/*
 * Copyright (C) 2011 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.inputmethod.keyboard;

import android.content.Context;
import android.content.pm.PackageManager;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Paint.Align;
import android.graphics.Typeface;
import android.graphics.drawable.Drawable;
import android.os.Message;
import android.text.TextUtils;
import android.util.AttributeSet;
import android.util.Log;
import android.view.GestureDetector;
import android.view.LayoutInflater;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.accessibility.AccessibilityEvent;
import android.widget.PopupWindow;

import com.android.inputmethod.accessibility.AccessibilityUtils;
import com.android.inputmethod.accessibility.AccessibleKeyboardViewProxy;
import com.android.inputmethod.deprecated.VoiceProxy;
import com.android.inputmethod.keyboard.PointerTracker.DrawingProxy;
import com.android.inputmethod.keyboard.PointerTracker.TimerProxy;
import com.android.inputmethod.latin.LatinIME;
import com.android.inputmethod.latin.LatinImeLogger;
import com.android.inputmethod.latin.R;
import com.android.inputmethod.latin.StaticInnerHandlerWrapper;
import com.android.inputmethod.latin.Utils;
import com.android.inputmethod.latin.Utils.UsabilityStudyLogUtils;

import java.util.Locale;
import java.util.WeakHashMap;

/**
 * A view that is responsible for detecting key presses and touch movements.
 *
 * @attr ref R.styleable#KeyboardView_keyHysteresisDistance
 * @attr ref R.styleable#KeyboardView_verticalCorrection
 * @attr ref R.styleable#KeyboardView_popupLayout
 */
public class LatinKeyboardView extends KeyboardView implements PointerTracker.KeyEventHandler,
        SuddenJumpingTouchEventHandler.ProcessMotionEvent {
    private static final String TAG = LatinKeyboardView.class.getSimpleName();

    private static final boolean ENABLE_CAPSLOCK_BY_DOUBLETAP = true;

    // TODO: Kill process when the usability study mode was changed.
    private static final boolean ENABLE_USABILITY_STUDY_LOG = LatinImeLogger.sUsabilityStudy;

    /** Listener for {@link KeyboardActionListener}. */
    private KeyboardActionListener mKeyboardActionListener;

    /* Space key and its icons */
    private Key mSpaceKey;
    private Drawable mSpaceIcon;
    // Stuff to draw language name on spacebar.
    private boolean mNeedsToDisplayLanguage;
    private Locale mSpacebarLocale;
    private float mSpacebarTextFadeFactor = 0.0f;
    private final float mSpacebarTextRatio;
    private float mSpacebarTextSize;
    private final int mSpacebarTextColor;
    private final int mSpacebarTextShadowColor;
    // Height in space key the language name will be drawn. (proportional to space key height)
    private static final float SPACEBAR_LANGUAGE_BASELINE = 0.6f;
    // If the full language name needs to be smaller than this value to be drawn on space key,
    // its short language name will be used instead.
    private static final float MINIMUM_SCALE_OF_LANGUAGE_NAME = 0.8f;
    // Stuff to draw auto correction LED on spacebar.
    private boolean mAutoCorrectionSpacebarLedOn;
    private final boolean mAutoCorrectionSpacebarLedEnabled;
    private final Drawable mAutoCorrectionSpacebarLedIcon;
    private static final int SPACE_LED_LENGTH_PERCENT = 80;

    // Mini keyboard
    private PopupWindow mMoreKeysWindow;
    private MoreKeysPanel mMoreKeysPanel;
    private int mMoreKeysPanelPointerTrackerId;
    private final WeakHashMap<Key, MoreKeysPanel> mMoreKeysPanelCache =
            new WeakHashMap<Key, MoreKeysPanel>();
    private final boolean mConfigShowMiniKeyboardAtTouchedPoint;

    private final boolean mIsSpacebarTriggeringPopupByLongPress;
    private final SuddenJumpingTouchEventHandler mTouchScreenRegulator;

    protected KeyDetector mKeyDetector;
    private boolean mHasDistinctMultitouch;
    private int mOldPointerCount = 1;
    private Key mOldKey;

