///////////////////////////////////////////////////////////////////////////
//  Copyright (C) Wizardry and Steamworks 2017 - License: GNU GPLv3      //
//  Please see: http://www.gnu.org/licenses/gpl.html for legal details,  //
//  rights of fair usage, the disclaimer and warranty conditions.        //
///////////////////////////////////////////////////////////////////////////

using System;
using System.Diagnostics;
using System.IO;

namespace wasSharpNET.IO.Utilities
{
    public static class IOExtensions
    {
        /// <summary>
        ///     Attempt to obtain a filestream by polling a file till the handle becomes available.
        /// </summary>
        /// <param name="path">the path to the file</param>
        /// <param name="mode">the file mode to use</param>
        /// <param name="access">the level of access to the file</param>
        /// <param name="share">the type of file share locking</param>
        /// <param name="timeout">the timeout in milliseconds to fail opening the file</param>
        /// <returns>a filestream if the file was opened successfully</returns>
        public static FileStream GetWriteStream(string path, FileMode mode, FileAccess access, FileShare share,
            int timeout)
        {
            var time = Stopwatch.StartNew();
            while (time.ElapsedMilliseconds < timeout)
                try
                {
                    return new FileStream(path, mode, access, share);
                }
                catch (IOException e)
                {
                    // access error
                    if (e.HResult != -2147024864)
                        throw;
                }

            throw new TimeoutException($"Failed to get a write handle to {path} within {timeout}ms.");
        }

        public static bool isRootedIn(this string path, string root)
        {
            // Path is empty and root is empty.
            if (string.IsNullOrEmpty(path) && string.IsNullOrEmpty(root))
                return true;

            // Path is empty but the root path is not empty.
            if (string.IsNullOrEmpty(path) && !string.IsNullOrEmpty(root))
                return true;

            // The supplied root path is empty.
            if (string.IsNullOrEmpty(root))
                return false;

            // The path is empty and the root is not.
            if (string.IsNullOrEmpty(path))
                return true;

            var p = new DirectoryInfo(path);
            var r = new DirectoryInfo(root);

            return string.Equals(p.Parent?.FullName, r.Parent?.FullName) || isRootedIn(p.Parent?.FullName, root);
        }

        public static void Empty(this string directory)
        {
            var dir = new DirectoryInfo(directory);

            foreach (var fi in dir.GetFiles())
                fi.Delete();

            foreach (var di in dir.GetDirectories())
            {
                Empty(di.FullName);
                di.Delete();
            }
        }
    }
}