"""default_language on site configs

Revision ID: 0004
Revises: 0003
Create Date: 2026-06-15

Allows site owners to set a default language for the banner,
overriding the browser's auto-detection. The banner script uses
this when loading translations.

The column is nullable — NULL means "auto-detect from browser".
"""

from collections.abc import Sequence

import sqlalchemy as sa

from alembic import op

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


def upgrade() -> None:
    op.add_column(
        "site_configs",
        sa.Column("default_language", sa.String(10), nullable=True),
    )


def downgrade() -> None:
    op.drop_column("site_configs", "default_language")