/*
 * Copyright (C) 2019 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.permissioncontroller.role.ui;

import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Checkable;
import android.widget.LinearLayout;

import androidx.annotation.AttrRes;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.annotation.StyleRes;

/**
 * This is a simple wrapper for {@link android.widget.LinearLayout} that implements the
 * {@link android.widget.Checkable} interface by keeping an internal 'checked' state flag.
 * <p>
 * This can be used as the root view for a custom list item layout for
 * {@link android.widget.AbsListView} elements with a
 * {@link android.widget.AbsListView#setChoiceMode(int) choiceMode} set.
 */
public class CheckableLinearLayout extends LinearLayout implements Checkable {

    private static final int[] CHECKED_STATE_SET = { android.R.attr.state_checked };

    private boolean mChecked = false;

    public CheckableLinearLayout(@NonNull Context context) {
        super(context);
    }

    public CheckableLinearLayout(@NonNull Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public CheckableLinearLayout(@NonNull Context context, @Nullable AttributeSet attrs,
            @AttrRes int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    public CheckableLinearLayout(@NonNull Context context, @Nullable AttributeSet attrs,
            @AttrRes int defStyleAttr, @StyleRes int defStyleRes) {
        super(context, attrs, defStyleAttr, defStyleRes);
    }

    @Override
    public boolean isChecked() {
        return mChecked;
    }

    @Override
    public void setChecked(boolean checked) {
        if (mChecked == checked) {
            return;
        }

        mChecked = checked;
        refreshDrawableState();
        updateChildrenChecked();
    }

    @Override
    public void toggle() {
        setChecked(!mChecked);
    }

    @NonNull
    @Override
    public int[] onCreateDrawableState(int extraSpace) {
        int[] state = super.onCreateDrawableState(extraSpace + 1);
        if (isChecked()) {
            mergeDrawableStates(state, CHECKED_STATE_SET);
        }
        return state;
    }

    private void updateChildrenChecked() {
        updateChildrenChecked(this, mChecked);
    }

    // We call setChecked() on checkable children so that accessibility can get the correct state.
    private static void updateChildrenChecked(@NonNull ViewGroup viewGroup, boolean checked) {
        int count = viewGroup.getChildCount();
        for (int i = 0; i < count; i++) {
            View child = viewGroup.getChildAt(i);
            if (child instanceof Checkable) {
                ((Checkable) child).setChecked(checked);
            } else if (child instanceof ViewGroup) {
                updateChildrenChecked((ViewGroup) child, checked);
            }
        }
    }
}