/*
 * Copyright (C) 2016 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.wifi;

import static org.hamcrest.core.IsEqual.equalTo;
import static org.junit.Assert.assertEquals;
import static org.junit.Assert.assertTrue;
import static org.mockito.Matchers.any;
import static org.mockito.Mockito.inOrder;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.spy;

import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.test.suitebuilder.annotation.SmallTest;

import org.junit.Before;
import org.junit.Rule;
import org.junit.Test;
import org.junit.rules.ErrorCollector;
import org.mockito.ArgumentCaptor;
import org.mockito.InOrder;
import org.mockito.MockitoAnnotations;

/**
 * Test MockLooperAbstractTime which provides control over "time". Note that
 * real-time is being used as well. Therefore small time increments are NOT
 * reliable. All tests are in "K" units (i.e. *1000).
 */

@SmallTest
public class MockLooperTest {
    private MockLooper mMockLooper;
    private Handler mHandler;
    private Handler mHandlerSpy;

    @Rule
    public ErrorCollector collector = new ErrorCollector();

    @Before
    public void setUp() throws Exception {
        MockitoAnnotations.initMocks(this);

        mMockLooper = new MockLooper();
        mHandler = new Handler(mMockLooper.getLooper());
        mHandlerSpy = spy(mHandler);
    }

    /**
     * Basic test with no time stamps: dispatch 4 messages, check that all 4
     * delivered (in correct order).
     */
    @Test
    public void testNoTimeMovement() {
        final int messageA = 1;
        final int messageB = 2;
        final int messageC = 3;

        InOrder inOrder = inOrder(mHandlerSpy);
        ArgumentCaptor<Message> messageCaptor = ArgumentCaptor.forClass(Message.class);

        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageA));
        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageA));
        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageB));
        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageC));
        mMockLooper.dispatchAll();

        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("1: messageA", messageA, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("2: messageA", messageA, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("3: messageB", messageB, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("4: messageC", messageC, equalTo(messageCaptor.getValue().what));

        inOrder.verify(mHandlerSpy, never()).handleMessage(any(Message.class));
    }

    /**
     * Test message sequence: A, B, C@5K, A@10K. Don't move time.
     * <p>
     * Expected: only get A, B
     */
    @Test
    public void testDelayedDispatchNoTimeMove() {
        final int messageA = 1;
        final int messageB = 2;
        final int messageC = 3;

        InOrder inOrder = inOrder(mHandlerSpy);
        ArgumentCaptor<Message> messageCaptor = ArgumentCaptor.forClass(Message.class);

        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageA));
        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageB));
        mHandlerSpy.sendMessageDelayed(mHandler.obtainMessage(messageC), 5000);
        mHandlerSpy.sendMessageDelayed(mHandler.obtainMessage(messageA), 10000);
        mMockLooper.dispatchAll();

        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("1: messageA", messageA, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("2: messageB", messageB, equalTo(messageCaptor.getValue().what));

        inOrder.verify(mHandlerSpy, never()).handleMessage(any(Message.class));
    }

    /**
     * Test message sequence: A, B, C@5K, A@10K, Advance time by 5K.
     * <p>
     * Expected: only get A, B, C
     */
    @Test
    public void testDelayedDispatchAdvanceTimeOnce() {
        final int messageA = 1;
        final int messageB = 2;
        final int messageC = 3;

        InOrder inOrder = inOrder(mHandlerSpy);
        ArgumentCaptor<Message> messageCaptor = ArgumentCaptor.forClass(Message.class);

        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageA));
        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageB));
        mHandlerSpy.sendMessageDelayed(mHandler.obtainMessage(messageC), 5000);
        mHandlerSpy.sendMessageDelayed(mHandler.obtainMessage(messageA), 10000);
        mMockLooper.moveTimeForward(5000);
        mMockLooper.dispatchAll();

