/*
 * Copyright (C) 2007 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 android.widget;

import com.android.internal.R;

import android.annotation.Widget;
import android.content.Context;
import android.content.res.TypedArray;
import android.os.Parcel;
import android.os.Parcelable;
import android.text.TextUtils;
import android.text.format.DateFormat;
import android.text.format.DateUtils;
import android.util.AttributeSet;
import android.util.Log;
import android.util.SparseArray;
import android.view.LayoutInflater;
import android.view.accessibility.AccessibilityEvent;
import android.widget.NumberPicker.OnValueChangeListener;

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Arrays;
import java.util.Calendar;
import java.util.Locale;
import java.util.TimeZone;

/**
 * This class is a widget for selecting a date. The date can be selected by a
 * year, month, and day spinners or a {@link CalendarView}. The set of spinners
 * and the calendar view are automatically synchronized. The client can
 * customize whether only the spinners, or only the calendar view, or both to be
 * displayed. Also the minimal and maximal date from which dates to be selected
 * can be customized.
 * <p>
 * See the <a href="{@docRoot}resources/tutorials/views/hello-datepicker.html">Date
 * Picker tutorial</a>.
 * </p>
 * <p>
 * For a dialog using this view, see {@link android.app.DatePickerDialog}.
 * </p>
 *
 * @attr ref android.R.styleable#DatePicker_startYear
 * @attr ref android.R.styleable#DatePicker_endYear
 * @attr ref android.R.styleable#DatePicker_maxDate
 * @attr ref android.R.styleable#DatePicker_minDate
 * @attr ref android.R.styleable#DatePicker_spinnersShown
 * @attr ref android.R.styleable#DatePicker_calendarViewShown
 */
@Widget
public class DatePicker extends FrameLayout {

    private static final String LOG_TAG = DatePicker.class.getSimpleName();

    private static final String DATE_FORMAT = "MM/dd/yyyy";

    private static final int DEFAULT_START_YEAR = 1900;

    private static final int DEFAULT_END_YEAR = 2100;

    private static final boolean DEFAULT_CALENDAR_VIEW_SHOWN = true;

    private static final boolean DEFAULT_SPINNERS_SHOWN = true;

    private static final boolean DEFAULT_ENABLED_STATE = true;

    private final NumberPicker mDaySpinner;

    private final LinearLayout mSpinners;

    private final NumberPicker mMonthSpinner;

    private final NumberPicker mYearSpinner;

    private final CalendarView mCalendarView;

    private OnDateChangedListener mOnDateChangedListener;

    private Locale mMonthLocale;

    private final Calendar mTempDate = Calendar.getInstance();

    private final int mNumberOfMonths = mTempDate.getActualMaximum(Calendar.MONTH) + 1;

    private final String[] mShortMonths = new String[mNumberOfMonths];

    private final java.text.DateFormat mDateFormat = new SimpleDateFormat(DATE_FORMAT);

    private final Calendar mMinDate = Calendar.getInstance();

    private final Calendar mMaxDate = Calendar.getInstance();

    private final Calendar mCurrentDate = Calendar.getInstance();

    private boolean mIsEnabled = DEFAULT_ENABLED_STATE;

    /**
     * The callback used to indicate the user changes\d the date.
     */
    public interface OnDateChangedListener {

        /**
         * Called upon a date change.
         *
         * @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 onDateChanged(DatePicker view, int year, int monthOfYear, int dayOfMonth);
    }

    public DatePicker(Context context) {
        this(context, null);
    }

    public DatePicker(Context context, AttributeSet attrs) {
        this(context, attrs, R.attr.datePickerStyle);
    }

