import logging
from abc import ABC, abstractmethod
from email.message import EmailMessage

import aiosmtplib

from app.core.config import settings

logger = logging.getLogger(__name__)


class EmailSender(ABC):
    @abstractmethod
    async def send(self, to: str, subject: str, html_body: str) -> None: ...


class LoggingEmailSender(EmailSender):
    """Dev/test fallback: logs instead of sending. Wire a real provider
    (SES, Postmark, SMTP) behind this interface before going to prod."""

    async def send(self, to: str, subject: str, html_body: str) -> None:
        logger.info(f"[EMAIL to={to}] {subject}\n{html_body}")


class SmtpEmailSender(EmailSender):
    """Sends via SMTP. Works with any provider that exposes SMTP
    credentials (SES, Postmark, Sendgrid, a plain mailbox, etc)."""

    async def send(self, to: str, subject: str, html_body: str) -> None:
        message = EmailMessage()
        message["From"] = f"{settings.EMAIL_FROM_NAME} <{settings.EMAIL_FROM_ADDRESS}>"
        message["To"] = to
        message["Subject"] = subject
        message.set_content("Ce message nécessite un client compatible HTML.")
        message.add_alternative(html_body, subtype="html")

        try:
            await aiosmtplib.send(
                message,
                hostname=settings.SMTP_HOST,
                port=settings.SMTP_PORT,
                username=settings.SMTP_USERNAME or None,
                password=settings.SMTP_PASSWORD or None,
                start_tls=settings.SMTP_USE_TLS,
                timeout=10,
            )
        except (aiosmtplib.SMTPException, OSError) as exc:
            # Don't let a transient SMTP outage 500 the caller's whole
            # request (e.g. invite-member already committed the DB write) --
            # log loudly so it's visible in monitoring, and let the caller
            # decide whether to surface a degraded-but-successful response.
            logger.error("Failed to send email to %s: %s", to, exc)
            raise EmailDeliveryError(str(exc)) from exc


class EmailDeliveryError(Exception):
    pass


def get_email_sender() -> EmailSender:
    if settings.ENVIRONMENT == "PYTEST" or not settings.SMTP_HOST:
        return LoggingEmailSender()
    return SmtpEmailSender()