from django.conf import settings
from django.core.mail import EmailMessage, get_connection

from .branding import get_branded_from_email
from .models import SystemEmailConfig, WorkflowConfig


def _active_smtp_config() -> SystemEmailConfig | None:
    return SystemEmailConfig.objects.filter(is_active=True).order_by('-updated_at').first()


def _effective_smtp_settings() -> dict:
    cfg = _active_smtp_config()
    if not cfg or not cfg.host:
        workflow_cfg = WorkflowConfig.objects.order_by('id').first()
        if workflow_cfg and workflow_cfg.smtp_server:
            return {
                'host': workflow_cfg.smtp_server,
                'port': workflow_cfg.smtp_port or settings.EMAIL_PORT,
                'username': workflow_cfg.email_account or settings.EMAIL_HOST_USER,
                'password': workflow_cfg.email_password or settings.EMAIL_HOST_PASSWORD,
                'use_tls': workflow_cfg.smtp_use_tls,
                'use_ssl': workflow_cfg.smtp_use_ssl,
                'from_email': workflow_cfg.email_account or settings.DEFAULT_FROM_EMAIL,
            }

        return {
            'host': settings.EMAIL_HOST,
            'port': settings.EMAIL_PORT,
            'username': settings.EMAIL_HOST_USER,
            'password': settings.EMAIL_HOST_PASSWORD,
            'use_tls': settings.EMAIL_USE_TLS,
            'use_ssl': settings.EMAIL_USE_SSL,
            'from_email': settings.DEFAULT_FROM_EMAIL,
        }

    return {
        'host': cfg.host,
        'port': cfg.port,
        'username': cfg.username,
        'password': cfg.password,
        'use_tls': cfg.use_tls,
        'use_ssl': cfg.use_ssl,
        'from_email': cfg.from_email or settings.DEFAULT_FROM_EMAIL,
    }


def send_system_email(
    subject: str,
    body: str,
    to: list[str],
    attachments: list[str] | None = None,
    from_email: str | None = None,
) -> None:
    smtp = _effective_smtp_settings()
    connection = get_connection(
        backend='django.core.mail.backends.smtp.EmailBackend',
        host=smtp['host'],
        port=smtp['port'],
        username=smtp['username'],
        password=smtp['password'],
        use_tls=smtp['use_tls'],
        use_ssl=smtp['use_ssl'],
        timeout=settings.SMTP_TIMEOUT_SECONDS,
    )

    msg = EmailMessage(
        subject=subject,
        body=body,
        from_email=get_branded_from_email(from_email or smtp['from_email']) or (from_email or smtp['from_email']),
        to=to,
        connection=connection,
    )
    for path in attachments or []:
        msg.attach_file(path)
    msg.send(fail_silently=False)