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

        TypedArray attributesArray = context.obtainStyledAttributes(attrs, R.styleable.DatePicker,
                defStyle, 0);
        boolean spinnersShown = attributesArray.getBoolean(R.styleable.DatePicker_spinnersShown,
                DEFAULT_SPINNERS_SHOWN);
        boolean calendarViewShown = attributesArray.getBoolean(
                R.styleable.DatePicker_calendarViewShown, DEFAULT_CALENDAR_VIEW_SHOWN);
        int startYear = attributesArray.getInt(R.styleable.DatePicker_startYear,
                DEFAULT_START_YEAR);
        int endYear = attributesArray.getInt(R.styleable.DatePicker_endYear, DEFAULT_END_YEAR);
        String minDate = attributesArray.getString(R.styleable.DatePicker_minDate);
        String maxDate = attributesArray.getString(R.styleable.DatePicker_maxDate);
        int layoutResourceId = attributesArray.getResourceId(R.styleable.DatePicker_layout,
                R.layout.date_picker);
        attributesArray.recycle();

        LayoutInflater inflater = (LayoutInflater) context
                .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
        inflater.inflate(layoutResourceId, this, true);

        OnValueChangeListener onChangeListener = new OnValueChangeListener() {
            public void onValueChange(NumberPicker picker, int oldVal, int newVal) {
                mTempDate.setTimeInMillis(mCurrentDate.getTimeInMillis());
                // take care of wrapping of days and months to update greater fields
                if (picker == mDaySpinner) {
                    int maxDayOfMonth = mTempDate.getActualMaximum(Calendar.DAY_OF_MONTH);
                    if (oldVal == maxDayOfMonth && newVal == 1) {
                        mTempDate.add(Calendar.DAY_OF_MONTH, 1);
                    } else if (oldVal == 1 && newVal == maxDayOfMonth) {
                        mTempDate.add(Calendar.DAY_OF_MONTH, -1);
                    } else {
                        mTempDate.add(Calendar.DAY_OF_MONTH, newVal - oldVal);
                    }
                } else if (picker == mMonthSpinner) {
                    if (oldVal == 11 && newVal == 0) {
                        mTempDate.add(Calendar.MONTH, 1);
                    } else if (oldVal == 0 && newVal == 11) {
                        mTempDate.add(Calendar.MONTH, -1);
                    } else {
                        mTempDate.add(Calendar.MONTH, newVal - oldVal);
                    }
                } else if (picker == mYearSpinner) {
                    mTempDate.set(Calendar.YEAR, newVal);
                } else {
                    throw new IllegalArgumentException();
                }
                // now set the date to the adjusted one
                setDate(mTempDate.get(Calendar.YEAR), mTempDate.get(Calendar.MONTH),
                        mTempDate.get(Calendar.DAY_OF_MONTH));
                updateSpinners();
                updateCalendarView();
                notifyDateChanged();
            }
        };

        mSpinners = (LinearLayout) findViewById(R.id.pickers);

        // calendar view day-picker
        mCalendarView = (CalendarView) findViewById(R.id.calendar_view);
        mCalendarView.setOnDateChangeListener(new CalendarView.OnDateChangeListener() {
            public void onSelectedDayChange(CalendarView view, int year, int month, int monthDay) {
                setDate(year, month, monthDay);
                updateSpinners();
                notifyDateChanged();
            }
        });

        // day
        mDaySpinner = (NumberPicker) findViewById(R.id.day);
        mDaySpinner.setFormatter(NumberPicker.TWO_DIGIT_FORMATTER);
        mDaySpinner.setOnLongPressUpdateInterval(100);
        mDaySpinner.setOnValueChangedListener(onChangeListener);

        // month
        mMonthSpinner = (NumberPicker) findViewById(R.id.month);
        mMonthSpinner.setMinValue(0);
        mMonthSpinner.setMaxValue(mNumberOfMonths - 1);
        mMonthSpinner.setDisplayedValues(getShortMonths());
        mMonthSpinner.setOnLongPressUpdateInterval(200);
        mMonthSpinner.setOnValueChangedListener(onChangeListener);

