"""push notifications about new mail (Web Push, RFC 8030/8291/8292)

``push_subscriptions`` holds one row per browser (or installed app) that asked
to be told about new mail: the push service URL it gave, and the two keys the
message is encrypted to. ``session_sid`` is the sign-in it was made under — once
that session is gone (signed out, revoked, expired) nothing is sent there any
more, so a signed-out device never shows a subject line again.

The server signs every push with its own key pair (VAPID). It is generated on
first use and kept in ``app_settings``; the private half is vault-encrypted
with MASTER_KEY like every other server secret.

Revision ID: 0022
Revises: 0021
Create Date: 2026-10-08
"""

from __future__ import annotations

from collections.abc import Sequence

from alembic import op

revision: str = "0022"
down_revision: str | None = "0021"
branch_labels: str | Sequence[str] | None = None
depends_on: str | Sequence[str] | None = None


def upgrade() -> None:
    op.execute(
        """
        CREATE TABLE push_subscriptions (
          id uuid PRIMARY KEY DEFAULT gen_random_uuid(),
          user_id uuid NOT NULL REFERENCES users(id) ON DELETE CASCADE,
          endpoint text NOT NULL UNIQUE,
          p256dh text NOT NULL,
          auth text NOT NULL,
          session_sid text NOT NULL,
          user_agent text NOT NULL DEFAULT '',
          created_at timestamptz NOT NULL DEFAULT now(),
          last_used_at timestamptz
        )
        """
    )
    op.execute("CREATE INDEX ix_push_subscriptions_user ON push_subscriptions (user_id)")
    op.execute("ALTER TABLE app_settings ADD COLUMN vapid_public text NOT NULL DEFAULT ''")
    op.execute("ALTER TABLE app_settings ADD COLUMN vapid_private_ct bytea")


def downgrade() -> None:
    op.execute("ALTER TABLE app_settings DROP COLUMN IF EXISTS vapid_private_ct")
    op.execute("ALTER TABLE app_settings DROP COLUMN IF EXISTS vapid_public")
    op.execute("DROP TABLE IF EXISTS push_subscriptions")