Split up Context class into more extension methods

PluralKit.Bot/CommandSystem/ContextArgumentsExt.cs

@@ -0,0 +1,59 @@
+using System;
+using System.Linq;
+
+namespace PluralKit.Bot
+{
+    public static class ContextArgumentsExt
+    {
+        public static string PopArgument(this Context ctx) =>
+            ctx.Parameters.Pop();
+        
+        public static string PeekArgument(this Context ctx) => 
+            ctx.Parameters.Peek();
+
+        public static string RemainderOrNull(this Context ctx, bool skipFlags = true) =>
+            ctx.Parameters.Remainder(skipFlags).Length == 0 ? null : ctx.Parameters.Remainder(skipFlags);
+
+        public static bool HasNext(this Context ctx, bool skipFlags = true) =>
+            ctx.RemainderOrNull(skipFlags) != null;
+        
+        public static string FullCommand(this Context ctx) => 
+            ctx.Parameters.FullCommand;
+        
+        /// <summary>
+        /// Checks if the next parameter is equal to one of the given keywords. Case-insensitive.
+        /// </summary>
+        public static bool Match(this Context ctx, ref string used, params string[] potentialMatches)
+        {
+            var arg = ctx.PeekArgument();
+            foreach (var match in potentialMatches)
+            {
+                if (arg.Equals(match, StringComparison.InvariantCultureIgnoreCase))
+                {
+                    used = ctx.PopArgument();
+                    return true;
+                }
+            }
+
+            return false;
+        }
+
+        /// <summary>
+        /// Checks if the next parameter is equal to one of the given keywords. Case-insensitive.
+        /// </summary>
+        public static bool Match(this Context ctx, params string[] potentialMatches)
+        {
+            string used = null; // Unused and unreturned, we just yeet it
+            return ctx.Match(ref used, potentialMatches);
+        }
+
+        public static bool MatchFlag(this Context ctx, params string[] potentialMatches)
+        {
+            // Flags are *ALWAYS PARSED LOWERCASE*. This means we skip out on a "ToLower" call here.
+            // Can assume the caller array only contains lowercase *and* the set below only contains lowercase
+            
+            var flags = ctx.Parameters.Flags();
+            return potentialMatches.Any(potentialMatch => flags.Contains(potentialMatch));
+        }
+    }
+}