Move Submission votes count logic into model, add improved verification system, add verification that the bot is always reacting to the message (on every reaction add/removal)

bot/cogs/contest.py

@@ -232,16 +232,20 @@ class ContestCog(commands.Cog):
         with self.bot.get_session() as session:
             guild: Guild = session.query(Guild).get(payload.guild_id)
             if payload.channel_id == guild.submission_channel:
-                if payload.emoji.id != constants.Emoji.UPVOTE:
                 channel: discord.TextChannel = self.bot.get_channel(payload.channel_id)
                 message: discord.PartialMessage = channel.get_partial_message(payload.message_id)
+                if payload.emoji.id != constants.Emoji.UPVOTE:
                     await message.remove_reaction(payload.emoji, payload.member)
                 else:
                     submission: Submission = session.query(Submission).get(payload.message_id)
                     if submission is None:
                         logger.warning(f'Upvote reaction added to message {payload.message_id}, but no Submission found in database.')
                     else:
-                        submission.votes += 1
+                        submission.increment()
+                        # Make sure our reaction exists, verify vote count
+                        self_reacted = await submission.verify(await message.fetch(), self.bot.user)
+                        if not self_reacted:
+                            await message.add_reaction(self.bot.get_emoji(constants.Emoji.UPVOTE))
 
     @commands.Cog.listener()
     async def on_raw_reaction_remove(self, payload: discord.RawReactionActionEvent) -> None:
@@ -262,16 +266,16 @@ class ContestCog(commands.Cog):
                 if submission is None:
                     logger.warning(f'Upvote reaction removed from message {payload.message_id}, but no Submission found in database.')
                 else:
-                    submission.votes -= 1
+                    submission.decrement()
 
                     # Get the actual number of votes from the message
                     channel: discord.TextChannel = self.bot.get_channel(payload.channel_id)
                     message: discord.Message = await channel.fetch_message(payload.message_id)
-                    reaction: discord.Reaction
-                    for reaction in filter(lambda _reaction: isinstance(_reaction.emoji, (discord.Emoji, discord.PartialEmoji))
-                                                             and _reaction.emoji.id == constants.Emoji.UPVOTE,
-                                           message.reactions):
-                        submission.set_votes(reaction.count)
+                    self_reacted = await submission.verify(await message.fetch(), self.bot.user)
+
+                    # Make sure our reaction exists
+                    if not self_reacted:
+                        await message.add_reaction(self.bot.get_emoji(constants.Emoji.UPVOTE))
 
     @commands.Cog.listener()
     async def on_raw_reaction_clear(self, payload: discord.RawReactionActionEvent) -> None:

bot/models.py

@@ -2,8 +2,9 @@ import datetime
 import enum
 import functools
 import logging
-from typing import List
+from typing import List, Optional, Union
 
+import discord
 from sqlalchemy import Boolean, Column, DateTime, Enum, ForeignKey, Integer, Text
 from sqlalchemy.ext.declarative import declarative_base
 from sqlalchemy.orm import relationship
@@ -80,11 +81,38 @@ class Submission(Base):
     period_id = Column(Integer, ForeignKey("period.id"))  # The id of the period this Submission relates to.
     period = relationship("Period", back_populates="submissions")  # The period this submission was made in.
 
-    def set_votes(self, n: int) -> None:
+    def increment(self) -> None:
+        """Increase the number of votes by one."""
+        self.votes += 1
+
+    def decrement(self) -> None:
+        """Decrease the number of votes by one."""
+        self.votes -= 1
+
+    async def verify(self, message: discord.Message, user: Optional[Union[discord.ClientUser, discord.User]] = None) -> bool:
         """Sets the number of votes for this Submission."""
-        if self.votes != n:
-            logger.warning(f'True vote count was off for Submission {self.id} by {n - self.votes}.')
-            self.votes = n
+        saw_user = False
+        for reaction in message.reactions:
+            # Check that it's a custom Emoji and that the Emoji is the expected Upvote emoji
+            if isinstance(reaction.emoji, (discord.Emoji, discord.PartialEmoji)):
+                if reaction.emoji.id == constants.Emoji.UPVOTE:
+                    # If a user was specified, look for him in the reactions
+                    if user is not None:
+                        reacting_user: Union[discord.Member, discord.User]
+                        async for reacting_user in reaction.users():
+                            # Check if the user who reacted to this emoji is the user we are looking for
+                            if reacting_user.id == user.id:
+                                saw_user = True
+                                break
+
+                    # Tally the number of votes
+                    votes = reaction.count - 1
+                    if votes != self.votes:
+                        # Make a racket if we counted wrong or somehow missed reactions
+                        logger.warning(f'True vote count was off for Submission {self.id} by {votes - self.votes}.')
+                        self.votes = votes
+
+        return saw_user
 
 
 class Period(Base):