Initial split of the modules

NadekoBot.Core/_Extensions/StringExtensions.cs

@@ -0,0 +1,141 @@
+using System;
+using System.IO;
+using System.Linq;
+using System.Text;
+using System.Text.RegularExpressions;
+using System.Threading.Tasks;
+
+namespace NadekoBot.Extensions
+{
+    public static class StringExtensions
+    {
+        public static string StripHTML(this string input)
+        {
+            return Regex.Replace(input, "<.*?>", String.Empty);
+        }
+
+        /// <summary>
+        /// Easy use of fast, efficient case-insensitive Contains check with StringComparison Member Types 
+        /// CurrentCulture, CurrentCultureIgnoreCase, InvariantCulture, InvariantCultureIgnoreCase, Ordinal, OrdinalIgnoreCase
+        /// </summary>    
+        public static bool ContainsNoCase(this string str, string contains, StringComparison compare)
+        {
+            return str.IndexOf(contains, compare) >= 0;
+        }
+
+        public static string TrimTo(this string str, int maxLength, bool hideDots = false)
+        {
+            if (maxLength < 0)
+                throw new ArgumentOutOfRangeException(nameof(maxLength), $"Argument {nameof(maxLength)} can't be negative.");
+            if (maxLength == 0)
+                return string.Empty;
+            if (maxLength <= 3)
+                return string.Concat(str.Select(c => '.'));
+            if (str.Length < maxLength)
+                return str;
+            return string.Concat(str.Take(maxLength - 3)) + (hideDots ? "" : "...");
+        }
+
+        public static string ToTitleCase(this string str)
+        {
+            var tokens = str.Split(new[] { " " }, StringSplitOptions.RemoveEmptyEntries);
+            for (var i = 0; i < tokens.Length; i++)
+            {
+                var token = tokens[i];
+                tokens[i] = token.Substring(0, 1).ToUpper() + token.Substring(1);
+            }
+
+            return string.Join(" ", tokens);
+        }
+
+        /// <summary>
+        /// Removes trailing S or ES (if specified) on the given string if the num is 1
+        /// </summary>
+        /// <param name="str"></param>
+        /// <param name="num"></param>
+        /// <param name="es"></param>
+        /// <returns>String with the correct singular/plural form</returns>
+        public static string SnPl(this string str, int? num, bool es = false)
+        {
+            if (str == null)
+                throw new ArgumentNullException(nameof(str));
+            if (num == null)
+                throw new ArgumentNullException(nameof(num));
+            return num == 1 ? str.Remove(str.Length - 1, es ? 2 : 1) : str;
+        }
+
+        //http://www.dotnetperls.com/levenshtein
+        public static int LevenshteinDistance(this string s, string t)
+        {
+            var n = s.Length;
+            var m = t.Length;
+            var d = new int[n + 1, m + 1];
+
+            // Step 1
+            if (n == 0)
+            {
+                return m;
+            }
+
+            if (m == 0)
+            {
+                return n;
+            }
+
+            // Step 2
+            for (var i = 0; i <= n; d[i, 0] = i++)
+            {
+            }
+
+            for (var j = 0; j <= m; d[0, j] = j++)
+            {
+            }
+
+            // Step 3
+            for (var i = 1; i <= n; i++)
+            {
+                //Step 4
+                for (var j = 1; j <= m; j++)
+                {
+                    // Step 5
+                    var cost = (t[j - 1] == s[i - 1]) ? 0 : 1;
+
+                    // Step 6
+                    d[i, j] = Math.Min(
+                        Math.Min(d[i - 1, j] + 1, d[i, j - 1] + 1),
+                        d[i - 1, j - 1] + cost);
+                }
+            }
+            // Step 7
+            return d[n, m];
+        }
+
+        public static async Task<Stream> ToStream(this string str)
+        {
+            var ms = new MemoryStream();
+            var sw = new StreamWriter(ms);
+            await sw.WriteAsync(str);
+            await sw.FlushAsync();
+            ms.Position = 0;
+            return ms;
+        }
+
+        private static readonly Regex filterRegex = new Regex(@"(?:discord(?:\.gg|.me|app\.com\/invite)\/(?<id>([\w]{16}|(?:[\w]+-?){3})))", RegexOptions.Compiled | RegexOptions.IgnoreCase);
+        public static bool IsDiscordInvite(this string str)
+            => filterRegex.IsMatch(str);
+
+        public static string Unmention(this string str) => str.Replace("@", "ම");
+
+        public static string SanitizeMentions(this string str) =>
+            str.Replace("@everyone", "@everyοne").Replace("@here", "@һere");
+
+        public static string ToBase64(this string plainText)
+        {
+            var plainTextBytes = Encoding.UTF8.GetBytes(plainText);
+            return Convert.ToBase64String(plainTextBytes);
+        }
+
+        public static string GetInitials(this string txt, string glue = "") =>
+            string.Join(glue, txt.Split(' ').Select(x => x.FirstOrDefault()));
+    }
+}