"""invites.lang — the language this person asked us in

Revision ID: 0082_invite_lang
Revises: 0081_invite_invited_at
Create Date: 2026-09-05

The mails an access request produces — approved, denied, invited — go to an address that often has
no account yet, so there is no `preferences.language` to read. The signal does exist, though, and
only at the moment of the request: the language of the page the form was submitted from, or the
locale Google reported for a sign-in we refused. Recording it there is what lets the decision mail
answer in the requester's own language instead of an admin's guess about a stranger.

Captured rather than derived, for the third time in this epic: `preferences.language` (S6) and
`google_email` (S3) both taught that a signal which exists only in one moment cannot be backfilled
later. So no backfill here either — NULL means "we were never told", which is the honest state for
every historic row, and for every address an admin whitelists by hand. Those fall back to English
unless the admin picks otherwise on the invitation send.
"""

import sqlalchemy as sa
from alembic import op

revision: str = "0082_invite_lang"
down_revision: str | None = "0081_invite_invited_at"
branch_labels: str | None = None
depends_on: str | None = None


def upgrade() -> None:
    op.add_column("invites", sa.Column("lang", sa.String(length=8), nullable=True))


def downgrade() -> None:
    op.drop_column("invites", "lang")