/*
 * 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.junit.Assert.assertEquals;
import static org.junit.Assert.assertFalse;
import static org.junit.Assert.assertTrue;
import static org.mockito.AdditionalAnswers.answerVoid;
import static org.mockito.ArgumentMatchers.anyString;
import static org.mockito.Mockito.anyInt;
import static org.mockito.Mockito.atLeast;
import static org.mockito.Mockito.atMost;
import static org.mockito.Mockito.doAnswer;
import static org.mockito.Mockito.never;
import static org.mockito.Mockito.times;
import static org.mockito.Mockito.verify;
import static org.mockito.Mockito.when;

import android.content.Context;
import android.content.res.Resources;
import android.net.NetworkAgent;
import android.net.wifi.WifiConfiguration;
import android.net.wifi.WifiInfo;

import androidx.test.filters.SmallTest;

import com.android.internal.R;

import org.junit.After;
import org.junit.Before;
import org.junit.Test;
import org.mockito.Mock;
import org.mockito.MockitoAnnotations;

import java.io.PrintWriter;

/**
 * Unit tests for {@link com.android.server.wifi.WifiScoreReport}.
 */
@SmallTest
public class WifiScoreReportTest {


    class FakeClock extends Clock {
        long mWallClockMillis = 1500000000000L;
        int mStepMillis = 1001;

        @Override
        public long getWallClockMillis() {
            mWallClockMillis += mStepMillis;
            return mWallClockMillis;
        }
    }

    FakeClock mClock;
    WifiConfiguration mWifiConfiguration;
    WifiScoreReport mWifiScoreReport;
    ScanDetailCache mScanDetailCache;
    WifiInfo mWifiInfo;
    ScoringParams mScoringParams;
    @Mock Context mContext;
    @Mock NetworkAgent mNetworkAgent;
    @Mock Resources mResources;
    @Mock WifiMetrics mWifiMetrics;
    @Mock PrintWriter mPrintWriter;

    /**
     * Sets up resource values for testing
     *
     * See frameworks/base/core/res/res/values/config.xml
     */
    private void setUpResources(Resources resources) {
        when(resources.getInteger(
                R.integer.config_wifi_framework_wifi_score_bad_rssi_threshold_5GHz))
            .thenReturn(-82);
        when(resources.getInteger(
                R.integer.config_wifi_framework_wifi_score_entry_rssi_threshold_5GHz))
            .thenReturn(-77);
        when(resources.getInteger(
                R.integer.config_wifi_framework_wifi_score_low_rssi_threshold_5GHz))
            .thenReturn(-70);
        when(resources.getInteger(
                R.integer.config_wifi_framework_wifi_score_good_rssi_threshold_5GHz))
            .thenReturn(-57);
        when(resources.getInteger(
                R.integer.config_wifi_framework_wifi_score_bad_rssi_threshold_24GHz))
            .thenReturn(-85);
        when(resources.getInteger(
                R.integer.config_wifi_framework_wifi_score_entry_rssi_threshold_24GHz))
            .thenReturn(-80);
        when(resources.getInteger(
                R.integer.config_wifi_framework_wifi_score_low_rssi_threshold_24GHz))
            .thenReturn(-73);
        when(resources.getInteger(
                R.integer.config_wifi_framework_wifi_score_good_rssi_threshold_24GHz))
            .thenReturn(-60);
    }

    /**
     * Sets up for unit test
     */
    @Before
    public void setUp() throws Exception {
        MockitoAnnotations.initMocks(this);
        setUpResources(mResources);
        mWifiInfo = new WifiInfo();
        mWifiInfo.setFrequency(2412);
        int maxSize = 10;
        int trimSize = 5;
        when(mContext.getResources()).thenReturn(mResources);
        mClock = new FakeClock();
        mScoringParams = new ScoringParams(mContext);
        mWifiScoreReport = new WifiScoreReport(mScoringParams, mClock);
    }

    /**
     * Cleans up after test
     */
    @After
    public void tearDown() throws Exception {
        mResources = null;
        mWifiScoreReport = null;
        mWifiMetrics = null;
    }

    /**
     * Test for score reporting
     *
     * The score should be sent to both the NetworkAgent and the
     * WifiMetrics
     */
    @Test
    public void calculateAndReportScoreSucceeds() throws Exception {
        mWifiInfo.setRssi(-77);
        mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
        verify(mNetworkAgent).sendNetworkScore(anyInt());
        verify(mWifiMetrics).incrementWifiScoreCount(anyInt());
    }

