#!/usr/bin/env python3
"""
SMTP email service for outbound notifications (access requests, etc).

Reads credentials from env vars loaded by api_server.load_environment_config():
    SMTP_SERVER, SMTP_PORT, SMTP_USER, SMTP_PASSWORD, SENDER_EMAIL

Usage:
    from email_service import send_email
    ok, err = send_email(
        ['admin@example.com'],
        subject='Access request',
        body='Plain text body',
        html_body='<p>HTML body</p>',  # optional
    )
"""

import os
import smtplib
import ssl
from email.message import EmailMessage
from typing import Iterable, Optional, Tuple


def is_configured() -> bool:
    return all(os.environ.get(k) for k in ('SMTP_SERVER', 'SMTP_USER', 'SMTP_PASSWORD', 'SENDER_EMAIL'))


def send_email(
    to_addresses: Iterable[str],
    subject: str,
    body: str,
    html_body: Optional[str] = None,
    reply_to: Optional[str] = None,
) -> Tuple[bool, Optional[str]]:
    """Send an email via SMTP with STARTTLS. Returns (success, error_message)."""
    recipients = [a for a in (to_addresses or []) if a]
    if not recipients:
        return False, 'No recipients provided'

    if not is_configured():
        return False, 'SMTP is not configured (missing SMTP_SERVER / SMTP_USER / SMTP_PASSWORD / SENDER_EMAIL)'

    server = os.environ['SMTP_SERVER']
    port = int(os.environ.get('SMTP_PORT', '587'))
    user = os.environ['SMTP_USER']
    password = os.environ['SMTP_PASSWORD']
    sender = os.environ['SENDER_EMAIL']

    msg = EmailMessage()
    msg['Subject'] = subject
    msg['From'] = sender
    msg['To'] = ', '.join(recipients)
    if reply_to:
        msg['Reply-To'] = reply_to
    msg.set_content(body)
    if html_body:
        msg.add_alternative(html_body, subtype='html')

    try:
        context = ssl.create_default_context()
        with smtplib.SMTP(server, port, timeout=15) as smtp:
            smtp.ehlo()
            smtp.starttls(context=context)
            smtp.ehlo()
            smtp.login(user, password)
            smtp.send_message(msg)
        return True, None
    except Exception as e:
        print(f'[email_service] send_email failed: {e}')
        return False, str(e)