refactor add_keyword to better account for duplicates

nomen/notifications.py

@@ -126,32 +126,56 @@ class Notifications(Cog):
         """
         await ctx.send_help(self.keyword)
 
-    async def _add_keyword(self, ctx, keyword, regex):
+    async def _add_keyword(self, ctx, keyword: str, regex: bool):
         log.debug(
             f"Adding {'regex' if regex else 'keyword'}: {keyword} of {ctx.author} ({ctx.author.id}) on {ctx.guild} ({ctx.guild.id})"
         )
 
+        params = {
+            "keyword": keyword,
+            "guild_id": ctx.guild.id,
+            "user_id": ctx.author.id,
+            "regex": regex,
+        }
+
+        existing = """
+        SELECT keyword FROM keywords
+        WHERE guild_id=:guild_id
+        AND user_id=:user_id
+        AND contains(:keyword, keyword, regex)
+        """
+        redundant = """
+        SELECT keyword FROM keywords
+        WHERE guild_id=:guild_id
+        AND user_id=:user_id
+        AND contains(keyword, :keyword, :regex)
+        """
+
         if test_keyword(keyword, regex):
             await ctx.send(f"{'Regex' if regex else 'Keyword'} matches a word that is too common")
             return
 
-        cur = await ctx.bot.db.execute(
+        conflicts = await fetch_unpacked(ctx.bot.db, existing, params)
-            "SELECT keyword FROM keywords WHERE guild_id=? AND user_id=? AND contains(?, keyword, regex)",
-            (ctx.guild.id, ctx.author.id, keyword),
-        )
-
-        conflicts = unpack(await cur.fetchall())
 
         if conflicts:
-            await ctx.send(f"Any instance of keyword `{keyword}` would be matched by existing keywords (check DMs)")
+            await ctx.send(f"Any instance of `{keyword}` would be matched by existing keywords (check DMs)")
             await ctx.author.send(
                 f"Conflicts with keyword `{keyword}`:\n" + "\n".join(f"- `{conflict}`" for conflict in conflicts)
             )
             return
 
+        conflicts = await fetch_unpacked(ctx.bot.db, redundant, params)
+
+        if conflicts:
+            await ctx.send(f"Adding `{keyword}` will cause existing keywords to never match (check DMs)")
+            await ctx.author.send(
+                f"Keywords redundant from `{keyword}`:\n" + "\n".join(f" - `{conflict}`" for conflict in conflicts)
+            )
+            return
+
         await ctx.bot.db.execute(
-            "INSERT INTO keywords (guild_id, keyword, user_id, regex) VALUES (?, ?, ?, ?)",
+            "INSERT INTO keywords (guild_id, keyword, user_id, regex) VALUES (:guild_id, :keyword, :user_id, :regex)",
-            (ctx.guild.id, keyword, ctx.author.id, regex),
+            params,
         )
         await ctx.bot.db.commit()
         await ctx.send(f"Added `{keyword}` to your list of keywords")

nomen/utils.py

@@ -107,6 +107,13 @@ def unpack(lst_of_tpl):
     return list(map(first, lst_of_tpl))
 
 
+async def fetch_unpacked(db, sql, params=None):
+    cur = db.cursor()
+    cur.row_factory = first
+    cur = await cur.execute(sql, params)
+    return await cur.fetchall()
+
+
 async def in_thread(member, thread):
     # FIXME: Currently overlooks the situation where a moderator isn't in a thread but has manage threads
     return any(member.id == thread_member.id for thread_member in await thread.fetch_members())