/*
 * DiskUtility.cs
 * 
 * Copyright © 2009
 * Diversified Technical Systems, Inc.
 * All Rights Reserved
 */

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Runtime.InteropServices;

namespace DTS.Common.Utilities
{
    /// <summary>
    /// A collection of handy disk-related methods.
    /// </summary>
    public class DiskUtility : Exceptional
    {
        /// <summary>
        /// substitutes doubles from a file into the list of doubles starting at 0 and going until either the list is out of numbers
        /// or the file is
        /// originally created for 29654 dp 4.0 476 3D IRTRACC DATA does not match expected data when injecting dc input per test steps
        /// </summary>
        /// <param name="list">list to substitute values into, this as a ref to make it obvious it will be modified</param>
        /// <param name="fileName">file to read values from</param>
        public static void ReplaceDataIfNeeded(ref List<double> list, string fileName)
        {
            if (!File.Exists(fileName)) { return; }
            var lines = File.ReadAllLines(fileName);

            for (var i = 0; i < list.Count && i < lines.Length; i++)
            {
                if (double.TryParse(lines[i], out var dTemp))
                {
                    list[i] = dTemp;
                }
            }
        }
        /// <summary>
        /// just a helper function to translates bytes to a more readable string
        /// </summary>
        /// <param name="bytes"></param>
        /// <returns></returns>
        public static string GetHumanReadableBytes(ulong bytes)
        {
            var bytesReadable = string.Format("{0} bytes", bytes);
            if (bytes > 1073741824)
            {
                bytesReadable = string.Format("{0:##.##} GB", bytes / 1073741824.0);
            }
            else if (bytes > 1048576)
            {
                bytesReadable = string.Format("{0:##.##} MB", bytes / 1048576.0);
            }
            else if (bytes > 1024)
            {
                bytesReadable = string.Format("{0:##.##} KB", (double)bytes / 1024);
            }
            return bytesReadable;
        }

        /// <summary>
        /// checks to see if a string contains illegal characters for file and/or path names
        /// </summary>
        /// <param name="nameToValidate"></param>
        /// <returns></returns>
        public static bool ValidateFileAndPathNameChars(string nameToValidate)
        {
            var bValid = true;
            var name = nameToValidate;
            if (name.Trim().Length < 1) { bValid = false; }
            foreach (var invalidChar in Path.GetInvalidFileNameChars())
                if (name.Contains(invalidChar)) { bValid = false; }
            foreach (var invalidChar in Path.GetInvalidPathChars())
                if (name.Contains(invalidChar)) { bValid = false; }
            if (name.Contains('.')) { bValid = false; }
            return bValid;
        }

        /// <summary>
        /// checks to see if a path contains a proper length. Full string is no greater than 260char and path is no greater than 248char
        /// </summary>
        /// <param name="nameToValidate"></param>
        /// <returns></returns>
        public static bool ValidateFileAndPathNameLength(string nameToValidate)
        {
            try
            {
                var fullPath = Path.GetFullPath(nameToValidate);
            }
            catch (PathTooLongException)
            {
                return false;
            }
            catch (Exception)
            {
                // All This function cares about is length. Ignore this exception. Dont need to log.
                return true;
            }
            return true;
        }

        /// 
        /// <summary>
        /// Get useful disk usage statistics.
        /// </summary>
        /// 
        /// <param name="directoryName">
        /// The <see cref="string"/> directory name to be queried for usage numbers.
        /// </param>
        /// 
        /// <param name="freeBytesAvailable">
        /// The <see cref="ulong"/> number of free bytes available on the specified volume.
        /// </param>
        /// 
        /// <param name="totalNumberOfBytes">
        /// The <see cref="ulong"/> total number of bytes available on the specified volume.
        /// </param>
        /// 
        /// <param name="totalNumberOfFreeBytes">
        /// The <see cref="ulong"/> total number of free bytes available on the specified volume. 
        /// </param>
        /// 
        /// <returns>
        /// <see cref="int"/> status code, determined by windows.
        /// </returns>
        /// 
        [DllImport("kernel32", CharSet = CharSet.Auto)]
        public static extern int GetDiskFreeSpaceEx(
        string directoryName,
        out ulong freeBytesAvailable,
        out ulong totalNumberOfBytes,
        out ulong totalNumberOfFreeBytes);
    }
}