/*
 * 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.internal.net.ipsec.ike.shim;

import android.content.Context;
import android.net.Network;
import android.net.SocketKeepalive;
import android.net.ipsec.ike.exceptions.IkeException;
import android.os.Build;

import com.android.internal.net.ipsec.ike.net.IkeConnectionController;
import com.android.modules.utils.build.SdkLevel;

import java.io.IOException;

/**
 * The base shim utilities class.
 *
 * <p>Subclasses (like ShimUtilsRAndS) are tied to specific Android SDK versions to provide SDK
 * specific behaviors.
 *
 * <p>Callers should call getInstance to get a correct version of ShimUtils object.
 */
public abstract class ShimUtils {
    private static final ShimUtils INSTANCE;

    static {
        if (Build.VERSION.SDK_INT > Build.VERSION_CODES.VANILLA_ICE_CREAM) {
            INSTANCE = new ShimUtilsMinW();
        } else if (SdkLevel.isAtLeastU()) {
            INSTANCE = new ShimUtilsU();
        } else if (SdkLevel.isAtLeastT()) {
            INSTANCE = new ShimUtilsT();
        } else {
            INSTANCE = new ShimUtilsRAndS();
        }
    }

    // Package protected constructor
    ShimUtils() {}

    /** Get a ShimUtils instance based on the platform version */
    public static ShimUtils getInstance() {
        return INSTANCE;
    }

    /**
     * Wrap the Exception as an IkeException or do nothing if the input is already an IkeException.
     */
    public abstract IkeException getWrappedIkeException(Exception exception);

    /** Create an Exception for a retransmission failure */
    public abstract Exception getRetransmissionFailedException(String errMsg);

    /** Create an IOException for a DNS lookup failure */
    public abstract IOException getDnsFailedException(String errMsg);

    /** Handle network loss on an IkeSessionStateMachine without mobility */
    public abstract void onUnderlyingNetworkDiedWithoutMobility(
            IIkeSessionStateMachineShim ikeSession, Network network);

    /**
     * Handle all IkeConnectionController calls that are not initiated from the
     * IkeSessionStateMachine.
     */
    public abstract void executeOrSendFatalError(Runnable r, IkeConnectionController.Callback cb);

    /**
     * Start the given Socketkeepalive.
     */
    public abstract void startKeepalive(SocketKeepalive keepalive, int keepaliveDelaySeconds,
            int keepaliveOptions, Network underpinnedNetwork);

    /**
     * Return if IkeConnectionController can skip a mobility update when the underlying network and
     * addresses do not change
     */
    public abstract boolean shouldSkipIfSameNetwork(boolean skipIfSameNetwork);

    /** Returns if the device supports kernel migration without encap socket changes. */
    public abstract boolean supportsSameSocketKernelMigration(Context context);

    /** Returns if supports suspend on network loss. */
    public abstract boolean suspendOnNetworkLossEnabled();
}