complete submission tracking in database, old submission auto deletion

contest/cogs/contest.py

@@ -1,10 +1,17 @@
+import logging
+
 import discord
 from discord.ext import commands
 from discord.ext.commands import Context
 
-from contest import checks
+from contest import checks, constants
 from contest.bot import ContestBot
 
+logger = logging.getLogger(__file__)
+logger.setLevel(constants.LOGGING_LEVEL)
+
+expected_deletions = []
+
 
 class ContestCog(commands.Cog):
     def __init__(self, bot: ContestBot):
@@ -43,18 +50,33 @@ class ContestCog(commands.Cog):
         if message.author == self.bot.user or message.author.bot or not message.guild: return
         cur_submission = await self.bot.db.get_submission_channel(message.guild.id)
 
-        if message.channel.id == cur_submission:
+        channel: discord.TextChannel = message.channel
+        if channel.id == cur_submission:
             attachments = message.attachments
             if len(attachments) == 0:
                 await message.delete(delay=1)
-                warning = await message.channel.send(
+                warning = await channel.send(
                     f':no_entry_sign: {message.author.mention} Each submission must contain exactly one image.')
                 await warning.delete(delay=5)
             elif len(attachments) > 1:
                 await message.delete(delay=1)
-                warning = await message.channel.send(
+                warning = await channel.send(
                     f':no_entry_sign: {message.author.mention} Each submission must contain exactly one image.')
                 await warning.delete(delay=5)
+            else:
+                last_submission = await self.bot.db.get_submission(message.guild.id, message.author.id)
+
+                if last_submission is not None:
+                    # delete last submission
+                    submission_msg = await channel.fetch_message(last_submission)
+                    if submission_msg is None:
+                        logger.error(f'Unexpected: submission message {last_submission} could not be found.')
+                    else:
+                        await submission_msg.delete()
+                        logger.info(f'Old submission deleted. {last_submission} (Old) -> {message.id} (New)')
+
+                await self.bot.db.add_submission(message.id, channel.guild.id, message.author.id, message.created_at)
+                logger.info(f'New submission created ({message.id}).')
 
     @commands.Cog.listener()
     async def on_raw_reaction_add(self, payload: discord.RawReactionActionEvent) -> None:

contest/db.py

@@ -1,6 +1,8 @@
 import logging
 import os
 import sqlite3
+from datetime import datetime
+from typing import Optional
 
 import aiosqlite
 
@@ -43,6 +45,15 @@ class ContestDatabase(object):
                                             prefix TEXT DEFAULT '$',
                                             submission INTEGER NULLABLE)''')
                 logger.info(f"'guild' table created.")
+
+            await cur.execute('''SELECT name FROM sqlite_master WHERE type='table' AND name = ?;''', ['submission'])
+            if await cur.fetchone() is None:
+                await self.conn.execute('''CREATE TABLE IF NOT EXISTS submission
+                                            (id INTEGER PRIMARY KEY,
+                                            user INTEGER,
+                                            guild INTEGER,
+                                            timestamp DATETIME)''')
+                logger.info(f"'submission' table created.")
         finally:
             await cur.close()
 
@@ -93,3 +104,21 @@ class ContestDatabase(object):
         """Removes a guild from the database while completing appropriate teardown actions."""
         await self.conn.execute('''DELETE FROM guild WHERE id = ?''', [guild_id])
         await self.conn.commit()
+
+    async def get_submission(self, guild_id: int, user_id: int) -> Optional[int]:
+        cur = await self.conn.cursor()
+        try:
+            await cur.execute('''SELECT id FROM submission WHERE guild = ? AND user = ?''', [guild_id, user_id])
+            row = await cur.fetchone()
+            if row is None:
+                return None
+            return row[0]
+        finally:
+            await cur.close()
+
+    async def add_submission(self, submission_id: int, guild_id: int, user_id: int, timestamp: int = None) -> None:
+        await self.conn.execute(
+            '''INSERT INTO submission (id, user, guild, timestamp) VALUES (?, ?, ?, ?)''',
+            [submission_id, user_id, guild_id, timestamp or datetime.utcnow().timestamp()]
+        )
+        await self.conn.commit()