// 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.Collections;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Runtime.Serialization;

namespace Microsoft.CodeAnalysis.SolutionCrawler;

[DataContract]
internal partial struct InvocationReasons(ImmutableHashSet<string> reasons) : IEnumerable<string>
{
    public static readonly InvocationReasons Empty = new([]);

    [DataMember(Order = 0)]
    private readonly ImmutableHashSet<string> _reasons = reasons ?? [];

    public InvocationReasons(string reason)
        : this([reason])
    {
    }

    public bool IsEmpty => _reasons.IsEmpty;

    public bool Contains(string reason)
        => _reasons.Contains(reason);

    public InvocationReasons With(InvocationReasons invocationReasons)
        => new(_reasons.Union(invocationReasons._reasons));

    public InvocationReasons With(string reason)
        => new(_reasons.Add(reason));

    public ImmutableHashSet<string>.Enumerator GetEnumerator()
        => _reasons.GetEnumerator();

    IEnumerator<string> IEnumerable<string>.GetEnumerator()
        => _reasons.GetEnumerator();

    IEnumerator IEnumerable.GetEnumerator()
        => _reasons.GetEnumerator();

    public override string ToString()
        => string.Join("|", _reasons ?? []);
}