        // year
        mYearSpinner = (NumberPicker) findViewById(R.id.year);
        mYearSpinner.setOnLongPressUpdateInterval(100);
        mYearSpinner.setOnValueChangedListener(onChangeListener);

        // show only what the user required but make sure we
        // show something and the spinners have higher priority
        if (!spinnersShown && !calendarViewShown) {
            setSpinnersShown(true);
        } else {
            setSpinnersShown(spinnersShown);
            setCalendarViewShown(calendarViewShown);
        }

        // set the min date giving priority of the minDate over startYear
        mTempDate.clear();
        if (!TextUtils.isEmpty(minDate)) {
            if (!parseDate(minDate, mTempDate)) {
                mTempDate.set(startYear, 0, 1);
            }
        } else {
            mTempDate.set(startYear, 0, 1);
        }
        setMinDate(mTempDate.getTimeInMillis());

        // set the max date giving priority of the maxDate over endYear
        mTempDate.clear();
        if (!TextUtils.isEmpty(maxDate)) {
            if (!parseDate(maxDate, mTempDate)) {
                mTempDate.set(endYear, 11, 31);
            }
        } else {
            mTempDate.set(endYear, 11, 31);
        }
        setMaxDate(mTempDate.getTimeInMillis());

        // initialize to current date
        mCurrentDate.setTimeInMillis(System.currentTimeMillis());
        init(mCurrentDate.get(Calendar.YEAR), mCurrentDate.get(Calendar.MONTH), mCurrentDate
                .get(Calendar.DAY_OF_MONTH), null);

        // re-order the number spinners to match the current date format
        reorderSpinners();
    }

    /**
     * Gets the minimal date supported by this {@link DatePicker} in
     * milliseconds since January 1, 1970 00:00:00 in
     * {@link TimeZone#getDefault()} time zone.
     * <p>
     * Note: The default minimal date is 01/01/1900.
     * <p>
     *
     * @return The minimal supported date.
     */
    public long getMinDate() {
        return mCalendarView.getMinDate();
    }

    /**
     * Sets the minimal date supported by this {@link NumberPicker} in
     * milliseconds since January 1, 1970 00:00:00 in
     * {@link TimeZone#getDefault()} time zone.
     *
     * @param minDate The minimal supported date.
     */
    public void setMinDate(long minDate) {
        mTempDate.setTimeInMillis(minDate);
        if (mTempDate.get(Calendar.YEAR) == mMinDate.get(Calendar.YEAR)
                && mTempDate.get(Calendar.DAY_OF_YEAR) != mMinDate.get(Calendar.DAY_OF_YEAR)) {
            return;
        }
        mMinDate.setTimeInMillis(minDate);
        mCalendarView.setMinDate(minDate);
        if (mCurrentDate.before(mMinDate)) {
            mCurrentDate.setTimeInMillis(mMinDate.getTimeInMillis());
            updateCalendarView();
        }
        updateSpinners();
    }

    /**
     * Gets the maximal date supported by this {@link DatePicker} in
     * milliseconds since January 1, 1970 00:00:00 in
     * {@link TimeZone#getDefault()} time zone.
     * <p>
     * Note: The default maximal date is 12/31/2100.
     * <p>
     *
     * @return The maximal supported date.
     */
    public long getMaxDate() {
        return mCalendarView.getMaxDate();
    }

    /**
     * Sets the maximal date supported by this {@link DatePicker} in
     * milliseconds since January 1, 1970 00:00:00 in
     * {@link TimeZone#getDefault()} time zone.
     *
     * @param maxDate The maximal supported date.
     */
    public void setMaxDate(long maxDate) {
        mTempDate.setTimeInMillis(maxDate);
        if (mTempDate.get(Calendar.YEAR) == mMaxDate.get(Calendar.YEAR)
                && mTempDate.get(Calendar.DAY_OF_YEAR) != mMaxDate.get(Calendar.DAY_OF_YEAR)) {
            return;
        }
        mMaxDate.setTimeInMillis(maxDate);
        mCalendarView.setMaxDate(maxDate);
        if (mCurrentDate.after(mMaxDate)) {
            mCurrentDate.setTimeInMillis(mMaxDate.getTimeInMillis());
            updateCalendarView();
        }
        updateSpinners();
    }

