"""邮件发送服务 - SMTP email sending for alarm notifications and report delivery."""
import logging
import smtplib
import ssl
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from email.mime.base import MIMEBase
from email import encoders
from pathlib import Path
from typing import Optional

from app.core.config import get_settings

logger = logging.getLogger("email_service")


async def send_email(
    to: list[str],
    subject: str,
    body_html: str,
    attachments: Optional[list[str]] = None,
) -> bool:
    """
    Send an email via SMTP.

    Args:
        to: List of recipient email addresses.
        subject: Email subject line.
        body_html: HTML body content.
        attachments: Optional list of file paths to attach.

    Returns:
        True if sent successfully, False otherwise.
    """
    settings = get_settings()

    if not settings.SMTP_ENABLED:
        logger.warning("SMTP is not enabled (SMTP_ENABLED=False). Skipping email send.")
        return False

    if not settings.SMTP_HOST:
        logger.warning("SMTP_HOST is not configured. Skipping email send.")
        return False

    if not to:
        logger.warning("No recipients specified. Skipping email send.")
        return False

    try:
        msg = MIMEMultipart("mixed")
        msg["From"] = settings.SMTP_FROM
        msg["To"] = ", ".join(to)
        msg["Subject"] = subject

        # HTML body
        html_part = MIMEText(body_html, "html", "utf-8")
        msg.attach(html_part)

        # Attachments
        if attachments:
            for filepath in attachments:
                path = Path(filepath)
                if not path.exists():
                    logger.warning(f"Attachment not found, skipping: {filepath}")
                    continue

                with open(path, "rb") as f:
                    part = MIMEBase("application", "octet-stream")
                    part.set_payload(f.read())
                encoders.encode_base64(part)
                part.add_header(
                    "Content-Disposition",
                    f'attachment; filename="{path.name}"',
                )
                msg.attach(part)

        # Send via SMTP
        context = ssl.create_default_context()

        if settings.SMTP_PORT == 465:
            # SSL connection
            with smtplib.SMTP_SSL(settings.SMTP_HOST, settings.SMTP_PORT, context=context) as server:
                if settings.SMTP_USER and settings.SMTP_PASSWORD:
                    server.login(settings.SMTP_USER, settings.SMTP_PASSWORD)
                server.sendmail(settings.SMTP_FROM, to, msg.as_string())
        else:
            # STARTTLS connection (port 587 or 25)
            with smtplib.SMTP(settings.SMTP_HOST, settings.SMTP_PORT) as server:
                server.ehlo()
                if settings.SMTP_PORT == 587:
                    server.starttls(context=context)
                    server.ehlo()
                if settings.SMTP_USER and settings.SMTP_PASSWORD:
                    server.login(settings.SMTP_USER, settings.SMTP_PASSWORD)
                server.sendmail(settings.SMTP_FROM, to, msg.as_string())

        logger.info(f"Email sent successfully to {to}, subject: {subject}")
        return True

    except smtplib.SMTPException as e:
        logger.error(f"SMTP error sending email to {to}: {e}")
        return False
    except Exception as e:
        logger.error(f"Unexpected error sending email to {to}: {e}")
        return False