/*
 * Copyright (C) 2018 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.compatibility.common.util;

import android.app.UiAutomation;

import androidx.test.platform.app.InstrumentationRegistry;

import java.util.function.BiFunction;
import java.util.function.Supplier;

/**
 * Provides utility methods to invoke system and privileged APIs as the shell user.
 */
public class ShellIdentityUtils {

    /**
     * Utility interface to invoke a method against the target object.
     *
     * @param <T> the type returned by the invoked method.
     * @param <U> the type of the object against which the method is invoked.
     */
    public interface ShellPermissionMethodHelper<T, U> {
        /**
         * Invokes the method against the target object.
         *
         * @param targetObject the object against which the method should be invoked.
         * @return the result of the invoked method.
         */
        T callMethod(U targetObject);
    }

    /**
     * Utility interface to invoke a method against the target object.
     *
     * @param <U> the type of the object against which the method is invoked.
     */
    public interface ShellPermissionMethodHelperNoReturn<U> {
        /**
         * Invokes the method against the target object.
         *
         * @param targetObject the object against which the method should be invoked.
         */
        void callMethod(U targetObject);
    }

    /**
     * Utility interface to invoke a method against the target object that may throw an Exception.
     *
     * @param <U> the type of the object against which the method is invoked.
     */
    public interface ShellPermissionThrowableMethodHelper<T, U, E extends Throwable> {
        /**
         * Invokes the method against the target object.
         *
         * @param targetObject the object against which the method should be invoked.
         * @return the result of the target method.
         */
        T callMethod(U targetObject) throws E;
    }

    /**
     * Utility interface to invoke a method against the target object that may throw an Exception.
     *
     * @param <U> the type of the object against which the method is invoked.
     */
    public interface ShellPermissionThrowableMethodHelperNoReturn<U, E extends Throwable> {
        /**
         * Invokes the method against the target object.
         *
         * @param targetObject the object against which the method should be invoked.
         */
        void callMethod(U targetObject) throws E;
    }

    /**
     * Invokes the specified method on the targetObject as the shell user. The method can be invoked
     * as follows:
     *
     * {@code ShellIdentityUtils.invokeMethodWithShellPermissions(mTelephonyManager,
     *        (tm) -> tm.getDeviceId());}
     */
    public static <T, U> T invokeMethodWithShellPermissions(U targetObject,
            ShellPermissionMethodHelper<T, U> methodHelper) {
        UiAutomation uiAutomation = null;
        //Retry multiple times for UIAutomation connection timed out fail
        for (int i = 0; i < 5; i++) {
            uiAutomation = InstrumentationRegistry.getInstrumentation().getUiAutomation();
            if (uiAutomation != null) {
                break;
            }
        }
        if (uiAutomation == null) {
            throw new IllegalStateException("Could not get UiAutomation");
        }
        try {
            uiAutomation.adoptShellPermissionIdentity();
            return methodHelper.callMethod(targetObject);
        } finally {
            uiAutomation.dropShellPermissionIdentity();
        }
    }

    /**
     * Invokes the specified method on the targetObject as the shell user with only the subset of
     * permissions specified. The method can be invoked as follows:
     *
     * {@code ShellIdentityUtils.invokeMethodWithShellPermissions(mTelephonyManager,
     *        (tm) -> tm.getDeviceId(), "android.permission.READ_PHONE_STATE");}
     */
    public static <T, U> T invokeMethodWithShellPermissions(U targetObject,
            ShellPermissionMethodHelper<T, U> methodHelper, String... permissions) {
        final UiAutomation uiAutomation =
                InstrumentationRegistry.getInstrumentation().getUiAutomation();
        try {
            uiAutomation.adoptShellPermissionIdentity(permissions);
            return methodHelper.callMethod(targetObject);
        } finally {
            uiAutomation.dropShellPermissionIdentity();
        }
    }

    /** A three argument {@link java.util.function.Function}. */
    public interface TriFunction<T, U, V, R> {
        R apply(T t, U u, V v);
    }

    /** A four argument {@link java.util.function.Function}. */
    public interface QuadFunction<T, U, V, W, R> {
        R apply(T t, U u, V v, W w);
    }

    /**
     * Invokes the specified method wht arg1 and arg2, as the shell user
     * with only the subset of permissions specified. The method can be invoked as follows:
     *
     * {@code ShellIdentityUtils.invokeMethodWithShellPermissions(op, pers,
     *        mTelephonyManager::setNetworkSelectionModeManual(on, p),
     *        "android.permission.MODIFY_PHONE_STATE");}
     */
    public static <T, U, R> R invokeMethodWithShellPermissions(T arg1, U arg2,
            BiFunction<? super T, ? super U, ? extends R>  methodHelper, String... permissions) {
        final UiAutomation uiAutomation =
                InstrumentationRegistry.getInstrumentation().getUiAutomation();
        try {
            uiAutomation.adoptShellPermissionIdentity(permissions);
            return methodHelper.apply(arg1, arg2);
        } finally {
            uiAutomation.dropShellPermissionIdentity();
        }
    }

