// 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.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Reflection;
using System.Reflection.Metadata;
using System.Reflection.PortableExecutable;

namespace Microsoft.DotNet.SharedFramework.Sdk
{
    internal static partial class FileUtilities
    {
        private static readonly HashSet<string> s_assemblyExtensions = new HashSet<string>(
            new[] { ".dll", ".exe" },
            StringComparer.OrdinalIgnoreCase);

        public static Version GetFileVersion(string sourcePath)
        {
            var fvi = FileVersionInfo.GetVersionInfo(sourcePath);

            if (fvi != null)
            {
                return new Version(fvi.FileMajorPart, fvi.FileMinorPart, fvi.FileBuildPart, fvi.FilePrivatePart);
            }

            return null;
        }

        public static AssemblyName GetAssemblyName(string path)
        {
            if (!s_assemblyExtensions.Contains(Path.GetExtension(path)))
            {
                return null;
            }

            try
            {
                using (var stream = File.OpenRead(path))
                using (var peReader = new PEReader(stream))
                {
                    if (peReader.HasMetadata)
                    {
                        return peReader.GetMetadataReader().GetAssemblyDefinition().GetAssemblyName();
                    }
                }
            }
            catch (BadImageFormatException)
            {
                // Not a valid assembly.
                return null;
            }
            return null;
        }
    }

    internal struct AssemblyInformation
    {
        public string SimpleName { get; set; }

        public Version Version { get; set; }

        public string PublicKeyToken { get; set; }
    }
}