feat: make group member add/remove response code less confusing; add tests

PluralKit.Bot/Commands/Groups.cs

@@ -457,7 +457,7 @@ namespace PluralKit.Bot
             }
             else return; // otherwise toAction "may be undefined"
 
-            await ctx.Reply(MiscUtils.GroupAddRemoveResponse<MemberId>(members, toAction, op));
+            await ctx.Reply(GroupAddRemoveResponseService.GenerateResponse(op, members.Count, 1, members.Count - existingMembersInGroup.Count, existingMembersInGroup.Count));
         }
 
         public async Task ListGroupMembers(Context ctx, PKGroup target)

PluralKit.Bot/Commands/MemberGroup.cs

@@ -55,7 +55,7 @@ namespace PluralKit.Bot
             }
             else return; // otherwise toAction "may be unassigned"
 
-            await ctx.Reply(MiscUtils.GroupAddRemoveResponse<GroupId>(groups, toAction, op));
+            await ctx.Reply(GroupAddRemoveResponseService.GenerateResponse(op, 1, groups.Count, groups.Count - existingGroups.Count, existingGroups.Count));
         }
 
         public async Task List(Context ctx, PKMember target)

PluralKit.Bot/Services/GroupAddRemoveResponseService.cs

@@ -0,0 +1,109 @@
+using System;
+
+using PluralKit.Core;
+
+namespace PluralKit.Bot
+{
+    public static class GroupAddRemoveResponseService
+    {
+        public static string GenerateResponse(Groups.AddRemoveOperation action, int memberCount, int groupCount, int actionedOn, int notActionedOn)
+            => new Response(action, memberCount, groupCount, actionedOn, notActionedOn).ToString();
+
+        private class Response
+        {
+            private readonly Groups.AddRemoveOperation _op;
+            
+            private readonly string _actionStr;
+            private readonly string _containStr;
+            private readonly string _emojiStr;
+
+            private readonly bool _memberPlural;
+            private readonly bool _groupPlural;
+            
+            private readonly int _actionedOn;
+            private readonly int _notActionedOn;
+
+            public Response(Groups.AddRemoveOperation action, int memberCount, int groupCount, int actionedOn,
+                            int notActionedOn)
+            {
+                _op = action;
+                
+                _actionStr = action == Groups.AddRemoveOperation.Add ? "added to" : "removed from";
+                _containStr = action == Groups.AddRemoveOperation.Add ? "in" : "not in";
+                _emojiStr = actionedOn > 0 ? Emojis.Success : Emojis.Error;
+
+                _memberPlural = memberCount > 1;
+                _groupPlural = groupCount > 1;
+                
+                // sanity checking: we can't add multiple groups to multiple members (at least for now)
+                if (_memberPlural && _groupPlural)
+                    throw new ArgumentOutOfRangeException();
+               
+                // sanity checking: we can't act/not act on a different number of entities than we have
+                if (_memberPlural && (actionedOn + notActionedOn) != memberCount)
+                    throw new ArgumentOutOfRangeException();
+                if (_groupPlural && (actionedOn + notActionedOn) != groupCount)
+                    throw new ArgumentOutOfRangeException();
+
+                _actionedOn = actionedOn;
+                _notActionedOn = notActionedOn;
+            }
+            
+            // name generators
+            private string MemberString(bool capitalize = false)
+                => capitalize
+                    ? (_memberPlural ? "Members" : "Member")
+                    : (_memberPlural ? "members" : "member");
+
+            private string MemberString(int count, bool capitalize = false)
+                => capitalize
+                    ? (count == 1 ? "Member" : "Members")
+                    : (count == 1 ? "member" : "members");
+            
+            private string GroupString() => _groupPlural ? "groups" : "group";
+
+            private string GroupString(int count)
+                => count == 1 ? "group" : "groups";
+
+            // string generators
+            
+            private string ResponseString()
+            {
+                if (_actionedOn > 0 && _notActionedOn > 0 && _memberPlural)
+                    return $"{_actionedOn} {MemberString(_actionedOn)} {_actionStr} {GroupString()}";
+                if (_actionedOn > 0 && _notActionedOn > 0 && _groupPlural)
+                    return $"{MemberString(capitalize: true)} {_actionStr} {_actionedOn} {GroupString(_actionedOn)}";
+                if (_notActionedOn == 0)
+                    return $"{MemberString(capitalize: true)} {_actionStr} {GroupString()}";
+                if (_actionedOn == 0)
+                    return $"{MemberString(capitalize: true)} not {_actionStr} {GroupString()}";
+
+                throw new ArgumentOutOfRangeException();
+            }
+
+            private string InfoMessage()
+            {
+                if (_notActionedOn == 0) return $"";
+
+                var msg = "";
+                if (_actionedOn > 0 && _memberPlural)
+                    msg += $"{_notActionedOn} {MemberString(_notActionedOn)}";
+                else
+                    msg += $"{MemberString()}";
+
+                msg += $" already {_containStr}";
+
+                if (_actionedOn > 0 && _groupPlural)
+                    msg += $" {_notActionedOn} {GroupString(_notActionedOn)}";
+                else
+                    msg += $" {GroupString()}";
+
+                return $" ({msg})";
+            }
+            
+            public string ToString() => $"{_emojiStr} {ResponseString()}{InfoMessage()}.";
+            
+            // |
+        }
+    }
+}

