/*
 * Copyright 2014, 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.managedprovisioning;

import static android.app.admin.DeviceAdminReceiver.ACTION_PROFILE_PROVISIONING_COMPLETE;
import static android.app.admin.DevicePolicyManager.EXTRA_PROVISIONING_ADMIN_EXTRAS_BUNDLE;

import android.app.AlarmManager;
import android.app.Service;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.IBinder;
import android.os.UserHandle;
import android.support.v4.content.LocalBroadcastManager;
import android.text.TextUtils;

import com.android.internal.app.LocalePicker;
import com.android.managedprovisioning.task.AddWifiNetworkTask;
import com.android.managedprovisioning.task.DeleteNonRequiredAppsTask;
import com.android.managedprovisioning.task.DownloadPackageTask;
import com.android.managedprovisioning.task.InstallPackageTask;
import com.android.managedprovisioning.task.SetDevicePolicyTask;

import java.lang.Runnable;
import java.util.Locale;

/**
 * This service does the work for the DeviceOwnerProvisioningActivity.
 * Feedback is sent back to the activity via intents.
 *
 * <p>
 * If the corresponding activity is killed and restarted, the service is
 * called twice. The service will not start the provisioning flow a second time, but instead
 * send a status update to the activity.
 * </p>
 */
public class DeviceOwnerProvisioningService extends Service {
    private static final boolean DEBUG = false; // To control logging.

    /**
     * Intent action to activate the CDMA phone connection by OTASP.
     * This is not necessary for a GSM phone connection, which is activated automatically.
     * String must agree with the constants in com.android.phone.InCallScreenShowActivation.
     */
    private static final String ACTION_PERFORM_CDMA_PROVISIONING =
            "com.android.phone.PERFORM_CDMA_PROVISIONING";

    // Intent actions and extras for communication from DeviceOwnerProvisioningService to Activity.
    protected static final String EXTRA_PROVISIONING_PARAMS =
            "ProvisioningParams";

    // Intent actions and extras for communication from DeviceOwnerProvisioningActivity to Service.
    protected static final String ACTION_PROVISIONING_SUCCESS =
            "com.android.managedprovisioning.provisioning_success";
    protected static final String ACTION_PROVISIONING_ERROR =
            "com.android.managedprovisioning.error";
    protected static final String EXTRA_USER_VISIBLE_ERROR_ID_KEY =
            "UserVisibleErrorMessage-Id";
    protected static final String ACTION_PROGRESS_UPDATE =
            "com.android.managedprovisioning.progress_update";
    protected static final String EXTRA_PROGRESS_MESSAGE_ID_KEY =
            "ProgressMessageId";
    protected static final String ACTION_REQUEST_WIFI_PICK =
            "com.android.managedprovisioning.request_wifi_pick";

    // Intent action used by the HomeReceiverActivity to notify this Service that a HOME intent was
    // received, which indicates that the Setup wizard has closed after provisioning completed.
    protected static final String ACTION_HOME_INDIRECT =
            "com.android.managedprovisioning.home_indirect";

    // Indicates whether provisioning has started.
    private boolean mProvisioningInFlight = false;

    // MessageId of the last progress message.
    private int mLastProgressMessage = -1;

    // MessageId of the last error message.
    private int mLastErrorMessage = -1;

    // Indicates whether provisioning has finished succesfully (service waiting to stop).
    private boolean mDone = false;

    // Provisioning tasks.
    private AddWifiNetworkTask mAddWifiNetworkTask;
    private DownloadPackageTask mDownloadPackageTask;
    private InstallPackageTask mInstallPackageTask;
    private SetDevicePolicyTask mSetDevicePolicyTask;
    private DeleteNonRequiredAppsTask mDeleteNonRequiredAppsTask;

    private ProvisioningParams mParams;

    private BroadcastReceiver mIndirectHomeReceiver;

    @Override
    public int onStartCommand(final Intent intent, int flags, int startId) {
        if (DEBUG) ProvisionLogger.logd("Device owner provisioning service ONSTARTCOMMAND.");

        synchronized (this) { // Make operations on mProvisioningInFlight atomic.
            if (mProvisioningInFlight) {
                if (DEBUG) ProvisionLogger.logd("Provisioning already in flight.");

                sendProgressUpdateToActivity();

                // Send error message if currently in error state.
                if (mLastErrorMessage >= 0) {
                    sendError();
                }

