// 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.Generic;
using System.Collections.Immutable;
using System.Composition;
using System.IO;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.EmbeddedLanguages.StackFrame;
using Microsoft.CodeAnalysis.FindUsages;
using Microsoft.CodeAnalysis.Host.Mef;
using Microsoft.CodeAnalysis.Remote;
using Roslyn.Utilities;
 
namespace Microsoft.CodeAnalysis.StackTraceExplorer;
 
[ExportWorkspaceService(typeof(IStackTraceExplorerService)), Shared]
internal sealed class StackTraceExplorerService : IStackTraceExplorerService
{
    [ImportingConstructor]
    [System.Obsolete(MefConstruction.ImportingConstructorMessage, error: true)]
    public StackTraceExplorerService()
    {
    }
 
    public (Document? document, int line) GetDocumentAndLine(Solution solution, ParsedFrame frame)
    {
        if (frame is ParsedStackFrame parsedFrame)
        {
            var matches = GetFileMatches(solution, parsedFrame.Root, out var line);
            if (matches.IsEmpty)
            {
                return default;
            }
 
            return (matches[0], line);
        }
 
        return default;
    }
 
    public async Task<DefinitionItem?> TryFindDefinitionAsync(Solution solution, ParsedFrame frame, StackFrameSymbolPart symbolPart, CancellationToken cancellationToken)
    {
        if (frame is not ParsedStackFrame parsedFrame)
        {
            return null;
        }
 
        var client = await RemoteHostClient.TryGetClientAsync(solution.Services, cancellationToken).ConfigureAwait(false);
        if (client is not null)
        {
            var result = await client.TryInvokeAsync<IRemoteStackTraceExplorerService, SerializableDefinitionItem?>(
                solution,
                (service, solutionInfo, cancellationToken) => service.TryFindDefinitionAsync(solutionInfo, parsedFrame.ToString(), symbolPart, cancellationToken),
                cancellationToken).ConfigureAwait(false);
 
            if (!result.HasValue)
            {
                return null;
            }
 
            var serializedDefinition = result.Value;
            if (!serializedDefinition.HasValue)
            {
                return null;
            }
 
            return await serializedDefinition.Value.RehydrateAsync(solution, cancellationToken).ConfigureAwait(false);
        }
 
        return await StackTraceExplorerUtilities.GetDefinitionAsync(solution, parsedFrame.Root, symbolPart, cancellationToken).ConfigureAwait(false);
    }
 
    private static ImmutableArray<Document> GetFileMatches(Solution solution, StackFrameCompilationUnit root, out int lineNumber)
    {
        lineNumber = 0;
        if (root.FileInformationExpression is null)
        {
            return [];
        }
 
        var fileName = root.FileInformationExpression.Path.ToString();
        var lineString = root.FileInformationExpression.Line.ToString();
        RoslynDebug.AssertNotNull(lineString);
        lineNumber = int.Parse(lineString);
 
        var documentName = Path.GetFileName(fileName);
        var potentialMatches = new HashSet<Document>();
 
        foreach (var project in solution.Projects)
        {
            foreach (var document in project.Documents)
            {
                if (document.FilePath == fileName)
                {
                    return [document];
                }
 
                else if (document.Name == documentName)
                {
                    potentialMatches.Add(document);
                }
            }
        }
 
        return [.. potentialMatches];
    }
}