// 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.Generic;
using System.Composition;
using System.Diagnostics.CodeAnalysis;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CSharp.EditAndContinue;
using Microsoft.CodeAnalysis.Debugging;
using Microsoft.CodeAnalysis.ErrorReporting;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.Text;

namespace Microsoft.CodeAnalysis.CSharp.Debugging;

[ExportLanguageService(typeof(IBreakpointResolutionService), LanguageNames.CSharp), Shared]
internal sealed class CSharpBreakpointResolutionService : IBreakpointResolutionService
{
    [ImportingConstructor]
    [SuppressMessage("RoslynDiagnosticsReliability", "RS0033:Importing constructor should be [Obsolete]", Justification = "Used in test code: https://github.com/dotnet/roslyn/issues/42814")]
    public CSharpBreakpointResolutionService()
    {
    }

    /// <summary>
    /// Returns null if a breakpoint can't be placed at the specified position.
    /// </summary>
    public async Task<BreakpointResolutionResult?> ResolveBreakpointAsync(Document document, TextSpan textSpan, CancellationToken cancellationToken)
    {
        try
        {
            var tree = await document.GetSyntaxTreeAsync(cancellationToken).ConfigureAwait(false);
            if (tree == null || !BreakpointSpans.TryGetBreakpointSpan(tree, textSpan.Start, cancellationToken, out var span))
            {
                return null;
            }

            if (span.Length == 0)
            {
                return BreakpointResolutionResult.CreateLineResult(document);
            }

            return BreakpointResolutionResult.CreateSpanResult(document, span);
        }
        catch (Exception e) when (FatalError.ReportAndCatchUnlessCanceled(e, cancellationToken))
        {
            return null;
        }
    }

    public Task<IEnumerable<BreakpointResolutionResult>> ResolveBreakpointsAsync(Solution solution, string name, CancellationToken cancellationToken)
        => new BreakpointResolver(solution, name).DoAsync(cancellationToken);
}