"""Shared SMTP send helper for worker services.

Worker services historically called ``smtplib.SMTP("localhost", 25)`` directly,
which fails inside the workers container (no MTA on localhost:25) -- so every
authorization / signing-link / delivery email silently failed with
``[Errno 111] Connection refused`` and customers never received them. This routes
all worker email through the same authenticated SMTP relay the rest of the system
uses (Carbonio at co.carrierone.com:587 by default), configured via the standard
SMTP_* env vars.

Usage:
    from scripts.workers.worker_email import send_worker_email
    ok = send_worker_email(to, subject, html, attachments=[(filename, bytes, mime)])
"""
from __future__ import annotations

import logging
import os
import smtplib
import sys
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.application import MIMEApplication

# Shared HTML -> plaintext converter (scripts/_email_plaintext.py). Adding a
# text/plain part to every message is a deliverability win: a multipart/
# alternative with ONLY an HTML part is malformed, and HTML-only mail is a
# spam-score signal. Import is path-tolerant (module run from /app or scripts/).
try:
    from scripts._email_plaintext import html_to_text
except ImportError:  # pragma: no cover - fallback when scripts/ is on sys.path
    sys.path.insert(0, os.path.dirname(os.path.dirname(os.path.abspath(__file__))))
    from _email_plaintext import html_to_text  # type: ignore

LOG = logging.getLogger("workers.email")

SMTP_HOST = os.getenv("SMTP_HOST", "co.carrierone.com")
SMTP_PORT = int(os.getenv("SMTP_PORT", "587"))
SMTP_USER = os.getenv("SMTP_USER", "noreply@performancewest.net")
SMTP_PASS = os.getenv("SMTP_PASS", "")
SMTP_FROM = os.getenv("SMTP_FROM", "Performance West <noreply@performancewest.net>")


def send_worker_email(
    to: str,
    subject: str,
    html: str,
    *,
    text: str | None = None,
    attachments: list[tuple[str, bytes, str]] | None = None,
    cc: str | None = None,
) -> bool:
    """Send an email via the configured SMTP relay. Returns True on success.

    attachments: list of (filename, content_bytes, subtype) e.g. ("x.pdf", b"...", "pdf").
    Never raises -- logs and returns False so callers stay non-fatal.
    """
    try:
        msg = MIMEMultipart("mixed")
        msg["From"] = SMTP_FROM
        msg["To"] = to
        if cc:
            msg["Cc"] = cc
        msg["Subject"] = subject

        alt = MIMEMultipart("alternative")
        # Always include a text/plain part. If the caller did not supply one,
        # derive it from the HTML so the message is a well-formed multipart/
        # alternative (HTML-only is malformed + a spam signal). RFC 2046: list
        # the plain part first (least->most preferred).
        plain = text if text else html_to_text(html)
        if plain:
            alt.attach(MIMEText(plain, "plain"))
        alt.attach(MIMEText(html, "html"))
        msg.attach(alt)

        for fname, content, subtype in (attachments or []):
            part = MIMEApplication(content, _subtype=subtype)
            part.add_header("Content-Disposition", "attachment", filename=fname)
            msg.attach(part)

        recipients = [to] + ([cc] if cc else [])
        with smtplib.SMTP(SMTP_HOST, SMTP_PORT, timeout=30) as s:
            s.starttls()
            if SMTP_USER and SMTP_PASS:
                s.login(SMTP_USER, SMTP_PASS)
            s.sendmail(SMTP_FROM, recipients, msg.as_string())
        LOG.info("Worker email sent to %s (subject=%r)", to, subject[:60])
        return True
    except Exception as exc:  # noqa: BLE001
        LOG.warning("Worker email send failed to %s: %s", to, exc)
        return False