use sqlalchemy pattern

core/db/checkpoint.py

@@ -0,0 +1,43 @@
+"""Checkpoint queries."""
+
+from __future__ import annotations
+
+from uuid import UUID
+
+from sqlmodel import Session, select
+
+from .tables import Checkpoint
+
+
+def get_latest_checkpoint(session: Session, timeline_id: UUID, parent_id: UUID | None = None) -> Checkpoint | None:
+    stmt = select(Checkpoint).where(Checkpoint.timeline_id == timeline_id)
+    if parent_id is not None:
+        stmt = stmt.where(Checkpoint.parent_id == parent_id)
+    stmt = stmt.order_by(Checkpoint.created_at.desc())
+    return session.exec(stmt).first()
+
+
+def get_root_checkpoint(session: Session, timeline_id: UUID) -> Checkpoint | None:
+    stmt = select(Checkpoint).where(
+        Checkpoint.timeline_id == timeline_id,
+        Checkpoint.parent_id == None,
+    )
+    return session.exec(stmt).first()
+
+
+def list_checkpoints(session: Session, timeline_id: UUID) -> list[Checkpoint]:
+    stmt = (
+        select(Checkpoint)
+        .where(Checkpoint.timeline_id == timeline_id)
+        .order_by(Checkpoint.created_at)
+    )
+    return list(session.exec(stmt).all())
+
+
+def list_scenarios(session: Session) -> list[Checkpoint]:
+    stmt = (
+        select(Checkpoint)
+        .where(Checkpoint.is_scenario == True)
+        .order_by(Checkpoint.created_at.desc())
+    )
+    return list(session.exec(stmt).all())