    /**
     * Test for no score report if rssi is invalid
     *
     * The score should be sent to neither the NetworkAgent nor the
     * WifiMetrics
     */
    @Test
    public void calculateAndReportScoreDoesNotReportWhenRssiIsNotValid() throws Exception {
        mWifiInfo.setRssi(WifiInfo.INVALID_RSSI);
        mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
        verify(mNetworkAgent, never()).sendNetworkScore(anyInt());
        verify(mWifiMetrics, never()).incrementWifiScoreCount(anyInt());
    }

    /**
     * Test for operation with null NetworkAgent
     *
     * Expect to not die, and to calculate the score and report to metrics.
     */
    @Test
    public void networkAgentMayBeNull() throws Exception {
        mWifiInfo.setRssi(-33);
        mWifiScoreReport.enableVerboseLogging(true);
        mWifiScoreReport.calculateAndReportScore(mWifiInfo, null, mWifiMetrics);
        verify(mWifiMetrics).incrementWifiScoreCount(anyInt());
    }

    /**
     * Exercise the rates with low RSSI
     *
     * The setup has a low (not bad) RSSI, and data movement (txSuccessRate) above
     * the threshold.
     *
     * Expect a score above threshold.
     */
    @Test
    public void allowLowRssiIfDataIsMoving() throws Exception {
        mWifiInfo.setRssi(-80);
        mWifiInfo.setLinkSpeed(6); // Mbps
        mWifiInfo.txSuccessRate = 5.1; // proportional to pps
        mWifiInfo.rxSuccessRate = 5.1;
        for (int i = 0; i < 10; i++) {
            mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
        }
        int score = mWifiInfo.score;
        assertTrue(score > ConnectedScore.WIFI_TRANSITION_SCORE);
    }

    /**
     * Bad RSSI without data moving should allow handoff
     *
     * The setup has a bad RSSI, and the txSuccessRate is below threshold; several
     * scoring iterations are performed.
     *
     * Expect the score to drop below the handoff threshold.
     */
    @Test
    public void giveUpOnBadRssiWhenDataIsNotMoving() throws Exception {
        mWifiInfo.setRssi(-100);
        mWifiInfo.setLinkSpeed(6); // Mbps
        mWifiInfo.setFrequency(5220);
        mWifiScoreReport.enableVerboseLogging(true);
        mWifiInfo.txSuccessRate = 0.1;
        mWifiInfo.rxSuccessRate = 0.1;
        for (int i = 0; i < 10; i++) {
            mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
        }
        int score = mWifiInfo.score;
        assertTrue(score < ConnectedScore.WIFI_TRANSITION_SCORE);
        verify(mNetworkAgent, atLeast(1)).sendNetworkScore(score);
    }

    /**
     * When the score ramps down to the exit theshold, let go.
     */
    @Test
    public void giveUpOnBadRssiAggressively() throws Exception {
        String oops = "giveUpOnBadRssiAggressively";
        mWifiInfo.setFrequency(5220);
        for (int rssi = -60; rssi >= -83; rssi -= 1) {
            mWifiInfo.setRssi(rssi);
            oops += " " + mClock.mWallClockMillis + "," + rssi;
            mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
            oops += ":" + mWifiInfo.score;
        }
        int score = mWifiInfo.score;
        verify(mNetworkAgent, atLeast(1)).sendNetworkScore(score);
        assertTrue(oops, score < ConnectedScore.WIFI_TRANSITION_SCORE);
    }

    /**
     * RSSI that falls rapidly but does not cross entry threshold should not cause handoff
     *
     * Expect the score to not drop below the handoff threshold.
     */
    @Test
    public void stayOnIfRssiDoesNotGetBelowEntryThreshold() throws Exception {
        String oops = "didNotStickLanding";
        int minScore = 100;
        mWifiInfo.setLinkSpeed(6); // Mbps
        mWifiInfo.setFrequency(5220);
        mWifiScoreReport.enableVerboseLogging(true);
        mWifiInfo.txSuccessRate = 0.1;
        mWifiInfo.rxSuccessRate = 0.1;
        assertTrue(mScoringParams.update("rssi5=-83:-80:-66:-55"));
        for (int r = -30; r >= -100; r -= 1) {
            int rssi = Math.max(r, -80);
            mWifiInfo.setRssi(rssi);
            oops += " " + mClock.mWallClockMillis + "," + rssi;
            mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
            oops += ":" + mWifiInfo.score;
            if (mWifiInfo.score < minScore) minScore = mWifiInfo.score;
        }
        assertTrue(oops, minScore > ConnectedScore.WIFI_TRANSITION_SCORE);
    }

