/*
 * 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.bolt.txtracking;

import static java.time.Duration.ofMillis;
import static java.time.Duration.ofSeconds;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertThrows;
import static org.mockito.Mockito.doThrow;
import static org.mockito.Mockito.mock;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.verifyNoInteractions;
import static org.mockito.Mockito.when;
import static org.neo4j.kernel.api.exceptions.Status.Database.DatabaseNotFound;
import static org.neo4j.kernel.api.exceptions.Status.General.DatabaseUnavailable;
import static org.neo4j.kernel.api.exceptions.Status.Transaction.BookmarkTimeout;
import static org.neo4j.kernel.database.DatabaseIdFactory.from;
import static org.neo4j.storageengine.api.TransactionIdStore.BASE_TX_ID;

import java.time.Duration;
import java.util.UUID;
import org.junit.jupiter.api.BeforeEach;
import org.junit.jupiter.api.Test;
import org.neo4j.collection.Dependencies;
import org.neo4j.dbms.api.DatabaseManagementService;
import org.neo4j.dbms.api.DatabaseNotFoundException;
import org.neo4j.kernel.availability.DatabaseAvailabilityGuard;
import org.neo4j.kernel.database.AbstractDatabase;
import org.neo4j.kernel.database.Database;
import org.neo4j.kernel.database.NamedDatabaseId;
import org.neo4j.kernel.internal.GraphDatabaseAPI;
import org.neo4j.monitoring.Monitors;
import org.neo4j.storageengine.api.TransactionIdStore;
import org.neo4j.time.Clocks;

class TransactionIdTrackerTest {
    private static final Duration DEFAULT_DURATION = ofSeconds(10);

    private final TransactionIdStore transactionIdStore = mock(TransactionIdStore.class);
    private final DatabaseAvailabilityGuard databaseAvailabilityGuard = mock(DatabaseAvailabilityGuard.class);
    private final NamedDatabaseId namedDatabaseId = from("foo", UUID.randomUUID());
    private final Database db = mock(Database.class);
    private final DatabaseManagementService managementService = mock(DatabaseManagementService.class);

    private TransactionIdTracker transactionIdTracker;

    @BeforeEach
    void setup() {
        var dbApi = mock(GraphDatabaseAPI.class);
        var resolver = mock(Dependencies.class);

        when(managementService.database(namedDatabaseId.name())).thenReturn(dbApi);
        when(dbApi.getDependencyResolver()).thenReturn(resolver);

        when(db.getNamedDatabaseId()).thenReturn(namedDatabaseId);
        when(db.isSystem()).thenReturn(false);
        when(db.getDependencyResolver()).thenReturn(resolver);
        when(db.getDatabaseAvailabilityGuard()).thenReturn(databaseAvailabilityGuard);

        when(resolver.resolveDependency(AbstractDatabase.class)).thenReturn(db);
        when(resolver.resolveDependency(TransactionIdStore.class)).thenReturn(transactionIdStore);

        when(databaseAvailabilityGuard.isAvailable()).thenReturn(true);
        transactionIdTracker = new TransactionIdTracker(managementService, new Monitors(), Clocks.fakeClock());
    }

    @Test
    void shouldReturnImmediatelyForBaseTxIdOrLess() {
        // when
        transactionIdTracker.awaitUpToDate(namedDatabaseId, BASE_TX_ID, ofSeconds(5));

        // then
        verify(transactionIdStore, never()).getLastClosedTransactionId();
    }

    @Test
    void shouldReturnImmediatelyForBaseTxIdOrLessUsingSystemDb() {
        // given
        when(db.isSystem()).thenReturn(true);

        // when
        transactionIdTracker.awaitUpToDate(namedDatabaseId, BASE_TX_ID, ofSeconds(5));

        // then
        verifyNoInteractions(transactionIdStore);
    }

    @Test
    void shouldWaitForRequestedVersion() {
        // given
        var version = 5L;

        when(transactionIdStore.getLastClosedTransactionId())
                .thenReturn(1L)
                .thenReturn(2L)
                .thenReturn(6L);

        // when
        transactionIdTracker.awaitUpToDate(namedDatabaseId, version, DEFAULT_DURATION);

        // then
        verify(transactionIdStore, times(3)).getLastClosedTransactionId();
    }

    @Test
    void shouldWaitForRequestedVersionUsingSystemDb() {
        // given
        when(db.isSystem()).thenReturn(true);
        var version = 42L;
        when(transactionIdStore.getLastClosedTransactionId()).thenReturn(version);

        // when
        transactionIdTracker.awaitUpToDate(namedDatabaseId, version, DEFAULT_DURATION);

        // then
        verify(transactionIdStore, times(1)).getLastClosedTransactionId();
    }

    @Test
    void shouldWrapAnyStoreCheckExceptions() {
        // given
        var version = 5L;
        var checkException = new RuntimeException();
        doThrow(checkException).when(transactionIdStore).getLastClosedTransactionId();

        // when
        var exception = assertThrows(
                TransactionIdTrackerException.class,
                () -> transactionIdTracker.awaitUpToDate(namedDatabaseId, version + 1, ofMillis(50)));