    // To detect double tap.
    protected GestureDetector mGestureDetector;

    private final KeyTimerHandler mKeyTimerHandler = new KeyTimerHandler(this);

    private static class KeyTimerHandler extends StaticInnerHandlerWrapper<LatinKeyboardView>
            implements TimerProxy {
        private static final int MSG_REPEAT_KEY = 1;
        private static final int MSG_LONGPRESS_KEY = 2;
        private static final int MSG_IGNORE_DOUBLE_TAP = 3;
        private static final int MSG_KEY_TYPED = 4;

        private final int mKeyRepeatInterval;
        private boolean mInKeyRepeat;

        public KeyTimerHandler(LatinKeyboardView outerInstance) {
            super(outerInstance);
            // TODO: This should be the attribute of LatinKeyboardView.
            final Resources res = outerInstance.getContext().getResources();
            mKeyRepeatInterval = res.getInteger(R.integer.config_key_repeat_interval);
        }

        @Override
        public void handleMessage(Message msg) {
            final LatinKeyboardView keyboardView = getOuterInstance();
            final PointerTracker tracker = (PointerTracker) msg.obj;
            switch (msg.what) {
            case MSG_REPEAT_KEY:
                tracker.onRepeatKey(tracker.getKey());
                startKeyRepeatTimer(mKeyRepeatInterval, tracker);
                break;
            case MSG_LONGPRESS_KEY:
                keyboardView.openMiniKeyboardIfRequired(tracker.getKey(), tracker);
                break;
            }
        }

        @Override
        public void startKeyRepeatTimer(long delay, PointerTracker tracker) {
            mInKeyRepeat = true;
            sendMessageDelayed(obtainMessage(MSG_REPEAT_KEY, tracker), delay);
        }

        public void cancelKeyRepeatTimer() {
            mInKeyRepeat = false;
            removeMessages(MSG_REPEAT_KEY);
        }

        public boolean isInKeyRepeat() {
            return mInKeyRepeat;
        }

        @Override
        public void startLongPressTimer(long delay, PointerTracker tracker) {
            cancelLongPressTimer();
            sendMessageDelayed(obtainMessage(MSG_LONGPRESS_KEY, tracker), delay);
        }

        @Override
        public void cancelLongPressTimer() {
            removeMessages(MSG_LONGPRESS_KEY);
        }

        @Override
        public void startKeyTypedTimer(long delay) {
            removeMessages(MSG_KEY_TYPED);
            sendMessageDelayed(obtainMessage(MSG_KEY_TYPED), delay);
        }

        @Override
        public boolean isTyping() {
            return hasMessages(MSG_KEY_TYPED);
        }

        @Override
        public void cancelKeyTimers() {
            cancelKeyRepeatTimer();
            cancelLongPressTimer();
            removeMessages(MSG_IGNORE_DOUBLE_TAP);
        }

        public void startIgnoringDoubleTap() {
            sendMessageDelayed(obtainMessage(MSG_IGNORE_DOUBLE_TAP),
                    ViewConfiguration.getDoubleTapTimeout());
        }

        public boolean isIgnoringDoubleTap() {
            return hasMessages(MSG_IGNORE_DOUBLE_TAP);
        }

        public void cancelAllMessages() {
            cancelKeyTimers();
        }
    }

    class DoubleTapListener extends GestureDetector.SimpleOnGestureListener {
        private boolean mProcessingShiftDoubleTapEvent = false;

        @Override
        public boolean onDoubleTap(MotionEvent firstDown) {
            final Keyboard keyboard = getKeyboard();
            if (ENABLE_CAPSLOCK_BY_DOUBLETAP && keyboard.mId.isAlphabetKeyboard()) {
                final int pointerIndex = firstDown.getActionIndex();
                final int id = firstDown.getPointerId(pointerIndex);
                final PointerTracker tracker = PointerTracker.getPointerTracker(
                        id, LatinKeyboardView.this);
                final Key key = tracker.getKeyOn((int)firstDown.getX(), (int)firstDown.getY());
                // If the first down event is on shift key.
                if (key != null && key.isShift()) {
                    mProcessingShiftDoubleTapEvent = true;
                    return true;
                }
            }
            mProcessingShiftDoubleTapEvent = false;
            return false;
        }

