/*
 * Copyright (C) 2014 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.accessibility;

import android.content.Context;
import android.graphics.Rect;
import android.os.SystemClock;
import android.util.Log;
import android.util.SparseIntArray;
import android.view.MotionEvent;

import com.android.inputmethod.keyboard.Key;
import com.android.inputmethod.keyboard.KeyDetector;
import com.android.inputmethod.keyboard.Keyboard;
import com.android.inputmethod.keyboard.KeyboardId;
import com.android.inputmethod.keyboard.MainKeyboardView;
import com.android.inputmethod.keyboard.PointerTracker;
import com.android.inputmethod.latin.R;
import com.android.inputmethod.latin.utils.SubtypeLocaleUtils;

/**
 * This class represents a delegate that can be registered in {@link MainKeyboardView} to enhance
 * accessibility support via composition rather via inheritance.
 */
public final class MainKeyboardAccessibilityDelegate
        extends KeyboardAccessibilityDelegate<MainKeyboardView>
        implements AccessibilityLongPressTimer.LongPressTimerCallback {
    private static final String TAG = MainKeyboardAccessibilityDelegate.class.getSimpleName();

    /** Map of keyboard modes to resource IDs. */
    private static final SparseIntArray KEYBOARD_MODE_RES_IDS = new SparseIntArray();

    static {
        KEYBOARD_MODE_RES_IDS.put(KeyboardId.MODE_DATE, R.string.keyboard_mode_date);
        KEYBOARD_MODE_RES_IDS.put(KeyboardId.MODE_DATETIME, R.string.keyboard_mode_date_time);
        KEYBOARD_MODE_RES_IDS.put(KeyboardId.MODE_EMAIL, R.string.keyboard_mode_email);
        KEYBOARD_MODE_RES_IDS.put(KeyboardId.MODE_IM, R.string.keyboard_mode_im);
        KEYBOARD_MODE_RES_IDS.put(KeyboardId.MODE_NUMBER, R.string.keyboard_mode_number);
        KEYBOARD_MODE_RES_IDS.put(KeyboardId.MODE_PHONE, R.string.keyboard_mode_phone);
        KEYBOARD_MODE_RES_IDS.put(KeyboardId.MODE_TEXT, R.string.keyboard_mode_text);
        KEYBOARD_MODE_RES_IDS.put(KeyboardId.MODE_TIME, R.string.keyboard_mode_time);
        KEYBOARD_MODE_RES_IDS.put(KeyboardId.MODE_URL, R.string.keyboard_mode_url);
    }

    /** The most recently set keyboard mode. */
    private int mLastKeyboardMode = KEYBOARD_IS_HIDDEN;
    private static final int KEYBOARD_IS_HIDDEN = -1;
    // The rectangle region to ignore hover events.
    private final Rect mBoundsToIgnoreHoverEvent = new Rect();

    private final AccessibilityLongPressTimer mAccessibilityLongPressTimer;

    public MainKeyboardAccessibilityDelegate(final MainKeyboardView mainKeyboardView,
            final KeyDetector keyDetector) {
        super(mainKeyboardView, keyDetector);
        mAccessibilityLongPressTimer = new AccessibilityLongPressTimer(
                this /* callback */, mainKeyboardView.getContext());
    }

    /**
     * {@inheritDoc}
     */
    @Override
    public void setKeyboard(final Keyboard keyboard) {
        if (keyboard == null) {
            return;
        }
        final Keyboard lastKeyboard = getKeyboard();
        super.setKeyboard(keyboard);
        final int lastKeyboardMode = mLastKeyboardMode;
        mLastKeyboardMode = keyboard.mId.mMode;

        // Since this method is called even when accessibility is off, make sure
        // to check the state before announcing anything.
        if (!AccessibilityUtils.getInstance().isAccessibilityEnabled()) {
            return;
        }
        // Announce the language name only when the language is changed.
        if (lastKeyboard == null || !keyboard.mId.mSubtype.equals(lastKeyboard.mId.mSubtype)) {
            announceKeyboardLanguage(keyboard);
            return;
        }
        // Announce the mode only when the mode is changed.
        if (keyboard.mId.mMode != lastKeyboardMode) {
            announceKeyboardMode(keyboard);
            return;
        }
        // Announce the keyboard type only when the type is changed.
        if (keyboard.mId.mElementId != lastKeyboard.mId.mElementId) {
            announceKeyboardType(keyboard, lastKeyboard);
            return;
        }
    }