        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("1: messageA", messageA, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("2: messageB", messageB, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("3: messageC", messageC, equalTo(messageCaptor.getValue().what));

        inOrder.verify(mHandlerSpy, never()).handleMessage(any(Message.class));
    }

    /**
     * Test message sequence: A, B, C@5K, Advance time by 4K, A@1K, B@2K Advance
     * time by 1K.
     * <p>
     * Expected: get A, B, C, A
     */
    @Test
    public void testDelayedDispatchAdvanceTimeTwice() {
        final int messageA = 1;
        final int messageB = 2;
        final int messageC = 3;

        InOrder inOrder = inOrder(mHandlerSpy);
        ArgumentCaptor<Message> messageCaptor = ArgumentCaptor.forClass(Message.class);

        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageA));
        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageB));
        mHandlerSpy.sendMessageDelayed(mHandler.obtainMessage(messageC), 5000);
        mMockLooper.moveTimeForward(4000);
        mHandlerSpy.sendMessageDelayed(mHandler.obtainMessage(messageA), 1000);
        mHandlerSpy.sendMessageDelayed(mHandler.obtainMessage(messageB), 2000);
        mMockLooper.moveTimeForward(1000);
        mMockLooper.dispatchAll();

        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("1: messageA", messageA, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("2: messageB", messageB, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("3: messageC", messageC, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("4: messageA", messageA, equalTo(messageCaptor.getValue().what));

        inOrder.verify(mHandlerSpy, never()).handleMessage(any(Message.class));
    }

    /**
     * Test message sequence: A, B, C@5K, Advance time by 4K, A@5K, B@2K Advance
     * time by 3K.
     * <p>
     * Expected: get A, B, C, B
     */
    @Test
    public void testDelayedDispatchReverseOrder() {
        final int messageA = 1;
        final int messageB = 2;
        final int messageC = 3;

        InOrder inOrder = inOrder(mHandlerSpy);
        ArgumentCaptor<Message> messageCaptor = ArgumentCaptor.forClass(Message.class);

        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageA));
        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageB));
        mHandlerSpy.sendMessageDelayed(mHandler.obtainMessage(messageC), 5000);
        mMockLooper.moveTimeForward(4000);
        mHandlerSpy.sendMessageDelayed(mHandler.obtainMessage(messageA), 5000);
        mHandlerSpy.sendMessageDelayed(mHandler.obtainMessage(messageB), 2000);
        mMockLooper.moveTimeForward(3000);
        mMockLooper.dispatchAll();

        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("1: messageA", messageA, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("2: messageB", messageB, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("3: messageC", messageC, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("4: messageB", messageB, equalTo(messageCaptor.getValue().what));

        inOrder.verify(mHandlerSpy, never()).handleMessage(any(Message.class));
    }

    /**
     * Test message sequence: A, B, C@5K, Advance time by 4K, dispatch all,
     * A@5K, B@2K Advance time by 3K, dispatch all.
     * <p>
     * Expected: get A, B after first dispatch; then C, B after second dispatch
     */
    @Test
    public void testDelayedDispatchAllMultipleTimes() {
        final int messageA = 1;
        final int messageB = 2;
        final int messageC = 3;

        InOrder inOrder = inOrder(mHandlerSpy);
        ArgumentCaptor<Message> messageCaptor = ArgumentCaptor.forClass(Message.class);

        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageA));
        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageB));
        mHandlerSpy.sendMessageDelayed(mHandler.obtainMessage(messageC), 5000);
        mMockLooper.moveTimeForward(4000);
        mMockLooper.dispatchAll();

        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("1: messageA", messageA, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("2: messageB", messageB, equalTo(messageCaptor.getValue().what));

        mHandlerSpy.sendMessageDelayed(mHandler.obtainMessage(messageA), 5000);
        mHandlerSpy.sendMessageDelayed(mHandler.obtainMessage(messageB), 2000);
        mMockLooper.moveTimeForward(3000);
        mMockLooper.dispatchAll();

