/*
 * 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.datetimepicker.date;

import android.animation.ObjectAnimator;
import android.app.Activity;
import android.app.DialogFragment;
import android.content.Context;
import android.content.res.Resources;
import android.os.Bundle;
import android.os.SystemClock;
import android.os.Vibrator;
import android.text.format.DateFormat;
import android.text.format.DateUtils;
import android.text.format.Time;
import android.util.AttributeSet;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.view.Window;
import android.view.WindowManager;
import android.view.accessibility.AccessibilityEvent;
import android.view.animation.AlphaAnimation;
import android.view.animation.Animation;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.TextView;
import android.widget.ViewAnimator;

import com.android.datetimepicker.R;
import com.android.datetimepicker.Utils;
import com.android.datetimepicker.date.SimpleMonthAdapter.CalendarDay;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.HashSet;
import java.util.Iterator;
import java.util.Locale;

/**
 * Dialog allowing users to select a date.
 */
public class DatePickerDialog extends DialogFragment implements
        OnClickListener, DatePickerController {

    private static final String TAG = "DatePickerDialog";

    private static final int UNINITIALIZED = -1;
    private static final int MONTH_AND_DAY_VIEW = 0;
    private static final int YEAR_VIEW = 1;

    private static final String KEY_SELECTED_YEAR = "year";
    private static final String KEY_SELECTED_MONTH = "month";
    private static final String KEY_SELECTED_DAY = "day";
    private static final String KEY_LIST_POSITION = "list_position";
    private static final String KEY_WEEK_START = "week_start";
    private static final String KEY_YEAR_START = "year_start";
    private static final String KEY_YEAR_END = "year_end";
    private static final String KEY_CURRENT_VIEW = "current_view";
    private static final String KEY_LIST_POSITION_OFFSET = "list_position_offset";

    private static final int DEFAULT_START_YEAR = 1900;
    private static final int DEFAULT_END_YEAR = 2100;

    private static final int ANIMATION_DURATION = 300;
    private static final int ANIMATION_DELAY = 500;

    private static SimpleDateFormat YEAR_FORMAT = new SimpleDateFormat("yyyy", Locale.getDefault());
    private static SimpleDateFormat DAY_FORMAT = new SimpleDateFormat("dd", Locale.getDefault());

    private final Calendar mCalendar = Calendar.getInstance();
    private OnDateSetListener mCallBack;
    private HashSet<OnDateChangedListener> mListeners = new HashSet<OnDateChangedListener>();

    private AccessibleDateAnimator mAnimator;

    private TextView mDayOfWeekView;
    private LinearLayout mMonthAndDayView;
    private TextView mSelectedMonthTextView;
    private TextView mSelectedDayTextView;
    private TextView mYearView;
    private DayPickerView mDayPickerView;
    private YearPickerView mYearPickerView;
    private Button mDoneButton;

    private int mCurrentView = UNINITIALIZED;

    private int mWeekStart = mCalendar.getFirstDayOfWeek();
    private int mMinYear = DEFAULT_START_YEAR;
    private int mMaxYear = DEFAULT_END_YEAR;

    private Vibrator mVibrator;
    private long mLastVibrate;

    private boolean mDelayAnimation = true;

    // Accessibility strings.
    private String mDayPickerDescription;
    private String mSelectDay;
    private String mYearPickerDescription;
    private String mSelectYear;

    /**
     * The callback used to indicate the user is done filling in the date.
     */
    public interface OnDateSetListener {

        /**
         * @param view The view associated with this listener.
         * @param year The year that was set.
         * @param monthOfYear The month that was set (0-11) for compatibility
         *            with {@link java.util.Calendar}.
         * @param dayOfMonth The day of the month that was set.
         */
        void onDateSet(DatePickerDialog dialog, int year, int monthOfYear, int dayOfMonth);
    }

    /**
     * The callback used to notify other date picker components of a change in selected date.
     */
    interface OnDateChangedListener {

        public void onDateChanged();
    }


    public DatePickerDialog() {
        // Empty constructor required for dialog fragment.
    }

