"""send retries for 24 hours, and an account's sync health

A send the mail server could not take (SMTP unreachable, a temporary 4xx) is no
longer failed at once: the outbox row goes to ``retrying`` and is tried again
with growing gaps until ``retry_until`` (24 hours after the first failure).
``attempts`` counts the tries, ``next_attempt_at`` is when the next one runs.

An account whose server cannot be reached for a while carries ``sync_error``
(``unreachable``) and ``sync_error_since``; both clear on the next success.

Revision ID: 0021
Revises: 0020
Create Date: 2026-10-06
"""

from __future__ import annotations

from collections.abc import Sequence

from alembic import op

revision: str = "0021"
down_revision: str | None = "0020"
branch_labels: str | Sequence[str] | None = None
depends_on: str | Sequence[str] | None = None

_COLUMNS = (
    ("outbox", "attempts", "integer NOT NULL DEFAULT 0"),
    ("outbox", "next_attempt_at", "timestamptz"),
    ("outbox", "retry_until", "timestamptz"),
    ("accounts", "sync_error", "text"),
    ("accounts", "sync_error_since", "timestamptz"),
)


def upgrade() -> None:
    for table, name, ddl in _COLUMNS:
        op.execute(f"ALTER TABLE {table} ADD COLUMN {name} {ddl}")


def downgrade() -> None:
    for table, name, _ in reversed(_COLUMNS):
        op.execute(f"ALTER TABLE {table} DROP COLUMN IF EXISTS {name}")