/*
 * Copyright (C) 2017 Simon Vig Therkildsen
 *
 * 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.datetimepicker.time;

import android.animation.ObjectAnimator;
import android.app.ActionBar.LayoutParams;
import android.app.Activity;
import android.content.res.ColorStateList;
import android.content.res.Resources;
import android.os.Bundle;
import android.text.format.DateFormat;
import android.util.Log;
import android.view.KeyCharacterMap;
import android.view.KeyEvent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnKeyListener;
import android.view.ViewGroup;
import android.view.Window;
import android.widget.RelativeLayout;
import android.widget.TextView;
import androidx.fragment.app.DialogFragment;
import com.android.datetimepicker.HapticFeedbackController;
import com.android.datetimepicker.R;
import com.android.datetimepicker.Utils;
import com.android.datetimepicker.time.RadialPickerLayout.OnValueSelectedListener;
import java.text.DateFormatSymbols;
import java.util.ArrayList;
import java.util.Locale;

/**
 * Dialog to set a time.
 */
public class TimePickerDialog extends DialogFragment implements OnValueSelectedListener {
  private static final String TAG = "TimePickerDialog";

  private static final String ARG_HOUR = "com.android.datetimepicker.time.TimePickerDialog.hour";
  private static final String ARG_MINUTE =
      "com.android.datetimepicker.time.TimePickerDialog.minute";

  private static final String KEY_HOUR_OF_DAY = "hour_of_day";
  private static final String KEY_MINUTE = "minute";
  private static final String KEY_CURRENT_ITEM_SHOWING = "current_item_showing";
  private static final String KEY_IN_KB_MODE = "in_kb_mode";
  private static final String KEY_TYPED_TIMES = "typed_times";
  private static final String KEY_DARK_THEME = "dark_theme";

  public static final int HOUR_INDEX = 0;
  public static final int MINUTE_INDEX = 1;
  // NOT a real index for the purpose of what's showing.
  public static final int AMPM_INDEX = 2;
  // Also NOT a real index, just used for keyboard mode.
  public static final int ENABLE_PICKER_INDEX = 3;
  public static final int AM = 0;
  public static final int PM = 1;

  // Delay before starting the pulse animation, in ms.
  private static final int PULSE_ANIMATOR_DELAY = 300;

  private OnTimeSetListener mCallback;

  private HapticFeedbackController mHapticFeedbackController;

  private TextView mDoneButton;
  private TextView mHourView;
  private TextView mHourSpaceView;
  private TextView mMinuteView;
  private TextView mMinuteSpaceView;
  private TextView mAmPmTextView;
  private View mAmPmHitspace;
  private RadialPickerLayout mTimePicker;

  private int mSelectedColor;
  private int mUnselectedColor;
  private String mAmText;
  private String mPmText;

  private boolean mAllowAutoAdvance;
  private int mInitialHourOfDay;
  private int mInitialMinute;
  private boolean mIs24HourMode;
  private boolean mThemeDark;

  // For hardware IME input.
  private char mPlaceholderText;
  private String mDoublePlaceholderText;
  private String mDeletedKeyFormat;
  private boolean mInKbMode;
  private ArrayList<Integer> mTypedTimes;
  private Node mLegalTimesTree;
  private int mAmKeyCode;
  private int mPmKeyCode;

  // Accessibility strings.
  private String mHourPickerDescription;
  private String mSelectHours;
  private String mMinutePickerDescription;
  private String mSelectMinutes;

  /**
   * The callback interface used to indicate the user is done filling in
   * the time (they clicked on the 'Set' button).
   */
  public interface OnTimeSetListener {

    /**
     * @param view The view associated with this listener.
     * @param hourOfDay The hour that was set.
     * @param minute The minute that was set.
     */
    void onTimeSet(RadialPickerLayout view, int hourOfDay, int minute);
  }

  public static TimePickerDialog newInstance(int hourOfDay, int minute) {
    TimePickerDialog ret = new TimePickerDialog();

    Bundle args = new Bundle();
    args.putInt(ARG_HOUR, hourOfDay);
    args.putInt(ARG_MINUTE, minute);
    ret.setArguments(args);

    return ret;
  }

  @Override public void onAttach(Activity activity) {
    super.onAttach(activity);
    if (activity instanceof OnTimeSetListener) {
      mCallback = (OnTimeSetListener) activity;
    } else {
      mCallback = (OnTimeSetListener) getTargetFragment();
    }
  }

  /**
   * Set a dark or light theme. NOTE: this will only take effect for the next onCreateView.
   */
  public void setThemeDark(boolean dark) {
    mThemeDark = dark;
  }

  public boolean isThemeDark() {
    return mThemeDark;
  }

  public void setOnTimeSetListener(OnTimeSetListener callback) {
    mCallback = callback;
  }

  public void setStartTime(int hourOfDay, int minute) {
    mInitialHourOfDay = hourOfDay;
    mInitialMinute = minute;
    mInKbMode = false;
  }

