/*
 * Copyright (C) 2017 The Android Open Source Project
 *
 * Licensed 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 androidx.room.integration.testapp.test;

import static org.hamcrest.CoreMatchers.is;
import static org.hamcrest.CoreMatchers.notNullValue;
import static org.hamcrest.MatcherAssert.assertThat;

import android.support.test.InstrumentationRegistry;
import android.support.test.filters.SmallTest;

import androidx.annotation.NonNull;
import androidx.arch.core.executor.ArchTaskExecutor;
import androidx.arch.core.executor.testing.CountingTaskExecutorRule;
import androidx.lifecycle.Lifecycle;
import androidx.lifecycle.LiveData;
import androidx.paging.DataSource;
import androidx.paging.LivePagedListBuilder;
import androidx.paging.PagedList;
import androidx.paging.PositionalDataSource;
import androidx.room.Dao;
import androidx.room.Database;
import androidx.room.Entity;
import androidx.room.Ignore;
import androidx.room.Insert;
import androidx.room.PrimaryKey;
import androidx.room.Query;
import androidx.room.Relation;
import androidx.room.Room;
import androidx.room.RoomDatabase;
import androidx.room.RoomWarnings;
import androidx.room.Transaction;
import androidx.room.paging.LimitOffsetDataSource;

import org.junit.After;
import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.junit.runners.Parameterized;

import java.util.Collections;
import java.util.List;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;
import java.util.concurrent.TimeUnit;
import java.util.concurrent.TimeoutException;
import java.util.concurrent.atomic.AtomicInteger;

import io.reactivex.Flowable;
import io.reactivex.Maybe;
import io.reactivex.Single;
import io.reactivex.observers.TestObserver;
import io.reactivex.schedulers.Schedulers;
import io.reactivex.subscribers.TestSubscriber;

@SmallTest
@RunWith(Parameterized.class)
@SuppressWarnings("CheckReturnValue")
public class QueryTransactionTest {
    @Rule
    public CountingTaskExecutorRule countingTaskExecutorRule = new CountingTaskExecutorRule();
    private static final AtomicInteger sStartedTransactionCount = new AtomicInteger(0);
    private TransactionDb mDb;
    private final boolean mUseTransactionDao;
    private Entity1Dao mDao;
    private final LiveDataQueryTest.TestLifecycleOwner mLifecycleOwner = new LiveDataQueryTest
            .TestLifecycleOwner();

    @NonNull
    @Parameterized.Parameters(name = "useTransaction_{0}")
    public static Boolean[] getParams() {
        return new Boolean[]{false, true};
    }

    public QueryTransactionTest(boolean useTransactionDao) {
        mUseTransactionDao = useTransactionDao;
    }

    @Before
    public void initDb() {
        InstrumentationRegistry.getInstrumentation().runOnMainSync(
                () -> mLifecycleOwner.handleEvent(Lifecycle.Event.ON_START));

        resetTransactionCount();
        mDb = Room.inMemoryDatabaseBuilder(InstrumentationRegistry.getTargetContext(),
                TransactionDb.class).build();
        mDao = mUseTransactionDao ? mDb.transactionDao() : mDb.dao();
        drain();
    }

    @After
    public void closeDb() {
        InstrumentationRegistry.getInstrumentation().runOnMainSync(
                () -> mLifecycleOwner.handleEvent(Lifecycle.Event.ON_DESTROY));
        drain();
        mDb.close();
    }

    @Test
    public void readList() {
        mDao.insert(new Entity1(1, "foo"));
        resetTransactionCount();

        int expectedTransactionCount = mUseTransactionDao ? 1 : 0;
        List<Entity1> allEntities = mDao.allEntities();
        assertTransactionCount(allEntities, expectedTransactionCount);
    }

    @Test
    public void liveData() {
        LiveData<List<Entity1>> listLiveData = mDao.liveData();
        observeForever(listLiveData);
        drain();
        assertThat(listLiveData.getValue(), is(Collections.<Entity1>emptyList()));

        resetTransactionCount();
        mDao.insert(new Entity1(1, "foo"));
        drain();

        //noinspection ConstantConditions
        assertThat(listLiveData.getValue().size(), is(1));
        int expectedTransactionCount = mUseTransactionDao ? 2 : 1;
        assertTransactionCount(listLiveData.getValue(), expectedTransactionCount);
    }

    @Test
    public void flowable() {
        Flowable<List<Entity1>> flowable = mDao.flowable();
        TestSubscriber<List<Entity1>> subscriber = observe(flowable);
        drain();
        assertThat(subscriber.values().size(), is(1));

        resetTransactionCount();
        mDao.insert(new Entity1(1, "foo"));
        drain();