    /**
     * @param callBack How the parent is notified that the date is set.
     * @param year The initial year of the dialog.
     * @param monthOfYear The initial month of the dialog.
     * @param dayOfMonth The initial day of the dialog.
     */
    public static DatePickerDialog newInstance(OnDateSetListener callBack, int year,
            int monthOfYear,
            int dayOfMonth) {
        DatePickerDialog ret = new DatePickerDialog();
        ret.initialize(callBack, year, monthOfYear, dayOfMonth);
        return ret;
    }

    public void initialize(OnDateSetListener callBack, int year, int monthOfYear, int dayOfMonth) {
        mCallBack = callBack;
        mCalendar.set(Calendar.YEAR, year);
        mCalendar.set(Calendar.MONTH, monthOfYear);
        mCalendar.set(Calendar.DAY_OF_MONTH, dayOfMonth);
    }

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        final Activity activity = getActivity();
        activity.getWindow().setSoftInputMode(
                WindowManager.LayoutParams.SOFT_INPUT_STATE_ALWAYS_HIDDEN);
        mVibrator = (Vibrator) activity.getSystemService(Context.VIBRATOR_SERVICE);
        if (savedInstanceState != null) {
            mCalendar.set(Calendar.YEAR, savedInstanceState.getInt(KEY_SELECTED_YEAR));
            mCalendar.set(Calendar.MONTH, savedInstanceState.getInt(KEY_SELECTED_MONTH));
            mCalendar.set(Calendar.DAY_OF_MONTH, savedInstanceState.getInt(KEY_SELECTED_DAY));
        }
    }

    @Override
    public void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        outState.putInt(KEY_SELECTED_YEAR, mCalendar.get(Calendar.YEAR));
        outState.putInt(KEY_SELECTED_MONTH, mCalendar.get(Calendar.MONTH));
        outState.putInt(KEY_SELECTED_DAY, mCalendar.get(Calendar.DAY_OF_MONTH));
        outState.putInt(KEY_WEEK_START, mWeekStart);
        outState.putInt(KEY_YEAR_START, mMinYear);
        outState.putInt(KEY_YEAR_END, mMaxYear);
        outState.putInt(KEY_CURRENT_VIEW, mCurrentView);
        int listPosition = -1;
        if (mCurrentView == MONTH_AND_DAY_VIEW) {
            listPosition = mDayPickerView.getMostVisiblePosition();
        } else if (mCurrentView == YEAR_VIEW) {
            listPosition = mYearPickerView.getFirstVisiblePosition();
            outState.putInt(KEY_LIST_POSITION_OFFSET, mYearPickerView.getFirstPositionOffset());
        }
        outState.putInt(KEY_LIST_POSITION, listPosition);
    }

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

        View view = inflater.inflate(R.layout.date_picker_dialog, null);

        mDayOfWeekView = (TextView) view.findViewById(R.id.date_picker_header);
        mMonthAndDayView = (LinearLayout) view.findViewById(R.id.date_picker_month_and_day);
        mMonthAndDayView.setOnClickListener(this);
        mSelectedMonthTextView = (TextView) view.findViewById(R.id.date_picker_month);
        mSelectedDayTextView = (TextView) view.findViewById(R.id.date_picker_day);
        mYearView = (TextView) view.findViewById(R.id.date_picker_year);
        mYearView.setOnClickListener(this);

        int listPosition = -1;
        int listPositionOffset = 0;
        int currentView = MONTH_AND_DAY_VIEW;
        if (savedInstanceState != null) {
            mWeekStart = savedInstanceState.getInt(KEY_WEEK_START);
            mMinYear = savedInstanceState.getInt(KEY_YEAR_START);
            mMaxYear = savedInstanceState.getInt(KEY_YEAR_END);
            currentView = savedInstanceState.getInt(KEY_CURRENT_VIEW);
            listPosition = savedInstanceState.getInt(KEY_LIST_POSITION);
            listPositionOffset = savedInstanceState.getInt(KEY_LIST_POSITION_OFFSET);
        }

        final Activity activity = getActivity();
        mDayPickerView = new DayPickerView(activity, this);
        mYearPickerView = new YearPickerView(activity, this);

