using System;
using System.Runtime.InteropServices;

namespace Developpez.Dotnet.System
{
    /// <summary>
    /// Représente une opération de copie de fichier qui peut signaler
    /// sa progression.
    /// </summary>
    public class FileCopyOperation : FileOperationBase
    {
        /// <summary>
        /// Initialise une nouvelle instance de FileCopyOperation
        /// </summary>
        /// <param name="source">Fichier source</param>
        /// <param name="destination">Fichier destination</param>
        public FileCopyOperation(string source, string destination)
            : base(source, destination)
        {
        }

        /// <summary>
        /// Exécute la copie
        /// </summary>
        protected override void ExecuteCore()
        {
            bool cancel = false;
            var flags = default(CopyFileFlags);
            if (!ReplaceExisting)
                flags |= CopyFileFlags.FailIfExists;

            bool r = CopyFileEx(
                Source,
                Destination,
                ProgressCallback,
                IntPtr.Zero,
                ref cancel,
                flags);

            CheckError(r);
        }

        /// <summary>
        /// Renvoie FileOperationType.Copy
        /// </summary>
        public override FileOperationType OperationType
        {
            get { return FileOperationType.Copy; }
        }

        #region Interop declarations

        [DllImport("kernel32", SetLastError = true)]
        private static extern bool CopyFileEx(
            string lpExistingFileName,
            string lpNewFileName,
            CopyProgressRoutine lpProgressRoutine,
            IntPtr lpData,
            ref bool pbCancel,
            CopyFileFlags dwCopyFlags);

        [Flags]
        private enum CopyFileFlags
        {
            // ReSharper disable UnusedMember.Local
            FailIfExists = 0x0001,
            Restartable = 0x0002,
            OpenSourceForWrite = 0x0004,
            AllowDecryptedDestination = 0x0008,
            CopySymlink = 0x0800,
            NoBuffering = 0x1000
            // ReSharper restore UnusedMember.Local
        }

        #endregion
    }
}