        @Override
        public boolean onDoubleTapEvent(MotionEvent secondTap) {
            if (mProcessingShiftDoubleTapEvent
                    && secondTap.getAction() == MotionEvent.ACTION_DOWN) {
                final MotionEvent secondDown = secondTap;
                final int pointerIndex = secondDown.getActionIndex();
                final int id = secondDown.getPointerId(pointerIndex);
                final PointerTracker tracker = PointerTracker.getPointerTracker(
                        id, LatinKeyboardView.this);
                final Key key = tracker.getKeyOn((int)secondDown.getX(), (int)secondDown.getY());
                // If the second down event is also on shift key.
                if (key != null && key.isShift()) {
                    // Detected a double tap on shift key. If we are in the ignoring double tap
                    // mode, it means we have already turned off caps lock in
                    // {@link KeyboardSwitcher#onReleaseShift} .
                    onDoubleTapShiftKey(mKeyTimerHandler.isIgnoringDoubleTap());
                    return true;
                }
                // Otherwise these events should not be handled as double tap.
                mProcessingShiftDoubleTapEvent = false;
            }
            return mProcessingShiftDoubleTapEvent;
        }
    }

    public LatinKeyboardView(Context context, AttributeSet attrs) {
        this(context, attrs, R.attr.latinKeyboardViewStyle);
    }

    public LatinKeyboardView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);

        mTouchScreenRegulator = new SuddenJumpingTouchEventHandler(getContext(), this);

        final Resources res = getResources();
        // TODO: This should be the attribute of LatinKeyboardView.
        mConfigShowMiniKeyboardAtTouchedPoint = res.getBoolean(
                R.bool.config_show_mini_keyboard_at_touched_point);
        // TODO: This should be the attribute of LatinKeyboardView.
        final float keyHysteresisDistance = res.getDimension(R.dimen.key_hysteresis_distance);
        mKeyDetector = new KeyDetector(keyHysteresisDistance);

        final boolean ignoreMultitouch = true;
        mGestureDetector = new GestureDetector(
                getContext(), new DoubleTapListener(), null, ignoreMultitouch);
        mGestureDetector.setIsLongpressEnabled(false);

        mHasDistinctMultitouch = context.getPackageManager()
                .hasSystemFeature(PackageManager.FEATURE_TOUCHSCREEN_MULTITOUCH_DISTINCT);

        PointerTracker.init(mHasDistinctMultitouch, getContext());

        // TODO: This should be the attribute of LatinKeyboardView.
        final int longPressSpaceKeyTimeout =
                res.getInteger(R.integer.config_long_press_space_key_timeout);
        mIsSpacebarTriggeringPopupByLongPress = (longPressSpaceKeyTimeout > 0);

        final TypedArray a = context.obtainStyledAttributes(
                attrs, R.styleable.LatinKeyboardView, defStyle, R.style.LatinKeyboardView);
        mAutoCorrectionSpacebarLedEnabled = a.getBoolean(
                R.styleable.LatinKeyboardView_autoCorrectionSpacebarLedEnabled, false);
        mAutoCorrectionSpacebarLedIcon = a.getDrawable(
                R.styleable.LatinKeyboardView_autoCorrectionSpacebarLedIcon);
        mSpacebarTextRatio = a.getFraction(R.styleable.LatinKeyboardView_spacebarTextRatio,
                1000, 1000, 1) / 1000.0f;
        mSpacebarTextColor = a.getColor(R.styleable.LatinKeyboardView_spacebarTextColor, 0);
        mSpacebarTextShadowColor = a.getColor(
                R.styleable.LatinKeyboardView_spacebarTextShadowColor, 0);
        a.recycle();
    }

    public void startIgnoringDoubleTap() {
        if (ENABLE_CAPSLOCK_BY_DOUBLETAP)
            mKeyTimerHandler.startIgnoringDoubleTap();
    }

    public void setKeyboardActionListener(KeyboardActionListener listener) {
        mKeyboardActionListener = listener;
        PointerTracker.setKeyboardActionListener(listener);
    }

    /**
     * Returns the {@link KeyboardActionListener} object.
     * @return the listener attached to this keyboard
     */
    @Override
    public KeyboardActionListener getKeyboardActionListener() {
        return mKeyboardActionListener;
    }

    @Override
    public KeyDetector getKeyDetector() {
        return mKeyDetector;
    }

    @Override
    public DrawingProxy getDrawingProxy() {
        return this;
    }

    @Override
    public TimerProxy getTimerProxy() {
        return mKeyTimerHandler;
    }

