refactor: Update study module structure.

Prepare `study` module for session and timer systems.
Move regular sync to the studybadge loop.

bot/modules/study/tracking/time_tracker.py

@@ -0,0 +1,109 @@
+import itertools
+import traceback
+import logging
+import asyncio
+from time import time
+
+from meta import client
+from core import Lion
+
+from ..module import module
+from .settings import untracked_channels, hourly_reward, hourly_live_bonus
+
+
+last_scan = {}  # guildid -> timestamp
+
+
+def _scan(guild):
+    """
+    Scan the tracked voice channels and add time and coins to each user.
+    """
+    # Current timestamp
+    now = time()
+
+    # Get last scan timestamp
+    try:
+        last = last_scan[guild.id]
+    except KeyError:
+        return
+    finally:
+        last_scan[guild.id] = now
+
+    # Calculate time since last scan
+    interval = now - last
+
+    # Discard if it has been more than 20 minutes (discord outage?)
+    if interval > 60 * 20:
+        return
+
+    untracked = untracked_channels.get(guild.id).data
+    guild_hourly_reward = hourly_reward.get(guild.id).data
+    guild_hourly_live_bonus = hourly_live_bonus.get(guild.id).data
+
+    channel_members = (
+        channel.members for channel in guild.voice_channels if channel.id not in untracked
+    )
+
+    members = itertools.chain(*channel_members)
+    # TODO filter out blacklisted users
+
+    blacklist = client.objects['blacklisted_users']
+    guild_blacklist = client.objects['ignored_members'][guild.id]
+
+    for member in members:
+        if member.bot:
+            continue
+        if member.id in blacklist or member.id in guild_blacklist:
+            continue
+        lion = Lion.fetch(guild.id, member.id)
+
+        # Add time
+        lion.addTime(interval, flush=False)
+
+        # Add coins
+        hour_reward = guild_hourly_reward
+        if member.voice.self_stream or member.voice.self_video:
+            hour_reward += guild_hourly_live_bonus
+
+        lion.addCoins(hour_reward * interval / (3600), flush=False)
+
+
+async def _study_tracker():
+    """
+    Scanner launch loop.
+    """
+    while True:
+        while not client.is_ready():
+            await asyncio.sleep(1)
+
+        await asyncio.sleep(5)
+
+        # Launch scanners on each guild
+        for guild in client.guilds:
+            # Short wait to pass control to other asyncio tasks if they need it
+            await asyncio.sleep(0)
+            try:
+                # Scan the guild
+                _scan(guild)
+            except Exception:
+                # Unknown exception. Catch it so the loop doesn't die.
+                client.log(
+                    "Error while scanning guild '{}'(gid:{})! "
+                    "Exception traceback follows.\n{}".format(
+                        guild.name,
+                        guild.id,
+                        traceback.format_exc()
+                    ),
+                    context="VOICE_ACTIVITY_SCANNER",
+                    level=logging.ERROR
+                )
+
+
+@module.launch_task
+async def launch_study_tracker(client):
+    # First pre-load the untracked channels
+    await untracked_channels.launch_task(client)
+    asyncio.create_task(_study_tracker())
+
+
+# TODO: Logout handler, sync