    /**
     * Invokes the specified method with arg1, arg2 and arg3, as the shell user
     * with only the subset of permissions specified. The method can be invoked as follows:
     *
     * {@code ShellIdentityUtils.invokeMethodWithShellPermissions(req, cb, exe,
     *        mTelephonyManager::requestNetworkScan,
     *        "android.permission.MODIFY_PHONE_STATE",
     *        "android.permission.ACCESS_FINE_LOCATION");}
     */
    public static <T, U, V, R> R invokeMethodWithShellPermissions(T arg1, U arg2, V arg3,
            TriFunction<? super T, ? super U, ? super V, ? extends R>  methodHelper,
            String... permissions) {
        final UiAutomation uiAutomation =
                InstrumentationRegistry.getInstrumentation().getUiAutomation();
        try {
            uiAutomation.adoptShellPermissionIdentity(permissions);
            return methodHelper.apply(arg1, arg2, arg3);
        } finally {
            uiAutomation.dropShellPermissionIdentity();
        }
    }

    /**
     * Invokes the specified method with arg1, arg2, arg3 and arg4, as the shell
     * user with only the subset of permissions specified. The method can be invoked as follows:
     *
     * {@code ShellIdentityUtils.invokeMethodWithShellPermissions(a, b, c, d,
     *        mTelephonyManager::requestSomething,
     *        "android.permission.MODIFY_PHONE_STATE",
     *        "android.permission.ACCESS_FINE_LOCATION");}
     */
    public static <T, U, V, W, R> R invokeMethodWithShellPermissions(T arg1, U arg2, V arg3, W arg4,
            QuadFunction<? super T, ? super U, ? super V, ? super W, ? extends R>  methodHelper,
            String... permissions) {
        final UiAutomation uiAutomation =
                InstrumentationRegistry.getInstrumentation().getUiAutomation();
        try {
            uiAutomation.adoptShellPermissionIdentity(permissions);
            return methodHelper.apply(arg1, arg2, arg3, arg4);
        } finally {
            uiAutomation.dropShellPermissionIdentity();
        }
    }

    /**
     * Invokes the specified method on the targetObject as the shell user with only the subset of
     * permissions specified. The method can be invoked as follows:
     *
     * {@code ShellIdentityUtils.invokeMethodWithShellPermissions(mRcsUceAdapter,
     *        (m) -> RcsUceAdapter::getUcePublishState, ImsException.class,
     *                     "android.permission.READ_PRIVILEGED_PHONE_STATE")}
     */
    public static <T, U, E extends Throwable> T invokeThrowableMethodWithShellPermissions(
            U targetObject, ShellPermissionThrowableMethodHelper<T, U, E> methodHelper,
            Class<E> clazz, String... permissions) throws E {
        final UiAutomation uiAutomation =
                InstrumentationRegistry.getInstrumentation().getUiAutomation();
        try {
            uiAutomation.adoptShellPermissionIdentity(permissions);
            return methodHelper.callMethod(targetObject);
        } finally {
            uiAutomation.dropShellPermissionIdentity();
        }
    }

    /**
     * Invokes the specified method on the targetObject as the shell user for only the permissions
     * specified. The method can be invoked as follows:
     *
     * {@code ShellIdentityUtils.invokeMethodWithShellPermissions(mTelephonyManager,
     *        (tm) -> tm.getDeviceId(), "android.permission.READ_PHONE_STATE");}
     */
    public static <U> void invokeMethodWithShellPermissionsNoReturn(
            U targetObject, ShellPermissionMethodHelperNoReturn<U> methodHelper,
            String... permissions) {
        final UiAutomation uiAutomation =
                InstrumentationRegistry.getInstrumentation().getUiAutomation();
        try {
            uiAutomation.adoptShellPermissionIdentity(permissions);
            methodHelper.callMethod(targetObject);
        } finally {
            uiAutomation.dropShellPermissionIdentity();
        }
    }

