// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
using System.IO;
using System.Text;
using Xunit;
using Xunit.Abstractions;
 
namespace Microsoft.VisualStudio.Razor.IntegrationTests;
 
public class MEFComponentTests(ITestOutputHelper testOutputHelper) : AbstractRazorEditorTest(testOutputHelper)
{
    [IdeFact]
    public static void EnsureCompositionCreation()
    {
        var hiveDirectory = VisualStudioLogging.GetHiveDirectory();
        var cmcPath = Path.Combine(hiveDirectory, "ComponentModelCache");
 
        Assert.True(Directory.Exists(cmcPath), "ComponentModelCache directory doesn't exist");
 
        var mefErrorFile = Path.Combine(cmcPath, "Microsoft.VisualStudio.Default.err");
 
        Assert.True(File.Exists(mefErrorFile), "Expected ComponentModelCache error file to exist");
 
        var errors = new StringBuilder();
 
        var section = new StringBuilder();
        foreach (var line in File.ReadLines(mefErrorFile))
        {
            // Individual errors are separated by a blank lines, or with an "Error #" header
            if (line.StartsWith("Error #") ||
                string.IsNullOrWhiteSpace(line))
            {
                var error = section.ToString();
                section.Clear();
 
                if (error.Contains("Razor") && !IsAllowedFailure(error))
                {
                    errors.AppendLine(error);
                }
            }
            else if (line.Equals("----------- Used assemblies -----------"))
            {
                // Finished processing errors
                break;
            }
            else
            {
                section.AppendLine(line);
            }
        }
 
        Assert.True(errors.Length == 0, $"Unexpected MEF failures: {Environment.NewLine}{errors}");
    }
 
    private static bool IsAllowedFailure(string error)
    {
        return error switch
        {
            // This isn't real, obviously, but stops build warnings about unused parameters
            "Example allowed error" => true,
            _ => false
        };
    }
}