    /**
     * Called when the keyboard is hidden and accessibility is enabled.
     */
    public void onHideWindow() {
        announceKeyboardHidden();
        mLastKeyboardMode = KEYBOARD_IS_HIDDEN;
    }

    /**
     * Announces which language of keyboard is being displayed.
     *
     * @param keyboard The new keyboard.
     */
    private void announceKeyboardLanguage(final Keyboard keyboard) {
        final String languageText = SubtypeLocaleUtils.getSubtypeDisplayNameInSystemLocale(
                keyboard.mId.mSubtype);
        sendWindowStateChanged(languageText);
    }

    /**
     * Announces which type of keyboard is being displayed.
     * If the keyboard type is unknown, no announcement is made.
     *
     * @param keyboard The new keyboard.
     */
    private void announceKeyboardMode(final Keyboard keyboard) {
        final Context context = mKeyboardView.getContext();
        final int modeTextResId = KEYBOARD_MODE_RES_IDS.get(keyboard.mId.mMode);
        if (modeTextResId == 0) {
            return;
        }
        final String modeText = context.getString(modeTextResId);
        final String text = context.getString(R.string.announce_keyboard_mode, modeText);
        sendWindowStateChanged(text);
    }

    /**
     * Announces which type of keyboard is being displayed.
     *
     * @param keyboard The new keyboard.
     * @param lastKeyboard The last keyboard.
     */
    private void announceKeyboardType(final Keyboard keyboard, final Keyboard lastKeyboard) {
        final int lastElementId = lastKeyboard.mId.mElementId;
        final int resId;
        switch (keyboard.mId.mElementId) {
        case KeyboardId.ELEMENT_ALPHABET_AUTOMATIC_SHIFTED:
        case KeyboardId.ELEMENT_ALPHABET:
            if (lastElementId == KeyboardId.ELEMENT_ALPHABET
                    || lastElementId == KeyboardId.ELEMENT_ALPHABET_AUTOMATIC_SHIFTED) {
                // Transition between alphabet mode and automatic shifted mode should be silently
                // ignored because it can be determined by each key's talk back announce.
                return;
            }
            resId = R.string.spoken_description_mode_alpha;
            break;
        case KeyboardId.ELEMENT_ALPHABET_MANUAL_SHIFTED:
            if (lastElementId == KeyboardId.ELEMENT_ALPHABET_AUTOMATIC_SHIFTED) {
                // Resetting automatic shifted mode by pressing the shift key causes the transition
                // from automatic shifted to manual shifted that should be silently ignored.
                return;
            }
            resId = R.string.spoken_description_shiftmode_on;
            break;
        case KeyboardId.ELEMENT_ALPHABET_SHIFT_LOCK_SHIFTED:
            if (lastElementId == KeyboardId.ELEMENT_ALPHABET_SHIFT_LOCKED) {
                // Resetting caps locked mode by pressing the shift key causes the transition
                // from shift locked to shift lock shifted that should be silently ignored.
                return;
            }
            resId = R.string.spoken_description_shiftmode_locked;
            break;
        case KeyboardId.ELEMENT_ALPHABET_SHIFT_LOCKED:
            resId = R.string.spoken_description_shiftmode_locked;
            break;
        case KeyboardId.ELEMENT_SYMBOLS:
            resId = R.string.spoken_description_mode_symbol;
            break;
        case KeyboardId.ELEMENT_SYMBOLS_SHIFTED:
            resId = R.string.spoken_description_mode_symbol_shift;
            break;
        case KeyboardId.ELEMENT_PHONE:
            resId = R.string.spoken_description_mode_phone;
            break;
        case KeyboardId.ELEMENT_PHONE_SYMBOLS:
            resId = R.string.spoken_description_mode_phone_shift;
            break;
        default:
            return;
        }
        sendWindowStateChanged(resId);
    }

    /**
     * Announces that the keyboard has been hidden.
     */
    private void announceKeyboardHidden() {
        sendWindowStateChanged(R.string.announce_keyboard_hidden);
    }

