/*
 * Copyright (C) 2013 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 android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.location.LocationManager;
import android.net.wifi.WifiManager;
import android.os.Handler;
import android.os.Looper;
import android.os.Message;
import android.os.SystemClock;
import android.provider.Settings;
import android.util.Log;

import com.android.internal.R;
import com.android.internal.util.Protocol;
import com.android.internal.util.State;
import com.android.internal.util.StateMachine;
import com.android.server.wifi.util.WifiPermissionsUtil;

/**
 * WifiController is the class used to manage wifi state for various operating
 * modes (normal, airplane, wifi hotspot, etc.).
 */
public class WifiController extends StateMachine {
    private static final String TAG = "WifiController";
    private static final boolean DBG = false;
    private Context mContext;
    private boolean mFirstUserSignOnSeen = false;

    /**
     * See {@link Settings.Global#WIFI_REENABLE_DELAY_MS}.  This is the default value if a
     * Settings.Global value is not present.  This is the minimum time after wifi is disabled
     * we'll act on an enable.  Enable requests received before this delay will be deferred.
     */
    private static final long DEFAULT_REENABLE_DELAY_MS = 500;

    // Maximum limit to use for timeout delay if the value from overlay setting is too large.
    private static final int MAX_RECOVERY_TIMEOUT_DELAY_MS = 4000;

    // finding that delayed messages can sometimes be delivered earlier than expected
    // probably rounding errors.  add a margin to prevent problems
    private static final long DEFER_MARGIN_MS = 5;

    /* References to values tracked in WifiService */
    private final ClientModeImpl mClientModeImpl;
    private final Looper mClientModeImplLooper;
    private final ActiveModeWarden mActiveModeWarden;
    private final WifiSettingsStore mSettingsStore;
    private final FrameworkFacade mFacade;
    private final WifiPermissionsUtil mWifiPermissionsUtil;

    private long mReEnableDelayMillis;

    private int mRecoveryDelayMillis;

    private static final int BASE = Protocol.BASE_WIFI_CONTROLLER;

    static final int CMD_EMERGENCY_MODE_CHANGED                 = BASE + 1;
    static final int CMD_SCAN_ALWAYS_MODE_CHANGED               = BASE + 7;
    static final int CMD_WIFI_TOGGLED                           = BASE + 8;
    static final int CMD_AIRPLANE_TOGGLED                       = BASE + 9;
    static final int CMD_SET_AP                                 = BASE + 10;
    static final int CMD_DEFERRED_TOGGLE                        = BASE + 11;
    static final int CMD_AP_START_FAILURE                       = BASE + 13;
    static final int CMD_EMERGENCY_CALL_STATE_CHANGED           = BASE + 14;
    static final int CMD_AP_STOPPED                             = BASE + 15;
    static final int CMD_STA_START_FAILURE                      = BASE + 16;
    // Command used to trigger a wifi stack restart when in active mode
    static final int CMD_RECOVERY_RESTART_WIFI                  = BASE + 17;
    // Internal command used to complete wifi stack restart
    private static final int CMD_RECOVERY_RESTART_WIFI_CONTINUE = BASE + 18;
    // Command to disable wifi when SelfRecovery is throttled or otherwise not doing full recovery
    static final int CMD_RECOVERY_DISABLE_WIFI                  = BASE + 19;
    static final int CMD_STA_STOPPED                            = BASE + 20;
    static final int CMD_SCANNING_STOPPED                       = BASE + 21;
    static final int CMD_DEFERRED_RECOVERY_RESTART_WIFI         = BASE + 22;

    private DefaultState mDefaultState = new DefaultState();
    private StaEnabledState mStaEnabledState = new StaEnabledState();
    private StaDisabledState mStaDisabledState = new StaDisabledState();
    private StaDisabledWithScanState mStaDisabledWithScanState = new StaDisabledWithScanState();
    private EcmState mEcmState = new EcmState();

    private ScanOnlyModeManager.Listener mScanOnlyModeCallback = new ScanOnlyCallback();
    private ClientModeManager.Listener mClientModeCallback = new ClientModeCallback();

    WifiController(Context context, ClientModeImpl clientModeImpl, Looper clientModeImplLooper,
                   WifiSettingsStore wss, Looper wifiServiceLooper, FrameworkFacade f,
                   ActiveModeWarden amw, WifiPermissionsUtil wifiPermissionsUtil) {
        super(TAG, wifiServiceLooper);
        mFacade = f;
        mContext = context;
        mClientModeImpl = clientModeImpl;
        mClientModeImplLooper = clientModeImplLooper;
        mActiveModeWarden = amw;
        mSettingsStore = wss;
        mWifiPermissionsUtil = wifiPermissionsUtil;

