Added command map

src/Discord.Net.Commands/CommandMap.cs

@@ -0,0 +1,71 @@
+using System.Collections.Concurrent;
+using System.Collections.Generic;
+using System.Collections.Immutable;
+
+namespace Discord.Commands
+{
+    public class CommandMap
+    {
+        private readonly ConcurrentDictionary<string, List<Command>> _map;
+
+        public CommandMap()
+        {
+            _map = new ConcurrentDictionary<string, List<Command>>();
+        }
+
+        public void Add(string key, Command cmd)
+        {
+            var list = _map.GetOrAdd(key, _ => new List<Command>());
+            lock (list)
+                list.Add(cmd);
+        }
+        public void Remove(string key, Command cmd)
+        {
+            List<Command> list;
+            if (_map.TryGetValue(key, out list))
+            {
+                lock (list)
+                    list.Remove(cmd);
+            }
+        }
+        public IReadOnlyList<Command> Get(string key)
+        {
+            List<Command> list;
+            if (_map.TryGetValue(key, out list))
+            {
+                lock (list)
+                    return list.ToImmutableArray();
+            }
+            return ImmutableArray.Create<Command>();
+        }
+
+        //TODO: C#7 Candidate for tuple
+        public CommandSearchResults Search(string input)
+        {
+            string lowerInput = input.ToLowerInvariant();
+
+            List<Command> bestGroup = null, group;
+            int startPos = 0, endPos;
+
+            while (true)
+            {
+                endPos = input.IndexOf(' ', startPos);
+                string cmdText = endPos == -1 ? input.Substring(startPos) : input.Substring(startPos, endPos - startPos);
+                startPos = endPos + 1;
+                if (!_map.TryGetValue(cmdText, out group))
+                    break;
+                bestGroup = group;
+            }
+
+            ImmutableArray<Command> cmds;
+            if (bestGroup != null)
+            {
+                lock (bestGroup)
+                    cmds = bestGroup.ToImmutableArray();
+            }
+            else
+                cmds = ImmutableArray.Create<Command>();
+            return new CommandSearchResults(cmds, startPos);
+        }
+    }
+}

src/Discord.Net.Commands/CommandSearchResults.cs

@@ -0,0 +1,16 @@
+using System.Collections.Generic;
+
+namespace Discord.Commands
+{
+    public struct CommandSearchResults
+    {
+        IReadOnlyList<Command> Commands { get; }
+        int ArgsPos { get; }
+
+        public CommandSearchResults(IReadOnlyList<Command> commands, int argsPos)
+        {
+            Commands = commands;
+            ArgsPos = argsPos;
+        }
+    }
+}