    @Override
    public void performClickOn(final Key key) {
        final int x = key.getHitBox().centerX();
        final int y = key.getHitBox().centerY();
        if (DEBUG_HOVER) {
            Log.d(TAG, "performClickOn: key=" + key
                    + " inIgnoreBounds=" + mBoundsToIgnoreHoverEvent.contains(x, y));
        }
        if (mBoundsToIgnoreHoverEvent.contains(x, y)) {
            // This hover exit event points to the key that should be ignored.
            // Clear the ignoring region to handle further hover events.
            mBoundsToIgnoreHoverEvent.setEmpty();
            return;
        }
        super.performClickOn(key);
    }

    @Override
    protected void onHoverEnterTo(final Key key) {
        final int x = key.getHitBox().centerX();
        final int y = key.getHitBox().centerY();
        if (DEBUG_HOVER) {
            Log.d(TAG, "onHoverEnterTo: key=" + key
                    + " inIgnoreBounds=" + mBoundsToIgnoreHoverEvent.contains(x, y));
        }
        mAccessibilityLongPressTimer.cancelLongPress();
        if (mBoundsToIgnoreHoverEvent.contains(x, y)) {
            return;
        }
        // This hover enter event points to the key that isn't in the ignoring region.
        // Further hover events should be handled.
        mBoundsToIgnoreHoverEvent.setEmpty();
        super.onHoverEnterTo(key);
        if (key.isLongPressEnabled()) {
            mAccessibilityLongPressTimer.startLongPress(key);
        }
    }

    @Override
    protected void onHoverExitFrom(final Key key) {
        final int x = key.getHitBox().centerX();
        final int y = key.getHitBox().centerY();
        if (DEBUG_HOVER) {
            Log.d(TAG, "onHoverExitFrom: key=" + key
                    + " inIgnoreBounds=" + mBoundsToIgnoreHoverEvent.contains(x, y));
        }
        mAccessibilityLongPressTimer.cancelLongPress();
        super.onHoverExitFrom(key);
    }

    @Override
    public void performLongClickOn(final Key key) {
        if (DEBUG_HOVER) {
            Log.d(TAG, "performLongClickOn: key=" + key);
        }
        final PointerTracker tracker = PointerTracker.getPointerTracker(HOVER_EVENT_POINTER_ID);
        final long eventTime = SystemClock.uptimeMillis();
        final int x = key.getHitBox().centerX();
        final int y = key.getHitBox().centerY();
        final MotionEvent downEvent = MotionEvent.obtain(
                eventTime, eventTime, MotionEvent.ACTION_DOWN, x, y, 0 /* metaState */);
        // Inject a fake down event to {@link PointerTracker} to handle a long press correctly.
        tracker.processMotionEvent(downEvent, mKeyDetector);
        // The above fake down event triggers an unnecessary long press timer that should be
        // canceled.
        tracker.cancelLongPressTimer();
        downEvent.recycle();
        // Invoke {@link MainKeyboardView#onLongPress(PointerTracker)} as if a long press timeout
        // has passed.
        mKeyboardView.onLongPress(tracker);
        // If {@link Key#hasNoPanelAutoMoreKeys()} is true (such as "0 +" key on the phone layout)
        // or a key invokes IME switcher dialog, we should just ignore the next
        // {@link #onRegisterHoverKey(Key,MotionEvent)}. It can be determined by whether
        // {@link PointerTracker} is in operation or not.
        if (tracker.isInOperation()) {
            // This long press shows a more keys keyboard and further hover events should be
            // handled.
            mBoundsToIgnoreHoverEvent.setEmpty();
            return;
        }
        // This long press has handled at {@link MainKeyboardView#onLongPress(PointerTracker)}.
        // We should ignore further hover events on this key.
        mBoundsToIgnoreHoverEvent.set(key.getHitBox());
        if (key.hasNoPanelAutoMoreKey()) {
            // This long press has registered a code point without showing a more keys keyboard.
            // We should talk back the code point if possible.
            final int codePointOfNoPanelAutoMoreKey = key.getMoreKeys()[0].mCode;
            final String text = KeyCodeDescriptionMapper.getInstance().getDescriptionForCodePoint(
                    mKeyboardView.getContext(), codePointOfNoPanelAutoMoreKey);
            if (text != null) {
                sendWindowStateChanged(text);
            }
        }
    }
}