    /**
     * Attaches a keyboard to this view. The keyboard can be switched at any time and the
     * view will re-layout itself to accommodate the keyboard.
     * @see Keyboard
     * @see #getKeyboard()
     * @param keyboard the keyboard to display in this view
     */
    @Override
    public void setKeyboard(Keyboard keyboard) {
        // Remove any pending messages, except dismissing preview
        mKeyTimerHandler.cancelKeyTimers();
        super.setKeyboard(keyboard);
        mKeyDetector.setKeyboard(
                keyboard, -getPaddingLeft(), -getPaddingTop() + mVerticalCorrection);
        mKeyDetector.setProximityThreshold(keyboard.mMostCommonKeyWidth);
        PointerTracker.setKeyDetector(mKeyDetector);
        mTouchScreenRegulator.setKeyboard(keyboard);
        mMoreKeysPanelCache.clear();

        mSpaceKey = keyboard.getKey(Keyboard.CODE_SPACE);
        mSpaceIcon = keyboard.mIconsSet.getIconByAttrId(R.styleable.Keyboard_iconSpaceKey);
        final int keyHeight = keyboard.mMostCommonKeyHeight - keyboard.mVerticalGap;
        mSpacebarTextSize = keyHeight * mSpacebarTextRatio;
        mSpacebarLocale = keyboard.mId.mLocale;
    }

    /**
     * Returns whether the device has distinct multi-touch panel.
     * @return true if the device has distinct multi-touch panel.
     */
    public boolean hasDistinctMultitouch() {
        return mHasDistinctMultitouch;
    }

    public void setDistinctMultitouch(boolean hasDistinctMultitouch) {
        mHasDistinctMultitouch = hasDistinctMultitouch;
    }

    /**
     * When enabled, calls to {@link KeyboardActionListener#onCodeInput} will include key
     * codes for adjacent keys.  When disabled, only the primary key code will be
     * reported.
     * @param enabled whether or not the proximity correction is enabled
     */
    public void setProximityCorrectionEnabled(boolean enabled) {
        mKeyDetector.setProximityCorrectionEnabled(enabled);
    }

    /**
     * Returns true if proximity correction is enabled.
     */
    public boolean isProximityCorrectionEnabled() {
        return mKeyDetector.isProximityCorrectionEnabled();
    }

    @Override
    public void cancelAllMessages() {
        mKeyTimerHandler.cancelAllMessages();
        super.cancelAllMessages();
    }

    private boolean openMiniKeyboardIfRequired(Key parentKey, PointerTracker tracker) {
        // Check if we have a popup layout specified first.
        if (mMoreKeysLayout == 0) {
            return false;
        }

        // Check if we are already displaying popup panel.
        if (mMoreKeysPanel != null)
            return false;
        if (parentKey == null)
            return false;
        return onLongPress(parentKey, tracker);
    }

    private void onDoubleTapShiftKey(final boolean ignore) {
        // When shift key is double tapped, the first tap is correctly processed as usual tap. And
        // the second tap is treated as this double tap event, so that we need not mark tracker
        // calling setAlreadyProcessed() nor remove the tracker from mPointerQueue.
        if (ignore) {
            invokeCustomRequest(LatinIME.CODE_HAPTIC_AND_AUDIO_FEEDBACK);
        } else {
            invokeCodeInput(Keyboard.CODE_CAPSLOCK);
        }
    }

    // This default implementation returns a more keys panel.
    protected MoreKeysPanel onCreateMoreKeysPanel(Key parentKey) {
        if (parentKey.mMoreKeys == null)
            return null;

        final View container = LayoutInflater.from(getContext()).inflate(mMoreKeysLayout, null);
        if (container == null)
            throw new NullPointerException();

        final MiniKeyboardView miniKeyboardView =
                (MiniKeyboardView)container.findViewById(R.id.mini_keyboard_view);
        final Keyboard parentKeyboard = getKeyboard();
        final Keyboard miniKeyboard = new MiniKeyboard.Builder(
                this, parentKeyboard.mMoreKeysTemplate, parentKey, parentKeyboard).build();
        miniKeyboardView.setKeyboard(miniKeyboard);
        container.measure(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);

