Cleanup and simpler command handlers (#241)

* replace all duplicate Notice events with one universal event

* delete sync methods wrapper around async

* Typo

* remove unused Enum

* <inheritdoc/>

* rewrite: command workflow

* old/new command handlers

* merge dev and fix error

TwitchLib.Client.Models/CommandInfo.cs

@@ -0,0 +1,101 @@
+namespace TwitchLib.Client.Models;
+
+/// <summary>Object representing a command received via Twitch chat.</summary>
+public class CommandInfo
+{
+    /// <summary>Property representing the command identifier (ie command prefix).</summary>
+    public char Identifier { get; }
+
+    /// <summary>Property representing the actual command (without the command prefix).</summary>
+    public string Name { get; }
+
+    /// <summary>Property representing all arguments received in a string form.</summary>
+    public string ArgumentsAsString { get; }
+
+    /// <summary>Property representing all arguments received in a List form.</summary>
+    public List<string> ArgumentsAsList { get; }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="CommandInfo"/> class.
+    /// </summary>
+    public CommandInfo(char identifier, string name) : this(identifier, name, string.Empty, new())
+    { }
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="CommandInfo"/> class.
+    /// </summary>
+    public CommandInfo(char identifier, string name, string argumentsAsString, List<string> argumentsAsList)
+    {
+        Identifier = identifier;
+        Name = name;
+        ArgumentsAsString = argumentsAsString;
+        ArgumentsAsList = argumentsAsList;
+    }
+
+    public static bool TryParse(ReadOnlySpan<char> s, out CommandInfo result)
+    {
+        result = default;
+        s = s.Trim();
+        if (s.IsEmpty)
+            return false;
+        var commandIdentifier = s[0];
+        s = s.Slice(1);
+        if (s.IsEmpty || s[0] == ' ') // if string contains only the identifier or the first char after identifier is space, then it is invalid input
+            return false;
+        var indexOfSpace = s.IndexOf(' ');
+        if (indexOfSpace == -1)
+        {
+            var name = s.ToString();
+            result = new(commandIdentifier, name);
+        }
+        else
+        {
+            var name = s.Slice(0, indexOfSpace).ToString();
+            s = s.Slice(indexOfSpace + 1).TrimStart();
+            var argumentsAsString = s.ToString();
+            result = new(commandIdentifier, name, argumentsAsString, ParseArgumentsToList(s));
+        }
+        return true;
+
+        static List<string> ParseArgumentsToList(ReadOnlySpan<char> s)
+        {
+            int index;
+            var arguments = new List<string>();
+            while (!s.IsEmpty)
+            {
+                bool isQuote = s[0] == '"';
+                if (s[0] == '"')
+                {
+                    s = s.Slice(1);
+                    index = s.IndexOf('"');
+                }
+                else
+                {
+                    index = s.IndexOfAny('"', ' ');
+                }
+                if (index == -1)
+                {
+                    arguments.Add(s.ToString());
+                    s = default;
+                }
+                else
+                {
+                    arguments.Add(s.Slice(0, index).ToString());
+                    if (!isQuote && s[index] == '"') // s"txt"   we dont want remove quote after s
+                        index--;
+                    s = s.Slice(index + 1);
+                }
+                s = s.TrimStart();
+            }
+            return arguments;
+        }
+    }
+
+    /// <inheritdoc/>
+    public override string ToString()
+    {
+        return ArgumentsAsString.Length == 0
+            ? $"{Identifier}{Name}"
+            : $"{Identifier}{Name} {ArgumentsAsString}";
+    }
+}