implement chat/podcast staleness

surfsense_backend/alembic/versions/32_add_podcast_staleness_detection.py

@@ -0,0 +1,42 @@
+"""Add podcast staleness detection columns
+
+Revision ID: 32
+Revises: 31
+"""
+
+from collections.abc import Sequence
+
+import sqlalchemy as sa
+
+from alembic import op
+
+# revision identifiers
+revision: str = "32"
+down_revision: str | None = "31"
+branch_labels: str | Sequence[str] | None = None
+depends_on: str | Sequence[str] | None = None
+
+
+def upgrade() -> None:
+    """Add state_version to chats table and chat_state_version to podcasts table."""
+
+    # Add state_version column to chats table with default value of 1
+    op.add_column(
+        "chats",
+        sa.Column("state_version", sa.BigInteger(), nullable=False, server_default="1"),
+    )
+
+    # Add chat_state_version column to podcasts table (nullable, set when podcast is generated)
+    op.add_column(
+        "podcasts", sa.Column("chat_state_version", sa.BigInteger(), nullable=True)
+    )
+
+
+def downgrade() -> None:
+    """Remove state_version and chat_state_version columns."""
+
+    # Remove chat_state_version from podcasts table
+    op.drop_column("podcasts", "chat_state_version")
+
+    # Remove state_version from chats table
+    op.drop_column("chats", "state_version")