//
// Copyright 2023 Google LLC
//
// Licensed to the Apache Software Foundation (ASF) under one
// or more contributor license agreements.  See the NOTICE file
// distributed with this work for additional information
// regarding copyright ownership.  The ASF licenses this file
// to you 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.
//

using System;
using System.Threading.Tasks;

namespace Google.Solutions.Mvvm.Binding
{
    /// <summary>
    /// A property sheet that can be displayed in a
    /// property dialog.
    /// </summary>
    public interface IPropertiesSheetView : IView<PropertiesSheetViewModelBase>
    {
        /// <summary>
        /// Type of the associated view model. Must be a subclass of
        /// PropertySheetViewModelBase.
        /// </summary>
        Type ViewModel { get; }
    }

    public abstract class PropertiesSheetViewModelBase : ViewModelBase
    {
        /// <summary>
        /// Title of property sheet.
        /// </summary>
        public string Title { get; }

        /// <summary>
        /// True if any values on property sheet have been
        /// changed.
        /// </summary>
        public abstract ObservableProperty<bool> IsDirty { get; }

        /// <summary>
        /// Apply and persist changes.
        /// </summary>
        public virtual Task ApplyChangesAsync()
        {
            ApplyChanges();
            return Task.CompletedTask;
        }

        /// <summary>
        /// Apply and persist changes.
        /// </summary>
        protected virtual void ApplyChanges()
        { }

        protected PropertiesSheetViewModelBase(string title)
        {
            this.Title = title;
        }
    }
}