        // CHECKSTYLE:OFF IndentationCheck
        addState(mDefaultState);
            addState(mStaDisabledState, mDefaultState);
            addState(mStaEnabledState, mDefaultState);
            addState(mStaDisabledWithScanState, mDefaultState);
            addState(mEcmState, mDefaultState);
        // CHECKSTYLE:ON IndentationCheck

        setLogRecSize(100);
        setLogOnlyTransitions(false);

        // register for state updates via callbacks (vs the intents registered below)
        mActiveModeWarden.registerScanOnlyCallback(mScanOnlyModeCallback);
        mActiveModeWarden.registerClientModeCallback(mClientModeCallback);

        readWifiReEnableDelay();
        readWifiRecoveryDelay();
    }

    @Override
    public void start() {
        boolean isAirplaneModeOn = mSettingsStore.isAirplaneModeOn();
        boolean isWifiEnabled = mSettingsStore.isWifiToggleEnabled();
        boolean isScanningAlwaysAvailable = mSettingsStore.isScanAlwaysAvailable();
        boolean isLocationModeActive = mWifiPermissionsUtil.isLocationModeEnabled();

        log("isAirplaneModeOn = " + isAirplaneModeOn
                + ", isWifiEnabled = " + isWifiEnabled
                + ", isScanningAvailable = " + isScanningAlwaysAvailable
                + ", isLocationModeActive = " + isLocationModeActive);

        if (checkScanOnlyModeAvailable()) {
            setInitialState(mStaDisabledWithScanState);
        } else {
            setInitialState(mStaDisabledState);
        }
        IntentFilter filter = new IntentFilter();
        filter.addAction(WifiManager.WIFI_AP_STATE_CHANGED_ACTION);
        filter.addAction(WifiManager.WIFI_STATE_CHANGED_ACTION);
        filter.addAction(LocationManager.MODE_CHANGED_ACTION);
        mContext.registerReceiver(
                new BroadcastReceiver() {
                    @Override
                    public void onReceive(Context context, Intent intent) {
                        String action = intent.getAction();
                        if (action.equals(WifiManager.WIFI_AP_STATE_CHANGED_ACTION)) {
                            int state = intent.getIntExtra(
                                    WifiManager.EXTRA_WIFI_AP_STATE,
                                    WifiManager.WIFI_AP_STATE_FAILED);
                            if (state == WifiManager.WIFI_AP_STATE_FAILED) {
                                Log.e(TAG, "SoftAP start failed");
                                sendMessage(CMD_AP_START_FAILURE);
                            } else if (state == WifiManager.WIFI_AP_STATE_DISABLED) {
                                sendMessage(CMD_AP_STOPPED);
                            }
                        } else if (action.equals(LocationManager.MODE_CHANGED_ACTION)) {
                            // Location mode has been toggled...  trigger with the scan change
                            // update to make sure we are in the correct mode
                            sendMessage(CMD_SCAN_ALWAYS_MODE_CHANGED);
                        }
                    }
                },
                new IntentFilter(filter));
        super.start();
    }

    private boolean checkScanOnlyModeAvailable() {
        // first check if Location service is disabled, if so return false
        if (!mWifiPermissionsUtil.isLocationModeEnabled()) {
            return false;
        }
        return mSettingsStore.isScanAlwaysAvailable();
    }

    /**
     * Listener used to receive scan mode updates - really needed for disabled updates to trigger
     * mode changes.
     */
    private class ScanOnlyCallback implements ScanOnlyModeManager.Listener {
        @Override
        public void onStateChanged(int state) {
            if (state == WifiManager.WIFI_STATE_UNKNOWN) {
                Log.d(TAG, "ScanOnlyMode unexpected failure: state unknown");
            } else if (state == WifiManager.WIFI_STATE_DISABLED) {
                Log.d(TAG, "ScanOnlyMode stopped");
                sendMessage(CMD_SCANNING_STOPPED);
            } else if (state == WifiManager.WIFI_STATE_ENABLED) {
                // scan mode is ready to go
                Log.d(TAG, "scan mode active");
            } else {
                Log.d(TAG, "unexpected state update: " + state);
            }
        }
    }