        List<Entity1> allEntities = subscriber.values().get(1);
        assertThat(allEntities.size(), is(1));
        int expectedTransactionCount = mUseTransactionDao ? 2 : 1;
        assertTransactionCount(allEntities, expectedTransactionCount);
    }

    @Test
    public void maybe() {
        mDao.insert(new Entity1(1, "foo"));
        resetTransactionCount();

        int expectedTransactionCount = mUseTransactionDao ? 1 : 0;
        Maybe<List<Entity1>> listMaybe = mDao.maybe();
        TestObserver<List<Entity1>> observer = observe(listMaybe);
        drain();
        List<Entity1> allEntities = observer.values().get(0);
        assertTransactionCount(allEntities, expectedTransactionCount);
    }

    @Test
    public void single() {
        mDao.insert(new Entity1(1, "foo"));
        resetTransactionCount();

        int expectedTransactionCount = mUseTransactionDao ? 1 : 0;
        Single<List<Entity1>> listMaybe = mDao.single();
        TestObserver<List<Entity1>> observer = observe(listMaybe);
        drain();
        List<Entity1> allEntities = observer.values().get(0);
        assertTransactionCount(allEntities, expectedTransactionCount);
    }

    @Test
    public void relation() {
        mDao.insert(new Entity1(1, "foo"));
        mDao.insert(new Child(1, 1));
        mDao.insert(new Child(2, 1));
        resetTransactionCount();

        List<Entity1WithChildren> result = mDao.withRelation();
        int expectedTransactionCount = mUseTransactionDao ? 1 : 0;
        assertTransactionCountWithChildren(result, expectedTransactionCount);
    }

    @Test
    public void pagedList() {
        LiveData<PagedList<Entity1>> pagedList =
                new LivePagedListBuilder<>(mDao.pagedList(), 10).build();
        observeForever(pagedList);
        drain();
        assertThat(sStartedTransactionCount.get(), is(mUseTransactionDao ? 0 : 0));

        mDao.insert(new Entity1(1, "foo"));
        drain();
        //noinspection ConstantConditions
        assertThat(pagedList.getValue().size(), is(1));
        assertTransactionCount(pagedList.getValue(), mUseTransactionDao ? 2 : 1);

        mDao.insert(new Entity1(2, "bar"));
        drain();
        assertThat(pagedList.getValue().size(), is(2));
        assertTransactionCount(pagedList.getValue(), mUseTransactionDao ? 4 : 2);
    }

    @Test
    public void dataSource() {
        mDao.insert(new Entity1(2, "bar"));
        drain();
        resetTransactionCount();
        @SuppressWarnings("deprecation")
        LimitOffsetDataSource<Entity1> dataSource =
                (LimitOffsetDataSource<Entity1>) mDao.dataSource();
        dataSource.loadRange(0, 10);
        assertThat(sStartedTransactionCount.get(), is(mUseTransactionDao ? 1 : 0));
    }

    private void assertTransactionCount(List<Entity1> allEntities, int expectedTransactionCount) {
        assertThat(sStartedTransactionCount.get(), is(expectedTransactionCount));
        assertThat(allEntities.isEmpty(), is(false));
        for (Entity1 entity1 : allEntities) {
            assertThat(entity1.transactionId, is(expectedTransactionCount));
        }
    }

    private void assertTransactionCountWithChildren(List<Entity1WithChildren> allEntities,
            int expectedTransactionCount) {
        assertThat(sStartedTransactionCount.get(), is(expectedTransactionCount));
        assertThat(allEntities.isEmpty(), is(false));
        for (Entity1WithChildren entity1 : allEntities) {
            assertThat(entity1.transactionId, is(expectedTransactionCount));
            assertThat(entity1.children, notNullValue());
            assertThat(entity1.children.isEmpty(), is(false));
            for (Child child : entity1.children) {
                assertThat(child.transactionId, is(expectedTransactionCount));
            }
        }
    }

    private void resetTransactionCount() {
        sStartedTransactionCount.set(0);
    }

    private void drain() {
        try {
            countingTaskExecutorRule.drainTasks(30, TimeUnit.SECONDS);
        } catch (InterruptedException e) {
            throw new AssertionError("interrupted", e);
        } catch (TimeoutException e) {
            throw new AssertionError("drain timed out", e);
        }
    }

    private <T> TestSubscriber<T> observe(final Flowable<T> flowable) {
        TestSubscriber<T> subscriber = new TestSubscriber<>();
        flowable.observeOn(Schedulers.from(ArchTaskExecutor.getMainThreadExecutor()))
                .subscribeWith(subscriber);
        return subscriber;
    }

    private <T> TestObserver<T> observe(final Maybe<T> maybe) {
        TestObserver<T> observer = new TestObserver<>();
        maybe.observeOn(Schedulers.from(ArchTaskExecutor.getMainThreadExecutor()))
                .subscribeWith(observer);
        return observer;
    }

