from __future__ import annotations

from dataclasses import dataclass
from email.message import EmailMessage
import smtplib
import ssl


@dataclass
class MailServerSettings:
    smtp_host: str
    smtp_port: int
    smtp_username: str | None
    smtp_password: str | None
    from_email: str
    from_name: str
    use_starttls: bool
    use_ssl: bool
    verify_tls: bool
    timeout_seconds: int = 15


def _build_context(verify_tls: bool) -> ssl.SSLContext:
    context = ssl.create_default_context()
    if verify_tls:
        return context
    context.check_hostname = False
    context.verify_mode = ssl.CERT_NONE
    return context


def send_email(
    *,
    settings: MailServerSettings,
    to_email: str,
    subject: str,
    text_body: str,
) -> None:
    if not settings.smtp_host.strip():
        raise ValueError("SMTP host is empty")
    if not settings.from_email.strip():
        raise ValueError("From email is empty")

    msg = EmailMessage()
    msg["Subject"] = subject
    msg["From"] = f"{settings.from_name} <{settings.from_email}>"
    msg["To"] = to_email
    msg.set_content(text_body)

    ssl_context = _build_context(settings.verify_tls)
    if settings.use_ssl:
        with smtplib.SMTP_SSL(
            settings.smtp_host,
            settings.smtp_port,
            timeout=settings.timeout_seconds,
            context=ssl_context,
        ) as smtp:
            if settings.smtp_username:
                smtp.login(settings.smtp_username, settings.smtp_password or "")
            smtp.send_message(msg)
        return

    with smtplib.SMTP(settings.smtp_host, settings.smtp_port, timeout=settings.timeout_seconds) as smtp:
        smtp.ehlo()
        if settings.use_starttls:
            smtp.starttls(context=ssl_context)
            smtp.ehlo()
        if settings.smtp_username:
            smtp.login(settings.smtp_username, settings.smtp_password or "")
        smtp.send_message(msg)