    /**
     * Listener used to receive client mode updates
     */
    private class ClientModeCallback implements ClientModeManager.Listener {
        @Override
        public void onStateChanged(int state) {
            if (state == WifiManager.WIFI_STATE_UNKNOWN) {
                logd("ClientMode unexpected failure: state unknown");
                sendMessage(CMD_STA_START_FAILURE);
            } else if (state == WifiManager.WIFI_STATE_DISABLED) {
                logd("ClientMode stopped");
                sendMessage(CMD_STA_STOPPED);
            } else if (state == WifiManager.WIFI_STATE_ENABLED) {
                // scan mode is ready to go
                logd("client mode active");
            } else {
                logd("unexpected state update: " + state);
            }
        }
    }

    private void readWifiReEnableDelay() {
        mReEnableDelayMillis = mFacade.getLongSetting(mContext,
                Settings.Global.WIFI_REENABLE_DELAY_MS, DEFAULT_REENABLE_DELAY_MS);
    }

    private void readWifiRecoveryDelay() {
        mRecoveryDelayMillis = mContext.getResources().getInteger(
                R.integer.config_wifi_framework_recovery_timeout_delay);
        if (mRecoveryDelayMillis > MAX_RECOVERY_TIMEOUT_DELAY_MS) {
            mRecoveryDelayMillis = MAX_RECOVERY_TIMEOUT_DELAY_MS;
            Log.w(TAG, "Overriding timeout delay with maximum limit value");
        }
    }

    class DefaultState extends State {
        @Override
        public boolean processMessage(Message msg) {
            switch (msg.what) {
                case CMD_SCAN_ALWAYS_MODE_CHANGED:
                case CMD_WIFI_TOGGLED:
                case CMD_AP_START_FAILURE:
                case CMD_SCANNING_STOPPED:
                case CMD_STA_STOPPED:
                case CMD_STA_START_FAILURE:
                case CMD_RECOVERY_RESTART_WIFI_CONTINUE:
                case CMD_DEFERRED_RECOVERY_RESTART_WIFI:
                    break;
                case CMD_RECOVERY_DISABLE_WIFI:
                    log("Recovery has been throttled, disable wifi");
                    mActiveModeWarden.shutdownWifi();
                    transitionTo(mStaDisabledState);
                    break;
                case CMD_RECOVERY_RESTART_WIFI:
                    deferMessage(obtainMessage(CMD_DEFERRED_RECOVERY_RESTART_WIFI));
                    mActiveModeWarden.shutdownWifi();
                    transitionTo(mStaDisabledState);
                    break;
                case CMD_DEFERRED_TOGGLE:
                    log("DEFERRED_TOGGLE ignored due to state change");
                    break;
                case CMD_SET_AP:
                    // note: CMD_SET_AP is handled/dropped in ECM mode - will not start here
                    if (msg.arg1 == 1) {
                        SoftApModeConfiguration config = (SoftApModeConfiguration) msg.obj;
                        mActiveModeWarden.enterSoftAPMode((SoftApModeConfiguration) msg.obj);
                    } else {
                        mActiveModeWarden.stopSoftAPMode(msg.arg2);
                    }
                    break;
                case CMD_AIRPLANE_TOGGLED:
                    if (mSettingsStore.isAirplaneModeOn()) {
                        log("Airplane mode toggled, shutdown all modes");
                        mActiveModeWarden.shutdownWifi();
                        transitionTo(mStaDisabledState);
                    } else {
                        log("Airplane mode disabled, determine next state");
                        if (mSettingsStore.isWifiToggleEnabled()) {
                            transitionTo(mStaEnabledState);
                        } else if (checkScanOnlyModeAvailable()) {
                            transitionTo(mStaDisabledWithScanState);
                        }
                        // wifi should remain disabled, do not need to transition
                    }
                    break;
                case CMD_EMERGENCY_CALL_STATE_CHANGED:
                case CMD_EMERGENCY_MODE_CHANGED:
                    if (msg.arg1 == 1) {
                        transitionTo(mEcmState);
                    }
                    break;
                case CMD_AP_STOPPED:
                    log("SoftAp mode disabled, determine next state");
                    if (mSettingsStore.isWifiToggleEnabled()) {
                        transitionTo(mStaEnabledState);
                    } else if (checkScanOnlyModeAvailable()) {
                        transitionTo(mStaDisabledWithScanState);
                    }
                    // wifi should remain disabled, do not need to transition
                    break;
                default:
                    throw new RuntimeException("WifiController.handleMessage " + msg.what);
            }
            return HANDLED;
        }

