/*
 * 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.incallui;

import com.google.common.base.Objects;

import android.content.Context;
import android.content.res.Configuration;
import android.hardware.display.DisplayManager;
import android.hardware.display.DisplayManager.DisplayListener;
import android.os.PowerManager;
import android.telecom.CallAudioState;
import android.view.Display;

import com.android.incallui.AudioModeProvider.AudioModeListener;
import com.android.incallui.InCallPresenter.InCallState;
import com.android.incallui.InCallPresenter.InCallStateListener;

/**
 * Class manages the proximity sensor for the in-call UI.
 * We enable the proximity sensor while the user in a phone call. The Proximity sensor turns off
 * the touchscreen and display when the user is close to the screen to prevent user's cheek from
 * causing touch events.
 * The class requires special knowledge of the activity and device state to know when the proximity
 * sensor should be enabled and disabled. Most of that state is fed into this class through
 * public methods.
 */
public class ProximitySensor implements AccelerometerListener.OrientationListener,
        InCallStateListener, AudioModeListener {
    private static final String TAG = ProximitySensor.class.getSimpleName();

    private final PowerManager mPowerManager;
    private final PowerManager.WakeLock mProximityWakeLock;
    private final AudioModeProvider mAudioModeProvider;
    private final AccelerometerListener mAccelerometerListener;
    private final ProximityDisplayListener mDisplayListener;
    private int mOrientation = AccelerometerListener.ORIENTATION_UNKNOWN;
    private boolean mUiShowing = false;
    private boolean mIsPhoneOffhook = false;
    private boolean mDialpadVisible;

    // True if the keyboard is currently *not* hidden
    // Gets updated whenever there is a Configuration change
    private boolean mIsHardKeyboardOpen;

    public ProximitySensor(Context context, AudioModeProvider audioModeProvider,
            AccelerometerListener accelerometerListener) {
        mPowerManager = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
        if (mPowerManager.isWakeLockLevelSupported(PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK)) {
            mProximityWakeLock = mPowerManager.newWakeLock(
                    PowerManager.PROXIMITY_SCREEN_OFF_WAKE_LOCK, TAG);
        } else {
            Log.w(TAG, "Device does not support proximity wake lock.");
            mProximityWakeLock = null;
        }
        mAccelerometerListener = accelerometerListener;
        mAccelerometerListener.setListener(this);

        mDisplayListener = new ProximityDisplayListener(
                (DisplayManager) context.getSystemService(Context.DISPLAY_SERVICE));
        mDisplayListener.register();

        mAudioModeProvider = audioModeProvider;
        mAudioModeProvider.addListener(this);
    }

    public void tearDown() {
        mAudioModeProvider.removeListener(this);

        mAccelerometerListener.enable(false);
        mDisplayListener.unregister();

        turnOffProximitySensor(true);
    }

    /**
     * Called to identify when the device is laid down flat.
     */
    @Override
    public void orientationChanged(int orientation) {
        mOrientation = orientation;
        updateProximitySensorMode();
    }

    /**
     * Called to keep track of the overall UI state.
     */
    @Override
    public void onStateChange(InCallState oldState, InCallState newState, CallList callList) {
        // We ignore incoming state because we do not want to enable proximity
        // sensor during incoming call screen. We check hasLiveCall() because a disconnected call
        // can also put the in-call screen in the INCALL state.
        boolean hasOngoingCall = InCallState.INCALL == newState && callList.hasLiveCall();
        boolean isOffhook = (InCallState.OUTGOING == newState) || hasOngoingCall;

        if (isOffhook != mIsPhoneOffhook) {
            mIsPhoneOffhook = isOffhook;

            mOrientation = AccelerometerListener.ORIENTATION_UNKNOWN;
            mAccelerometerListener.enable(mIsPhoneOffhook);

            updateProximitySensorMode();
        }
    }

    @Override
    public void onSupportedAudioMode(int modeMask) {
    }

    @Override
    public void onMute(boolean muted) {
    }

    /**
     * Called when the audio mode changes during a call.
     */
    @Override
    public void onAudioMode(int mode) {
        updateProximitySensorMode();
    }

    public void onDialpadVisible(boolean visible) {
        mDialpadVisible = visible;
        updateProximitySensorMode();
    }

    /**
     * Called by InCallActivity to listen for hard keyboard events.
     */
    public void onConfigurationChanged(Configuration newConfig) {
        mIsHardKeyboardOpen = newConfig.hardKeyboardHidden == Configuration.HARDKEYBOARDHIDDEN_NO;

        // Update the Proximity sensor based on keyboard state
        updateProximitySensorMode();
    }

    /**
     * Used to save when the UI goes in and out of the foreground.
     */
    public void onInCallShowing(boolean showing) {
        if (showing) {
            mUiShowing = true;

        // We only consider the UI not showing for instances where another app took the foreground.
        // If we stopped showing because the screen is off, we still consider that showing.
        } else if (mPowerManager.isScreenOn()) {
            mUiShowing = false;
        }
        updateProximitySensorMode();
    }

    void onDisplayStateChanged(boolean isDisplayOn) {
        Log.i(this, "isDisplayOn: " + isDisplayOn);
        mAccelerometerListener.enable(isDisplayOn);
    }