    private <T> TestObserver<T> observe(final Single<T> single) {
        TestObserver<T> observer = new TestObserver<>();
        single.observeOn(Schedulers.from(ArchTaskExecutor.getMainThreadExecutor()))
                .subscribeWith(observer);
        return observer;
    }

    private <T> void observeForever(final LiveData<T> liveData) {
        FutureTask<Void> futureTask = new FutureTask<>(() -> {
            liveData.observe(mLifecycleOwner, t -> {
            });
            return null;
        });
        ArchTaskExecutor.getMainThreadExecutor().execute(futureTask);
        try {
            futureTask.get();
        } catch (InterruptedException e) {
            throw new AssertionError("interrupted", e);
        } catch (ExecutionException e) {
            throw new AssertionError("execution error", e);
        }
    }

    @SuppressWarnings("WeakerAccess")
    static class Entity1WithChildren extends Entity1 {
        @Relation(entity = Child.class, parentColumn = "id",
                entityColumn = "entity1Id")
        public List<Child> children;

        Entity1WithChildren(int id, String value) {
            super(id, value);
        }
    }

    @SuppressWarnings("WeakerAccess")
    @Entity
    static class Child {
        @PrimaryKey(autoGenerate = true)
        public int id;
        public int entity1Id;
        @Ignore
        public final int transactionId = sStartedTransactionCount.get();

        Child(int id, int entity1Id) {
            this.id = id;
            this.entity1Id = entity1Id;
        }
    }

    @SuppressWarnings("WeakerAccess")
    @Entity
    static class Entity1 {
        @PrimaryKey(autoGenerate = true)
        public int id;
        public String value;
        @Ignore
        public final int transactionId = sStartedTransactionCount.get();

        Entity1(int id, String value) {
            this.id = id;
            this.value = value;
        }
    }

    // we don't support dao inheritance for queries so for now, go with this
    interface Entity1Dao {
        String SELECT_ALL = "select * from Entity1";

        List<Entity1> allEntities();

        Flowable<List<Entity1>> flowable();

        Maybe<List<Entity1>> maybe();

        Single<List<Entity1>> single();

        LiveData<List<Entity1>> liveData();

        List<Entity1WithChildren> withRelation();

        DataSource.Factory<Integer, Entity1> pagedList();

        PositionalDataSource<Entity1> dataSource();

        @Insert
        void insert(Entity1 entity1);

        @Insert
        void insert(Child entity1);
    }

    @Dao
    interface EntityDao extends Entity1Dao {
        @Override
        @Query(SELECT_ALL)
        List<Entity1> allEntities();

        @Override
        @Query(SELECT_ALL)
        Flowable<List<Entity1>> flowable();

        @Override
        @Query(SELECT_ALL)
        LiveData<List<Entity1>> liveData();

        @Override
        @Query(SELECT_ALL)
        Maybe<List<Entity1>> maybe();

        @Override
        @Query(SELECT_ALL)
        Single<List<Entity1>> single();

        @Override
        @Query(SELECT_ALL)
        @SuppressWarnings(RoomWarnings.RELATION_QUERY_WITHOUT_TRANSACTION)
        List<Entity1WithChildren> withRelation();

        @Override
        @Query(SELECT_ALL)
        DataSource.Factory<Integer, Entity1> pagedList();

        @Override
        @Query(SELECT_ALL)
        PositionalDataSource<Entity1> dataSource();
    }

    @Dao
    interface TransactionDao extends Entity1Dao {
        @Override
        @Transaction
        @Query(SELECT_ALL)
        List<Entity1> allEntities();

        @Override
        @Transaction
        @Query(SELECT_ALL)
        Flowable<List<Entity1>> flowable();

        @Override
        @Transaction
        @Query(SELECT_ALL)
        LiveData<List<Entity1>> liveData();

        @Override
        @Transaction
        @Query(SELECT_ALL)
        Maybe<List<Entity1>> maybe();

        @Override
        @Transaction
        @Query(SELECT_ALL)
        Single<List<Entity1>> single();

        @Override
        @Transaction
        @Query(SELECT_ALL)
        List<Entity1WithChildren> withRelation();

        @Override
        @Transaction
        @Query(SELECT_ALL)
        DataSource.Factory<Integer, Entity1> pagedList();

        @Override
        @Transaction
        @Query(SELECT_ALL)
        PositionalDataSource<Entity1> dataSource();
    }

    @Database(version = 1, entities = {Entity1.class, Child.class}, exportSchema = false)
    abstract static class TransactionDb extends RoomDatabase {
        abstract EntityDao dao();

        abstract TransactionDao transactionDao();

        @Override
        public void beginTransaction() {
            super.beginTransaction();
            sStartedTransactionCount.incrementAndGet();
        }
    }
}