  @Override public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    if (savedInstanceState != null
        && savedInstanceState.containsKey(KEY_HOUR_OF_DAY)
        && savedInstanceState.containsKey(KEY_MINUTE)) {
      mInitialHourOfDay = savedInstanceState.getInt(KEY_HOUR_OF_DAY);
      mInitialMinute = savedInstanceState.getInt(KEY_MINUTE);
      mInKbMode = savedInstanceState.getBoolean(KEY_IN_KB_MODE);
      mThemeDark = savedInstanceState.getBoolean(KEY_DARK_THEME);
    } else {
      Bundle args = getArguments();
      mInitialHourOfDay = args.getInt(ARG_HOUR);
      mInitialMinute = args.getInt(ARG_MINUTE);
    }

    mIs24HourMode = DateFormat.is24HourFormat(getContext());
  }

  @Override public View onCreateView(LayoutInflater inflater, ViewGroup container,
      Bundle savedInstanceState) {
    getDialog().getWindow().requestFeature(Window.FEATURE_NO_TITLE);

    View view = inflater.inflate(R.layout.time_picker_dialog, null);
    KeyboardListener keyboardListener = new KeyboardListener();
    view.findViewById(R.id.time_picker_dialog).setOnKeyListener(keyboardListener);

    Resources res = getResources();
    mHourPickerDescription = res.getString(R.string.hour_picker_description);
    mSelectHours = res.getString(R.string.select_hours);
    mMinutePickerDescription = res.getString(R.string.minute_picker_description);
    mSelectMinutes = res.getString(R.string.select_minutes);
    mSelectedColor = res.getColor(mThemeDark ? R.color.red : R.color.blue);
    mUnselectedColor =
        res.getColor(mThemeDark ? android.R.color.white : R.color.numbers_text_color);

    mHourView = (TextView) view.findViewById(R.id.hours);
    mHourView.setOnKeyListener(keyboardListener);
    mHourSpaceView = (TextView) view.findViewById(R.id.hour_space);
    mMinuteSpaceView = (TextView) view.findViewById(R.id.minutes_space);
    mMinuteView = (TextView) view.findViewById(R.id.minutes);
    mMinuteView.setOnKeyListener(keyboardListener);
    mAmPmTextView = (TextView) view.findViewById(R.id.ampm_label);
    mAmPmTextView.setOnKeyListener(keyboardListener);
    String[] amPmTexts = new DateFormatSymbols().getAmPmStrings();
    mAmText = amPmTexts[0];
    mPmText = amPmTexts[1];

    mHapticFeedbackController = new HapticFeedbackController(getActivity());

    mTimePicker = (RadialPickerLayout) view.findViewById(R.id.time_picker);
    mTimePicker.setOnValueSelectedListener(this);
    mTimePicker.setOnKeyListener(keyboardListener);
    mTimePicker.initialize(getActivity(), mHapticFeedbackController, mInitialHourOfDay,
        mInitialMinute, mIs24HourMode);

    int currentItemShowing = HOUR_INDEX;
    if (savedInstanceState != null && savedInstanceState.containsKey(KEY_CURRENT_ITEM_SHOWING)) {
      currentItemShowing = savedInstanceState.getInt(KEY_CURRENT_ITEM_SHOWING);
    }
    setCurrentItemShowing(currentItemShowing, false, true, true);
    mTimePicker.invalidate();

    mHourView.setOnClickListener(new OnClickListener() {
      @Override public void onClick(View v) {
        setCurrentItemShowing(HOUR_INDEX, true, false, true);
        tryVibrate();
      }
    });
    mMinuteView.setOnClickListener(new OnClickListener() {
      @Override public void onClick(View v) {
        setCurrentItemShowing(MINUTE_INDEX, true, false, true);
        tryVibrate();
      }
    });

    mDoneButton = (TextView) view.findViewById(R.id.ok);
    mDoneButton.setOnClickListener(new OnClickListener() {
      @Override public void onClick(View v) {
        if (mInKbMode && isTypedTimeFullyLegal()) {
          finishKbMode(false);
        } else {
          tryVibrate();
        }
        if (mCallback != null) {
          mCallback.onTimeSet(mTimePicker, mTimePicker.getHours(), mTimePicker.getMinutes());
        }
        dismiss();
      }
    });
    mDoneButton.setOnKeyListener(keyboardListener);

    View cancelButton = view.findViewById(R.id.cancel);
    cancelButton.setOnClickListener(new OnClickListener() {
      @Override public void onClick(View v) {
        tryVibrate();
        dismiss();
      }
    });

