/*
 * Copyright (C) 2019 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 android.permission;

import android.annotation.NonNull;
import android.annotation.Nullable;
import android.annotation.UserIdInt;
import android.os.UserHandle;

import com.android.internal.util.function.TriFunction;

import java.util.function.BiFunction;

/**
 * Internal interfaces to be used by other components within the system server.
 *
 * <p>Only for use within the system server.
 *
 * @hide
 */
public abstract class PermissionManagerInternal {

    /**
     * Listener for package permission state (permissions or flags) changes.
     */
    public interface OnRuntimePermissionStateChangedListener {

        /**
         * Called when the runtime permission state (permissions or flags) changed.
         *
         * @param packageName The package for which the change happened.
         * @param userId the user id for which the change happened.
         */
        @Nullable
        void onRuntimePermissionStateChanged(@NonNull String packageName,
                @UserIdInt int userId);
    }

    /** Interface to override permission checks via composition */
    public interface CheckPermissionDelegate {
        /**
         * Checks whether the given package has been granted the specified permission.
         *
         * @return If the package has the permission, PERMISSION_GRANTED is
         * returned.  If it does not have the permission, PERMISSION_DENIED
         * is returned.
         *
         * @see android.content.pm.PackageManager#checkPermission(String, String)
         */
        int checkPermission(String permName, String pkgName, int userId,
                TriFunction<String, String, Integer, Integer> superImpl);

        /**
        /**
         * Checks whether the given uid has been granted the specified permission.
         *
         * @return If the package has the permission, PERMISSION_GRANTED is
         * returned.  If it does not have the permission, PERMISSION_DENIED
         * is returned.
         *
         */
        int checkUidPermission(String permName, int uid,
                BiFunction<String, Integer, Integer> superImpl);
    }

    /**
     * Get the state of the runtime permissions as xml file.
     *
     * @param user The user the data should be extracted for
     *
     * @return The state as a xml file
     */
    public abstract @Nullable byte[] backupRuntimePermissions(@NonNull UserHandle user);

    /**
     * Restore a permission state previously backed up via {@link #backupRuntimePermissions}.
     *
     * <p>If not all state can be restored, the un-restoreable state will be delayed and can be
     * re-tried via {@link #restoreDelayedRuntimePermissions}.
     *
     * @param backup The state as an xml file
     * @param user The user the data should be restored for
     */
    public abstract void restoreRuntimePermissions(@NonNull byte[] backup,
            @NonNull UserHandle user);

    /**
     * Try to apply permission backup of a package that was previously not applied.
     *
     * @param packageName The package that is newly installed
     * @param user The user the package is installed for
     *
     * @see #restoreRuntimePermissions
     */
    public abstract void restoreDelayedRuntimePermissions(@NonNull String packageName,
            @NonNull UserHandle user);

    /**
     * Adds a listener for runtime permission state (permissions or flags) changes.
     *
     * @param listener The listener.
     */
    public abstract void addOnRuntimePermissionStateChangedListener(
            @NonNull OnRuntimePermissionStateChangedListener listener);

    /**
     * Removes a listener for runtime permission state (permissions or flags) changes.
     *
     * @param listener The listener.
     */
    public abstract void removeOnRuntimePermissionStateChangedListener(
            @NonNull OnRuntimePermissionStateChangedListener listener);
}