        return miniKeyboardView;
    }

    /**
     * Called when a key is long pressed. By default this will open mini keyboard associated
     * with this key.
     * @param parentKey the key that was long pressed
     * @param tracker the pointer tracker which pressed the parent key
     * @return true if the long press is handled, false otherwise. Subclasses should call the
     * method on the base class if the subclass doesn't wish to handle the call.
     */
    protected boolean onLongPress(Key parentKey, PointerTracker tracker) {
        final int primaryCode = parentKey.mCode;
        final Keyboard keyboard = getKeyboard();
        if (primaryCode == Keyboard.CODE_DIGIT0 && keyboard.mId.isPhoneKeyboard()) {
            tracker.onLongPressed();
            // Long pressing on 0 in phone number keypad gives you a '+'.
            invokeCodeInput(Keyboard.CODE_PLUS);
            invokeReleaseKey(primaryCode);
            return true;
        }
        if (primaryCode == Keyboard.CODE_SHIFT && keyboard.mId.isAlphabetKeyboard()) {
            tracker.onLongPressed();
            invokeCodeInput(Keyboard.CODE_CAPSLOCK);
            invokeReleaseKey(primaryCode);
            return true;
        }
        if (primaryCode == Keyboard.CODE_SPACE) {
            // Long pressing the space key invokes IME switcher dialog.
            if (invokeCustomRequest(LatinIME.CODE_SHOW_INPUT_METHOD_PICKER)) {
                tracker.onLongPressed();
                invokeReleaseKey(primaryCode);
                return true;
            }
        }
        return openMoreKeysPanel(parentKey, tracker);
    }

    private boolean invokeCustomRequest(int code) {
        return mKeyboardActionListener.onCustomRequest(code);
    }

    private void invokeCodeInput(int primaryCode) {
        mKeyboardActionListener.onCodeInput(primaryCode, null,
                KeyboardActionListener.NOT_A_TOUCH_COORDINATE,
                KeyboardActionListener.NOT_A_TOUCH_COORDINATE);
    }

    private void invokeReleaseKey(int primaryCode) {
        mKeyboardActionListener.onReleaseKey(primaryCode, false);
    }

    private boolean openMoreKeysPanel(Key parentKey, PointerTracker tracker) {
        MoreKeysPanel moreKeysPanel = mMoreKeysPanelCache.get(parentKey);
        if (moreKeysPanel == null) {
            moreKeysPanel = onCreateMoreKeysPanel(parentKey);
            if (moreKeysPanel == null)
                return false;
            mMoreKeysPanelCache.put(parentKey, moreKeysPanel);
        }
        if (mMoreKeysWindow == null) {
            mMoreKeysWindow = new PopupWindow(getContext());
            mMoreKeysWindow.setBackgroundDrawable(null);
            mMoreKeysWindow.setAnimationStyle(R.style.MiniKeyboardAnimation);
        }
        mMoreKeysPanel = moreKeysPanel;
        mMoreKeysPanelPointerTrackerId = tracker.mPointerId;

        final Keyboard keyboard = getKeyboard();
        moreKeysPanel.setShifted(keyboard.isShiftedOrShiftLocked());
        final int pointX = (mConfigShowMiniKeyboardAtTouchedPoint) ? tracker.getLastX()
                : parentKey.mX + parentKey.mWidth / 2;
        final int pointY = parentKey.mY - keyboard.mVerticalGap;
        moreKeysPanel.showMoreKeysPanel(
                this, this, pointX, pointY, mMoreKeysWindow, mKeyboardActionListener);
        final int translatedX = moreKeysPanel.translateX(tracker.getLastX());
        final int translatedY = moreKeysPanel.translateY(tracker.getLastY());
        tracker.onShowMoreKeysPanel(translatedX, translatedY, moreKeysPanel);
        dimEntireKeyboard(true);
        return true;
    }

    public boolean isInSlidingKeyInput() {
        if (mMoreKeysPanel != null) {
            return true;
        } else {
            return PointerTracker.isAnyInSlidingKeyInput();
        }
    }

    public int getPointerCount() {
        return mOldPointerCount;
    }

    @Override
    public boolean onTouchEvent(MotionEvent me) {
        if (getKeyboard() == null) {
            return false;
        }
        return mTouchScreenRegulator.onTouchEvent(me);
    }

    @Override
    public boolean processMotionEvent(MotionEvent me) {
        final boolean nonDistinctMultitouch = !mHasDistinctMultitouch;
        final int action = me.getActionMasked();
        final int pointerCount = me.getPointerCount();
        final int oldPointerCount = mOldPointerCount;
        mOldPointerCount = pointerCount;

