// 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.Diagnostics;
using Microsoft.CodeAnalysis.Text;

namespace Microsoft.CodeAnalysis.Diagnostics
{
    internal sealed class CompilationUnitCompletedEvent : CompilationEvent
    {
        public CompilationUnitCompletedEvent(Compilation compilation, SyntaxTree compilationUnit, TextSpan? filterSpan = null)
            : base(compilation)
        {
            Debug.Assert(compilation.ContainsSyntaxTree(compilationUnit));

            this.CompilationUnit = compilationUnit;
            this.FilterSpan = filterSpan;
        }

        public SyntaxTree CompilationUnit { get; }

        /// <summary>
        /// Optional filter span for a synthesized CompilationUnitCompletedEvent generated for span-based semantic diagnostic computation.
        /// Such synthesized events are used primarily for performance improvements when running compiler analyzer in span-based mode in the IDE,
        /// such as computing diagnostics for the lightbulb for the current line.
        /// Note that such a synthesized CompilationUnitCompletedEvent with non-null FilterSpan is not a true
        /// compilation unit completed event, but just a stub event to drive span-based semantic model action callbacks
        /// for analyzer execution. This event will eventually be followed by a true CompilationUnitCompletedEvent
        /// with null FilterSpan when the entire compilation unit has actually completed.
        /// See https://github.com/dotnet/roslyn/issues/56843 for details.
        /// </summary>
        public TextSpan? FilterSpan { get; }

        public override string ToString()
            => $"CompilationUnitCompletedEvent({CompilationUnit.FilePath}){FilterSpan}";
    }
}