From 69571641f8424f930a3e0b262c9227dcb37f0926 Mon Sep 17 00:00:00 2001
From: hhvrc <github@heavenvr.tech>
Date: Thu, 12 Sep 2024 20:12:20 +0200
Subject: [PATCH] Simplify algorithms

---
 DiscordBot/MessageHandler/MessageHandler.cs | 71 +++++++++++----------
 1 file changed, 39 insertions(+), 32 deletions(-)

diff --git a/DiscordBot/MessageHandler/MessageHandler.cs b/DiscordBot/MessageHandler/MessageHandler.cs
index 24c19a3..2109b95 100644
--- a/DiscordBot/MessageHandler/MessageHandler.cs
+++ b/DiscordBot/MessageHandler/MessageHandler.cs
@@ -32,69 +32,76 @@ public sealed class MessageHandler
         { "ass",         0.2f },
     };
 
-    private readonly record struct WordRange(int Start, int Length);
-
     private static float CalculateWeight(float accumulated, float weight) => accumulated == 0 ? weight : MathF.Max(accumulated, weight) + 0.1f;
 
-    private static bool TryGetProfanityWeight(string str, out int count, out float weight)
+    private static void GetContainedWordsCountAndWeight(ReadOnlySpan<char> lowerCaseSpan, ref int count, ref float weight)
     {
-        count = 0;
-        weight = 0;
-
-        if (string.IsNullOrEmpty(str)) return false;
-
-        ReadOnlySpan<char> strSpan = str.AsSpan();
-
-        // Look trough string for all contained matches
         foreach (var item in _containedProfanities)
         {
-            ReadOnlySpan<char> badWord = item.Key.AsSpan();
-            float badWordWeight = item.Value;
-
-            int start = 0;
-            while (true) {
-                int index = strSpan[start..].IndexOf(badWord, StringComparison.OrdinalIgnoreCase);
+            while (true)
+            {
+                int index = lowerCaseSpan.IndexOf(item.Key, StringComparison.OrdinalIgnoreCase);
                 if (index < 0) break;
 
-                start += index + badWord.Length;
+                lowerCaseSpan = lowerCaseSpan[(index + item.Key.Length)..];
 
                 count++;
-                weight = CalculateWeight(weight, badWordWeight);
+                weight = CalculateWeight(weight, item.Value);
             }
         }
+    }
 
-        // Collect all word ranges
-        int rangeStart = 0;
+    private readonly record struct WordRange(int Start, int End);
+    private static List<WordRange> GetWordRanges(ReadOnlySpan<char> span)
+    {
         List<WordRange> wordRanges = [];
-        for (int i = 0; i < strSpan.Length; i++)
-        {
-            char c = strSpan[i];
 
-            if (c is not (' ' or '\t' or '\r' or '\n')) continue;
+        int rangeStart = 0;
+        for (int i = 0; i < span.Length; i++)
+        {
+            if (span[i] is not (' ' or '\t' or '\r' or '\n')) continue;
 
             if (rangeStart < i)
             {
-                wordRanges.Add(new WordRange(rangeStart, i - rangeStart));
+                wordRanges.Add(new WordRange(rangeStart, i));
             }
 
             rangeStart = i + 1;
         }
 
+        return wordRanges;
+    }
+
+    private static void GetStandaloneWordsCountAndWeight(ReadOnlySpan<char> lowerCaseSpan, ref int count, ref float weight)
+    {
+        List<WordRange> wordRanges = GetWordRanges(lowerCaseSpan);
+
         // Check if any of the words are standalone matches
         foreach (var item in _standaloneProfanities)
         {
-            ReadOnlySpan<char> badWord = item.Key.AsSpan();
-            float badWordWeight = item.Value;
-
             foreach (var wordRange in wordRanges)
             {
-                if (strSpan.Slice(wordRange.Start, wordRange.Length).Equals(badWord, StringComparison.OrdinalIgnoreCase))
+                if (lowerCaseSpan[wordRange.Start..wordRange.End].Equals(item.Key, StringComparison.OrdinalIgnoreCase))
                 {
                     count++;
-                    weight = CalculateWeight(weight, badWordWeight);
+                    weight = CalculateWeight(weight, item.Value);
                 }
             }
         }
+    }
+
+    private static bool TryGetProfanityWeight(string str, out int count, out float weight)
+    {
+        count = 0;
+        weight = 0;
+
+        if (string.IsNullOrEmpty(str)) return false;
+
+        str = str.ToLowerInvariant();
+        ReadOnlySpan<char> strSpan = str.AsSpan();
+
+        GetContainedWordsCountAndWeight(strSpan, ref count, ref weight);
+        GetStandaloneWordsCountAndWeight(strSpan, ref count, ref weight);
 
         // Roof the weight to 1.0
         weight = MathF.Min(weight, 1.0f);
@@ -113,7 +120,7 @@ public static async Task HandleMessageAsync(SocketMessage message)
         if (TryGetProfanityWeight(message.Content, out int count, out float weight))
         {
             // Respond to the message
-            await message.Channel.SendMessageAsync($"Profanity detected! {count} bad {(count > 1 ? "words" : "word")} with total weight: {weight}");
+            await message.Channel.SendMessageAsync($"Profanity detected! {count} bad {(count > 1 ? "words" : "word")}, shocking at {weight * 100f}%");
         }
     }
 }