    /**
     * TODO: There is no way to determine if a screen is off due to proximity or if it is
     * legitimately off, but if ever we can do that in the future, it would be useful here.
     * Until then, this function will simply return true of the screen is off.
     * TODO: Investigate whether this can be replaced with the ProximityDisplayListener.
     */
    public boolean isScreenReallyOff() {
        return !mPowerManager.isScreenOn();
    }

    private void turnOnProximitySensor() {
        if (mProximityWakeLock != null) {
            if (!mProximityWakeLock.isHeld()) {
                Log.i(this, "Acquiring proximity wake lock");
                mProximityWakeLock.acquire();
            } else {
                Log.i(this, "Proximity wake lock already acquired");
            }
        }
    }

    private void turnOffProximitySensor(boolean screenOnImmediately) {
        if (mProximityWakeLock != null) {
            if (mProximityWakeLock.isHeld()) {
                Log.i(this, "Releasing proximity wake lock");
                int flags =
                    (screenOnImmediately ? 0 : PowerManager.RELEASE_FLAG_WAIT_FOR_NO_PROXIMITY);
                mProximityWakeLock.release(flags);
            } else {
                Log.i(this, "Proximity wake lock already released");
            }
        }
    }

    /**
     * Updates the wake lock used to control proximity sensor behavior,
     * based on the current state of the phone.
     *
     * On devices that have a proximity sensor, to avoid false touches
     * during a call, we hold a PROXIMITY_SCREEN_OFF_WAKE_LOCK wake lock
     * whenever the phone is off hook.  (When held, that wake lock causes
     * the screen to turn off automatically when the sensor detects an
     * object close to the screen.)
     *
     * This method is a no-op for devices that don't have a proximity
     * sensor.
     *
     * Proximity wake lock will *not* be held if any one of the
     * conditions is true while on a call:
     * 1) If the audio is routed via Bluetooth
     * 2) If a wired headset is connected
     * 3) if the speaker is ON
     * 4) If the slider is open(i.e. the hardkeyboard is *not* hidden)
     */
    private synchronized void updateProximitySensorMode() {
        final int audioMode = mAudioModeProvider.getAudioMode();

        // turn proximity sensor off and turn screen on immediately if
        // we are using a headset, the keyboard is open, or the device
        // is being held in a horizontal position.
            boolean screenOnImmediately = (CallAudioState.ROUTE_WIRED_HEADSET == audioMode
                    || CallAudioState.ROUTE_SPEAKER == audioMode
                    || CallAudioState.ROUTE_BLUETOOTH == audioMode
                    || mIsHardKeyboardOpen);

            // We do not keep the screen off when the user is outside in-call screen and we are
            // horizontal, but we do not force it on when we become horizontal until the
            // proximity sensor goes negative.
            final boolean horizontal =
                    (mOrientation == AccelerometerListener.ORIENTATION_HORIZONTAL);
            screenOnImmediately |= !mUiShowing && horizontal;

            // We do not keep the screen off when dialpad is visible, we are horizontal, and
            // the in-call screen is being shown.
            // At that moment we're pretty sure users want to use it, instead of letting the
            // proximity sensor turn off the screen by their hands.
            screenOnImmediately |= mDialpadVisible && horizontal;

            Log.v(this, "screenonImmediately: ", screenOnImmediately);

            Log.i(this, Objects.toStringHelper(this)
                    .add("keybrd", mIsHardKeyboardOpen ? 1 : 0)
                    .add("dpad", mDialpadVisible ? 1 : 0)
                    .add("offhook", mIsPhoneOffhook ? 1 : 0)
                    .add("hor", horizontal ? 1 : 0)
                    .add("ui", mUiShowing ? 1 : 0)
                    .add("aud", CallAudioState.audioRouteToString(audioMode))
                    .toString());

            if (mIsPhoneOffhook && !screenOnImmediately) {
                Log.d(this, "Turning on proximity sensor");
                // Phone is in use!  Arrange for the screen to turn off
                // automatically when the sensor detects a close object.
                turnOnProximitySensor();
            } else {
                Log.d(this, "Turning off proximity sensor");
                // Phone is either idle, or ringing.  We don't want any special proximity sensor
                // behavior in either case.
                turnOffProximitySensor(screenOnImmediately);
            }
        }

    /**
     * Implementation of a {@link DisplayListener} that maintains a binary state:
     * Screen on vs screen off. Used by the proximity sensor manager to decide whether or not
     * it needs to listen to accelerometer events.
     */
    public class ProximityDisplayListener implements DisplayListener {
        private DisplayManager mDisplayManager;
        private boolean mIsDisplayOn = true;

        ProximityDisplayListener(DisplayManager displayManager) {
            mDisplayManager = displayManager;
        }

        void register() {
            mDisplayManager.registerDisplayListener(this, null);
        }

        void unregister() {
            mDisplayManager.unregisterDisplayListener(this);
        }

        @Override
        public void onDisplayRemoved(int displayId) {
        }

        @Override
        public void onDisplayChanged(int displayId) {
            if (displayId == Display.DEFAULT_DISPLAY) {
                final Display display = mDisplayManager.getDisplay(displayId);

                final boolean isDisplayOn = display.getState() != Display.STATE_OFF;
                // For call purposes, we assume that as long as the screen is not truly off, it is
                // considered on, even if it is in an unknown or low power idle state.
                if (isDisplayOn != mIsDisplayOn) {
                    mIsDisplayOn = isDisplayOn;
                    onDisplayStateChanged(mIsDisplayOn);
                }
            }
        }

        @Override
        public void onDisplayAdded(int displayId) {
        }
    }
}