    @Override
    public void setEnabled(boolean enabled) {
        if (mIsEnabled == enabled) {
            return;
        }
        super.setEnabled(enabled);
        mDaySpinner.setEnabled(enabled);
        mMonthSpinner.setEnabled(enabled);
        mYearSpinner.setEnabled(enabled);
        mCalendarView.setEnabled(enabled);
        mIsEnabled = enabled;
    }

    @Override
    public boolean isEnabled() {
        return mIsEnabled;
    }

    @Override
    public void onPopulateAccessibilityEvent(AccessibilityEvent event) {
        super.onPopulateAccessibilityEvent(event);

        final int flags = DateUtils.FORMAT_SHOW_DATE | DateUtils.FORMAT_SHOW_WEEKDAY
                | DateUtils.FORMAT_SHOW_YEAR;
        String selectedDateUtterance = DateUtils.formatDateTime(mContext,
                mCurrentDate.getTimeInMillis(), flags);
        event.getText().add(selectedDateUtterance);
    }

    /**
     * Gets whether the {@link CalendarView} is shown.
     *
     * @return True if the calendar view is shown.
     * @see #getCalendarView()
     */
    public boolean getCalendarViewShown() {
        return mCalendarView.isShown();
    }

    /**
     * Gets the {@link CalendarView}.
     *
     * @return The calendar view.
     * @see #getCalendarViewShown()
     */
    public CalendarView getCalendarView () {
        return mCalendarView;
    }

    /**
     * Sets whether the {@link CalendarView} is shown.
     *
     * @param shown True if the calendar view is to be shown.
     */
    public void setCalendarViewShown(boolean shown) {
        mCalendarView.setVisibility(shown ? VISIBLE : GONE);
    }

    /**
     * Gets whether the spinners are shown.
     *
     * @return True if the spinners are shown.
     */
    public boolean getSpinnersShown() {
        return mSpinners.isShown();
    }

    /**
     * Sets whether the spinners are shown.
     *
     * @param shown True if the spinners are to be shown.
     */
    public void setSpinnersShown(boolean shown) {
        mSpinners.setVisibility(shown ? VISIBLE : GONE);
    }

    /**
     * Reorders the spinners according to the date format that is
     * explicitly set by the user and if no such is set fall back
     * to the current locale's default format.
     */
    private void reorderSpinners() {
        mSpinners.removeAllViews();
        char[] order = DateFormat.getDateFormatOrder(getContext());
        for (int i = 0; i < order.length; i++) {
            switch (order[i]) {
                case DateFormat.DATE:
                    mSpinners.addView(mDaySpinner);
                    break;
                case DateFormat.MONTH:
                    mSpinners.addView(mMonthSpinner);
                    break;
                case DateFormat.YEAR:
                    mSpinners.addView(mYearSpinner);
                    break;
                default:
                    throw new IllegalArgumentException();
            }
        }
    }

    /**
     * Updates the current date.
     *
     * @param year The year.
     * @param month The month which is <strong>starting from zero</strong>.
     * @param dayOfMonth The day of the month.
     */
    public void updateDate(int year, int month, int dayOfMonth) {
        if (!isNewDate(year, month, dayOfMonth)) {
            return;
        }
        setDate(year, month, dayOfMonth);
        updateSpinners();
        updateCalendarView();
        notifyDateChanged();
    }

    // Override so we are in complete control of save / restore for this widget.
    @Override
    protected void dispatchRestoreInstanceState(SparseArray<Parcelable> container) {
        dispatchThawSelfOnly(container);
    }