                // Send success if provisioning was succesful.
                if (mDone) {
                    onProvisioningSuccess(mParams.mDeviceAdminPackageName);
                }
            } else {
                mProvisioningInFlight = true;
                if (DEBUG) ProvisionLogger.logd("First start of the service.");
                progressUpdate(R.string.progress_data_process);

                // Load the ProvisioningParams (from message in Intent).
                mParams = (ProvisioningParams) intent.getParcelableExtra(EXTRA_PROVISIONING_PARAMS);

                registerHomeIntentReceiver();

                // Do the work on a separate thread.
                new Thread(new Runnable() {
                        public void run() {
                            initializeProvisioningEnvironment(mParams);
                            startDeviceOwnerProvisioning(mParams);
                        }
                    }).start();
            }
        }
        return START_NOT_STICKY;
    }

    // Register the receiver for the ACTION_HOME_INDIRECT intent.
    // The ACTION_HOME_INDIRECT intent is used to notify this service that the home intent was send.
    // After receiving that intent we send the complete intent to the mdm.
    // Note: if we would send the complete intent earlier, the home intent can close the mdm.
    private void registerHomeIntentReceiver() {
        mIndirectHomeReceiver = new IndirectHomeReceiver();
        IntentFilter filter = new IntentFilter();
        filter.addAction(DeviceOwnerProvisioningService.ACTION_HOME_INDIRECT);
        LocalBroadcastManager.getInstance(this).registerReceiver(mIndirectHomeReceiver, filter);
    }

    class IndirectHomeReceiver extends BroadcastReceiver {
        @Override
        public void onReceive(Context context, Intent intent) {
            if (!mDone) {
                return;
            }

            // Disable the HomeReceiverActivity. It's no longer of use.
            PackageManager pm = getPackageManager();
            pm.setComponentEnabledSetting(new ComponentName(DeviceOwnerProvisioningService.this,
                            HomeReceiverActivity.class), PackageManager
                    .COMPONENT_ENABLED_STATE_DISABLED, PackageManager.DONT_KILL_APP);

            // Send complete intent to mdm.
            Intent result = new Intent(ACTION_PROFILE_PROVISIONING_COMPLETE);
            result.setPackage(mParams.mDeviceAdminPackageName);
            result.addFlags(Intent.FLAG_INCLUDE_STOPPED_PACKAGES |
                    Intent.FLAG_RECEIVER_FOREGROUND);
            if (mParams.mAdminExtrasBundle != null) {
                result.putExtra(EXTRA_PROVISIONING_ADMIN_EXTRAS_BUNDLE,
                        mParams.mAdminExtrasBundle);
            }
            sendBroadcast(result);
            stopSelf();
        }
    }


    /**
     * This is the core method of this class. It goes through every provisioning step.
     */
    private void startDeviceOwnerProvisioning(final ProvisioningParams params) {
        if (DEBUG) ProvisionLogger.logd("Starting device owner provisioning");

        // Construct Tasks. Do not start them yet.
        if (TextUtils.isEmpty(params.mWifiSsid)) {
            mAddWifiNetworkTask = null;
        } else {
            mAddWifiNetworkTask = new AddWifiNetworkTask(this, params.mWifiSsid,
                    params.mWifiHidden, params.mWifiSecurityType, params.mWifiPassword,
                    params.mWifiProxyHost, params.mWifiProxyPort, params.mWifiProxyBypassHosts,
                    params.mWifiPacUrl, new AddWifiNetworkTask.Callback() {
                            @Override
                            public void onSuccess() {
                                if (!TextUtils.isEmpty(params.mDeviceAdminPackageDownloadLocation)) {
                                    // Download, install, set as device owner, delete apps.
                                    progressUpdate(R.string.progress_download);
                                    mDownloadPackageTask.run();
                                } else {
                                    // Device Admin will not be downloaded (but is already present):
                                    // Just set as device owner, delete apps.
                                    progressUpdate(R.string.progress_set_owner);
                                    mSetDevicePolicyTask.run();
                                }
                            }

                            @Override
                            public void onError(){
                                error(R.string.device_owner_error_wifi);
                            }
                        });
        }

        mDownloadPackageTask = new DownloadPackageTask(this,
                params.mDeviceAdminPackageDownloadLocation, params.mDeviceAdminPackageChecksum,
                params.mDeviceAdminPackageDownloadCookieHeader, new DownloadPackageTask.Callback() {
                        @Override
                        public void onSuccess() {
                            String downloadLocation =
                                    mDownloadPackageTask.getDownloadedPackageLocation();
                            progressUpdate(R.string.progress_install);
                            mInstallPackageTask.run(downloadLocation);
                        }

