"""Créneau : lien optionnel vers le créneau type (day_part)

Revision ID: 0004_shift_day_part
Revises: 0003_drop_assignment_status
Create Date: 2026-09-10

"""

from collections.abc import Sequence

import sqlalchemy as sa
from alembic import op

revision: str = "0004_shift_day_part"
down_revision: str | None = "0003_drop_assignment_status"
branch_labels: str | Sequence[str] | None = None
depends_on: str | Sequence[str] | None = None


_FK = "shift_day_part_id_fkey"


def upgrade() -> None:
    op.add_column("shift", sa.Column("day_part_id", sa.Uuid(), nullable=True))
    op.create_index("ix_shift_day_part_id", "shift", ["day_part_id"])
    op.create_foreign_key(
        _FK, "shift", "day_part", ["day_part_id"], ["id"], ondelete="SET NULL"
    )


def downgrade() -> None:
    op.drop_constraint(_FK, "shift", type_="foreignkey")
    op.drop_index("ix_shift_day_part_id", table_name="shift")
    op.drop_column("shift", "day_part_id")