"""Drop the unique constraint on ``asset_legal_entities.code``
introduced in migration 132.

Reason: in practice multiple Chinese legal entities (e.g. 北京星云
深图 / 平凯星辰 北京 / 北京平凯星辰) all share the same ``CN``
country slug from the asset-tag generation rule
``IT-{code}-{cat_no_p}-{YYYYMMDDHHMMSS}``. Forcing global uniqueness
would compel admins to invent fake-distinct codes per entity
(``CN1`` / ``CN2`` / ``CN3``) that leak into asset tags as
meaningless noise.

Tag uniqueness is preserved by the timestamp suffix + the
``asset_items.asset_tag`` UNIQUE column constraint at the asset
row level — the entity ``code`` only contributes its 2nd-segment
prefix and is not required to be unique.

Schema-only — no data backfill.
"""
from __future__ import annotations

from alembic import op

revision = "133"
down_revision = "132"
branch_labels = None
depends_on = None


def upgrade() -> None:
    op.drop_index(
        "uq_asset_legal_entities_code",
        table_name="asset_legal_entities",
    )


def downgrade() -> None:
    op.create_index(
        "uq_asset_legal_entities_code",
        "asset_legal_entities",
        ["code"],
        unique=True,
    )