Add util methods for WorkPolicy in SettingsLib

/*

 * 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.settingslib.utils;

import android.app.admin.DevicePolicyManager;

import android.content.ComponentName;

import android.content.Context;

import android.content.Intent;

import android.content.pm.PackageManager;

import android.content.pm.ResolveInfo;

import android.os.UserHandle;

import android.os.UserManager;

import android.provider.Settings;

import java.util.List;

/**

 * Utility class for find out when to show WorkPolicyInfo

 */

public class WorkPolicyUtils {

    Context mContext;

    PackageManager mPackageManager;

    UserManager mUserManager;

    DevicePolicyManager mDevicePolicyManager;

    private static final int USER_NULL = -10000;

    public WorkPolicyUtils(

            Context applicationContext,

            PackageManager mPm,

            UserManager mUm,

            DevicePolicyManager mDpm

    ) {

        mContext = applicationContext;

        mPackageManager = mPm;

        mUserManager = mUm;

        mDevicePolicyManager = mDpm;

    }

    /**

     * Returns {@code true} if it is possilbe to resolve an Intent to launch the "Your work policy

     * info" page provided by the active Device Owner or Profile Owner app if it exists, {@code

     * false} otherwise.

     */

    public boolean hasWorkPolicy() {

        return getWorkPolicyInfoIntentDO() != null || getWorkPolicyInfoIntentPO() != null;

    }

    /**

     * Launches the Device Owner or Profile Owner's activity that displays the "Your work policy

     * info" page. Returns {@code true} if the activity has indeed been launched.

     */

    public boolean showWorkPolicyInfo(Context activityContext) {

        Intent intent = getWorkPolicyInfoIntentDO();

        if (intent != null) {

            activityContext.startActivity(intent);

            return true;

        }

        intent = getWorkPolicyInfoIntentPO();

        final int userId = getManagedProfileUserId();

        if (intent != null && userId != USER_NULL) {

            activityContext.startActivityAsUser(intent, UserHandle.of(userId));

            return true;

        }

        return false;

    }

    private Intent getWorkPolicyInfoIntentDO() {

        final ComponentName ownerComponent = getDeviceOwnerComponent();

        if (ownerComponent == null) {

            return null;

        }

        // Only search for the required action in the Device Owner's package

        final Intent intent =

                new Intent(Settings.ACTION_SHOW_WORK_POLICY_INFO)

                        .setPackage(ownerComponent.getPackageName());

        final List<ResolveInfo> activities = mPackageManager.queryIntentActivities(intent, 0);

        if (activities.size() != 0) {

            return intent;

        }

        return null;

    }

    private Intent getWorkPolicyInfoIntentPO() {

        try {

            final int managedUserId = getManagedProfileUserId();

            if (managedUserId == USER_NULL) {

                return null;

            }

            Context managedProfileContext =

                    mContext.createPackageContextAsUser(

                            mContext.getPackageName(), 0, UserHandle.of(managedUserId)

                    );

            DevicePolicyManager managedProfileDevicePolicyManager =

                    (DevicePolicyManager)

                            managedProfileContext.getSystemService(Context.DEVICE_POLICY_SERVICE);

            ComponentName ownerComponent = managedProfileDevicePolicyManager.getProfileOwner();

            if (ownerComponent == null) {

                return null;

            }

            // Only search for the required action in the Profile Owner's package

            final Intent intent =

                    new Intent(Settings.ACTION_SHOW_WORK_POLICY_INFO)

                            .setPackage(ownerComponent.getPackageName());

            final List<ResolveInfo> activities =

                    mPackageManager.queryIntentActivitiesAsUser(

                            intent, 0, UserHandle.of(managedUserId));

            if (activities.size() != 0) {

                return intent;

            }

            return null;

        } catch (PackageManager.NameNotFoundException e) {

            return null;

        }

    }

    private ComponentName getDeviceOwnerComponent() {

        if (!mPackageManager.hasSystemFeature(PackageManager.FEATURE_DEVICE_ADMIN)) {

            return null;

        }

        return mDevicePolicyManager.getDeviceOwnerComponentOnAnyUser();

    }

    private int getManagedProfileUserId() {

        List<UserHandle> allProfiles = mUserManager.getAllProfiles();

        for (UserHandle uh : allProfiles) {

            int id = uh.getIdentifier();

            if (mUserManager.isManagedProfile(id)) {

                return id;

            }

        }

        return USER_NULL;

    }

}