using System;
using System.Collections.Generic;
using System.Collections.Immutable;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using Microsoft.CodeAnalysis.CodeFixes;
using Microsoft.VisualStudio.Composition;
using Spectre.Console.Analyzer.FixProviders;

namespace Spectre.Console.Analyzer.Tests
{
    internal static class CodeFixProviderDiscovery
    {
        private static readonly Lazy<IExportProviderFactory> _exportProviderFactory;

        static CodeFixProviderDiscovery()
        {
            _exportProviderFactory = new Lazy<IExportProviderFactory>(
                () =>
                {
                    var discovery = new AttributedPartDiscovery(Resolver.DefaultInstance, isNonPublicSupported: true);
                    var parts = Task.Run(() => discovery.CreatePartsAsync(typeof(SystemConsoleToAnsiConsoleFix).Assembly)).GetAwaiter().GetResult();
                    var catalog = ComposableCatalog.Create(Resolver.DefaultInstance).AddParts(parts);

                    var configuration = CompositionConfiguration.Create(catalog);
                    var runtimeComposition = RuntimeComposition.CreateRuntimeComposition(configuration);
                    return runtimeComposition.CreateExportProviderFactory();
                },
                LazyThreadSafetyMode.ExecutionAndPublication);
        }

        public static IEnumerable<CodeFixProvider> GetCodeFixProviders(string language)
        {
            var exportProvider = _exportProviderFactory.Value.CreateExportProvider();
            var exports = exportProvider.GetExports<CodeFixProvider, LanguageMetadata>();
            return exports.Where(export => export.Metadata.Languages.Contains(language)).Select(export => export.Value);
        }

        private class LanguageMetadata
        {
            public LanguageMetadata(IDictionary<string, object> data)
            {
                if (!data.TryGetValue(nameof(ExportCodeFixProviderAttribute.Languages), out var languages))
                {
                    languages = Array.Empty<string>();
                }

                Languages = ((string[])languages).ToImmutableArray();
            }

            public ImmutableArray<string> Languages { get; }
        }
    }
}