// Copyright (c) 2010-2014 SharpDX - Alexandre Mutel
// 
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
// 
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
// 
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

using System;
using System.Collections.Generic;
using System.Collections.ObjectModel;
using System.Collections.Specialized;
using System.Diagnostics;
using System.Linq;
using Microsoft.CodeAnalysis;
using SharpGen.Config;
using SharpGen.CppModel;
using SharpGen.Transform;

namespace SharpGen.Model
{
    /// <summary>
    /// Root class for all model elements.
    /// </summary>
    [DebuggerDisplay("Name: {" + nameof(Name) + "}")]
    public abstract class CsBase
    {
        private ObservableCollection<CsBase> _items;
        private string _cppElementName;
        private string description;

        protected CsBase(CppElement cppElement, string name)
        {
            CppElement = cppElement;
            Name = name;

            if (cppElement == null)
                return;

            var tag = cppElement.Rule;
            Visibility = tag.Visibility ?? Visibility;
        }

        private void ItemsChanged(object sender, NotifyCollectionChangedEventArgs e)
        {
            if (e.OldItems != null)
            {
                foreach (var item in e.OldItems.OfType<CsBase>())
                {
                    item.Parent = null;
                }
            }

            if (e.NewItems != null)
            {
                foreach (var item in e.NewItems.OfType<CsBase>())
                {
                    item.Parent = this;
                }
            }

            OnItemsChanged();
            ExpireOnItemsChange();
        }

        private void ExpireOnItemsChange()
        {
            if (_items == null)
                return;

            foreach (var itemList in ExpiringOnItemsChange)
                itemList?.Expire();
        }

        protected virtual void OnItemsChanged()
        {
        }

        /// <summary>
        /// Gets or sets the parent of this container.
        /// </summary>
        /// <value>The parent.</value>
        public CsBase Parent { get; private set; }

        /// <summary>
        /// Gets the parent of a specified type. This method goes back
        /// to all parent and returns the first parent of the type T or null if no parent were found.
        /// </summary>
        /// <typeparam name="T">Type of the parent</typeparam>
        /// <returns>a valid reference to the parent T or null if no parent of this type</returns>
        public T GetParent<T>() where T : CsBase
        {
            var parent = Parent;
            while (parent is { } and not T)
                parent = parent.Parent;
            return (T) parent;
        }

        /// <summary>
        /// Gets items stored in this container.
        /// </summary>
        /// <value>The items.</value>
        public IReadOnlyCollection<CsBase> Items => ItemsImpl;

        private ObservableCollection<CsBase> ItemsImpl
        {
            get
            {
                if (_items == null) ResetItems();

                return _items;
            }
        }

        public virtual IEnumerable<CsBase> AdditionalItems => Enumerable.Empty<CsBase>();

        protected void ResetItems()
        {
            ExpireOnItemsChange();
            _items = new ObservableCollection<CsBase>();
            _items.CollectionChanged += ItemsChanged;
        }

        /// <summary>
        /// Adds the specified inner container to this container.
        /// </summary>
        /// <remarks>
        /// The Parent property of the innerContainer is set to this container.
        /// </remarks>
        /// <param name="innerCs">The inner container.</param>
        public void Add(CsBase innerCs)
        {
            ItemsImpl.Add(innerCs);
        }

        /// <summary>
        /// Removes the specified inner container from this container
        /// </summary>
        /// <remarks>
        /// The Parent property of the innerContainer is set to null.
        /// </remarks>
        /// <param name="innerCs">The inner container.</param>
        public void Remove(CsBase innerCs)
        {
            ItemsImpl.Remove(innerCs);
        }

        /// <summary>
        /// Gets or sets the name of this element.
        /// </summary>
        /// <value>The name.</value>
        public string Name { get; private protected set; }

        /// <summary>
        /// Gets or sets the <see cref="Visibility"/> of this element. Default is public.
        /// </summary>
        /// <value>The visibility.</value>
        public Visibility Visibility { get; set; } = Visibility.Public;

        public SyntaxTokenList VisibilityTokenList => ModelUtilities.VisibilityToTokenList(Visibility);

        /// <summary>
        /// Gets the full qualified name of this type.
        /// </summary>
        /// <value>The full name.</value>
        public virtual string QualifiedName
        {
            get
            {
                var path = Parent?.QualifiedName;
                var name = Name ?? string.Empty;
                return string.IsNullOrEmpty(path) ? name : path + "." + name;
            }
        }

        /// <summary>
        /// Gets or sets the C++ element associated to this container.
        /// </summary>
        /// <value>The C++ element.</value>
        public CppElement CppElement { get; }

        /// <summary>
        /// Gets the name of the C++ element.
        /// </summary>
        /// <value>The name of the C++ element.</value>
        public string CppElementName
        {
            get => string.IsNullOrEmpty(_cppElementName) ? CppElement?.Name : _cppElementName;
            set => _cppElementName = value;
        }

        /// <summary>
        /// Gets or sets the doc id.
        /// </summary>
        public string DocId { get; set; }

        /// <summary>
        /// Gets or sets the description documentation.
        /// </summary>
        public virtual string Description
        {
            get => string.IsNullOrEmpty(description) ? DefaultDescription : description;
            set => description = value;
        }

        protected virtual string DefaultDescription => "No documentation.";

        /// <summary>
        /// Gets or sets the remarks documentation.
        /// </summary>
        public string Remarks { get; set; } = string.Empty;

        public virtual void FillDocItems(IList<string> docItems, IDocumentationLinker manager)
        {
        }

        public virtual string DocUnmanagedName => CppElementName;

        public virtual string DocUnmanagedShortName => CppElementName;

        [ExcludeFromCodeCoverage]
        public override string ToString() => QualifiedName;

        protected void ResetParentAfterClone()
        {
            Parent = null;
        }

        private protected virtual IEnumerable<IExpiring> ExpiringOnItemsChange => Enumerable.Empty<IExpiring>();

        private protected static IEnumerable<CsBase> AppendNonNull(IEnumerable<CsBase> source, params CsBase[] values)
            => source.Concat(values.Where(x => x != null).Distinct());
    }
}