                        @Override
                        public void onError(int errorCode) {
                            switch(errorCode) {
                                case DownloadPackageTask.ERROR_HASH_MISMATCH:
                                    error(R.string.device_owner_error_hash_mismatch);
                                    break;
                                case DownloadPackageTask.ERROR_DOWNLOAD_FAILED:
                                    error(R.string.device_owner_error_download_failed);
                                    break;
                                default:
                                    error(R.string.device_owner_error_general);
                                    break;
                            }
                        }
                    });

        mInstallPackageTask = new InstallPackageTask(this,
                params.mDeviceAdminPackageName,
                new InstallPackageTask.Callback() {
                    @Override
                    public void onSuccess() {
                        progressUpdate(R.string.progress_set_owner);
                        mSetDevicePolicyTask.run();
                    }

                    @Override
                    public void onError(int errorCode) {
                        switch(errorCode) {
                            case InstallPackageTask.ERROR_PACKAGE_INVALID:
                                error(R.string.device_owner_error_package_invalid);
                                break;
                            case InstallPackageTask.ERROR_INSTALLATION_FAILED:
                                error(R.string.device_owner_error_installation_failed);
                                break;
                            default:
                                error(R.string.device_owner_error_general);
                                break;
                        }
                    }
                });

        mSetDevicePolicyTask = new SetDevicePolicyTask(this,
                params.mDeviceAdminPackageName,
                getResources().getString(R.string.default_owned_device_username),
                new SetDevicePolicyTask.Callback() {
                    @Override
                    public void onSuccess() {
                        if (params.mLeaveAllSystemAppsEnabled) {
                            onProvisioningSuccess(params.mDeviceAdminPackageName);
                        } else {
                            mDeleteNonRequiredAppsTask.run();
                        }
                    }

                    @Override
                    public void onError(int errorCode) {
                        switch(errorCode) {
                            case SetDevicePolicyTask.ERROR_PACKAGE_NOT_INSTALLED:
                                error(R.string.device_owner_error_package_not_installed);
                                break;
                            case SetDevicePolicyTask.ERROR_NO_RECEIVER:
                                error(R.string.device_owner_error_package_invalid);
                                break;
                            default:
                                error(R.string.device_owner_error_general);
                                break;
                        }
                    }
                });

        mDeleteNonRequiredAppsTask = new DeleteNonRequiredAppsTask(
                this, params.mDeviceAdminPackageName, UserHandle.USER_OWNER,
                R.array.required_apps_managed_device, R.array.vendor_required_apps_managed_device,
                true /* We are creating a new profile */,
                false /* Do not disable INSTALL_SHORTCUT listeners */,
                new DeleteNonRequiredAppsTask.Callback() {
                    public void onSuccess() {
                        // Done with provisioning. Success.
                        onProvisioningSuccess(params.mDeviceAdminPackageName);
                    }

                    @Override
                    public void onError() {
                        error(R.string.device_owner_error_general);
                    };
                });

        // Start first task, which starts next task in its callback, etc.
        startFirstTask(params);
    }

    private void startFirstTask(final ProvisioningParams params) {
        if (mAddWifiNetworkTask != null) {

            // Connect to wifi.
            progressUpdate(R.string.progress_connect_to_wifi);
            mAddWifiNetworkTask.run();
        } else if (!TextUtils.isEmpty(params.mDeviceAdminPackageDownloadLocation)) {

            // Download, install, set as device owner, delete apps.
            progressUpdate(R.string.progress_download);
            mDownloadPackageTask.run();
        } else {