    // Enable or disable the AM/PM view.
    mAmPmHitspace = view.findViewById(R.id.ampm_hitspace);
    if (mIs24HourMode) {
      mAmPmTextView.setVisibility(View.GONE);

      RelativeLayout.LayoutParams paramsSeparator =
          new RelativeLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
      paramsSeparator.addRule(RelativeLayout.CENTER_IN_PARENT);
      TextView separatorView = (TextView) view.findViewById(R.id.separator);
      separatorView.setLayoutParams(paramsSeparator);
    } else {
      mAmPmTextView.setVisibility(View.VISIBLE);
      updateAmPmDisplay(mInitialHourOfDay < 12 ? AM : PM);
      mAmPmHitspace.setOnClickListener(new OnClickListener() {
        @Override public void onClick(View v) {
          tryVibrate();
          int amOrPm = mTimePicker.getIsCurrentlyAmOrPm();
          if (amOrPm == AM) {
            amOrPm = PM;
          } else if (amOrPm == PM) {
            amOrPm = AM;
          }
          updateAmPmDisplay(amOrPm);
          mTimePicker.setAmOrPm(amOrPm);
        }
      });
    }

    mAllowAutoAdvance = true;
    setHour(mInitialHourOfDay, true);
    setMinute(mInitialMinute);

    // Set up for keyboard mode.
    mDoublePlaceholderText = res.getString(R.string.time_placeholder);
    mDeletedKeyFormat = res.getString(R.string.deleted_key);
    mPlaceholderText = mDoublePlaceholderText.charAt(0);
    mAmKeyCode = mPmKeyCode = -1;
    generateLegalTimesTree();
    if (mInKbMode) {
      mTypedTimes = savedInstanceState.getIntegerArrayList(KEY_TYPED_TIMES);
      tryStartingKbMode(-1);
      mHourView.invalidate();
    } else if (mTypedTimes == null) {
      mTypedTimes = new ArrayList<Integer>();
    }

    // Set the theme at the end so that the initialize()s above don't counteract the theme.
    mTimePicker.setTheme(getActivity().getApplicationContext(), mThemeDark);
    // Prepare some colors to use.
    int white = res.getColor(android.R.color.white);
    int circleBackground = res.getColor(R.color.circle_background);
    int line = res.getColor(R.color.line_background);
    int timeDisplay = res.getColor(R.color.numbers_text_color);
    ColorStateList doneTextColor = res.getColorStateList(R.color.done_text_color);
    int doneBackground = R.drawable.done_background_color;

    int darkGray = res.getColor(R.color.dark_gray);
    int lightGray = res.getColor(R.color.light_gray);
    int darkLine = res.getColor(R.color.line_dark);
    ColorStateList darkDoneTextColor = res.getColorStateList(R.color.done_text_color_dark);
    int darkDoneBackground = R.drawable.done_background_color_dark;

    // Set the colors for each view based on the theme.
    view.findViewById(R.id.time_display_background)
        .setBackgroundColor(mThemeDark ? darkGray : white);
    view.findViewById(R.id.time_display).setBackgroundColor(mThemeDark ? darkGray : white);
    ((TextView) view.findViewById(R.id.separator)).setTextColor(mThemeDark ? white : timeDisplay);
    ((TextView) view.findViewById(R.id.ampm_label)).setTextColor(mThemeDark ? white : timeDisplay);
    mTimePicker.setBackgroundColor(mThemeDark ? lightGray : circleBackground);
    return view;
  }

  @Override public void onResume() {
    super.onResume();
    mHapticFeedbackController.start();
  }

  @Override public void onPause() {
    super.onPause();
    mHapticFeedbackController.stop();
  }

  public void tryVibrate() {
    mHapticFeedbackController.tryVibrate();
  }

  private void updateAmPmDisplay(int amOrPm) {
    if (amOrPm == AM) {
      mAmPmTextView.setText(mAmText);
      Utils.tryAccessibilityAnnounce(mTimePicker, mAmText);
      mAmPmHitspace.setContentDescription(mAmText);
    } else if (amOrPm == PM) {
      mAmPmTextView.setText(mPmText);
      Utils.tryAccessibilityAnnounce(mTimePicker, mPmText);
      mAmPmHitspace.setContentDescription(mPmText);
    } else {
      mAmPmTextView.setText(mDoublePlaceholderText);
    }
  }

  @Override public void onSaveInstanceState(Bundle outState) {
    if (mTimePicker != null) {
      outState.putInt(KEY_HOUR_OF_DAY, mTimePicker.getHours());
      outState.putInt(KEY_MINUTE, mTimePicker.getMinutes());
      outState.putInt(KEY_CURRENT_ITEM_SHOWING, mTimePicker.getCurrentItemShowing());
      outState.putBoolean(KEY_IN_KB_MODE, mInKbMode);
      if (mInKbMode) {
        outState.putIntegerArrayList(KEY_TYPED_TIMES, mTypedTimes);
      }
      outState.putBoolean(KEY_DARK_THEME, mThemeDark);
    }
  }

