"""platform/mailer — the outbound email port (SD-0001 §6.2).

A one-method port `send(to, subject, body)` with two adapters: `LogMailer` (dev/tests —
the message lands in the app log and an in-memory outbox tests read back, §6.8) and the
deployed `SmtpMailer` (SLICE-4). The adapter is chosen by configuration at startup
(INV-8), so no deployment shape lives in the domain. LogMailer logs the full body on
purpose: that is PUC-10's "local dev channel" — the one-time code reaches the developer in
the terminal. The deployed mailer (SLICE-4) will NOT log the body (INV-3 / §6.6 log hygiene).
"""
from __future__ import annotations

import logging
from dataclasses import dataclass
from typing import Protocol

logger = logging.getLogger("ecomm.mailer")


@dataclass(frozen=True)
class SentMessage:
    to: str
    subject: str
    body: str


class Mailer(Protocol):
    """The outbound-message port. Raises on delivery failure (INV-9 → §6.4 502)."""

    def send(self, to: str, subject: str, body: str) -> None: ...


class LogMailer:
    """Dev/test adapter: records to an in-memory outbox and logs the message (PUC-10)."""

    def __init__(self) -> None:
        self.outbox: list[SentMessage] = []

    def send(self, to: str, subject: str, body: str) -> None:
        self.outbox.append(SentMessage(to=to, subject=subject, body=body))
        # Full body incl. the code — the local dev channel. Dev/test only (never deployed).
        logger.info("LogMailer -> %s | %s\n%s", to, subject, body)


def build_mailer(kind: str) -> Mailer:
    """Select the mailer adapter by configured kind (config.mailer_kind(), INV-8)."""
    if kind == "log":
        return LogMailer()
    if kind == "smtp":
        raise NotImplementedError("SmtpMailer arrives in SLICE-4 (deployed environments)")
    raise ValueError(f"unknown mailer kind: {kind!r}")