/*
 * Copyright 2021 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 androidx.leanback.widget;

import android.annotation.SuppressLint;

import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.leanback.widget.ItemAlignmentFacet.ItemAlignmentDef;
import androidx.recyclerview.widget.RecyclerView;

/**
 * Interface for receiving notification when a child of this ViewGroup has been selected.
 * There are two methods:
 * <ul>
 * <li>
 *     {link {@link #onChildViewHolderSelected(RecyclerView, RecyclerView.ViewHolder, int, int)}}
 *     is called when the view holder is about to be selected.  The listener could change size
 *     of the view holder in this callback.
 * </li>
 * <li>
 *     {link {@link #onChildViewHolderSelectedAndPositioned(RecyclerView, RecyclerView.ViewHolder,
 *     int, int)} is called when view holder has been selected and laid out in RecyclerView.
 * </li>
 * </ul>
 */
@SuppressLint("ListenerInterface")
public abstract class OnChildViewHolderSelectedListener {
    /**
     * Callback method to be invoked when a child of this ViewGroup has been selected. Listener
     * might change the size of the child and the position of the child is not finalized. To get
     * the final layout position of child, override {@link #onChildViewHolderSelectedAndPositioned(
     *RecyclerView, RecyclerView.ViewHolder, int, int)}.
     *
     * @param parent      The RecyclerView where the selection happened.
     * @param child       The ViewHolder within the RecyclerView that is selected, or null if no
     *                    view is selected.
     * @param position    The position of the view in the adapter, or NO_POSITION
     *                    if no view is selected.
     * @param subposition The index of which {@link ItemAlignmentDef} being used,
     *                    0 if there is no ItemAlignmentDef defined for the item.
     */
    public void onChildViewHolderSelected(@NonNull RecyclerView parent,
            @Nullable RecyclerView.ViewHolder child,
            int position, int subposition) {
    }

    /**
     * Callback method to be invoked when a child of this ViewGroup has been selected and
     * positioned.
     *
     * @param parent      The RecyclerView where the selection happened.
     * @param child       The ViewHolder within the RecyclerView that is selected, or null if no
     *                    view is selected.
     * @param position    The position of the view in the adapter, or NO_POSITION
     *                    if no view is selected.
     * @param subposition The index of which {@link ItemAlignmentDef} being used,
     *                    0 if there is no ItemAlignmentDef defined for the item.
     */
    public void onChildViewHolderSelectedAndPositioned(@NonNull RecyclerView parent,
            @Nullable RecyclerView.ViewHolder child, int position, int subposition) {
    }
}