    /**
     * Invokes the specified throwable method on the targetObject as the shell user with only the
     * subset of permissions specified specified. The method can be invoked as follows:
     *
     * {@code ShellIdentityUtils.invokeMethodWithShellPermissions(mImsMmtelManager,
     *        (m) -> m.isSupported(...), ImsException.class);}
     */
    public static <U, E extends Throwable> void invokeThrowableMethodWithShellPermissionsNoReturn(
            U targetObject, ShellPermissionThrowableMethodHelperNoReturn<U, E> methodHelper,
            Class<E> clazz) throws E {
        final UiAutomation uiAutomation =
                InstrumentationRegistry.getInstrumentation().getUiAutomation();
        try {
            uiAutomation.adoptShellPermissionIdentity();
            methodHelper.callMethod(targetObject);
        } finally {
            uiAutomation.dropShellPermissionIdentity();
        }
    }

    /**
     * Invokes the specified throwable method on the targetObject as the shell user with only the
     * subset of permissions specified specified. The method can be invoked as follows:
     *
     * {@code ShellIdentityUtils.invokeMethodWithShellPermissions(mImsMmtelManager,
     *        (m) -> m.isSupported(...), ImsException.class,
     *        "android.permission.READ_PRIVILEGED_PHONE_STATE");}
     */
    public static <U, E extends Throwable> void invokeThrowableMethodWithShellPermissionsNoReturn(
            U targetObject, ShellPermissionThrowableMethodHelperNoReturn<U, E> methodHelper,
            Class<E> clazz, String... permissions) throws E {
        final UiAutomation uiAutomation =
                InstrumentationRegistry.getInstrumentation().getUiAutomation();
        try {
            uiAutomation.adoptShellPermissionIdentity(permissions);
            methodHelper.callMethod(targetObject);
        } finally {
            uiAutomation.dropShellPermissionIdentity();
        }
    }


    /**
     * Invokes the specified method on the targetObject as the shell user. The method can be invoked
     * as follows:
     *
     * {@code ShellIdentityUtils.invokeMethodWithShellPermissions(mTelephonyManager,
     *        (tm) -> tm.getDeviceId());}
     */
    public static <U> void invokeMethodWithShellPermissionsNoReturn(
            U targetObject, ShellPermissionMethodHelperNoReturn<U> methodHelper) {
        final UiAutomation uiAutomation =
                InstrumentationRegistry.getInstrumentation().getUiAutomation();
        try {
            uiAutomation.adoptShellPermissionIdentity();
            methodHelper.callMethod(targetObject);
        } finally {
            uiAutomation.dropShellPermissionIdentity();
        }
    }

    /**
     * Utility interface to invoke a static method.
     *
     * @param <T> the type returned by the invoked method.
     */
    public interface StaticShellPermissionMethodHelper<T> {
        /**
         * Invokes the static method.
         *
         * @return the result of the invoked method.
         */
        T callMethod();
    }

    /**
     * Invokes the specified static method as the shell user. This method can be invoked as follows:
     *
     * {@code ShellIdentityUtils.invokeStaticMethodWithShellPermissions(Build::getSerial));}
     */
    public static <T> T invokeStaticMethodWithShellPermissions(
            StaticShellPermissionMethodHelper<T> methodHelper) {
        final UiAutomation uiAutomation =
                InstrumentationRegistry.getInstrumentation().getUiAutomation();
        try {
            uiAutomation.adoptShellPermissionIdentity();
            return methodHelper.callMethod();
        } finally {
            uiAutomation.dropShellPermissionIdentity();
        }
    }

    /**
     * Drop the shell permission identity adopted by a previous call to
     * {@link UiAutomation#adoptShellPermissionIdentity()}.
     */
    public static void dropShellPermissionIdentity() {
        final UiAutomation uiAutomation =
                InstrumentationRegistry.getInstrumentation().getUiAutomation();

        uiAutomation.dropShellPermissionIdentity();
    }

    /**
     * Run an arbitrary piece of code while holding shell permissions.
     *
     * @param supplier an expression that performs the desired operation with shell permissions
     * @param <T> the return type of the expression
     * @return the return value of the expression
     */
    public static <T> T invokeWithShellPermissions(Supplier<T> supplier) {
        final UiAutomation uiAutomation =
                InstrumentationRegistry.getInstrumentation().getUiAutomation();
        try {
            uiAutomation.adoptShellPermissionIdentity();
            return supplier.get();
        } finally {
            uiAutomation.dropShellPermissionIdentity();
        }
    }

    /**
     * Run an arbitrary piece of code while holding shell permissions.
     *
     * @param runnable an expression that performs the desired operation with shell permissions
     * @return the return value of the expression
     */
    public static void invokeWithShellPermissions(Runnable runnable) {
        final UiAutomation uiAutomation =
                InstrumentationRegistry.getInstrumentation().getUiAutomation();
        try {
            uiAutomation.adoptShellPermissionIdentity();
            runnable.run();
        } finally {
            uiAutomation.dropShellPermissionIdentity();
        }
    }
}