    }

    class StaDisabledState extends State {
        private int mDeferredEnableSerialNumber = 0;
        private boolean mHaveDeferredEnable = false;
        private long mDisabledTimestamp;

        @Override
        public void enter() {
            mActiveModeWarden.disableWifi();
            // Supplicant can't restart right away, so note the time we switched off
            mDisabledTimestamp = SystemClock.elapsedRealtime();
            mDeferredEnableSerialNumber++;
            mHaveDeferredEnable = false;
        }
        @Override
        public boolean processMessage(Message msg) {
            switch (msg.what) {
                case CMD_WIFI_TOGGLED:
                    if (mSettingsStore.isWifiToggleEnabled()) {
                        if (doDeferEnable(msg)) {
                            if (mHaveDeferredEnable) {
                                //  have 2 toggles now, inc serial number and ignore both
                                mDeferredEnableSerialNumber++;
                            }
                            mHaveDeferredEnable = !mHaveDeferredEnable;
                            break;
                        }
                        transitionTo(mStaEnabledState);
                    } else if (checkScanOnlyModeAvailable()) {
                        // only go to scan mode if we aren't in airplane mode
                        if (mSettingsStore.isAirplaneModeOn()) {
                            transitionTo(mStaDisabledWithScanState);
                        }
                    }
                    break;
                case CMD_SCAN_ALWAYS_MODE_CHANGED:
                    if (checkScanOnlyModeAvailable()) {
                        transitionTo(mStaDisabledWithScanState);
                        break;
                    }
                    break;
                case CMD_SET_AP:
                    if (msg.arg1 == 1) {
                        // remember that we were disabled, but pass the command up to start softap
                        mSettingsStore.setWifiSavedState(WifiSettingsStore.WIFI_DISABLED);
                    }
                    return NOT_HANDLED;
                case CMD_DEFERRED_TOGGLE:
                    if (msg.arg1 != mDeferredEnableSerialNumber) {
                        log("DEFERRED_TOGGLE ignored due to serial mismatch");
                        break;
                    }
                    log("DEFERRED_TOGGLE handled");
                    sendMessage((Message)(msg.obj));
                    break;
                case CMD_DEFERRED_RECOVERY_RESTART_WIFI:
                    // wait mRecoveryDelayMillis for letting driver clean reset.
                    sendMessageDelayed(CMD_RECOVERY_RESTART_WIFI_CONTINUE, mRecoveryDelayMillis);
                    break;
                case CMD_RECOVERY_RESTART_WIFI_CONTINUE:
                    if (mSettingsStore.isWifiToggleEnabled()) {
                        // wifi is currently disabled but the toggle is on, must have had an
                        // interface down before the recovery triggered
                        transitionTo(mStaEnabledState);
                        break;
                    } else if (checkScanOnlyModeAvailable()) {
                        transitionTo(mStaDisabledWithScanState);
                        break;
                    }
                    break;
                default:
                    return NOT_HANDLED;
            }
            return HANDLED;
        }

        private boolean doDeferEnable(Message msg) {
            long delaySoFar = SystemClock.elapsedRealtime() - mDisabledTimestamp;
            if (delaySoFar >= mReEnableDelayMillis) {
                return false;
            }

            log("WifiController msg " + msg + " deferred for " +
                    (mReEnableDelayMillis - delaySoFar) + "ms");

            // need to defer this action.
            Message deferredMsg = obtainMessage(CMD_DEFERRED_TOGGLE);
            deferredMsg.obj = Message.obtain(msg);
            deferredMsg.arg1 = ++mDeferredEnableSerialNumber;
            sendMessageDelayed(deferredMsg, mReEnableDelayMillis - delaySoFar + DEFER_MARGIN_MS);
            return true;
        }

    }

    class StaEnabledState extends State {
        @Override
        public void enter() {
            log("StaEnabledState.enter()");
            mActiveModeWarden.enterClientMode();
        }