    @Override
    protected Parcelable onSaveInstanceState() {
        Parcelable superState = super.onSaveInstanceState();
        return new SavedState(superState, getYear(), getMonth(), getDayOfMonth());
    }

    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        SavedState ss = (SavedState) state;
        super.onRestoreInstanceState(ss.getSuperState());
        setDate(ss.mYear, ss.mMonth, ss.mDay);
        updateSpinners();
        updateCalendarView();
    }

    /**
     * Initialize the state. If the provided values designate an inconsistent
     * date the values are normalized before updating the spinners.
     *
     * @param year The initial year.
     * @param monthOfYear The initial month <strong>starting from zero</strong>.
     * @param dayOfMonth The initial day of the month.
     * @param onDateChangedListener How user is notified date is changed by
     *            user, can be null.
     */
    public void init(int year, int monthOfYear, int dayOfMonth,
            OnDateChangedListener onDateChangedListener) {
        setDate(year, monthOfYear, dayOfMonth);
        updateSpinners();
        updateCalendarView();
        mOnDateChangedListener = onDateChangedListener;
    }

    /**
     * Parses the given <code>date</code> and in case of success sets the result
     * to the <code>outDate</code>.
     *
     * @return True if the date was parsed.
     */
    private boolean parseDate(String date, Calendar outDate) {
        try {
            outDate.setTime(mDateFormat.parse(date));
            return true;
        } catch (ParseException e) {
            Log.w(LOG_TAG, "Date: " + date + " not in format: " + DATE_FORMAT);
            return false;
        }
    }

    /**
     * @return The short month abbreviations.
     */
    private String[] getShortMonths() {
        final Locale currentLocale = Locale.getDefault();
        if (currentLocale.equals(mMonthLocale)) {
            return mShortMonths;
        } else {
            for (int i = 0; i < mNumberOfMonths; i++) {
                mShortMonths[i] = DateUtils.getMonthString(Calendar.JANUARY + i,
                        DateUtils.LENGTH_MEDIUM);
            }
            mMonthLocale = currentLocale;
            return mShortMonths;
        }
    }

    private boolean isNewDate(int year, int month, int dayOfMonth) {
        return (mCurrentDate.get(Calendar.YEAR) != year
                || mCurrentDate.get(Calendar.MONTH) != dayOfMonth
                || mCurrentDate.get(Calendar.DAY_OF_MONTH) != month);
    }

    private void setDate(int year, int month, int dayOfMonth) {
        mCurrentDate.set(year, month, dayOfMonth);
        if (mCurrentDate.before(mMinDate)) {
            mCurrentDate.setTimeInMillis(mMinDate.getTimeInMillis());
        } else if (mCurrentDate.after(mMaxDate)) {
            mCurrentDate.setTimeInMillis(mMaxDate.getTimeInMillis());
        }
    }

    private void updateSpinners() {
        // set the spinner ranges respecting the min and max dates
        if (mCurrentDate.equals(mMinDate)) {
            mDaySpinner.setMinValue(mCurrentDate.get(Calendar.DAY_OF_MONTH));
            mDaySpinner.setMaxValue(mCurrentDate.getActualMaximum(Calendar.DAY_OF_MONTH));
            mDaySpinner.setWrapSelectorWheel(false);
            mMonthSpinner.setDisplayedValues(null);
            mMonthSpinner.setMinValue(mCurrentDate.get(Calendar.MONTH));
            mMonthSpinner.setMaxValue(mCurrentDate.getActualMaximum(Calendar.MONTH));
            mMonthSpinner.setWrapSelectorWheel(false);
        } else if (mCurrentDate.equals(mMaxDate)) {
            mDaySpinner.setMinValue(mCurrentDate.getActualMinimum(Calendar.DAY_OF_MONTH));
            mDaySpinner.setMaxValue(mCurrentDate.get(Calendar.DAY_OF_MONTH));
            mDaySpinner.setWrapSelectorWheel(false);
            mMonthSpinner.setDisplayedValues(null);
            mMonthSpinner.setMinValue(mCurrentDate.getActualMinimum(Calendar.MONTH));
            mMonthSpinner.setMaxValue(mCurrentDate.get(Calendar.MONTH));
            mMonthSpinner.setWrapSelectorWheel(false);
        } else {
            mDaySpinner.setMinValue(1);
            mDaySpinner.setMaxValue(mCurrentDate.getActualMaximum(Calendar.DAY_OF_MONTH));
            mDaySpinner.setWrapSelectorWheel(true);
            mMonthSpinner.setDisplayedValues(null);
            mMonthSpinner.setMinValue(0);
            mMonthSpinner.setMaxValue(11);
            mMonthSpinner.setWrapSelectorWheel(true);
        }