        // TODO: cleanup this code into a multi-touch to single-touch event converter class?
        // If the device does not have distinct multi-touch support panel, ignore all multi-touch
        // events except a transition from/to single-touch.
        if (nonDistinctMultitouch && pointerCount > 1 && oldPointerCount > 1) {
            return true;
        }

        // Gesture detector must be enabled only when mini-keyboard is not on the screen.
        if (mMoreKeysPanel == null && mGestureDetector != null
                && mGestureDetector.onTouchEvent(me)) {
            PointerTracker.dismissAllKeyPreviews();
            mKeyTimerHandler.cancelKeyTimers();
            return true;
        }

        final long eventTime = me.getEventTime();
        final int index = me.getActionIndex();
        final int id = me.getPointerId(index);
        final int x, y;
        if (mMoreKeysPanel != null && id == mMoreKeysPanelPointerTrackerId) {
            x = mMoreKeysPanel.translateX((int)me.getX(index));
            y = mMoreKeysPanel.translateY((int)me.getY(index));
        } else {
            x = (int)me.getX(index);
            y = (int)me.getY(index);
        }
        if (ENABLE_USABILITY_STUDY_LOG) {
            final String eventTag;
            switch (action) {
                case MotionEvent.ACTION_UP:
                    eventTag = "[Up]";
                    break;
                case MotionEvent.ACTION_DOWN:
                    eventTag = "[Down]";
                    break;
                case MotionEvent.ACTION_POINTER_UP:
                    eventTag = "[PointerUp]";
                    break;
                case MotionEvent.ACTION_POINTER_DOWN:
                    eventTag = "[PointerDown]";
                    break;
                case MotionEvent.ACTION_MOVE: // Skip this as being logged below
                    eventTag = "";
                    break;
                default:
                    eventTag = "[Action" + action + "]";
                    break;
            }
            if (!TextUtils.isEmpty(eventTag)) {
                UsabilityStudyLogUtils.getInstance().write(
                        eventTag + eventTime + "," + id + "," + x + "," + y + "\t\t");
            }
        }

        if (mKeyTimerHandler.isInKeyRepeat()) {
            final PointerTracker tracker = PointerTracker.getPointerTracker(id, this);
            // Key repeating timer will be canceled if 2 or more keys are in action, and current
            // event (UP or DOWN) is non-modifier key.
            if (pointerCount > 1 && !tracker.isModifier()) {
                mKeyTimerHandler.cancelKeyRepeatTimer();
            }
            // Up event will pass through.
        }

        // TODO: cleanup this code into a multi-touch to single-touch event converter class?
        // Translate mutli-touch event to single-touch events on the device that has no distinct
        // multi-touch panel.
        if (nonDistinctMultitouch) {
            // Use only main (id=0) pointer tracker.
            final PointerTracker tracker = PointerTracker.getPointerTracker(0, this);
            if (pointerCount == 1 && oldPointerCount == 2) {
                // Multi-touch to single touch transition.
                // Send a down event for the latest pointer if the key is different from the
                // previous key.
                final Key newKey = tracker.getKeyOn(x, y);
                if (mOldKey != newKey) {
                    tracker.onDownEvent(x, y, eventTime, this);
                    if (action == MotionEvent.ACTION_UP)
                        tracker.onUpEvent(x, y, eventTime);
                }
            } else if (pointerCount == 2 && oldPointerCount == 1) {
                // Single-touch to multi-touch transition.
                // Send an up event for the last pointer.
                final int lastX = tracker.getLastX();
                final int lastY = tracker.getLastY();
                mOldKey = tracker.getKeyOn(lastX, lastY);
                tracker.onUpEvent(lastX, lastY, eventTime);
            } else if (pointerCount == 1 && oldPointerCount == 1) {
                tracker.processMotionEvent(action, x, y, eventTime, this);
            } else {
                Log.w(TAG, "Unknown touch panel behavior: pointer count is " + pointerCount
                        + " (old " + oldPointerCount + ")");
            }
            return true;
        }