  /**
   * Called by the picker for updating the header display.
   */
  @Override public void onValueSelected(int pickerIndex, int newValue, boolean autoAdvance) {
    if (pickerIndex == HOUR_INDEX) {
      setHour(newValue, false);
      String announcement = String.format("%d", newValue);
      if (mAllowAutoAdvance && autoAdvance) {
        setCurrentItemShowing(MINUTE_INDEX, true, true, false);
        announcement += ". " + mSelectMinutes;
      } else {
        mTimePicker.setContentDescription(mHourPickerDescription + ": " + newValue);
      }

      Utils.tryAccessibilityAnnounce(mTimePicker, announcement);
    } else if (pickerIndex == MINUTE_INDEX) {
      setMinute(newValue);
      mTimePicker.setContentDescription(mMinutePickerDescription + ": " + newValue);
    } else if (pickerIndex == AMPM_INDEX) {
      updateAmPmDisplay(newValue);
    } else if (pickerIndex == ENABLE_PICKER_INDEX) {
      if (!isTypedTimeFullyLegal()) {
        mTypedTimes.clear();
      }
      finishKbMode(true);
    }
  }

  private void setHour(int value, boolean announce) {
    String format;
    if (mIs24HourMode) {
      format = "%02d";
    } else {
      format = "%d";
      value = value % 12;
      if (value == 0) {
        value = 12;
      }
    }

    CharSequence text = String.format(format, value);
    mHourView.setText(text);
    mHourSpaceView.setText(text);
    if (announce) {
      Utils.tryAccessibilityAnnounce(mTimePicker, text);
    }
  }

  private void setMinute(int value) {
    if (value == 60) {
      value = 0;
    }
    CharSequence text = String.format(Locale.getDefault(), "%02d", value);
    Utils.tryAccessibilityAnnounce(mTimePicker, text);
    mMinuteView.setText(text);
    mMinuteSpaceView.setText(text);
  }

  // Show either Hours or Minutes.
  private void setCurrentItemShowing(int index, boolean animateCircle, boolean delayLabelAnimate,
      boolean announce) {
    mTimePicker.setCurrentItemShowing(index, animateCircle);

    TextView labelToAnimate;
    if (index == HOUR_INDEX) {
      int hours = mTimePicker.getHours();
      if (!mIs24HourMode) {
        hours = hours % 12;
      }
      mTimePicker.setContentDescription(mHourPickerDescription + ": " + hours);
      if (announce) {
        Utils.tryAccessibilityAnnounce(mTimePicker, mSelectHours);
      }
      labelToAnimate = mHourView;
    } else {
      int minutes = mTimePicker.getMinutes();
      mTimePicker.setContentDescription(mMinutePickerDescription + ": " + minutes);
      if (announce) {
        Utils.tryAccessibilityAnnounce(mTimePicker, mSelectMinutes);
      }
      labelToAnimate = mMinuteView;
    }

    int hourColor = (index == HOUR_INDEX) ? mSelectedColor : mUnselectedColor;
    int minuteColor = (index == MINUTE_INDEX) ? mSelectedColor : mUnselectedColor;
    mHourView.setTextColor(hourColor);
    mMinuteView.setTextColor(minuteColor);

    ObjectAnimator pulseAnimator = Utils.getPulseAnimator(labelToAnimate, 0.85f, 1.1f);
    if (delayLabelAnimate) {
      pulseAnimator.setStartDelay(PULSE_ANIMATOR_DELAY);
    }
    pulseAnimator.start();
  }

