// Copyright (c) Microsoft.  All Rights Reserved.  Licensed under the Apache License, Version 2.0.  See License.txt in the project root for license information.

using System;
using System.Collections.Concurrent;
using System.Composition;
using System.IO;
using Microsoft.CodeAnalysis.Host.Mef;

namespace Microsoft.CodeAnalysis.Host
{
    [ExportWorkspaceServiceFactory(typeof(IDocumentationProviderService), ServiceLayer.Default), Shared]
    internal sealed class DocumentationProviderServiceFactory : IWorkspaceServiceFactory
    {
        public IWorkspaceService CreateService(HostWorkspaceServices workspaceServices)
        {
            return new DocumentationProviderService();
        }

        internal sealed class DocumentationProviderService : IDocumentationProviderService
        {
            private readonly ConcurrentDictionary<string, DocumentationProvider> _assemblyPathToDocumentationProviderMap =
                new ConcurrentDictionary<string, DocumentationProvider>();

            public DocumentationProvider GetDocumentationProvider(string assemblyPath)
            {
                if (assemblyPath == null)
                {
                    throw new ArgumentNullException(nameof(assemblyPath));
                }

                assemblyPath = Path.ChangeExtension(assemblyPath, "xml");
                if (!_assemblyPathToDocumentationProviderMap.TryGetValue(assemblyPath, out var provider))
                {
                    provider = _assemblyPathToDocumentationProviderMap.GetOrAdd(assemblyPath, _path => XmlDocumentationProvider.CreateFromFile(_path));
                }

                return provider;
            }
        }
    }
}