        // make sure the month names are a zero based array
        // with the months in the month spinner
        String[] displayedValues = Arrays.copyOfRange(getShortMonths(),
                mMonthSpinner.getMinValue(), mMonthSpinner.getMaxValue() + 1);
        mMonthSpinner.setDisplayedValues(displayedValues);

        // year spinner range does not change based on the current date
        mYearSpinner.setMinValue(mMinDate.get(Calendar.YEAR));
        mYearSpinner.setMaxValue(mMaxDate.get(Calendar.YEAR));
        mYearSpinner.setWrapSelectorWheel(false);

        // set the spinner values
        mYearSpinner.setValue(mCurrentDate.get(Calendar.YEAR));
        mMonthSpinner.setValue(mCurrentDate.get(Calendar.MONTH));
        mDaySpinner.setValue(mCurrentDate.get(Calendar.DAY_OF_MONTH));
    }

    /**
     * Updates the calendar view with the current date.
     */
    private void updateCalendarView() {
         mCalendarView.setDate(mCurrentDate.getTimeInMillis(), false, false);
    }

    /**
     * @return The selected year.
     */
    public int getYear() {
        return mCurrentDate.get(Calendar.YEAR);
    }

    /**
     * @return The selected month.
     */
    public int getMonth() {
        return mCurrentDate.get(Calendar.MONTH);
    }

    /**
     * @return The selected day of month.
     */
    public int getDayOfMonth() {
        return mCurrentDate.get(Calendar.DAY_OF_MONTH);
    }

    /**
     * Notifies the listener, if such, for a change in the selected date.
     */
    private void notifyDateChanged() {
        sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_SELECTED);
        if (mOnDateChangedListener != null) {
            mOnDateChangedListener.onDateChanged(this, getYear(), getMonth(), getDayOfMonth());
        }
    }

    /**
     * Class for managing state storing/restoring.
     */
    private static class SavedState extends BaseSavedState {

        private final int mYear;

        private final int mMonth;

        private final int mDay;

        /**
         * Constructor called from {@link DatePicker#onSaveInstanceState()}
         */
        private SavedState(Parcelable superState, int year, int month, int day) {
            super(superState);
            mYear = year;
            mMonth = month;
            mDay = day;
        }

        /**
         * Constructor called from {@link #CREATOR}
         */
        private SavedState(Parcel in) {
            super(in);
            mYear = in.readInt();
            mMonth = in.readInt();
            mDay = in.readInt();
        }

        @Override
        public void writeToParcel(Parcel dest, int flags) {
            super.writeToParcel(dest, flags);
            dest.writeInt(mYear);
            dest.writeInt(mMonth);
            dest.writeInt(mDay);
        }

        @SuppressWarnings("all")
        // suppress unused and hiding
        public static final Parcelable.Creator<SavedState> CREATOR = new Creator<SavedState>() {

            public SavedState createFromParcel(Parcel in) {
                return new SavedState(in);
            }

            public SavedState[] newArray(int size) {
                return new SavedState[size];
            }
        };
    }
}