  /**
   * For keyboard mode, processes key events.
   *
   * @param keyCode the pressed key.
   * @return true if the key was successfully processed, false otherwise.
   */
  private boolean processKeyUp(int keyCode) {
    if (keyCode == KeyEvent.KEYCODE_ESCAPE || keyCode == KeyEvent.KEYCODE_BACK) {
      dismiss();
      return true;
    } else if (keyCode == KeyEvent.KEYCODE_TAB) {
      if (mInKbMode) {
        if (isTypedTimeFullyLegal()) {
          finishKbMode(true);
        }
        return true;
      }
    } else if (keyCode == KeyEvent.KEYCODE_ENTER) {
      if (mInKbMode) {
        if (!isTypedTimeFullyLegal()) {
          return true;
        }
        finishKbMode(false);
      }
      if (mCallback != null) {
        mCallback.onTimeSet(mTimePicker, mTimePicker.getHours(), mTimePicker.getMinutes());
      }
      dismiss();
      return true;
    } else if (keyCode == KeyEvent.KEYCODE_DEL) {
      if (mInKbMode) {
        if (!mTypedTimes.isEmpty()) {
          int deleted = deleteLastTypedKey();
          String deletedKeyStr;
          if (deleted == getAmOrPmKeyCode(AM)) {
            deletedKeyStr = mAmText;
          } else if (deleted == getAmOrPmKeyCode(PM)) {
            deletedKeyStr = mPmText;
          } else {
            deletedKeyStr = String.format("%d", getValFromKeyCode(deleted));
          }
          Utils.tryAccessibilityAnnounce(mTimePicker,
              String.format(mDeletedKeyFormat, deletedKeyStr));
          updateDisplay(true);
        }
      }
    } else if (keyCode == KeyEvent.KEYCODE_0
        || keyCode == KeyEvent.KEYCODE_1
        || keyCode == KeyEvent.KEYCODE_2
        || keyCode == KeyEvent.KEYCODE_3
        || keyCode == KeyEvent.KEYCODE_4
        || keyCode == KeyEvent.KEYCODE_5
        || keyCode == KeyEvent.KEYCODE_6
        || keyCode == KeyEvent.KEYCODE_7
        || keyCode == KeyEvent.KEYCODE_8
        || keyCode == KeyEvent.KEYCODE_9
        || (!mIs24HourMode && (keyCode == getAmOrPmKeyCode(AM) || keyCode == getAmOrPmKeyCode(
        PM)))) {
      if (!mInKbMode) {
        if (mTimePicker == null) {
          // Something's wrong, because time picker should definitely not be null.
          Log.e(TAG, "Unable to initiate keyboard mode, TimePicker was null.");
          return true;
        }
        mTypedTimes.clear();
        tryStartingKbMode(keyCode);
        return true;
      }
      // We're already in keyboard mode.
      if (addKeyIfLegal(keyCode)) {
        updateDisplay(false);
      }
      return true;
    }
    return false;
  }

  /**
   * Try to start keyboard mode with the specified key, as long as the timepicker is not in the
   * middle of a touch-event.
   *
   * @param keyCode The key to use as the first press. Keyboard mode will not be started if the
   * key is not legal to start with. Or, pass in -1 to get into keyboard mode without a starting
   * key.
   */
  private void tryStartingKbMode(int keyCode) {
    if (mTimePicker.trySettingInputEnabled(false) && (keyCode == -1 || addKeyIfLegal(keyCode))) {
      mInKbMode = true;
      mDoneButton.setEnabled(false);
      updateDisplay(false);
    }
  }

  private boolean addKeyIfLegal(int keyCode) {
    // If we're in 24hour mode, we'll need to check if the input is full. If in AM/PM mode,
    // we'll need to see if AM/PM have been typed.
    if ((mIs24HourMode && mTypedTimes.size() == 4) || (!mIs24HourMode && isTypedTimeFullyLegal())) {
      return false;
    }

    mTypedTimes.add(keyCode);
    if (!isTypedTimeLegalSoFar()) {
      deleteLastTypedKey();
      return false;
    }

    int val = getValFromKeyCode(keyCode);
    Utils.tryAccessibilityAnnounce(mTimePicker, String.format("%d", val));
    // Automatically fill in 0's if AM or PM was legally entered.
    if (isTypedTimeFullyLegal()) {
      if (!mIs24HourMode && mTypedTimes.size() <= 3) {
        mTypedTimes.add(mTypedTimes.size() - 1, KeyEvent.KEYCODE_0);
        mTypedTimes.add(mTypedTimes.size() - 1, KeyEvent.KEYCODE_0);
      }
      mDoneButton.setEnabled(true);
    }

    return true;
  }

  /**
   * Traverse the tree to see if the keys that have been typed so far are legal as is,
   * or may become legal as more keys are typed (excluding backspace).
   */
  private boolean isTypedTimeLegalSoFar() {
    Node node = mLegalTimesTree;
    for (int keyCode : mTypedTimes) {
      node = node.canReach(keyCode);
      if (node == null) {
        return false;
      }
    }
    return true;
  }

  /**
   * Check if the time that has been typed so far is completely legal, as is.
   */
  private boolean isTypedTimeFullyLegal() {
    if (mIs24HourMode) {
      // For 24-hour mode, the time is legal if the hours and minutes are each legal. Note:
      // getEnteredTime() will ONLY call isTypedTimeFullyLegal() when NOT in 24hour mode.
      int[] values = getEnteredTime(null);
      return (values[0] >= 0 && values[1] >= 0 && values[1] < 60);
    } else {
      // For AM/PM mode, the time is legal if it contains an AM or PM, as those can only be
      // legally added at specific times based on the tree's algorithm.
      return (mTypedTimes.contains(getAmOrPmKeyCode(AM)) || mTypedTimes.contains(
          getAmOrPmKeyCode(PM)));
    }
  }

  private int deleteLastTypedKey() {
    int deleted = mTypedTimes.remove(mTypedTimes.size() - 1);
    if (!isTypedTimeFullyLegal()) {
      mDoneButton.setEnabled(false);
    }
    return deleted;
  }