        if (action == MotionEvent.ACTION_MOVE) {
            for (int i = 0; i < pointerCount; i++) {
                final PointerTracker tracker = PointerTracker.getPointerTracker(
                        me.getPointerId(i), this);
                final int px, py;
                if (mMoreKeysPanel != null
                        && tracker.mPointerId == mMoreKeysPanelPointerTrackerId) {
                    px = mMoreKeysPanel.translateX((int)me.getX(i));
                    py = mMoreKeysPanel.translateY((int)me.getY(i));
                } else {
                    px = (int)me.getX(i);
                    py = (int)me.getY(i);
                }
                tracker.onMoveEvent(px, py, eventTime);
                if (ENABLE_USABILITY_STUDY_LOG) {
                    UsabilityStudyLogUtils.getInstance().write("[Move]"  + eventTime + ","
                            + me.getPointerId(i) + "," + px + "," + py + "\t\t");
                }
            }
        } else {
            final PointerTracker tracker = PointerTracker.getPointerTracker(id, this);
            tracker.processMotionEvent(action, x, y, eventTime, this);
        }

        return true;
    }

    @Override
    public void closing() {
        super.closing();
        dismissMoreKeysPanel();
        mMoreKeysPanelCache.clear();
    }

    @Override
    public boolean dismissMoreKeysPanel() {
        if (mMoreKeysWindow != null && mMoreKeysWindow.isShowing()) {
            mMoreKeysWindow.dismiss();
            mMoreKeysPanel = null;
            mMoreKeysPanelPointerTrackerId = -1;
            dimEntireKeyboard(false);
            return true;
        }
        return false;
    }

    public boolean handleBack() {
        return dismissMoreKeysPanel();
    }

    @Override
    public void draw(Canvas c) {
        Utils.GCUtils.getInstance().reset();
        boolean tryGC = true;
        for (int i = 0; i < Utils.GCUtils.GC_TRY_LOOP_MAX && tryGC; ++i) {
            try {
                super.draw(c);
                tryGC = false;
            } catch (OutOfMemoryError e) {
                tryGC = Utils.GCUtils.getInstance().tryGCOrWait("LatinKeyboardView", e);
            }
        }
    }

    @Override
    protected void onAttachedToWindow() {
        // Token is available from here.
        VoiceProxy.getInstance().onAttachedToWindow();
    }

    @Override
    public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) {
        if (AccessibilityUtils.getInstance().isTouchExplorationEnabled()) {
            return AccessibleKeyboardViewProxy.getInstance().dispatchPopulateAccessibilityEvent(
                    event) || super.dispatchPopulateAccessibilityEvent(event);
        }

        return super.dispatchPopulateAccessibilityEvent(event);
    }

    /**
     * Receives hover events from the input framework. This method overrides
     * View.dispatchHoverEvent(MotionEvent) on SDK version ICS or higher. On
     * lower SDK versions, this method is never called.
     *
     * @param event The motion event to be dispatched.
     * @return {@code true} if the event was handled by the view, {@code false}
     *         otherwise
     */
    public boolean dispatchHoverEvent(MotionEvent event) {
        if (AccessibilityUtils.getInstance().isTouchExplorationEnabled()) {
            final PointerTracker tracker = PointerTracker.getPointerTracker(0, this);
            return AccessibleKeyboardViewProxy.getInstance().dispatchHoverEvent(event, tracker);
        }

        // Reflection doesn't support calling superclass methods.
        return false;
    }

    public void updateShortcutKey(boolean available) {
        final Keyboard keyboard = getKeyboard();
        if (keyboard == null) return;
        final Key shortcutKey = keyboard.getKey(Keyboard.CODE_SHORTCUT);
        if (shortcutKey == null) return;
        shortcutKey.setEnabled(available);
        invalidateKey(shortcutKey);
    }

    public void updateSpacebar(float fadeFactor, boolean needsToDisplayLanguage) {
        mSpacebarTextFadeFactor = fadeFactor;
        mNeedsToDisplayLanguage = needsToDisplayLanguage;
        invalidateKey(mSpaceKey);
    }

    public void updateAutoCorrectionState(boolean isAutoCorrection) {
        if (!mAutoCorrectionSpacebarLedEnabled) return;
        mAutoCorrectionSpacebarLedOn = isAutoCorrection;
        invalidateKey(mSpaceKey);
    }

    @Override
    protected void onDrawKeyTopVisuals(Key key, Canvas canvas, Paint paint, KeyDrawParams params) {
        super.onDrawKeyTopVisuals(key, canvas, paint, params);

        if (key.mCode == Keyboard.CODE_SPACE) {
            drawSpacebar(key, canvas, paint);

