From d98b9c961a66e6180c6474904f126ade5aa28796 Mon Sep 17 00:00:00 2001
From: Khionu Terabite <abstractkitty@iamtrue.net>
Date: Tue, 6 Sep 2016 16:50:30 -0400
Subject: [PATCH] Added case insensitivity option to CommandService.Search()

---
 src/Discord.Net.Commands/CommandService.cs    | 14 ++--
 .../Extensions/FindEntityExtensions.cs        | 69 +++++++++++++++++++
 2 files changed, 78 insertions(+), 5 deletions(-)
 create mode 100644 src/Discord.Net/Extensions/FindEntityExtensions.cs

diff --git a/src/Discord.Net.Commands/CommandService.cs b/src/Discord.Net.Commands/CommandService.cs
index 814277b04..03e2d2648 100644
--- a/src/Discord.Net.Commands/CommandService.cs
+++ b/src/Discord.Net.Commands/CommandService.cs
@@ -176,12 +176,16 @@ namespace Discord.Commands
                 return false;
         }
 
-        public SearchResult Search(IUserMessage message, int argPos) => Search(message, message.Content.Substring(argPos));
-        public SearchResult Search(IUserMessage message, string input)
+        public SearchResult Search(IUserMessage message, int argPos, bool caseInsensitive = true) => Search(message, message.Content.Substring(argPos), caseInsensitive);
+        public SearchResult Search(IUserMessage message, string input, bool caseInsensitive = true)
         {
-            string lowerInput = input.ToLowerInvariant();
-            var matches = _map.GetCommands(input).ToImmutableArray();
-            
+            ImmutableArray<Command> matches;
+
+            if (caseInsensitive)
+                matches = _map.GetCommands(input.ToLowerInvariant()).ToImmutableArray();
+            else
+                matches = _map.GetCommands(input).ToImmutableArray();
+
             if (matches.Length > 0)
                 return SearchResult.FromSuccess(input, matches);
             else
diff --git a/src/Discord.Net/Extensions/FindEntityExtensions.cs b/src/Discord.Net/Extensions/FindEntityExtensions.cs
new file mode 100644
index 000000000..9a2c276b3
--- /dev/null
+++ b/src/Discord.Net/Extensions/FindEntityExtensions.cs
@@ -0,0 +1,69 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+
+namespace Discord.Extensions
+{
+    public static class FindEntityExtensions
+    {
+        // Guilds
+
+        public static async Task<IEnumerable<IGuildUser>> FindUsersAsync(this IGuild guild, string name)
+            => (await guild.GetUsersAsync()).Where(x => distance(name, x.Username) < 5);
+
+        public static IEnumerable<IRole> FindRoles(this IGuild guild, string name)
+            => guild.Roles.Where(x => distance(name, x.Name) < 5);
+
+        public static async Task<IEnumerable<IGuildChannel>> FindChannels(this IGuild guild, string name)
+            => (await guild.GetChannelsAsync()).Where(x => distance(name, x.Name) < 5);
+
+        public static async Task<IEnumerable<ITextChannel>> FindTextChannels(this IGuild guild, string name)
+            => (await guild.GetChannelsAsync()).Select(x => x as ITextChannel)
+                .Where(x => x != null).Where(x => distance(name, x.Name) < 5);
+
+        public static async Task<IEnumerable<IVoiceChannel>> FindVoiceChannels(this IGuild guild, string name)
+            => (await guild.GetChannelsAsync()).Select(x => x as IVoiceChannel)
+                .Where(x => x != null).Where(x => distance(name, x.Name) < 5);
+
+        // Channels
+
+        public static async Task<IEnumerable<IUser>> FindUsersAsync(this IChannel channel, string name)
+            => (await channel.GetUsersAsync()).Where(x => distance(name, x.Username) < 5);
+
+        /// <summary>
+        /// Compute the distance between two strings.
+        /// Copied from DotNetPerls
+        /// </summary>
+        private static int distance(string s, string t)
+        {
+            int n = s.Length;
+            int m = t.Length;
+            int[,] d = new int[n + 1, m + 1];
+
+            if (n == 0)
+                return m;
+
+            if (m == 0)
+                return n;
+
+            for (int i = 0; i <= n; d[i, 0] = i++) { }
+
+            for (int j = 0; j <= m; d[0, j] = j++) { }
+
+            for (int i = 1; i <= n; i++)
+            {
+                for (int j = 1; j <= m; j++)
+                {
+                    int cost = (t[j - 1] == s[i - 1]) ? 0 : 1;
+
+                    d[i, j] = Math.Min(
+                        Math.Min(d[i - 1, j] + 1, d[i, j - 1] + 1),
+                        d[i - 1, j - 1] + cost);
+                }
+            }
+
+            return d[n, m];
+        }
+    }
+}