"""instance-wide default quota for new users

The per-user ``users.quota_bytes`` stays authoritative for accounts that already
exist — changing the default must never resize anyone's mailbox retroactively.
This is only the value handed to the next user created.

Revision ID: 0017
Revises: 0016
Create Date: 2026-09-15
"""

from __future__ import annotations

from collections.abc import Sequence

from alembic import op

revision: str = "0017"
down_revision: str | None = "0016"
branch_labels: str | Sequence[str] | None = None
depends_on: str | Sequence[str] | None = None

# 5 GiB — the same figure users.quota_bytes has defaulted to since 0001.
_DEFAULT = 5 * 1024**3


def upgrade() -> None:
    op.execute(
        "ALTER TABLE app_settings ADD COLUMN default_quota_bytes bigint NOT NULL "
        f"DEFAULT {_DEFAULT}"
    )
    op.execute(
        "ALTER TABLE app_settings ADD CONSTRAINT ck_app_settings_quota_positive "
        "CHECK (default_quota_bytes > 0)"
    )


def downgrade() -> None:
    op.execute("ALTER TABLE app_settings DROP CONSTRAINT IF EXISTS ck_app_settings_quota_positive")
    op.execute("ALTER TABLE app_settings DROP COLUMN IF EXISTS default_quota_bytes")