/*
 * Copyright (C) 2022 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 com.android.ondevicepersonalization.services.data.user;

import static android.app.job.JobScheduler.RESULT_SUCCESS;

import static com.android.adservices.service.stats.AdServicesStatsLog.AD_SERVICES_BACKGROUND_JOBS_EXECUTION_REPORTED__EXECUTION_RESULT_CODE__SKIP_FOR_KILL_SWITCH_ON;
import static com.android.adservices.service.stats.AdServicesStatsLog.AD_SERVICES_BACKGROUND_JOBS_EXECUTION_REPORTED__EXECUTION_RESULT_CODE__SKIP_FOR_PERSONALIZATION_NOT_ENABLED;
import static com.android.adservices.shared.spe.JobServiceConstants.SCHEDULING_RESULT_CODE_FAILED;
import static com.android.adservices.shared.spe.JobServiceConstants.SCHEDULING_RESULT_CODE_SKIPPED;
import static com.android.adservices.shared.spe.JobServiceConstants.SCHEDULING_RESULT_CODE_SUCCESSFUL;
import static com.android.ondevicepersonalization.services.OnDevicePersonalizationConfig.USER_DATA_COLLECTION_ID;

import android.app.job.JobInfo;
import android.app.job.JobParameters;
import android.app.job.JobScheduler;
import android.app.job.JobService;
import android.content.ComponentName;
import android.content.Context;

import com.android.adservices.shared.spe.JobServiceConstants;
import com.android.internal.annotations.VisibleForTesting;
import com.android.ondevicepersonalization.internal.util.LoggerFactory;
import com.android.ondevicepersonalization.services.Flags;
import com.android.ondevicepersonalization.services.FlagsFactory;
import com.android.ondevicepersonalization.services.OnDevicePersonalizationExecutors;
import com.android.ondevicepersonalization.services.statsd.joblogging.OdpJobServiceLogger;

import com.google.common.util.concurrent.FutureCallback;
import com.google.common.util.concurrent.Futures;
import com.google.common.util.concurrent.ListenableFuture;
import com.google.common.util.concurrent.ListeningExecutorService;

/** JobService to collect user data in the background thread. */
public class UserDataCollectionJobService extends JobService {
    private static final LoggerFactory.Logger sLogger = LoggerFactory.getLogger();
    private static final String TAG = "UserDataCollectionJobService";
    // 4-hour interval.
    private static final long PERIOD_SECONDS = 14400;
    private ListenableFuture<Void> mFuture;
    private UserDataCollector mUserDataCollector;
    private RawUserData mUserData;

    private final Injector mInjector;

    public UserDataCollectionJobService() {
        mInjector = new Injector();
    }

    @VisibleForTesting
    public UserDataCollectionJobService(Injector injector) {
        mInjector = injector;
    }

    static class Injector {
        ListeningExecutorService getExecutor() {
            return OnDevicePersonalizationExecutors.getBackgroundExecutor();
        }

        Flags getFlags() {
            return FlagsFactory.getFlags();
        }
    }

    /** Schedules a unique instance of UserDataCollectionJobService to be run. */
    @JobServiceConstants.JobSchedulingResultCode
    public static int schedule(Context context, boolean forceSchedule) {
        JobScheduler jobScheduler = context.getSystemService(JobScheduler.class);
        if (jobScheduler == null) {
            sLogger.e(TAG, "Failed to get job scheduler from system service.");
            return SCHEDULING_RESULT_CODE_FAILED;
        }
        if (!forceSchedule && jobScheduler.getPendingJob(USER_DATA_COLLECTION_ID) != null) {
            sLogger.d(TAG + ": Job is already scheduled. Doing nothing,");
            return SCHEDULING_RESULT_CODE_SKIPPED;
        }
        ComponentName serviceComponent =
                new ComponentName(context, UserDataCollectionJobService.class);
        JobInfo.Builder builder = new JobInfo.Builder(USER_DATA_COLLECTION_ID, serviceComponent);

        // Constraints
        builder.setRequiresDeviceIdle(true);
        builder.setRequiresBatteryNotLow(true);
        builder.setRequiresStorageNotLow(true);
        builder.setRequiredNetworkType(JobInfo.NETWORK_TYPE_NONE);
        builder.setPeriodic(1000 * PERIOD_SECONDS); // JobScheduler uses Milliseconds.
        // persist this job across boots
        builder.setPersisted(true);

        int schedulingResult = jobScheduler.schedule(builder.build());
        return RESULT_SUCCESS == schedulingResult ? SCHEDULING_RESULT_CODE_SUCCESSFUL
                : SCHEDULING_RESULT_CODE_FAILED;
    }

