// 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.
 
#nullable disable
 
using System.Linq;
using System.Runtime.InteropServices;
using Microsoft.CodeAnalysis;
using Microsoft.VisualStudio.LanguageServices.Implementation.CodeModel.InternalElements;
using Microsoft.VisualStudio.LanguageServices.Implementation.CodeModel.Interop;
using Microsoft.VisualStudio.LanguageServices.Implementation.Interop;
 
namespace Microsoft.VisualStudio.LanguageServices.Implementation.CodeModel.Collections;
 
[ComVisible(true)]
[ComDefaultInterface(typeof(ICodeElements))]
public sealed class AttributeCollection : AbstractCodeElementCollection
{
    internal static EnvDTE.CodeElements Create(
        CodeModelState state,
        AbstractCodeElement parent)
    {
        var collection = new AttributeCollection(state, parent);
        return (EnvDTE.CodeElements)ComAggregate.CreateAggregatedObject(collection);
    }
 
    private AttributeCollection(
        CodeModelState state,
        AbstractCodeElement parent)
        : base(state, parent)
    {
    }
 
    private AbstractCodeElement ParentElement
    {
        get { return (AbstractCodeElement)Parent; }
    }
 
    private FileCodeModel FileCodeModel
    {
        get { return this.ParentElement.FileCodeModel; }
    }
 
    private SyntaxNode LookupNode()
        => this.ParentElement.LookupNode();
 
    private EnvDTE.CodeElement CreateCodeAttribute(SyntaxNode node, SyntaxNode parentNode)
    {
        CodeModelService.GetAttributeNameAndOrdinal(parentNode, node, out var name, out var ordinal);
 
        return (EnvDTE.CodeElement)CodeAttribute.Create(this.State, this.FileCodeModel, this.ParentElement, name, ordinal);
    }
 
    protected override bool TryGetItemByIndex(int index, out EnvDTE.CodeElement element)
    {
        var node = LookupNode();
 
        var attributeNodes = CodeModelService.GetAttributeNodes(node);
        if (index >= 0 && index < attributeNodes.Count())
        {
            var child = attributeNodes.ElementAt(index);
 
            element = CreateCodeAttribute(child, node);
            return true;
        }
 
        element = null;
        return false;
    }
 
    protected override bool TryGetItemByName(string name, out EnvDTE.CodeElement element)
    {
        var node = LookupNode();
 
        foreach (var child in CodeModelService.GetAttributeNodes(node))
        {
            CodeModelService.GetAttributeNameAndOrdinal(node, child, out var childName, out var ordinal);
            if (childName == name)
            {
                element = (EnvDTE.CodeElement)CodeAttribute.Create(State, FileCodeModel, this.ParentElement, childName, ordinal);
                return true;
            }
        }
 
        element = null;
        return false;
    }
 
    public override int Count
    {
        get
        {
            return CodeModelService.GetAttributeNodes(ParentElement.LookupNode()).Count();
        }
    }
}