using System;
using System.IO;

namespace ZXLT.FileSystem
{
    public sealed class FileInfo : FileSystemInfo
    {
        public string Extension => Path.GetExtension(this.FullName);
        public override bool Exists { get; }
        public override string Name => _name;
        public override FileSystemInfoType FileSystemInfoType { get; }
        public string? DirectoryName => Path.GetDirectoryName(this.FullPath);

        public DirectoryInfo Directory
        {
            get
            {
                string directoryName = this.DirectoryName;
                return new DirectoryInfo(directoryName);
            }
        }

        public FileInfo(string fileName)
        {
            fileName = fileName ?? throw new ArgumentNullException(nameof(fileName));
            _name = Path.GetFileName(fileName);
            this.FullPath = Path.GetFullPath(fileName);
            FileSystemInfoType = FileSystemInfoType.File;
        }
    }
}