/*
 * 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.annotation.NonNull;
import android.annotation.Nullable;
import android.annotation.StyleRes;
import android.content.Context;
import android.content.DialogInterface;
import android.content.DialogInterface.OnClickListener;
import android.os.Bundle;
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.
 */
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 OnDateSetListener mDateSetListener;

    /**
     * Creates a new date picker dialog for the current date using the parent
     * context's default date picker dialog theme.
     *
     * @param context the parent context
     */
    public DatePickerDialog(@NonNull Context context) {
        this(context, 0, null, Calendar.getInstance(), -1, -1, -1);
    }

    /**
     * Creates a new date picker dialog for the current date.
     *
     * @param context the parent context
     * @param themeResId the resource ID of the theme against which to inflate
     *                   this dialog, or {@code 0} to use the parent
     *                   {@code context}'s default alert dialog theme
     */
    public DatePickerDialog(@NonNull Context context, @StyleRes int themeResId) {
        this(context, themeResId, null, Calendar.getInstance(), -1, -1, -1);
    }

    /**
     * Creates a new date picker dialog for the specified date using the parent
     * context's default date picker dialog theme.
     *
     * @param context the parent context
     * @param listener the listener to call when the user sets the date
     * @param year the initially selected year
     * @param month the initially selected month (0-11 for compatibility with
     *              {@link Calendar#MONTH})
     * @param dayOfMonth the initially selected day of month (1-31, depending
     *                   on month)
     */
    public DatePickerDialog(@NonNull Context context, @Nullable OnDateSetListener listener,
            int year, int month, int dayOfMonth) {
        this(context, 0, listener, null, year, month, dayOfMonth);
    }

    /**
     * Creates a new date picker dialog for the specified date.
     *
     * @param context the parent context
     * @param themeResId the resource ID of the theme against which to inflate
     *                   this dialog, or {@code 0} to use the parent
     *                   {@code context}'s default alert dialog theme
     * @param listener the listener to call when the user sets the date
     * @param year the initially selected year
     * @param monthOfYear the initially selected month of the year (0-11 for
     *                    compatibility with {@link Calendar#MONTH})
     * @param dayOfMonth the initially selected day of month (1-31, depending
     *                   on month)
     */
    public DatePickerDialog(@NonNull Context context, @StyleRes int themeResId,
            @Nullable OnDateSetListener listener, int year, int monthOfYear, int dayOfMonth) {
        this(context, themeResId, listener, null, year, monthOfYear, dayOfMonth);
    }

    private DatePickerDialog(@NonNull Context context, @StyleRes int themeResId,
            @Nullable OnDateSetListener listener, @Nullable Calendar calendar, int year,
            int monthOfYear, int dayOfMonth) {
        super(context, resolveDialogTheme(context, themeResId));

        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);

        if (calendar != null) {
            year = calendar.get(Calendar.YEAR);
            monthOfYear = calendar.get(Calendar.MONTH);
            dayOfMonth = calendar.get(Calendar.DAY_OF_MONTH);
        }

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

        mDateSetListener = listener;
    }

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

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

    /**
     * Sets the listener to call when the user sets the date.
     *
     * @param listener the listener to call when the user sets the date
     */
    public void setOnDateSetListener(@Nullable OnDateSetListener listener) {
        mDateSetListener = listener;
    }

    @Override
    public void onClick(@NonNull DialogInterface dialog, int which) {
        switch (which) {
            case BUTTON_POSITIVE:
                if (mDateSetListener != null) {
                    // Clearing focus forces the dialog to commit any pending
                    // changes, e.g. typed text in a NumberPicker.
                    mDatePicker.clearFocus();
                    mDateSetListener.onDateSet(mDatePicker, mDatePicker.getYear(),
                            mDatePicker.getMonth(), mDatePicker.getDayOfMonth());
                }
                break;
            case BUTTON_NEGATIVE:
                cancel();
                break;
        }
    }

    /**
     * Returns the {@link DatePicker} contained in this dialog.
     *
     * @return the date picker
     */
    @NonNull
    public DatePicker getDatePicker() {
        return mDatePicker;
    }

    /**
     * Sets the current date.
     *
     * @param year the year
     * @param month the month (0-11 for compatibility with
     *              {@link Calendar#MONTH})
     * @param dayOfMonth the day of month (1-31, depending on month)
     */
    public void updateDate(int year, int month, int dayOfMonth) {
        mDatePicker.updateDate(year, month, dayOfMonth);
    }

    @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);
            }
        }
    };

    /**
     * The listener used to indicate the user has finished selecting a date.
     */
    public interface OnDateSetListener {
        /**
         * @param view the picker associated with the dialog
         * @param year the selected year
         * @param month the selected month (0-11 for compatibility with
         *              {@link Calendar#MONTH})
         * @param dayOfMonth th selected day of the month (1-31, depending on
         *                   month)
         */
        void onDateSet(DatePicker view, int year, int month, int dayOfMonth);
    }
}