        @Override
        public boolean processMessage(Message msg) {
            switch (msg.what) {
                case CMD_WIFI_TOGGLED:
                    if (! mSettingsStore.isWifiToggleEnabled()) {
                        if (checkScanOnlyModeAvailable()) {
                            transitionTo(mStaDisabledWithScanState);
                        } else {
                            transitionTo(mStaDisabledState);
                        }
                    }
                    break;
                case CMD_AIRPLANE_TOGGLED:
                    // airplane mode toggled on is handled in the default state
                    if (mSettingsStore.isAirplaneModeOn()) {
                        return NOT_HANDLED;
                    } else {
                        // when airplane mode is toggled off, but wifi is on, we can keep it on
                        log("airplane mode toggled - and airplane mode is off.  return handled");
                        return HANDLED;
                    }
                case CMD_STA_START_FAILURE:
                    if (!checkScanOnlyModeAvailable()) {
                        transitionTo(mStaDisabledState);
                    } else {
                        transitionTo(mStaDisabledWithScanState);
                    }
                    break;
                case CMD_SET_AP:
                    if (msg.arg1 == 1) {
                        // remember that we were enabled, but pass the command up to start softap
                        mSettingsStore.setWifiSavedState(WifiSettingsStore.WIFI_ENABLED);
                    }
                    return NOT_HANDLED;
                case CMD_AP_START_FAILURE:
                case CMD_AP_STOPPED:
                    // already in a wifi mode, no need to check where we should go with softap
                    // stopped
                    break;
                case CMD_STA_STOPPED:
                    // Client mode stopped.  head to Disabled to wait for next command
                    transitionTo(mStaDisabledState);
                    break;
                case CMD_RECOVERY_RESTART_WIFI:
                    final String bugTitle;
                    final String bugDetail;
                    if (msg.arg1 < SelfRecovery.REASON_STRINGS.length && msg.arg1 >= 0) {
                        bugDetail = SelfRecovery.REASON_STRINGS[msg.arg1];
                        bugTitle = "Wi-Fi BugReport: " + bugDetail;
                    } else {
                        bugDetail = "";
                        bugTitle = "Wi-Fi BugReport";
                    }
                    if (msg.arg1 != SelfRecovery.REASON_LAST_RESORT_WATCHDOG) {
                        (new Handler(mClientModeImplLooper)).post(() -> {
                            mClientModeImpl.takeBugReport(bugTitle, bugDetail);
                        });
                    }
                    // after the bug report trigger, more handling needs to be done
                    return NOT_HANDLED;
                default:
                    return NOT_HANDLED;
            }
            return HANDLED;
        }
    }

    class StaDisabledWithScanState extends State {
        private int mDeferredEnableSerialNumber = 0;
        private boolean mHaveDeferredEnable = false;
        private long mDisabledTimestamp;

        @Override
        public void enter() {
            // now trigger the actual mode switch in ActiveModeWarden
            mActiveModeWarden.enterScanOnlyMode();

            // TODO b/71559473: remove the defered enable after mode management changes are complete
            // Supplicant can't restart right away, so not the time we switched off
            mDisabledTimestamp = SystemClock.elapsedRealtime();
            mDeferredEnableSerialNumber++;
            mHaveDeferredEnable = false;
        }

        @Override
        public boolean processMessage(Message msg) {
            switch (msg.what) {
                case CMD_WIFI_TOGGLED:
                    if (mSettingsStore.isWifiToggleEnabled()) {
                        if (doDeferEnable(msg)) {
                            if (mHaveDeferredEnable) {
                                // have 2 toggles now, inc serial number and ignore both
                                mDeferredEnableSerialNumber++;
                            }
                            mHaveDeferredEnable = !mHaveDeferredEnable;
                            break;
                        }
                        transitionTo(mStaEnabledState);
                    }
                    break;
                case CMD_SCAN_ALWAYS_MODE_CHANGED:
                    if (!checkScanOnlyModeAvailable()) {
                        log("StaDisabledWithScanState: scan no longer available");
                        transitionTo(mStaDisabledState);
                    }
                    break;
                case CMD_SET_AP:
                    if (msg.arg1 == 1) {
                        // remember that we were disabled, but pass the command up to start softap
                        mSettingsStore.setWifiSavedState(WifiSettingsStore.WIFI_DISABLED);
                    }
                    return NOT_HANDLED;
                case CMD_DEFERRED_TOGGLE:
                    if (msg.arg1 != mDeferredEnableSerialNumber) {
                        log("DEFERRED_TOGGLE ignored due to serial mismatch");
                        break;
                    }
                    logd("DEFERRED_TOGGLE handled");
                    sendMessage((Message)(msg.obj));
                    break;
                case CMD_AP_START_FAILURE:
                case CMD_AP_STOPPED:
                    // already in a wifi mode, no need to check where we should go with softap
                    // stopped
                    break;
                case CMD_SCANNING_STOPPED:
                    // stopped due to interface destruction - return to disabled and wait
                    log("WifiController: SCANNING_STOPPED when in scan mode -> StaDisabled");
                    transitionTo(mStaDisabledState);
                    break;
                default:
                    return NOT_HANDLED;
            }
            return HANDLED;
        }

