/*
 * 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.app;

import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
import android.text.format.DateUtils;
import android.util.TypedValue;
import android.view.LayoutInflater;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.DatePicker.OnDateChangedListener;
import android.widget.DatePicker.ValidationCallback;

import com.android.internal.R;

import java.util.Calendar;

/**
 * A simple dialog containing an {@link android.widget.DatePicker}.
 *
 * <p>See the <a href="{@docRoot}guide/topics/ui/controls/pickers.html">Pickers</a>
 * guide.</p>
 */
public class DatePickerDialog extends AlertDialog implements OnClickListener,
        OnDateChangedListener {

    private static final String YEAR = "year";
    private static final String MONTH = "month";
    private static final String DAY = "day";

    private final DatePicker mDatePicker;
    private final OnDateSetListener mDateSetListener;
    private final Calendar mCalendar;

    private boolean mTitleNeedsUpdate = true;

    /**
     * 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(DatePicker view, int year, int monthOfYear, int dayOfMonth);
    }

    /**
     * @param context The context the dialog is to run in.
     * @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 DatePickerDialog(Context context,
            OnDateSetListener callBack,
            int year,
            int monthOfYear,
            int dayOfMonth) {
        this(context, 0, callBack, year, monthOfYear, dayOfMonth);
    }

    static int resolveDialogTheme(Context context, int resid) {
        if (resid == 0) {
            final TypedValue outValue = new TypedValue();
            context.getTheme().resolveAttribute(R.attr.datePickerDialogTheme, outValue, true);
            return outValue.resourceId;
        } else {
            return resid;
        }
    }

    /**
     * @param context The context the dialog is to run in.
     * @param theme the theme to apply to this dialog
     * @param listener 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 DatePickerDialog(Context context, int theme, OnDateSetListener listener, int year,
            int monthOfYear, int dayOfMonth) {
        super(context, resolveDialogTheme(context, theme));

        mDateSetListener = listener;
        mCalendar = Calendar.getInstance();

        final Context themeContext = getContext();
        final LayoutInflater inflater = LayoutInflater.from(themeContext);
        final View view = inflater.inflate(R.layout.date_picker_dialog, null);
        setView(view);
        setButton(BUTTON_POSITIVE, themeContext.getString(R.string.ok), this);
        setButton(BUTTON_NEGATIVE, themeContext.getString(R.string.cancel), this);
        setButtonPanelLayoutHint(LAYOUT_HINT_SIDE);

        mDatePicker = (DatePicker) view.findViewById(R.id.datePicker);
        mDatePicker.init(year, monthOfYear, dayOfMonth, this);
        mDatePicker.setValidationCallback(mValidationCallback);
    }

    @Override
    public void onDateChanged(DatePicker view, int year, int month, int day) {
        mDatePicker.init(year, month, day, this);
        updateTitle(year, month, day);
    }

    @Override
    public void onClick(DialogInterface dialog, int which) {
        switch (which) {
            case BUTTON_POSITIVE:
                if (mDateSetListener != null) {
                    mDateSetListener.onDateSet(mDatePicker, mDatePicker.getYear(),
                            mDatePicker.getMonth(), mDatePicker.getDayOfMonth());
                }
                break;
            case BUTTON_NEGATIVE:
                cancel();
                break;
        }
    }

    /**
     * Gets the {@link DatePicker} contained in this dialog.
     *
     * @return The calendar view.
     */
    public DatePicker getDatePicker() {
        return mDatePicker;
    }

    /**
     * Sets the current date.
     *
     * @param year The date year.
     * @param monthOfYear The date month.
     * @param dayOfMonth The date day of month.
     */
    public void updateDate(int year, int monthOfYear, int dayOfMonth) {
        mDatePicker.updateDate(year, monthOfYear, dayOfMonth);
    }

    private void updateTitle(int year, int month, int day) {
        if (!mDatePicker.getCalendarViewShown()) {
            mCalendar.set(Calendar.YEAR, year);
            mCalendar.set(Calendar.MONTH, month);
            mCalendar.set(Calendar.DAY_OF_MONTH, day);
            String title = DateUtils.formatDateTime(mContext,
                    mCalendar.getTimeInMillis(),
                    DateUtils.FORMAT_SHOW_DATE
                    | DateUtils.FORMAT_SHOW_WEEKDAY
                    | DateUtils.FORMAT_SHOW_YEAR
                    | DateUtils.FORMAT_ABBREV_MONTH
                    | DateUtils.FORMAT_ABBREV_WEEKDAY);
            setTitle(title);
            mTitleNeedsUpdate = true;
        } else {
            if (mTitleNeedsUpdate) {
                mTitleNeedsUpdate = false;
                setTitle(R.string.date_picker_dialog_title);
            }
        }
    }

    @Override
    public Bundle onSaveInstanceState() {
        final Bundle state = super.onSaveInstanceState();
        state.putInt(YEAR, mDatePicker.getYear());
        state.putInt(MONTH, mDatePicker.getMonth());
        state.putInt(DAY, mDatePicker.getDayOfMonth());
        return state;
    }

    @Override
    public void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);
        final int year = savedInstanceState.getInt(YEAR);
        final int month = savedInstanceState.getInt(MONTH);
        final int day = savedInstanceState.getInt(DAY);
        mDatePicker.init(year, month, day, this);
    }

    private final ValidationCallback mValidationCallback = new ValidationCallback() {
        @Override
        public void onValidationChanged(boolean valid) {
            final Button positive = getButton(BUTTON_POSITIVE);
            if (positive != null) {
                positive.setEnabled(valid);
            }
        }
    };
}