"""labels.updated_at (M8 sync hub, step 4 — LWW field for the label catalog)

Revision ID: 0017
Revises: 0016
Create Date: 2026-07-23

Labels need a last-edit timestamp so sync push can resolve label rename/recolor
conflicts by last-write-wins (client edit-time vs this). Backfilled from created_at.
"""
from alembic import op
import sqlalchemy as sa

revision = "0017"
down_revision = "0016"
branch_labels = None
depends_on = None


def upgrade() -> None:
    op.add_column(
        "labels",
        sa.Column("updated_at", sa.DateTime(timezone=True), nullable=False, server_default=sa.func.now()),
    )
    # Seed existing rows' updated_at from their created_at (best available edit time).
    op.execute("UPDATE labels SET updated_at = created_at")


def downgrade() -> None:
    op.drop_column("labels", "updated_at")