  /**
   * Get out of keyboard mode. If there is nothing in typedTimes, revert to TimePicker's time.
   *
   * @param changeDisplays If true, update the displays with the relevant time.
   */
  private void finishKbMode(boolean updateDisplays) {
    mInKbMode = false;
    if (!mTypedTimes.isEmpty()) {
      int values[] = getEnteredTime(null);
      mTimePicker.setTime(values[0], values[1]);
      if (!mIs24HourMode) {
        mTimePicker.setAmOrPm(values[2]);
      }
      mTypedTimes.clear();
    }
    if (updateDisplays) {
      updateDisplay(false);
      mTimePicker.trySettingInputEnabled(true);
    }
  }

  /**
   * Update the hours, minutes, and AM/PM displays with the typed times. If the typedTimes is
   * empty, either show an empty display (filled with the placeholder text), or update from the
   * timepicker's values.
   *
   * @param allowEmptyDisplay if true, then if the typedTimes is empty, use the placeholder text.
   * Otherwise, revert to the timepicker's values.
   */
  private void updateDisplay(boolean allowEmptyDisplay) {
    if (!allowEmptyDisplay && mTypedTimes.isEmpty()) {
      int hour = mTimePicker.getHours();
      int minute = mTimePicker.getMinutes();
      setHour(hour, true);
      setMinute(minute);
      if (!mIs24HourMode) {
        updateAmPmDisplay(hour < 12 ? AM : PM);
      }
      setCurrentItemShowing(mTimePicker.getCurrentItemShowing(), true, true, true);
      mDoneButton.setEnabled(true);
    } else {
      Boolean[] enteredZeros = { false, false };
      int[] values = getEnteredTime(enteredZeros);
      String hourFormat = enteredZeros[0] ? "%02d" : "%2d";
      String minuteFormat = (enteredZeros[1]) ? "%02d" : "%2d";
      String hourStr = (values[0] == -1) ? mDoublePlaceholderText
          : String.format(hourFormat, values[0]).replace(' ', mPlaceholderText);
      String minuteStr = (values[1] == -1) ? mDoublePlaceholderText
          : String.format(minuteFormat, values[1]).replace(' ', mPlaceholderText);
      mHourView.setText(hourStr);
      mHourSpaceView.setText(hourStr);
      mHourView.setTextColor(mUnselectedColor);
      mMinuteView.setText(minuteStr);
      mMinuteSpaceView.setText(minuteStr);
      mMinuteView.setTextColor(mUnselectedColor);
      if (!mIs24HourMode) {
        updateAmPmDisplay(values[2]);
      }
    }
  }

  private static int getValFromKeyCode(int keyCode) {
    switch (keyCode) {
      case KeyEvent.KEYCODE_0:
        return 0;
      case KeyEvent.KEYCODE_1:
        return 1;
      case KeyEvent.KEYCODE_2:
        return 2;
      case KeyEvent.KEYCODE_3:
        return 3;
      case KeyEvent.KEYCODE_4:
        return 4;
      case KeyEvent.KEYCODE_5:
        return 5;
      case KeyEvent.KEYCODE_6:
        return 6;
      case KeyEvent.KEYCODE_7:
        return 7;
      case KeyEvent.KEYCODE_8:
        return 8;
      case KeyEvent.KEYCODE_9:
        return 9;
      default:
        return -1;
    }
  }

  /**
   * Get the currently-entered time, as integer values of the hours and minutes typed.
   *
   * @param enteredZeros A size-2 boolean array, which the caller should initialize, and which
   * may then be used for the caller to know whether zeros had been explicitly entered as either
   * hours of minutes. This is helpful for deciding whether to show the dashes, or actual 0's.
   * @return A size-3 int array. The first value will be the hours, the second value will be the
   * minutes, and the third will be either TimePickerDialog.AM or TimePickerDialog.PM.
   */
  private int[] getEnteredTime(Boolean[] enteredZeros) {
    int amOrPm = -1;
    int startIndex = 1;
    if (!mIs24HourMode && isTypedTimeFullyLegal()) {
      int keyCode = mTypedTimes.get(mTypedTimes.size() - 1);
      if (keyCode == getAmOrPmKeyCode(AM)) {
        amOrPm = AM;
      } else if (keyCode == getAmOrPmKeyCode(PM)) {
        amOrPm = PM;
      }
      startIndex = 2;
    }
    int minute = -1;
    int hour = -1;
    for (int i = startIndex; i <= mTypedTimes.size(); i++) {
      int val = getValFromKeyCode(mTypedTimes.get(mTypedTimes.size() - i));
      if (i == startIndex) {
        minute = val;
      } else if (i == startIndex + 1) {
        minute += 10 * val;
        if (enteredZeros != null && val == 0) {
          enteredZeros[1] = true;
        }
      } else if (i == startIndex + 2) {
        hour = val;
      } else if (i == startIndex + 3) {
        hour += 10 * val;
        if (enteredZeros != null && val == 0) {
          enteredZeros[0] = true;
        }
      }
    }

