"""Shared claim and completion rules for the two durable email queues."""

import uuid


def queue_table(table: str) -> str:
    if table not in {"email_recap_deliveries", "newsletter_deliveries"}:
        raise ValueError("Unknown email queue")
    return table


def claim(conn, table: str, now: float) -> dict | None:
    table = queue_table(table)
    conn.execute(f"""UPDATE {table} SET state='unknown', detail='Delivery interrupted after sending began; check the mail server.', updated_at=?
        WHERE state='sending' AND lease_until<?""", (now, now))
    conn.execute(f"""UPDATE {table} SET state=CASE WHEN attempts>=3 THEN 'failed' ELSE 'retry' END,
        next_attempt_at=?, updated_at=?, detail='Email preparation interrupted.'
        WHERE state='preparing' AND lease_until<?""", (now, now, now))
    row = conn.execute(f"""SELECT * FROM {table} WHERE state IN ('queued', 'retry') AND next_attempt_at<=?
        ORDER BY created_at, id LIMIT 1""", (now,)).fetchone()
    if not row:
        return None
    claim_id = uuid.uuid4().hex
    conn.execute(f"""UPDATE {table} SET state='preparing', claim=?, lease_until=?,
        attempts=attempts+1, updated_at=? WHERE id=?""", (claim_id, now + 1800, now, row["id"]))
    return dict(conn.execute(f"SELECT * FROM {table} WHERE id=?", (row["id"],)).fetchone())


def finish(conn, table: str, delivery: dict, state: str, detail: str, now: float, delay: int = 0):
    table = queue_table(table)
    conn.execute(f"""UPDATE {table} SET state=?, detail=?, updated_at=?, next_attempt_at=?, lease_until=NULL
        WHERE id=? AND claim=? AND state IN ('preparing', 'sending')""",
        (state, detail, now, now + delay, delivery["id"], delivery["claim"]))