PluralKit.Bot/Utils/MiscUtils.cs

@@ -20,37 +20,6 @@ namespace PluralKit.Bot
         public static string ProxyTagsString(this PKMember member, string separator = ", ") => 
             string.Join(separator, member.ProxyTags.Select(t => t.ProxyString.AsCode()));
         
-        
-        private static String entityTerm<T>(int count, bool isTarget)
-        {
-            var ret = "";
-            ret += isTarget ? "Member" : "Group";
-            if ((
-                (typeof(T) == typeof(GroupId) && !isTarget) ||
-                (typeof(T) == typeof(MemberId) && isTarget)
-            ) && count > 1)
-                ret += "s";
-            return ret;
-        }
-
-        public static String GroupAddRemoveResponse<T>(List<T> entityList, List<T> actionedOn, Groups.AddRemoveOperation op)
-        {
-            var opStr = op == Groups.AddRemoveOperation.Add ? "added to" : "removed from";
-            var inStr = op == Groups.AddRemoveOperation.Add ? "in" : "not in";
-            var notActionedOn = entityList.Count - actionedOn.Count;
-
-            var groupNotActionedPosStr = typeof(T) == typeof(GroupId) ? notActionedOn.ToString() + " " : "";
-            var memberNotActionedPosStr = typeof(T) == typeof(MemberId) ? notActionedOn.ToString() + " " : "";
-            
-            if (actionedOn.Count == 0)
-                return $"{Emojis.Error} {entityTerm<T>(notActionedOn, true)} not {opStr} {entityTerm<T>(entityList.Count, false).ToLower()} ({entityTerm<T>(notActionedOn, true).ToLower()} already {inStr} {entityTerm<T>(entityList.Count, false).ToLower()}).";
-            else
-                if (notActionedOn == 0)
-                    return $"{Emojis.Success} {entityTerm<T>(actionedOn.Count, true)} {opStr} {entityTerm<T>(actionedOn.Count, false).ToLower()}.";
-                else
-                    return $"{Emojis.Success} {actionedOn.Count} {entityTerm<T>(actionedOn.Count, true).ToLower()} {opStr} {entityTerm<T>(actionedOn.Count, false).ToLower()} ({memberNotActionedPosStr}{entityTerm<T>(actionedOn.Count, true).ToLower()} already {inStr} {groupNotActionedPosStr}{entityTerm<T>(notActionedOn, false).ToLower()}).";
-        }
-
         public static bool IsOurProblem(this Exception e)
         {
             // This function filters out sporadic errors out of our control from being reported to Sentry