            // Device Admin will not be downloaded (but is already present):
            // Just set as device owner, delete apps.
            progressUpdate(R.string.progress_set_owner);
            mSetDevicePolicyTask.run();
        }
    }

    private void error(int dialogMessage) {
        mLastErrorMessage = dialogMessage;
        sendError();
        // Wait for stopService() call from the activity.
    }

    private void sendError() {
        if (DEBUG) {
            ProvisionLogger.logd("Reporting Error: " + getResources()
                .getString(mLastErrorMessage));
        }
        Intent intent = new Intent(ACTION_PROVISIONING_ERROR);
        intent.setClass(this, DeviceOwnerProvisioningActivity.ServiceMessageReceiver.class);
        intent.putExtra(EXTRA_USER_VISIBLE_ERROR_ID_KEY, mLastErrorMessage);
        LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
    }

    private void progressUpdate(int progressMessage) {
        if (DEBUG) {
            ProvisionLogger.logd("Reporting progress update: " + getResources()
                .getString(progressMessage));
        }
        mLastProgressMessage = progressMessage;
        sendProgressUpdateToActivity();
    }

    private void sendProgressUpdateToActivity() {
        Intent intent = new Intent(ACTION_PROGRESS_UPDATE);
        intent.putExtra(EXTRA_PROGRESS_MESSAGE_ID_KEY, mLastProgressMessage);
        intent.setClass(this, DeviceOwnerProvisioningActivity.ServiceMessageReceiver.class);
        LocalBroadcastManager.getInstance(this).sendBroadcast(intent);
    }

    private void onProvisioningSuccess(String deviceAdminPackage) {
        if (DEBUG) ProvisionLogger.logd("Reporting success.");
        mDone = true;

        // Enable the HomeReceiverActivity, since the DeviceOwnerProvisioningActivity will shutdown
        // the Setup wizard soon, which will result in a home intent that should be caught by the
        // HomeReceiverActivity.
        PackageManager pm = getPackageManager();
        pm.setComponentEnabledSetting(new ComponentName(DeviceOwnerProvisioningService.this,
                        HomeReceiverActivity.class), PackageManager.COMPONENT_ENABLED_STATE_ENABLED,
                PackageManager.DONT_KILL_APP);

        Intent successIntent = new Intent(ACTION_PROVISIONING_SUCCESS);
        successIntent.setClass(this, DeviceOwnerProvisioningActivity.ServiceMessageReceiver.class);
        LocalBroadcastManager.getInstance(this).sendBroadcast(successIntent);
        // Wait for stopService() call from the activity.
    }

    private void initializeProvisioningEnvironment(ProvisioningParams params) {
        setTimeAndTimezone(params.mTimeZone, params.mLocalTime);
        setLocale(params.mLocale);

        // Start CDMA activation to enable phone calls.
        final Intent intent = new Intent(ACTION_PERFORM_CDMA_PROVISIONING);
        intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        if (DEBUG) ProvisionLogger.logd("Starting cdma activation activity");
        startActivity(intent); // Activity will be a Nop if not a CDMA device.
    }

    private void setTimeAndTimezone(String timeZone, long localTime) {
        try {
            final AlarmManager am = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
            if (timeZone != null) {
                if (DEBUG) ProvisionLogger.logd("Setting time zone to " + timeZone);
                am.setTimeZone(timeZone);
            }
            if (localTime > 0) {
                if (DEBUG) ProvisionLogger.logd("Setting time to " + localTime);
                am.setTime(localTime);
            }
        } catch (Exception e) {
            ProvisionLogger.loge("Alarm manager failed to set the system time/timezone.");
            // Do not stop provisioning process, but ignore this error.
        }
    }

    private void setLocale(Locale locale) {
        if (locale == null || locale.equals(Locale.getDefault())) {
            return;
        }
        try {
            if (DEBUG) ProvisionLogger.logd("Setting locale to " + locale);
            // If locale is different from current locale this results in a configuration change,
            // which will trigger the restarting of the activity.
            LocalePicker.updateLocale(locale);
        } catch (Exception e) {
            ProvisionLogger.loge("Failed to set the system locale.");
            // Do not stop provisioning process, but ignore this error.
        }
    }

    @Override
    public void onCreate () {
        if (DEBUG) ProvisionLogger.logd("Device owner provisioning service ONCREATE.");
    }

    @Override
    public void onDestroy () {
        if (DEBUG) ProvisionLogger.logd("Device owner provisioning service ONDESTROY");
        if (mAddWifiNetworkTask != null) {
            mAddWifiNetworkTask.cleanUp();
        }
        if (mDownloadPackageTask != null) {
            mDownloadPackageTask.cleanUp();
        }
        if (mIndirectHomeReceiver != null) {
            LocalBroadcastManager.getInstance(this).unregisterReceiver(mIndirectHomeReceiver);
            mIndirectHomeReceiver = null;
        }

    }

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }
}