        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("3: messageC", messageC, equalTo(messageCaptor.getValue().what));
        inOrder.verify(mHandlerSpy).handleMessage(messageCaptor.capture());
        collector.checkThat("4: messageB", messageB, equalTo(messageCaptor.getValue().what));

        inOrder.verify(mHandlerSpy, never()).handleMessage(any(Message.class));
    }

    /**
     * Test AutoDispatch for a single message.
     * This test would ideally use the Channel sendMessageSynchronously.  At this time, the setup to
     * get a working test channel is cumbersome.  Until this is fixed, we substitute with a
     * sendMessage followed by a blocking call.  The main test thread blocks until the test handler
     * receives the test message (messageA) and sets a boolean true.  Once the boolean is true, the
     * main thread will exit the busy wait loop, stop autoDispatch and check the assert.
     *
     * Enable AutoDispatch, add message, block on message being handled and stop AutoDispatch.
     * <p>
     * Expected: handleMessage is called for messageA and stopAutoDispatch is called.
     */
    @Test
    public void testAutoDispatchWithSingleMessage() {
        final int mLoopSleepTimeMs = 5;

        final int messageA = 1;

        MockLooper mockLooper = new MockLooper();
        class TestHandler extends Handler {
            public volatile boolean handledMessage = false;
            TestHandler(Looper looper) {
                super(looper);
            }

            @Override
            public void handleMessage(Message msg) {
                if (msg.what == messageA) {
                    handledMessage = true;
                }
            }
        }

        TestHandler testHandler = new TestHandler(mockLooper.getLooper());
        mockLooper.startAutoDispatch();
        testHandler.sendMessage(testHandler.obtainMessage(messageA));
        while (!testHandler.handledMessage) {
            // Block until message is handled
            try {
                Thread.sleep(mLoopSleepTimeMs);
            } catch (InterruptedException e) {
                // Interrupted while sleeping.
            }
        }
        mockLooper.stopAutoDispatch();
        assertTrue("TestHandler should have received messageA", testHandler.handledMessage);
    }

    /**
     * Test starting AutoDispatch while already running throws IllegalStateException
     * Enable AutoDispatch two times in a row.
     * <p>
     * Expected: catch IllegalStateException on second call.
     */
    @Test(expected = IllegalStateException.class)
    public void testRepeatedStartAutoDispatchThrowsException() {
        mMockLooper.startAutoDispatch();
        mMockLooper.startAutoDispatch();
    }

    /**
     * Test stopping AutoDispatch without previously starting throws IllegalStateException
     * Stop AutoDispatch
     * <p>
     * Expected: catch IllegalStateException on second call.
     */
    @Test(expected = IllegalStateException.class)
    public void testStopAutoDispatchWithoutStartThrowsException() {
        mMockLooper.stopAutoDispatch();
    }

    /**
     * Test AutoDispatch exits and does not dispatch a later message.
     * Start and stop AutoDispatch then add a message.
     * <p>
     * Expected: After AutoDispatch is stopped, dispatchAll will return 1.
     */
    @Test
    public void testAutoDispatchStopsCleanlyWithoutDispatchingAMessage() {
        final int messageA = 1;

        InOrder inOrder = inOrder(mHandlerSpy);
        ArgumentCaptor<Message> messageCaptor = ArgumentCaptor.forClass(Message.class);

        mMockLooper.startAutoDispatch();
        try {
            mMockLooper.stopAutoDispatch();
        } catch (IllegalStateException e) {
            //  Stopping without a dispatch will throw an exception.
        }

        mHandlerSpy.sendMessage(mHandler.obtainMessage(messageA));
        assertEquals("One message should be dispatched", 1, mMockLooper.dispatchAll());
    }

    /**
     * Test AutoDispatch throws an exception when no messages are dispatched.
     * Start and stop AutoDispatch
     * <p>
     * Expected: Exception is thrown with the stopAutoDispatch call.
     */
    @Test(expected = IllegalStateException.class)
    public void testAutoDispatchThrowsExceptionWhenNoMessagesDispatched() {
        mMockLooper.startAutoDispatch();
        mMockLooper.stopAutoDispatch();
    }
}