// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
// See the LICENSE file in the project root for more information.

using System;
using System.Collections.Immutable;
using System.Linq;
using System.Runtime.Serialization;
using Microsoft.CodeAnalysis.Text;
using Roslyn.Utilities;

namespace Microsoft.CodeAnalysis.NavigationBar;

internal abstract partial class RoslynNavigationBarItem
{
    public sealed class SymbolItem(
        string name,
        string text,
        Glyph glyph,
        bool isObsolete,
        SymbolItemLocation location,
        ImmutableArray<RoslynNavigationBarItem> childItems = default,
        int indent = 0,
        bool bolded = false) : RoslynNavigationBarItem(
              RoslynNavigationBarItemKind.Symbol,
              text,
              glyph,
              bolded,
              grayed: location.OtherDocumentInfo != null,
              indent,
              childItems), IEquatable<SymbolItem>
    {
        public readonly string Name = name;
        public readonly bool IsObsolete = isObsolete;

        public readonly SymbolItemLocation Location = location;

        protected internal override SerializableNavigationBarItem Dehydrate()
            => SerializableNavigationBarItem.SymbolItem(Text, Glyph, Name, IsObsolete, Location, SerializableNavigationBarItem.Dehydrate(ChildItems), Indent, Bolded, Grayed);

        public override bool Equals(object? obj)
            => Equals(obj as SymbolItem);

        public bool Equals(SymbolItem? other)
            => base.Equals(other) &&
               Name == other.Name &&
               IsObsolete == other.IsObsolete &&
               Location.Equals(other.Location);

        public override int GetHashCode()
            => throw new NotImplementedException();
    }

    [DataContract]
    public readonly struct SymbolItemLocation : IEquatable<SymbolItemLocation>
    {
        /// <summary>
        /// The entity spans and navigation span in the originating document where this symbol was found.  Any time
        /// the caret is within any of the entity spans, the item should be appropriately 'selected' in whatever UI
        /// is displaying these.  The navigation span is the location in the starting document that should be
        /// navigated to when this item is selected If this symbol's location is in another document then this will
        /// be <see langword="null"/>.
        /// </summary>
        /// <remarks>Exactly one of <see cref="InDocumentInfo"/> and <see cref="OtherDocumentInfo"/> will be
        /// non-null.</remarks>
        [DataMember(Order = 0)]
        public readonly (ImmutableArray<TextSpan> spans, TextSpan navigationSpan)? InDocumentInfo;

        /// <summary>
        /// The document and navigation span this item should navigate to when the definition is not in the
        /// originating document. This is used for partial symbols where a child symbol is declared in another file,
        /// but should still be shown in the UI when in a part in a different file.
        /// </summary>
        /// <remarks>Exactly one of <see cref="InDocumentInfo"/> and <see cref="OtherDocumentInfo"/> will be
        /// non-null.</remarks>
        [DataMember(Order = 1)]
        public readonly (DocumentId documentId, TextSpan navigationSpan)? OtherDocumentInfo;

        public SymbolItemLocation(
            (ImmutableArray<TextSpan> spans, TextSpan navigationSpan)? inDocumentInfo,
            (DocumentId documentId, TextSpan navigationSpan)? otherDocumentInfo)
        {
            Contract.ThrowIfTrue(inDocumentInfo == null && otherDocumentInfo == null, "Both locations were null");
            Contract.ThrowIfTrue(inDocumentInfo != null && otherDocumentInfo != null, "Both locations were not null");

            if (inDocumentInfo != null)
            {
                Contract.ThrowIfTrue(inDocumentInfo.Value.spans.IsEmpty, "If location is in document, it must have non-empty spans");
            }

            InDocumentInfo = inDocumentInfo;
            OtherDocumentInfo = otherDocumentInfo;
        }

        public override bool Equals(object? obj)
            => obj is SymbolItemLocation location && Equals(location);

        public bool Equals(SymbolItemLocation other)
        {
            if ((InDocumentInfo == null) != (other.InDocumentInfo == null))
                return false;

            if ((OtherDocumentInfo == null) != (other.OtherDocumentInfo == null))
                return false;

            if (InDocumentInfo != null)
            {
                if (!this.InDocumentInfo.Value.spans.SequenceEqual(other.InDocumentInfo!.Value.spans) ||
                    this.InDocumentInfo.Value.navigationSpan != other.InDocumentInfo.Value.navigationSpan)
                {
                    return false;
                }
            }

            if (this.OtherDocumentInfo != null)
            {
                if (this.OtherDocumentInfo.Value != other.OtherDocumentInfo!.Value)
                    return false;
            }

            return true;
        }

        public override int GetHashCode()
            => throw new NotImplementedException();
    }
}