    int[] ret = { hour, minute, amOrPm };
    return ret;
  }

  /**
   * Get the keycode value for AM and PM in the current language.
   */
  private int getAmOrPmKeyCode(int amOrPm) {
    // Cache the codes.
    if (mAmKeyCode == -1 || mPmKeyCode == -1) {
      // Find the first character in the AM/PM text that is unique.
      KeyCharacterMap kcm = KeyCharacterMap.load(KeyCharacterMap.VIRTUAL_KEYBOARD);
      char amChar;
      char pmChar;
      for (int i = 0; i < Math.max(mAmText.length(), mPmText.length()); i++) {
        amChar = mAmText.toLowerCase(Locale.getDefault()).charAt(i);
        pmChar = mPmText.toLowerCase(Locale.getDefault()).charAt(i);
        if (amChar != pmChar) {
          KeyEvent[] events = kcm.getEvents(new char[] { amChar, pmChar });
          // There should be 4 events: a down and up for both AM and PM.
          if (events != null && events.length == 4) {
            mAmKeyCode = events[0].getKeyCode();
            mPmKeyCode = events[2].getKeyCode();
          } else {
            Log.e(TAG, "Unable to find keycodes for AM and PM.");
          }
          break;
        }
      }
    }
    if (amOrPm == AM) {
      return mAmKeyCode;
    } else if (amOrPm == PM) {
      return mPmKeyCode;
    }

    return -1;
  }

  /**
   * Create a tree for deciding what keys can legally be typed.
   */
  private void generateLegalTimesTree() {
    // Create a quick cache of numbers to their keycodes.
    int k0 = KeyEvent.KEYCODE_0;
    int k1 = KeyEvent.KEYCODE_1;
    int k2 = KeyEvent.KEYCODE_2;
    int k3 = KeyEvent.KEYCODE_3;
    int k4 = KeyEvent.KEYCODE_4;
    int k5 = KeyEvent.KEYCODE_5;
    int k6 = KeyEvent.KEYCODE_6;
    int k7 = KeyEvent.KEYCODE_7;
    int k8 = KeyEvent.KEYCODE_8;
    int k9 = KeyEvent.KEYCODE_9;

    // The root of the tree doesn't contain any numbers.
    mLegalTimesTree = new Node();
    if (mIs24HourMode) {
      // We'll be re-using these nodes, so we'll save them.
      Node minuteFirstDigit = new Node(k0, k1, k2, k3, k4, k5);
      Node minuteSecondDigit = new Node(k0, k1, k2, k3, k4, k5, k6, k7, k8, k9);
      // The first digit must be followed by the second digit.
      minuteFirstDigit.addChild(minuteSecondDigit);

      // The first digit may be 0-1.
      Node firstDigit = new Node(k0, k1);
      mLegalTimesTree.addChild(firstDigit);

      // When the first digit is 0-1, the second digit may be 0-5.
      Node secondDigit = new Node(k0, k1, k2, k3, k4, k5);
      firstDigit.addChild(secondDigit);
      // We may now be followed by the first minute digit. E.g. 00:09, 15:58.
      secondDigit.addChild(minuteFirstDigit);

      // When the first digit is 0-1, and the second digit is 0-5, the third digit may be 6-9.
      Node thirdDigit = new Node(k6, k7, k8, k9);
      // The time must now be finished. E.g. 0:55, 1:08.
      secondDigit.addChild(thirdDigit);

      // When the first digit is 0-1, the second digit may be 6-9.
      secondDigit = new Node(k6, k7, k8, k9);
      firstDigit.addChild(secondDigit);
      // We must now be followed by the first minute digit. E.g. 06:50, 18:20.
      secondDigit.addChild(minuteFirstDigit);

      // The first digit may be 2.
      firstDigit = new Node(k2);
      mLegalTimesTree.addChild(firstDigit);

      // When the first digit is 2, the second digit may be 0-3.
      secondDigit = new Node(k0, k1, k2, k3);
      firstDigit.addChild(secondDigit);
      // We must now be followed by the first minute digit. E.g. 20:50, 23:09.
      secondDigit.addChild(minuteFirstDigit);