            // Whether space key needs to show the "..." popup hint for special purposes
            if (mIsSpacebarTriggeringPopupByLongPress
                    && Utils.hasMultipleEnabledIMEsOrSubtypes(true /* include aux subtypes */)) {
                drawKeyPopupHint(key, canvas, paint, params);
            }
        }
    }

    private static int getSpacebarTextColor(int color, float fadeFactor) {
        final int newColor = Color.argb((int)(Color.alpha(color) * fadeFactor),
                Color.red(color), Color.green(color), Color.blue(color));
        return newColor;
    }

    // Compute width of text with specified text size using paint.
    private int getTextWidth(Paint paint, String text, float textSize) {
        paint.setTextSize(textSize);
        return (int)getLabelWidth(text, paint);
    }

    // Layout locale language name on spacebar.
    private String layoutLanguageOnSpacebar(Paint paint, Locale locale, int width,
            float origTextSize) {
        paint.setTextAlign(Align.CENTER);
        paint.setTypeface(Typeface.DEFAULT);
        // Estimate appropriate language name text size to fit in maxTextWidth.
        String language = Utils.getFullDisplayName(locale, true);
        int textWidth = getTextWidth(paint, language, origTextSize);
        // Assuming text width and text size are proportional to each other.
        float textSize = origTextSize * Math.min(width / textWidth, 1.0f);
        // allow variable text size
        textWidth = getTextWidth(paint, language, textSize);
        // If text size goes too small or text does not fit, use middle or short name
        final boolean useMiddleName = (textSize / origTextSize < MINIMUM_SCALE_OF_LANGUAGE_NAME)
                || (textWidth > width);

        final boolean useShortName;
        if (useMiddleName) {
            language = Utils.getMiddleDisplayLanguage(locale);
            textWidth = getTextWidth(paint, language, origTextSize);
            textSize = origTextSize * Math.min(width / textWidth, 1.0f);
            useShortName = (textSize / origTextSize < MINIMUM_SCALE_OF_LANGUAGE_NAME)
                    || (textWidth > width);
        } else {
            useShortName = false;
        }

        if (useShortName) {
            language = Utils.getShortDisplayLanguage(locale);
            textWidth = getTextWidth(paint, language, origTextSize);
            textSize = origTextSize * Math.min(width / textWidth, 1.0f);
        }
        paint.setTextSize(textSize);

        return language;
    }

    private void drawSpacebar(Key key, Canvas canvas, Paint paint) {
        final int width = key.mWidth;
        final int height = mSpaceIcon != null ? mSpaceIcon.getIntrinsicHeight() : key.mHeight;

        // If application locales are explicitly selected.
        if (mNeedsToDisplayLanguage) {
            final String language = layoutLanguageOnSpacebar(paint, mSpacebarLocale, width,
                    mSpacebarTextSize);
            // Draw language text with shadow
            // In case there is no space icon, we will place the language text at the center of
            // spacebar.
            final float descent = paint.descent();
            final float textHeight = -paint.ascent() + descent;
            final float baseline = (mSpaceIcon != null) ? height * SPACEBAR_LANGUAGE_BASELINE
                    : height / 2 + textHeight / 2;
            paint.setColor(getSpacebarTextColor(mSpacebarTextShadowColor, mSpacebarTextFadeFactor));
            canvas.drawText(language, width / 2, baseline - descent - 1, paint);
            paint.setColor(getSpacebarTextColor(mSpacebarTextColor, mSpacebarTextFadeFactor));
            canvas.drawText(language, width / 2, baseline - descent, paint);
        }

        // Draw the spacebar icon at the bottom
        if (mAutoCorrectionSpacebarLedOn) {
            final int iconWidth = width * SPACE_LED_LENGTH_PERCENT / 100;
            final int iconHeight = mAutoCorrectionSpacebarLedIcon.getIntrinsicHeight();
            int x = (width - iconWidth) / 2;
            int y = height - iconHeight;
            drawIcon(canvas, mAutoCorrectionSpacebarLedIcon, x, y, iconWidth, iconHeight);
        } else if (mSpaceIcon != null) {
            final int iconWidth = mSpaceIcon.getIntrinsicWidth();
            final int iconHeight = mSpaceIcon.getIntrinsicHeight();
            int x = (width - iconWidth) / 2;
            int y = height - iconHeight;
            drawIcon(canvas, mSpaceIcon, x, y, iconWidth, iconHeight);
        }
    }
}