/*
 * Copyright (C) 2020 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.server.vcn;

import static android.net.IpSecManager.IpSecTunnelInterface;

import static com.android.server.vcn.VcnGatewayConnection.DUMMY_ADDR;

import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertNull;
import static org.junit.Assert.assertTrue;
import static org.mockito.ArgumentMatchers.any;
import static org.mockito.ArgumentMatchers.anyInt;
import static org.mockito.ArgumentMatchers.eq;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.verify;

import android.net.IpSecManager;

import androidx.test.filters.SmallTest;
import androidx.test.runner.AndroidJUnit4;

import com.android.server.vcn.metrics.VcnMetrics;

import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;

@RunWith(AndroidJUnit4.class)
@SmallTest
public class VcnGatewayConnectionDisconnectedStateTest extends VcnGatewayConnectionTestBase {
    @Before
    public void setUp() throws Exception {
        super.setUp();

        final IpSecTunnelInterface tunnelIface =
                mContext.getSystemService(IpSecManager.class)
                        .createIpSecTunnelInterface(
                                DUMMY_ADDR, DUMMY_ADDR, TEST_UNDERLYING_NETWORK_RECORD_1.network);
        mGatewayConnection.setTunnelInterface(tunnelIface);

        // Don't need to transition to DisconnectedState because it is the starting state
        mTestLooper.dispatchAll();
    }

    @Test
    public void testEnterWhileQuittingTriggersQuit() throws Exception {
        final VcnGatewayConnection vgc =
                new VcnGatewayConnection(
                        mVcnContext,
                        TEST_SUB_GRP,
                        TEST_SUBSCRIPTION_SNAPSHOT,
                        mConfig,
                        mGatewayStatusCallback,
                        true /* isMobileDataEnabled */,
                        mDeps);

        vgc.setQuitting();
        vgc.transitionTo(vgc.mDisconnectedState);
        mTestLooper.dispatchAll();

        assertNull(vgc.getCurrentState());
    }

    @Test
    public void testNetworkChangesTriggerStateTransitions() throws Exception {
        mGatewayConnection
                .getUnderlyingNetworkControllerCallback()
                .onSelectedUnderlyingNetworkChanged(TEST_UNDERLYING_NETWORK_RECORD_1);
        mTestLooper.dispatchAll();

        assertEquals(mGatewayConnection.mConnectingState, mGatewayConnection.getCurrentState());
        verifySafeModeTimeoutAlarmAndGetCallback(false /* expectCanceled */);
    }

    @Test
    public void testNullNetworkDoesNotTriggerStateTransition() throws Exception {
        mGatewayConnection
                .getUnderlyingNetworkControllerCallback()
                .onSelectedUnderlyingNetworkChanged(null);
        mTestLooper.dispatchAll();

        assertEquals(mGatewayConnection.mDisconnectedState, mGatewayConnection.getCurrentState());
        verifyDisconnectRequestAlarmAndGetCallback(false /* expectCanceled */);
    }

    @Test
    public void testNonTeardownDisconnectRequest() throws Exception {
        mGatewayConnection.sendDisconnectRequestedAndAcquireWakelock("TEST", false);
        mTestLooper.dispatchAll();

        assertEquals(mGatewayConnection.mDisconnectedState, mGatewayConnection.getCurrentState());
        assertFalse(mGatewayConnection.isQuitting());
        verify(mGatewayStatusCallback, never()).onQuit();
        verify(mVcnMetrics, never()).logVcnGatewayTeardown(anyInt(), anyInt());
        // No safe mode timer changes expected.
    }

    @Test
    public void testTeardownDisconnectRequest() throws Exception {
        mGatewayConnection.sendDisconnectRequestedAndAcquireWakelock("TEST", true);
        mTestLooper.dispatchAll();

        assertNull(mGatewayConnection.getCurrentState());
        verify(mIpSecSvc).deleteTunnelInterface(eq(TEST_IPSEC_TUNNEL_RESOURCE_ID), any());
        verifySafeModeTimeoutAlarmAndGetCallback(true /* expectCanceled */);
        assertTrue(mGatewayConnection.isQuitting());
        verify(mGatewayStatusCallback).onQuit();
        verify(mVcnMetrics).logVcnGatewayTeardown(anyInt(), anyInt());
    }

    @Test
    public void testTeardown_subsequentNonTeardown_stillIsQuitting() throws Exception {
        mGatewayConnection.teardownAsynchronously();
        mTestLooper.dispatchAll();
        assertEquals(
                mGatewayConnection.getTeardownReason(),
                VcnMetrics.GATEWAY_TEARDOWN_REASON_REQUESTED);

        // Verify that sending a non-quitting disconnect request does not unset the isQuitting flag
        mGatewayConnection.sendDisconnectRequestedAndAcquireWakelock("TEST", false);
        mTestLooper.dispatchAll();

        assertNull(mGatewayConnection.getCurrentState());
        assertTrue(mGatewayConnection.isQuitting());
        assertEquals(
                mGatewayConnection.getTeardownReason(),
                VcnMetrics.GATEWAY_TEARDOWN_REASON_REQUESTED);
    }
}