    /**
     * Don't breach if the success rates are great
     *
     * Ramp the RSSI down, but maintain a high packet throughput
     *
     * Expect score to stay above above threshold.
     */
    @Test
    public void allowTerribleRssiIfDataIsMovingWell() throws Exception {
        mWifiInfo.txSuccessRate = mScoringParams.getYippeeSkippyPacketsPerSecond() + 0.1;
        mWifiInfo.rxSuccessRate = mScoringParams.getYippeeSkippyPacketsPerSecond() + 0.1;
        assertTrue(mWifiInfo.txSuccessRate > 10);
        mWifiInfo.setFrequency(5220);
        for (int r = -30; r >= -120; r -= 2) {
            mWifiInfo.setRssi(r);
            mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
            assertTrue(mWifiInfo.score > ConnectedScore.WIFI_TRANSITION_SCORE);
        }
        // If the throughput dips, we should let go
        mWifiInfo.rxSuccessRate = mScoringParams.getYippeeSkippyPacketsPerSecond() - 0.1;
        mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
        assertTrue(mWifiInfo.score < ConnectedScore.WIFI_TRANSITION_SCORE);
        // And even if throughput improves again, once we have decided to let go, disregard
        // the good rates.
        mWifiInfo.rxSuccessRate = mScoringParams.getYippeeSkippyPacketsPerSecond() + 0.1;
        mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
        assertTrue(mWifiInfo.score < ConnectedScore.WIFI_TRANSITION_SCORE);
    }

    /**
     * Never ask for nud check when nud=0
     */
    @Test
    public void neverAskForNudCheckWhenNudKnobIsZero() throws Exception {
        assertTrue(mScoringParams.update("nud=0"));
        assertEquals(0, mScoringParams.getNudKnob());
        mWifiInfo.setFrequency(5220);
        for (int rssi = -30; rssi >= -120; rssi -= 1) {
            mWifiInfo.setRssi(rssi);
            mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
            assertFalse(mWifiScoreReport.shouldCheckIpLayer());
        }
    }

    /**
     * Eventually ask for nud check when nud=1
     */
    @Test
    public void eventuallyAskForNudCheckWhenNudKnobIsOne() throws Exception {
        String oops = "nud=1";
        long lastAskedMillis = 0; // Check that we don't send too soon
        int asks = 0; // Keep track of how many time we asked
        assertTrue(mScoringParams.update("nud=1"));
        assertEquals(1, mScoringParams.getNudKnob());
        mWifiInfo.setFrequency(5220);
        for (int rssi = -40; rssi >= -120; rssi -= 1) {
            mWifiInfo.setRssi(rssi);
            mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
            boolean ask = mWifiScoreReport.shouldCheckIpLayer();
            if (ask) {
                assertTrue(mWifiInfo.score < ConnectedScore.WIFI_TRANSITION_SCORE);
                assertTrue(oops, mClock.mWallClockMillis >= lastAskedMillis + 5000);
                lastAskedMillis = mClock.mWallClockMillis;
                oops += " " + lastAskedMillis + ":" + mWifiInfo.score;
                mWifiScoreReport.noteIpCheck();
                asks++;
            }
        }
        assertTrue(oops + " asks:" + asks, asks > 5 && asks < 12);
    }


    /**
     * Ask for more nud checks when nud=10
     */
    @Test
    public void askForMoreNudChecksWhenNudKnobIsBigger() throws Exception {
        String oops = "nud=10";
        long lastAskedMillis = 0; // Check that we don't send too soon
        int asks = 0; // Keep track of how many time we asked
        assertTrue(mScoringParams.update("nud=10"));
        assertEquals(10, mScoringParams.getNudKnob());
        mWifiInfo.setFrequency(5220);
        for (int rssi = -40; rssi >= -120; rssi -= 1) {
            mWifiInfo.setRssi(rssi);
            mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
            boolean ask = mWifiScoreReport.shouldCheckIpLayer();
            if (ask) {
                assertTrue(mWifiInfo.score < ConnectedScore.WIFI_TRANSITION_SCORE);
                assertTrue(oops, mClock.mWallClockMillis >= lastAskedMillis + 5000);
                lastAskedMillis = mClock.mWallClockMillis;
                oops += " " + lastAskedMillis + ":" + mWifiInfo.score;
                mWifiScoreReport.noteIpCheck();
                asks++;
            }
        }
        assertTrue(oops + " asks:" + asks, asks > 12 && asks < 80);
    }