        Resources res = getResources();
        mDayPickerDescription = res.getString(R.string.day_picker_description);
        mSelectDay = res.getString(R.string.select_day);
        mYearPickerDescription = res.getString(R.string.year_picker_description);
        mSelectYear = res.getString(R.string.select_year);

        mAnimator = (AccessibleDateAnimator) view.findViewById(R.id.animator);
        mAnimator.addView(mDayPickerView);
        mAnimator.addView(mYearPickerView);
        mAnimator.setDateMillis(mCalendar.getTimeInMillis());
        // TODO: Replace with animation decided upon by the design team.
        Animation animation = new AlphaAnimation(0.0f, 1.0f);
        animation.setDuration(ANIMATION_DURATION);
        mAnimator.setInAnimation(animation);
        // TODO: Replace with animation decided upon by the design team.
        Animation animation2 = new AlphaAnimation(1.0f, 0.0f);
        animation2.setDuration(ANIMATION_DURATION);
        mAnimator.setOutAnimation(animation2);

        mDoneButton = (Button) view.findViewById(R.id.done);
        mDoneButton.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                tryVibrate();
                if (mCallBack != null) {
                    mCallBack.onDateSet(DatePickerDialog.this, mCalendar.get(Calendar.YEAR),
                            mCalendar.get(Calendar.MONTH), mCalendar.get(Calendar.DAY_OF_MONTH));
                }
                dismiss();
            }
        });

        updateDisplay(false);
        setCurrentView(currentView);

        if (listPosition != -1) {
            if (currentView == MONTH_AND_DAY_VIEW) {
                mDayPickerView.postSetSelection(listPosition);
            } else if (currentView == YEAR_VIEW) {
                mYearPickerView.postSetSelectionFromTop(listPosition, listPositionOffset);
            }
        }
        return view;
    }

    private void setCurrentView(final int viewIndex) {
        long millis = mCalendar.getTimeInMillis();

        switch (viewIndex) {
            case MONTH_AND_DAY_VIEW:
                ObjectAnimator pulseAnimator = Utils.getPulseAnimator(mMonthAndDayView, 0.9f,
                        1.05f);
                if (mDelayAnimation) {
                    pulseAnimator.setStartDelay(ANIMATION_DELAY);
                    mDelayAnimation = false;
                }
                mDayPickerView.onDateChanged();
                if (mCurrentView != viewIndex) {
                    mMonthAndDayView.setSelected(true);
                    mYearView.setSelected(false);
                    mAnimator.setDisplayedChild(MONTH_AND_DAY_VIEW);
                    mCurrentView = viewIndex;
                }
                pulseAnimator.start();

                int flags = DateUtils.FORMAT_SHOW_DATE;
                String dayString = DateUtils.formatDateTime(getActivity(), millis, flags);
                mAnimator.setContentDescription(mDayPickerDescription+": "+dayString);
                Utils.tryAccessibilityAnnounce(mAnimator, mSelectDay);
                break;
            case YEAR_VIEW:
                pulseAnimator = Utils.getPulseAnimator(mYearView, 0.85f, 1.1f);
                if (mDelayAnimation) {
                    pulseAnimator.setStartDelay(ANIMATION_DELAY);
                    mDelayAnimation = false;
                }
                mYearPickerView.onDateChanged();
                if (mCurrentView != viewIndex) {
                    mMonthAndDayView.setSelected(false);
                    mYearView.setSelected(true);
                    mAnimator.setDisplayedChild(YEAR_VIEW);
                    mCurrentView = viewIndex;
                }
                pulseAnimator.start();

                CharSequence yearString = YEAR_FORMAT.format(millis);
                mAnimator.setContentDescription(mYearPickerDescription+": "+yearString);
                Utils.tryAccessibilityAnnounce(mAnimator, mSelectYear);
                break;
        }
    }

    private void updateDisplay(boolean announce) {
        if (mDayOfWeekView != null) {
            mDayOfWeekView.setText(mCalendar.getDisplayName(Calendar.DAY_OF_WEEK, Calendar.LONG,
                    Locale.getDefault()).toUpperCase(Locale.getDefault()));
        }

        mSelectedMonthTextView.setText(mCalendar.getDisplayName(Calendar.MONTH, Calendar.SHORT,
                Locale.getDefault()).toUpperCase(Locale.getDefault()));
        mSelectedDayTextView.setText(DAY_FORMAT.format(mCalendar.getTime()));
        mYearView.setText(YEAR_FORMAT.format(mCalendar.getTime()));

