// Copyright (c) .NET Foundation. 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.IO;
using System.Runtime.Versioning;
using NuGet.Frameworks;

namespace NuGet.Packaging
{
    public class PhysicalPackageFile : IPackageFile
    {
        private readonly Func<Stream>? _streamFactory;
        private string? _targetPath;
        private DateTimeOffset _lastWriteTime;

        public PhysicalPackageFile()
        {
        }

        public PhysicalPackageFile(MemoryStream stream)
        {
            _memoryStream = stream;
        }

        internal PhysicalPackageFile(Func<Stream> streamFactory)
        {
            _streamFactory = streamFactory;
        }

        private readonly MemoryStream? _memoryStream;

        /// <summary>
        /// Path on disk
        /// </summary>
        public string? SourcePath { get; set; }

        /// <summary>
        /// Path in package
        /// </summary>
        public required string TargetPath
        {
            get
            {
                return _targetPath!;
            }
            set
            {
                if (string.Compare(_targetPath, value, StringComparison.OrdinalIgnoreCase) != 0)
                {
                    _targetPath = value;
                    string effectivePath;
                    NuGetFramework = FrameworkNameUtility.ParseNuGetFrameworkFromFilePath(_targetPath!, out effectivePath);
                    if (NuGetFramework != null && NuGetFramework.Version.Major < 5)
                    {
                        TargetFramework = new FrameworkName(NuGetFramework.DotNetFrameworkName);
                    }
                    EffectivePath = effectivePath;
                }
            }
        }

        public string Path => TargetPath;

        public string? EffectivePath
        {
            get;
            private set;
        }

        public FrameworkName? TargetFramework { get; private set; }

        public NuGetFramework? NuGetFramework { get; private set; }

        public Stream GetStream()
        {
            if (_streamFactory != null)
            {
                _lastWriteTime = DateTimeOffset.UtcNow;
                return _streamFactory();
            }
            else if (SourcePath != null)
            {
                _lastWriteTime = File.GetLastWriteTimeUtc(SourcePath);
                return File.OpenRead(SourcePath);
            }
            else
            {
                _lastWriteTime = DateTimeOffset.UtcNow;
                return _memoryStream!;
            }
        }

        public DateTimeOffset LastWriteTime
        {
            get
            {
                return _lastWriteTime;
            }
        }

        public override string? ToString()
        {
            return TargetPath;
        }

        public override bool Equals(object? obj)
        {
            var file = obj as PhysicalPackageFile;

            return file != null && String.Equals(SourcePath, file.SourcePath, StringComparison.OrdinalIgnoreCase) &&
                                   String.Equals(TargetPath, file.TargetPath, StringComparison.OrdinalIgnoreCase);
        }

        public override int GetHashCode()
        {
            int hash = 0;
            if (SourcePath != null)
            {
#if NETFRAMEWORK || NETSTANDARD
                hash = SourcePath.GetHashCode();
#else
                hash = SourcePath.GetHashCode(StringComparison.Ordinal);
#endif
            }

            if (TargetPath != null)
            {
#if NETFRAMEWORK || NETSTANDARD
                hash = hash * 4567 + TargetPath.GetHashCode();
#else
                hash = hash * 4567 + TargetPath.GetHashCode(StringComparison.Ordinal);
#endif
            }

            return hash;
        }
    }
}