content: /*
   * Copyright (C) 2012 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.amnesica.kryptey.inputmethod.event;
  
  import com.amnesica.kryptey.inputmethod.latin.common.Constants;
  import com.amnesica.kryptey.inputmethod.latin.common.StringUtils;
  
  /**
   * Class representing a generic input event as handled by Latin IME.
   * <p>
   * This contains information about the origin of the event, but it is generalized and should
   * represent a software keypress, hardware keypress, or d-pad move alike.
   * Very importantly, this does not necessarily result in inputting one character, or even anything
   * at all - it may be a dead key, it may be a partial input, it may be a special key on the
   * keyboard, it may be a cancellation of a keypress (e.g. in a soft keyboard the finger of the
   * user has slid out of the key), etc. It may also be a batch input from a gesture or handwriting
   * for example.
   * The combiner should figure out what to do with this.
   */
  public class Event {
    // Should the types below be represented by separate classes instead? It would be cleaner
    // but probably a bit too much
    // An event we don't handle in Latin IME, for example pressing Ctrl on a hardware keyboard.
    final public static int EVENT_TYPE_NOT_HANDLED = 0;
    // A key press that is part of input, for example pressing an alphabetic character on a
    // hardware qwerty keyboard. It may be part of a sequence that will be re-interpreted later
    // through combination.
    final public static int EVENT_TYPE_INPUT_KEYPRESS = 1;
    // A toggle event is triggered by a key that affects the previous character. An example would
    // be a numeric key on a 10-key keyboard, which would toggle between 1 - a - b - c with
    // repeated presses.
    final public static int EVENT_TYPE_TOGGLE = 2;
    // A mode event instructs the combiner to change modes. The canonical example would be the
    // hankaku/zenkaku key on a Japanese keyboard, or even the caps lock key on a qwerty keyboard
    // if handled at the combiner level.
    final public static int EVENT_TYPE_MODE_KEY = 3;
    // An event corresponding to a string generated by some software process.
    final public static int EVENT_TYPE_SOFTWARE_GENERATED_STRING = 6;
    // An event corresponding to a cursor move
    final public static int EVENT_TYPE_CURSOR_MOVE = 7;
  
    // 0 is a valid code point, so we use -1 here.
    final public static int NOT_A_CODE_POINT = -1;
    // -1 is a valid key code, so we use 0 here.
    final public static int NOT_A_KEY_CODE = 0;
  
    final private static int FLAG_NONE = 0;
    // This event is coming from a key repeat, software or hardware.
    final private static int FLAG_REPEAT = 0x2;
    // This event has already been consumed.
    final private static int FLAG_CONSUMED = 0x4;
  
    final private int mEventType; // The type of event - one of the constants above
    // The code point associated with the event, if relevant. This is a unicode code point, and
    // has nothing to do with other representations of the key. It is only relevant if this event
    // is of KEYPRESS type, but for a mode key like hankaku/zenkaku or ctrl, there is no code point
    // associated so this should be NOT_A_CODE_POINT to avoid unintentional use of its value when
    // it's not relevant.
    final public int mCodePoint;
  
    final public CharSequence mText;
  
    // The key code associated with the event, if relevant. This is relevant whenever this event
    // has been triggered by a key press, but not for a gesture for example. This has conceptually
    // no link to the code point, although keys that enter a straight code point may often set
    // this to be equal to mCodePoint for convenience. If this is not a key, this must contain
    // NOT_A_KEY_CODE.
    final public int mKeyCode;
  
    // Coordinates of the touch event, if relevant. If useful, we may want to replace this with
    // a MotionEvent or something in the future. This is only relevant when the keypress is from
    // a software keyboard obviously, unless there are touch-sensitive hardware keyboards in the
    // future or some other awesome sauce.
    final public int mX;
    final public int mY;
  
    // Some flags that can't go into the key code. It's a bit field of FLAG_*
    final private int mFlags;
  
    // The next event, if any. Null if there is no next event yet.
    final public Event mNextEvent;
  
    // This method is private - to create a new event, use one of the create* utility methods.
    private Event(final int type, final CharSequence text, final int codePoint, final int keyCode,
                  final int x, final int y, final int flags,
                  final Event next) {
      mEventType = type;
      mText = text;
      mCodePoint = codePoint;
      mKeyCode = keyCode;
      mX = x;
      mY = y;
      mFlags = flags;
      mNextEvent = next;
    }
  
    public static Event createSoftwareKeypressEvent(final int codePoint, final int keyCode,
                                                    final int x, final int y, final boolean isKeyRepeat) {
      return new Event(EVENT_TYPE_INPUT_KEYPRESS, null, codePoint, keyCode, x, y,
          isKeyRepeat ? FLAG_REPEAT : FLAG_NONE, null);
    }
  
    /**
     * Creates an input event with a CharSequence. This is used by some software processes whose
     * output is a string, possibly with styling. Examples include press on a multi-character key,
     * or combination that outputs a string.
     *
     * @param text    the CharSequence associated with this event.
     * @param keyCode the key code, or NOT_A_KEYCODE if not applicable.
     * @return an event for this text.
     */
    public static Event createSoftwareTextEvent(final CharSequence text, final int keyCode) {
      return new Event(EVENT_TYPE_SOFTWARE_GENERATED_STRING, text, NOT_A_CODE_POINT, keyCode,
          Constants.NOT_A_COORDINATE, Constants.NOT_A_COORDINATE,
          FLAG_NONE, null /* next */);
    }
  
    // Returns whether this is a function key like backspace, ctrl, settings... as opposed to keys
    // that result in input like letters or space.
    public boolean isFunctionalKeyEvent() {
      // This logic may need to be refined in the future
      return NOT_A_CODE_POINT == mCodePoint;
    }
  
    public boolean isKeyRepeat() {
      return 0 != (FLAG_REPEAT & mFlags);
    }
  
    public boolean isConsumed() {
      return 0 != (FLAG_CONSUMED & mFlags);
    }
  
    public CharSequence getTextToCommit() {
      if (isConsumed()) {
        return ""; // A consumed event should input no text.
      }
      switch (mEventType) {
        case EVENT_TYPE_MODE_KEY:
        case EVENT_TYPE_NOT_HANDLED:
        case EVENT_TYPE_TOGGLE:
        case EVENT_TYPE_CURSOR_MOVE:
          return "";
        case EVENT_TYPE_INPUT_KEYPRESS:
          return StringUtils.newSingleCodePointString(mCodePoint);
        case EVENT_TYPE_SOFTWARE_GENERATED_STRING:
          return mText;
      }
      throw new RuntimeException("Unknown event type: " + mEventType);
    }
  }
  