        // then
        assertEquals(BookmarkTimeout, exception.status());
        assertEquals(checkException, exception.getCause());
    }

    @Test
    void shouldWrapAnyStoreCheckExceptionsUsingSystemDb() {
        // given
        when(db.isSystem()).thenReturn(true);
        var version = 3L;
        var checkException = new RuntimeException();
        doThrow(checkException).when(transactionIdStore).getLastClosedTransactionId();

        // when
        var exception = assertThrows(
                TransactionIdTrackerException.class,
                () -> transactionIdTracker.awaitUpToDate(namedDatabaseId, version + 1, ofMillis(50)));

        // then
        assertEquals(BookmarkTimeout, exception.status());
        assertEquals(checkException, exception.getCause());
    }

    @Test
    void shouldThrowDatabaseIsShutdownWhenStoreShutdownAfterCheck() {
        // given
        var version = 5L;
        var checkException = new RuntimeException();
        doThrow(checkException).when(transactionIdStore).getLastClosedTransactionId();
        when(databaseAvailabilityGuard.isAvailable()).thenReturn(true, true, false);

        // when
        var exception = assertThrows(
                TransactionIdTrackerException.class,
                () -> transactionIdTracker.awaitUpToDate(namedDatabaseId, version + 1, ofMillis(50)));

        // then
        assertEquals(DatabaseUnavailable, exception.status());
        assertEquals(checkException, exception.getCause());
    }

    @Test
    void shouldThrowDatabaseIsShutdownWhenStoreShutdownAfterCheckUsingSystemDb() {
        // given
        when(db.isSystem()).thenReturn(true);
        var version = 42L;
        var checkException = new RuntimeException();
        doThrow(checkException).when(transactionIdStore).getLastClosedTransactionId();
        when(databaseAvailabilityGuard.isAvailable()).thenReturn(true, true, false);

        // when
        var exception = assertThrows(
                TransactionIdTrackerException.class,
                () -> transactionIdTracker.awaitUpToDate(namedDatabaseId, version + 1, ofMillis(50)));

        // then
        assertEquals(DatabaseUnavailable, exception.status());
        assertEquals(checkException, exception.getCause());
    }

    @Test
    void shouldNotWaitIfTheDatabaseIsUnavailable() {
        // given
        when(databaseAvailabilityGuard.isAvailable()).thenReturn(false);

        // when
        var exception = assertThrows(
                TransactionIdTrackerException.class,
                () -> transactionIdTracker.awaitUpToDate(namedDatabaseId, 1000, ofMillis(60_000)));

        // then
        assertEquals(DatabaseUnavailable, exception.status());
        verify(transactionIdStore, never()).getLastClosedTransactionId();
    }

    @Test
    void shouldNotWaitIfTheSystemDatabaseIsUnavailable() {
        // given
        when(db.isSystem()).thenReturn(true);
        when(databaseAvailabilityGuard.isAvailable()).thenReturn(false);

        // when
        var exception = assertThrows(
                TransactionIdTrackerException.class,
                () -> transactionIdTracker.awaitUpToDate(namedDatabaseId, 1000, ofMillis(60_000)));

        // then
        assertEquals(DatabaseUnavailable, exception.status());
        verifyNoInteractions(transactionIdStore);
    }

    @Test
    void shouldReturnNewestTransactionId() {
        // given
        when(transactionIdStore.getLastClosedTransactionId()).thenReturn(42L);
        when(transactionIdStore.getLastCommittedTransactionId()).thenReturn(4242L);

        // then
        assertEquals(4242L, transactionIdTracker.newestTransactionId(namedDatabaseId));
    }

    @Test
    void shouldReturnNewestTransactionIdUsingSystemDb() {
        // given
        when(db.isSystem()).thenReturn(true);
        when(transactionIdStore.getLastCommittedTransactionId()).thenReturn(42L);

        // then
        assertEquals(42L, transactionIdTracker.newestTransactionId(namedDatabaseId));
    }

    @Test
    void shouldNotReturnNewestTransactionIdForDatabaseThatDoesNotExist() {
        // given
        var unknownDatabaseId = from("bar", UUID.randomUUID());
        when(managementService.database(unknownDatabaseId.name())).thenThrow(DatabaseNotFoundException.class);

        // when
        var exception = assertThrows(
                TransactionIdTrackerException.class, () -> transactionIdTracker.newestTransactionId(unknownDatabaseId));

        // then
        assertEquals(DatabaseNotFound, exception.status());
    }

    @Test
    void shouldNotAwaitForTransactionForDatabaseThatDoesNotExist() {
        // given
        var unknownDatabaseId = from("bar", UUID.randomUUID());
        when(managementService.database(unknownDatabaseId.name())).thenThrow(DatabaseNotFoundException.class);

        // when
        var exception = assertThrows(
                TransactionIdTrackerException.class,
                () -> transactionIdTracker.awaitUpToDate(unknownDatabaseId, 1, ofMillis(1)));

        // then
        assertEquals(DatabaseNotFound, exception.status());
    }
}