      // When the first digit is 2, the second digit may be 4-5.
      secondDigit = new Node(k4, k5);
      firstDigit.addChild(secondDigit);
      // We must now be followd by the last minute digit. E.g. 2:40, 2:53.
      secondDigit.addChild(minuteSecondDigit);

      // The first digit may be 3-9.
      firstDigit = new Node(k3, k4, k5, k6, k7, k8, k9);
      mLegalTimesTree.addChild(firstDigit);
      // We must now be followed by the first minute digit. E.g. 3:57, 8:12.
      firstDigit.addChild(minuteFirstDigit);
    } else {
      // We'll need to use the AM/PM node a lot.
      // Set up AM and PM to respond to "a" and "p".
      Node ampm = new Node(getAmOrPmKeyCode(AM), getAmOrPmKeyCode(PM));

      // The first hour digit may be 1.
      Node firstDigit = new Node(k1);
      mLegalTimesTree.addChild(firstDigit);
      // We'll allow quick input of on-the-hour times. E.g. 1pm.
      firstDigit.addChild(ampm);

      // When the first digit is 1, the second digit may be 0-2.
      Node secondDigit = new Node(k0, k1, k2);
      firstDigit.addChild(secondDigit);
      // Also for quick input of on-the-hour times. E.g. 10pm, 12am.
      secondDigit.addChild(ampm);

      // When the first digit is 1, and the second digit is 0-2, the third digit may be 0-5.
      Node thirdDigit = new Node(k0, k1, k2, k3, k4, k5);
      secondDigit.addChild(thirdDigit);
      // The time may be finished now. E.g. 1:02pm, 1:25am.
      thirdDigit.addChild(ampm);

      // When the first digit is 1, the second digit is 0-2, and the third digit is 0-5,
      // the fourth digit may be 0-9.
      Node fourthDigit = new Node(k0, k1, k2, k3, k4, k5, k6, k7, k8, k9);
      thirdDigit.addChild(fourthDigit);
      // The time must be finished now. E.g. 10:49am, 12:40pm.
      fourthDigit.addChild(ampm);

      // When the first digit is 1, and the second digit is 0-2, the third digit may be 6-9.
      thirdDigit = new Node(k6, k7, k8, k9);
      secondDigit.addChild(thirdDigit);
      // The time must be finished now. E.g. 1:08am, 1:26pm.
      thirdDigit.addChild(ampm);

      // When the first digit is 1, the second digit may be 3-5.
      secondDigit = new Node(k3, k4, k5);
      firstDigit.addChild(secondDigit);

      // When the first digit is 1, and the second digit is 3-5, the third digit may be 0-9.
      thirdDigit = new Node(k0, k1, k2, k3, k4, k5, k6, k7, k8, k9);
      secondDigit.addChild(thirdDigit);
      // The time must be finished now. E.g. 1:39am, 1:50pm.
      thirdDigit.addChild(ampm);

      // The hour digit may be 2-9.
      firstDigit = new Node(k2, k3, k4, k5, k6, k7, k8, k9);
      mLegalTimesTree.addChild(firstDigit);
      // We'll allow quick input of on-the-hour-times. E.g. 2am, 5pm.
      firstDigit.addChild(ampm);

      // When the first digit is 2-9, the second digit may be 0-5.
      secondDigit = new Node(k0, k1, k2, k3, k4, k5);
      firstDigit.addChild(secondDigit);

      // When the first digit is 2-9, and the second digit is 0-5, the third digit may be 0-9.
      thirdDigit = new Node(k0, k1, k2, k3, k4, k5, k6, k7, k8, k9);
      secondDigit.addChild(thirdDigit);
      // The time must be finished now. E.g. 2:57am, 9:30pm.
      thirdDigit.addChild(ampm);
    }
  }

  /**
   * Simple node class to be used for traversal to check for legal times.
   * mLegalKeys represents the keys that can be typed to get to the node.
   * mChildren are the children that can be reached from this node.
   */
  private class Node {
    private int[] mLegalKeys;
    private ArrayList<Node> mChildren;

    public Node(int... legalKeys) {
      mLegalKeys = legalKeys;
      mChildren = new ArrayList<Node>();
    }

    public void addChild(Node child) {
      mChildren.add(child);
    }

    public boolean containsKey(int key) {
      for (int i = 0; i < mLegalKeys.length; i++) {
        if (mLegalKeys[i] == key) {
          return true;
        }
      }
      return false;
    }

    public Node canReach(int key) {
      if (mChildren == null) {
        return null;
      }
      for (Node child : mChildren) {
        if (child.containsKey(key)) {
          return child;
        }
      }
      return null;
    }
  }

  private class KeyboardListener implements OnKeyListener {
    @Override public boolean onKey(View v, int keyCode, KeyEvent event) {
      if (event.getAction() == KeyEvent.ACTION_UP) {
        return processKeyUp(keyCode);
      }
      return false;
    }
  }
}