        // Accessibility.
        long millis = mCalendar.getTimeInMillis();
        mAnimator.setDateMillis(millis);
        int flags = DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_NO_YEAR;
        String monthAndDayText = DateUtils.formatDateTime(getActivity(), millis, flags);
        mMonthAndDayView.setContentDescription(monthAndDayText);

        if (announce) {
            flags = DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_SHOW_YEAR;
            String fullDateText = DateUtils.formatDateTime(getActivity(), millis, flags);
            Utils.tryAccessibilityAnnounce(mAnimator, fullDateText);
        }
    }

    public void setFirstDayOfWeek(int startOfWeek) {
        if (startOfWeek < Calendar.SUNDAY || startOfWeek > Calendar.SATURDAY) {
            throw new IllegalArgumentException("Value must be between Calendar.SUNDAY and " +
                    "Calendar.SATURDAY");
        }
        mWeekStart = startOfWeek;
        if (mDayPickerView != null) {
            mDayPickerView.onChange();
        }
    }

    public void setYearRange(int startYear, int endYear) {
        if (endYear <= startYear) {
            throw new IllegalArgumentException("Year end must be larger than year start");
        }
        mMinYear = startYear;
        mMaxYear = endYear;
        if (mDayPickerView != null) {
            mDayPickerView.onChange();
        }
    }

    public void setOnDateSetListener(OnDateSetListener listener) {
        mCallBack = listener;
    }

    // If the newly selected month / year does not contain the currently selected day number,
    // change the selected day number to the last day of the selected month or year.
    //      e.g. Switching from Mar to Apr when Mar 31 is selected -> Apr 30
    //      e.g. Switching from 2012 to 2013 when Feb 29, 2012 is selected -> Feb 28, 2013
    private void adjustDayInMonthIfNeeded(int month, int year) {
        int day = mCalendar.get(Calendar.DAY_OF_MONTH);
        int daysInMonth = Utils.getDaysInMonth(month, year);
        if (day > daysInMonth) {
            mCalendar.set(Calendar.DAY_OF_MONTH, daysInMonth);
        }
    }

    @Override
    public void onClick(View v) {
        tryVibrate();
        if (v.getId() == R.id.date_picker_year) {
            setCurrentView(YEAR_VIEW);
        } else if (v.getId() == R.id.date_picker_month_and_day) {
            setCurrentView(MONTH_AND_DAY_VIEW);
        }
    }

    @Override
    public void onYearSelected(int year) {
        adjustDayInMonthIfNeeded(mCalendar.get(Calendar.MONTH), year);
        mCalendar.set(Calendar.YEAR, year);
        updatePickers();
        setCurrentView(MONTH_AND_DAY_VIEW);
        updateDisplay(true);
    }

    @Override
    public void onDayOfMonthSelected(int year, int month, int day) {
        mCalendar.set(Calendar.YEAR, year);
        mCalendar.set(Calendar.MONTH, month);
        mCalendar.set(Calendar.DAY_OF_MONTH, day);
        updatePickers();
        updateDisplay(true);
    }

    private void updatePickers() {
        Iterator<OnDateChangedListener> iterator = mListeners.iterator();
        while (iterator.hasNext()) {
            iterator.next().onDateChanged();
        }
    }


    @Override
    public CalendarDay getSelectedDay() {
        return new CalendarDay(mCalendar);
    }

    @Override
    public int getMinYear() {
        return mMinYear;
    }

    @Override
    public int getMaxYear() {
        return mMaxYear;
    }

    @Override
    public int getFirstDayOfWeek() {
        return mWeekStart;
    }

    @Override
    public void registerOnDateChangedListener(OnDateChangedListener listener) {
        mListeners.add(listener);
    }

    @Override
    public void unregisterOnDateChangedListener(OnDateChangedListener listener) {
        mListeners.remove(listener);
    }

    /**
     * Try to vibrate. To prevent this becoming a single continuous vibration, nothing will
     * happen if we have vibrated very recently.
     */
    @Override
    public void tryVibrate() {
        if (mVibrator != null) {
            long now = SystemClock.uptimeMillis();
            // We want to try to vibrate each individual tick discretely.
            if (now - mLastVibrate >= 125) {
                mVibrator.vibrate(5);
                mLastVibrate = now;
            }
        }
    }
}