From 65c17f11b22261663752f47d6369c8edd679e677 Mon Sep 17 00:00:00 2001
From: Conatum <cona@thewisewolf.dev>
Date: Fri, 30 Jun 2023 12:34:21 +0300
Subject: [PATCH] fix (schedule): Various bug fixes.

---
 src/modules/schedule/cog.py           |  3 ++-
 src/modules/schedule/core/timeslot.py | 29 ++++++++++++++-------------
 src/utils/data.py                     |  3 +++
 3 files changed, 20 insertions(+), 15 deletions(-)

diff --git a/src/modules/schedule/cog.py b/src/modules/schedule/cog.py
index 6cf93ae5..4883117a 100644
--- a/src/modules/schedule/cog.py
+++ b/src/modules/schedule/cog.py
@@ -489,7 +489,8 @@ class ScheduleCog(LionCog):
                         session = slot.sessions.get(guildid, None)
                         if session is None:
                             # Create a new session in the slot and set it up
-                            session = await slot.load_sessions(session_data[guildid, slotid])
+                            sessions = await slot.load_sessions([session_data[guildid, slotid]])
+                            session = sessions[guildid]
                             slot.sessions[guildid] = session
                             if slot.closing.is_set():
                                 # This should never happen
diff --git a/src/modules/schedule/core/timeslot.py b/src/modules/schedule/core/timeslot.py
index a16640d8..d7bee672 100644
--- a/src/modules/schedule/core/timeslot.py
+++ b/src/modules/schedule/core/timeslot.py
@@ -210,20 +210,21 @@ class TimeSlot:
             await batchrun_per_second(coros, 5)
 
             # Save messageids
-            tmptable = TemporaryTable(
-                '_gid', '_sid', '_mid',
-                types=('BIGINT', 'INTEGER', 'BIGINT')
-            )
-            tmptable.values = [
-                (sg.data.guildid, sg.data.slotid, sg.messageid)
-                for sg in sessions
-                if sg.messageid is not None
-            ]
-            await Data.ScheduleSession.table.update_where(
-                guildid=tmptable['_gid'], slotid=tmptable['_sid']
-            ).set(
-                messageid=tmptable['_mid']
-            ).from_expr(tmptable)
+            if sessions:
+                tmptable = TemporaryTable(
+                    '_gid', '_sid', '_mid',
+                    types=('BIGINT', 'INTEGER', 'BIGINT')
+                )
+                tmptable.values = [
+                    (sg.data.guildid, sg.data.slotid, sg.messageid)
+                    for sg in sessions
+                    if sg.messageid is not None
+                ]
+                await Data.ScheduleSession.table.update_where(
+                    guildid=tmptable['_gid'], slotid=tmptable['_sid']
+                ).set(
+                    messageid=tmptable['_mid']
+                ).from_expr(tmptable)
         except Exception:
             logger.exception(
                 f"Unhandled exception while preparing timeslot <slotid: {self.slotid}>."
diff --git a/src/utils/data.py b/src/utils/data.py
index 2a8795b0..6be3680b 100644
--- a/src/utils/data.py
+++ b/src/utils/data.py
@@ -123,6 +123,9 @@ class TemporaryTable(Expression):
         AS
         name (col1, col2)
         """
+        if not self.values:
+            raise ValueError("Cannot flatten CTE with no values.")
+
         single_value = sql.SQL("({})").format(sql.SQL(", ").join(sql.Placeholder() for _ in self.columns))
         if self.types:
             first_value = sql.SQL("({})").format(