    @Override
    public boolean onStartJob(JobParameters params) {
        sLogger.d(TAG + ": onStartJob()");
        OdpJobServiceLogger.getInstance(this).recordOnStartJob(USER_DATA_COLLECTION_ID);
        if (mInjector.getFlags().getGlobalKillSwitch()) {
            sLogger.d(TAG + ": GlobalKillSwitch enabled, finishing job.");
            return cancelAndFinishJob(
                    params,
                    AD_SERVICES_BACKGROUND_JOBS_EXECUTION_REPORTED__EXECUTION_RESULT_CODE__SKIP_FOR_KILL_SWITCH_ON);
        }
        // Reschedule jobs with SPE if it's enabled. Note scheduled jobs by this
        // UserDataCollectionJobService will be cancelled for the same job ID.
        if (mInjector.getFlags().getSpeOnUserDataCollectionJobEnabled()) {
            sLogger.i(
                    "SPE is enabled. Reschedule UserDataCollectionJobService with"
                            + " UserDataCollectionJob.");
            UserDataCollectionJob.schedule(/* context */ this);
            return false;
        }
        runPrivacyStatusChecksInBackground(params);
        return true;
    }

    private void runPrivacyStatusChecksInBackground(final JobParameters params) {
        OnDevicePersonalizationExecutors.getHighPriorityBackgroundExecutor().execute(() -> {
            boolean isProtectedAudienceAndMeasurementBothDisabled =
                    UserPrivacyStatus.getInstance()
                            .isProtectedAudienceAndMeasurementBothDisabled();
            sLogger.d(TAG + ": is ProtectedAudience and Measurement both disabled: %s",
                    isProtectedAudienceAndMeasurementBothDisabled);
            if (isProtectedAudienceAndMeasurementBothDisabled) {
                handlePrivacyControlsRevoked(params);
            } else {
                startUserDataCollectionJob(params);
            }
        });
    }

    private void handlePrivacyControlsRevoked(JobParameters params) {
        sLogger.d(TAG
                + ": user control is revoked, deleting existing user data and finishing job.");
        mUserDataCollector = UserDataCollector.getInstance(this);
        mUserData = RawUserData.getInstance();
        mUserDataCollector.clearUserData(mUserData);
        mUserDataCollector.clearMetadata();
        OdpJobServiceLogger.getInstance(this)
                .recordJobSkipped(
                        USER_DATA_COLLECTION_ID,
                        AD_SERVICES_BACKGROUND_JOBS_EXECUTION_REPORTED__EXECUTION_RESULT_CODE__SKIP_FOR_PERSONALIZATION_NOT_ENABLED);
        jobFinished(params, /* wantsReschedule= */ false);
    }

    private void startUserDataCollectionJob(final JobParameters params) {
        mUserDataCollector = UserDataCollector.getInstance(this);
        mUserData = RawUserData.getInstance();
        mFuture = Futures.submit(new Runnable() {
            @Override
            public void run() {
                sLogger.d(TAG + ": Running user data collection job");
                try {
                    mUserDataCollector.updateUserData(mUserData);
                } catch (Exception e) {
                    sLogger.e(TAG + ": Failed to collect user data", e);
                }
            }
        }, mInjector.getExecutor());

        Futures.addCallback(
                mFuture,
                new FutureCallback<Void>() {
                    @Override
                    public void onSuccess(Void result) {
                        sLogger.d(TAG + ": User data collection job completed.");
                        handleJobCompletion(params, /* isSuccessful= */ true);
                    }

                    @Override
                    public void onFailure(Throwable t) {
                        sLogger.e(t, TAG + ": Failed to handle JobService: " + params.getJobId());
                        handleJobCompletion(params, /* isSuccessful= */ false);
                    }
                },
                mInjector.getExecutor()
        );
    }

    private void handleJobCompletion(JobParameters params, boolean isSuccessful) {
        boolean wantsReschedule = false;
        OdpJobServiceLogger.getInstance(UserDataCollectionJobService.this)
                .recordJobFinished(
                        USER_DATA_COLLECTION_ID,
                        isSuccessful,
                        wantsReschedule);
        jobFinished(params, wantsReschedule);
    }

    @Override
    public boolean onStopJob(JobParameters params) {
        if (mFuture != null) {
            mFuture.cancel(true);
        }
        // Reschedule the job since it ended before finishing
        boolean wantsReschedule = true;
        OdpJobServiceLogger.getInstance(this)
                .recordOnStopJob(params, USER_DATA_COLLECTION_ID, wantsReschedule);
        return wantsReschedule;
    }

    private boolean cancelAndFinishJob(final JobParameters params, int skipReason) {
        JobScheduler jobScheduler = this.getSystemService(JobScheduler.class);
        if (jobScheduler != null) {
            jobScheduler.cancel(USER_DATA_COLLECTION_ID);
        }
        OdpJobServiceLogger.getInstance(this).recordJobSkipped(USER_DATA_COLLECTION_ID, skipReason);
        jobFinished(params, /* wantsReschedule= */ false);
        return true;
    }
}