRecord(1), createPropertyKeyTokenRecord(1))
        });
        permutations.put(Command.LabelTokenCommand.class, new Command[] {
            new Command.LabelTokenCommand(serialization, new LabelTokenRecord(1), createLabelTokenRecord(1))
        });
        permutations.put(Command.MetaDataCommand.class, new Command[] {
            new Command.MetaDataCommand(serialization, new MetaDataRecord(), new MetaDataRecord().initialize(true, 123))
        });

        // Counts commands
        permutations.put(NodeCountsCommand.class, new Command[] {new NodeCountsCommand(serialization, 42, 11)});
        permutations.put(
                RelationshipCountsCommand.class,
                new Command[] {new RelationshipCountsCommand(serialization, 17, 2, 13, -2)});
        permutations.put(
                Command.GroupDegreeCommand.class,
                new Command[] {new Command.GroupDegreeCommand(serialization, 42, RelationshipDirection.OUTGOING, 1)});

        // CDC - empty permutation as the read/write behaviour is different for enrichment commands
        permutations.put(Command.RecordEnrichmentCommand.class, new Command[0]);
    }

    @Test
    void testSerializationInFaceOfLogTruncation() throws Exception {
        for (Command cmd : enumerateCommands()) {
            assertHandlesLogTruncation(cmd);
        }
    }

    private Iterable<Command> enumerateCommands() {
        // We use this reflection approach rather than just iterating over the permutation map to force developers
        // writing new commands to add the new commands to this test. If you came here because of a test failure from
        // missing commands, add all permutations you can think of the command to the permutations map in the
        // beginning of this class.
        List<Command> commands = new ArrayList<>();
        for (Class<?> cmd : Command.class.getClasses()) {
            if (Command.class.isAssignableFrom(cmd)) {
                if (permutations.containsKey(cmd)) {
                    commands.addAll(asList(permutations.get(cmd)));
                } else if (!isAbstract(cmd.getModifiers())) {
                    throw new AssertionError("Unknown command type: " + cmd + ", please add missing instantiation to "
                            + "test serialization of this command.");
                }
            }
        }
        return commands;
    }

    private void assertHandlesLogTruncation(Command cmd) throws IOException {
        inMemoryChannel.reset();
        cmd.serialize(inMemoryChannel);
        int bytesSuccessfullyWritten = inMemoryChannel.writerPosition();
        try {
            StorageCommand command = serialization.read(inMemoryChannel);
            assertEquals(cmd, command);
        } catch (Exception e) {
            throw new AssertionError("Failed to deserialize " + cmd + ", because: ", e);
        }
        bytesSuccessfullyWritten--;
        while (bytesSuccessfullyWritten-- > 0) {
            inMemoryChannel.reset();
            cmd.serialize(inMemoryChannel);
            inMemoryChannel.truncateTo(bytesSuccessfullyWritten);
            StorageCommand command = null;
            try {
                command = serialization.read(inMemoryChannel);
            } catch (ReadPastEndException e) {
                assertNull(
                        command,
                        "Deserialization did not detect log truncation!" + "Record: " + cmd + ", deserialized: "
                                + command);
            }
        }
    }

    @Test
    void testInMemoryLogChannel() throws Exception {
        InMemoryClosableChannel channel = new InMemoryClosableChannel();
        for (int i = 0; i < 25; i++) {
            channel.putInt(i);
        }
        for (int i = 0; i < 25; i++) {
            assertEquals(i, channel.getInt());
        }
        channel.reset();
        for (long i = 0; i < 12; i++) {
            channel.putLong(i);
        }
        for (long i = 0; i < 12; i++) {
            assertEquals(i, channel.getLong());
        }
        channel.reset();
        for (long i = 0; i < 8; i++) {
            channel.putLong(i);
            channel.putInt((int) i);
        }
        for (long i = 0; i < 8; i++) {
            assertEquals(i, channel.getLong());
            assertEquals(i, channel.getInt());
        }
        channel.close();
    }

    private static LabelTokenRecord createLabelTokenRecord(int id) {
        LabelTokenRecord labelTokenRecord = new LabelTokenRecord(id);
        labelTokenRecord.setInUse(true);
        labelTokenRecord.setNameId(333);
        labelTokenRecord.addNameRecord(new DynamicRecord(43));
        return labelTokenRecord;
    }

    private static RelationshipTypeTokenRecord createRelationshipTypeTokenRecord(int id) {
        RelationshipTypeTokenRecord relationshipTypeTokenRecord = new RelationshipTypeTokenRecord(id);
        relationshipTypeTokenRecord.setInUse(true);
        relationshipTypeTokenRecord.setNameId(333);
        relationshipTypeTokenRecord.addNameRecord(new DynamicRecord(43));
        return relationshipTypeTokenRecord;
    }

    private static PropertyKeyTokenRecord createPropertyKeyTokenRecord(int id) {
        PropertyKeyTokenRecord propertyKeyTokenRecord = new PropertyKeyTokenRecord(id);
        propertyKeyTokenRecord.setInUse(true);
        propertyKeyTokenRecord.setNameId(333);
        propertyKeyTokenRecord.addNameRecord(new DynamicRecord(43));
        return propertyKeyTokenRecord;
    }
}