    /**
     * Test initial conditions, and after reset()
     */
    @Test
    public void exerciseReset() throws Exception {
        assertFalse(mWifiScoreReport.shouldCheckIpLayer());
        mWifiScoreReport.reset();
        assertFalse(mWifiScoreReport.shouldCheckIpLayer());
    }

    /**
     * This setup causes some reports to be generated when println
     * methods are called, to check for "concurrent" modification
     * errors.
     */
    private void setupToGenerateAReportWhenPrintlnIsCalled() {
        int[] counter = new int[1];
        doAnswer(answerVoid((String line) -> {
            if (counter[0]++ < 3) {
                mWifiScoreReport.calculateAndReportScore(
                        mWifiInfo, mNetworkAgent, mWifiMetrics);
            }
        })).when(mPrintWriter).println(anyString());
    }

    /**
     * Test data logging
     */
    @Test
    public void testDataLogging() throws Exception {
        for (int i = 0; i < 10; i++) {
            mWifiInfo.setRssi(-65 + i);
            mWifiInfo.setLinkSpeed(300);
            mWifiInfo.setFrequency(5220);
            mWifiInfo.txSuccessRate = 0.1 + i;
            mWifiInfo.txRetriesRate = 0.2 + i;
            mWifiInfo.txBadRate = 0.01 * i;
            mWifiInfo.rxSuccessRate = 0.3 + i;
            mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
        }
        setupToGenerateAReportWhenPrintlnIsCalled();
        mWifiScoreReport.dump(null, mPrintWriter, null);
        verify(mPrintWriter, times(11)).println(anyString());
    }

    /**
     *  Test data logging limit
     *  <p>
     *  Check that only a bounded amount of data is collected for dumpsys report
     */
    @Test
    public void testDataLoggingLimit() throws Exception {
        for (int i = 0; i < 3620; i++) {
            mWifiInfo.setRssi(-65 + i % 20);
            mWifiInfo.setLinkSpeed(300);
            mWifiInfo.setFrequency(5220);
            mWifiInfo.txSuccessRate = 0.1 + i % 100;
            mWifiInfo.txRetriesRate = 0.2 + i % 100;
            mWifiInfo.txBadRate = 0.0001 * i;
            mWifiInfo.rxSuccessRate = 0.3 + i % 200;
            mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
        }
        mWifiScoreReport.dump(null, mPrintWriter, null);
        verify(mPrintWriter, atMost(3601)).println(anyString());
    }

    /**
     * Test for staying at below transition score for a certain period of time.
     */
    @Test
    public void stayAtBelowTransitionScoreForCertainPeriodOfTime() throws Exception {
        mWifiScoreReport.enableVerboseLogging(true);
        mWifiInfo.setFrequency(5220);

        // Reduce RSSI value to fall below the transition score
        for (int rssi = -60; rssi >= -83; rssi -= 1) {
            mWifiInfo.setRssi(rssi);
            mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
        }
        assertTrue(mWifiInfo.score < ConnectedScore.WIFI_TRANSITION_SCORE);

        // Then, set high RSSI value to exceed the transition score
        mWifiInfo.setRssi(-50);
        // 8 seconds elapse
        for (int i = 0; i < 8; i++) {
            mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
        }
        assertTrue(mWifiInfo.score < ConnectedScore.WIFI_TRANSITION_SCORE);

        // 9 seconds elapse
        mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
        assertTrue(mWifiInfo.score > ConnectedScore.WIFI_TRANSITION_SCORE);
    }

    /**
     * Test for resetting the internal timer which is used to keep staying at
     * below transition score for a certain period of time.
     */
    @Test
    public void stayAtBelowTransitionScoreWithReset() throws Exception {
        mWifiScoreReport.enableVerboseLogging(true);
        mWifiInfo.setFrequency(5220);

        // Reduce RSSI value to fall below the transition score
        for (int rssi = -60; rssi >= -83; rssi -= 1) {
            mWifiInfo.setRssi(rssi);
            mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
        }
        assertTrue(mWifiInfo.score < ConnectedScore.WIFI_TRANSITION_SCORE);

        // Then, set high RSSI value to exceed the transition score
        mWifiInfo.setRssi(-50);
        // Reset the internal timer so that no need to wait for 9 seconds
        mWifiScoreReport.reset();
        mWifiScoreReport.calculateAndReportScore(mWifiInfo, mNetworkAgent, mWifiMetrics);
        assertTrue(mWifiInfo.score > ConnectedScore.WIFI_TRANSITION_SCORE);
    }
}