        private boolean doDeferEnable(Message msg) {
            long delaySoFar = SystemClock.elapsedRealtime() - mDisabledTimestamp;
            if (delaySoFar >= mReEnableDelayMillis) {
                return false;
            }

            log("WifiController msg " + msg + " deferred for " +
                    (mReEnableDelayMillis - delaySoFar) + "ms");

            // need to defer this action.
            Message deferredMsg = obtainMessage(CMD_DEFERRED_TOGGLE);
            deferredMsg.obj = Message.obtain(msg);
            deferredMsg.arg1 = ++mDeferredEnableSerialNumber;
            sendMessageDelayed(deferredMsg, mReEnableDelayMillis - delaySoFar + DEFER_MARGIN_MS);
            return true;
        }

    }

    /**
     * Determine the next state based on the current settings (e.g. saved
     * wifi state).
     */
    private State getNextWifiState() {
        if (mSettingsStore.getWifiSavedState() == WifiSettingsStore.WIFI_ENABLED) {
            return mStaEnabledState;
        }

        if (checkScanOnlyModeAvailable()) {
            return mStaDisabledWithScanState;
        }

        return mStaDisabledState;
    }

    class EcmState extends State {
        // we can enter EcmState either because an emergency call started or because
        // emergency callback mode started. This count keeps track of how many such
        // events happened; so we can exit after all are undone

        private int mEcmEntryCount;
        @Override
        public void enter() {
            mActiveModeWarden.stopSoftAPMode(WifiManager.IFACE_IP_MODE_UNSPECIFIED);
            boolean configWiFiDisableInECBM =
                    mFacade.getConfigWiFiDisableInECBM(mContext);
            log("WifiController msg getConfigWiFiDisableInECBM "
                    + configWiFiDisableInECBM);
            if (configWiFiDisableInECBM) {
                mActiveModeWarden.shutdownWifi();
            }
            mEcmEntryCount = 1;
        }

        /**
         * Handles messages received while in EcmMode.
         */
        @Override
        public boolean processMessage(Message msg) {
            switch (msg.what) {
                case CMD_EMERGENCY_CALL_STATE_CHANGED:
                    if (msg.arg1 == 1) {
                        // nothing to do - just says emergency call started
                        mEcmEntryCount++;
                    } else if (msg.arg1 == 0) {
                        // emergency call ended
                        decrementCountAndReturnToAppropriateState();
                    }
                    return HANDLED;
                case CMD_EMERGENCY_MODE_CHANGED:
                    if (msg.arg1 == 1) {
                        // Transitioned into emergency callback mode
                        mEcmEntryCount++;
                    } else if (msg.arg1 == 0) {
                        // out of emergency callback mode
                        decrementCountAndReturnToAppropriateState();
                    }
                    return HANDLED;
                case CMD_RECOVERY_RESTART_WIFI:
                case CMD_RECOVERY_DISABLE_WIFI:
                    // do not want to restart wifi if we are in emergency mode
                    return HANDLED;
                case CMD_AP_STOPPED:
                case CMD_SCANNING_STOPPED:
                case CMD_STA_STOPPED:
                    // do not want to trigger a mode switch if we are in emergency mode
                    return HANDLED;
                case CMD_SET_AP:
                    // do not want to start softap if we are in emergency mode
                    return HANDLED;
                default:
                    return NOT_HANDLED;
            }
        }

        private void decrementCountAndReturnToAppropriateState() {
            boolean exitEcm = false;

            if (mEcmEntryCount == 0) {
                loge("mEcmEntryCount is 0; exiting Ecm");
                exitEcm = true;
            } else if (--mEcmEntryCount == 0) {
                exitEcm = true;
            }

            if (exitEcm) {
                if (mSettingsStore.isWifiToggleEnabled()) {
                    transitionTo(mStaEnabledState);
                } else if (checkScanOnlyModeAvailable()) {
                    transitionTo(mStaDisabledWithScanState);
                } else {
                    transitionTo(mStaDisabledState);
                }
            }
        }
    }
}