import smtplib
from email.message import EmailMessage

from sqlalchemy.orm import Session

from app.core.config import get_settings
from app.core.security import decrypt_secret, encrypt_secret
from app.models.entities import MailSetting
from app.schemas.common import MailSettingsIn, MailSettingsOut


def get_mail_settings(db: Session) -> MailSetting:
    settings = db.get(MailSetting, 1)
    if not settings:
        settings = MailSetting(id=1)
        db.add(settings)
        db.flush()
    return settings


def serialize_mail_settings(settings: MailSetting) -> MailSettingsOut:
    return MailSettingsOut(
        smtp_host=settings.smtp_host,
        smtp_port=settings.smtp_port,
        smtp_user=settings.smtp_user,
        has_password=bool(settings.smtp_password_encrypted),
        use_tls=settings.use_tls,
        use_starttls=settings.use_starttls,
        sender_address=settings.sender_address,
        sender_name=settings.sender_name,
    )


def update_mail_settings(db: Session, payload: MailSettingsIn) -> MailSetting:
    settings = get_mail_settings(db)
    settings.smtp_host = payload.smtp_host
    settings.smtp_port = payload.smtp_port
    settings.smtp_user = payload.smtp_user
    if payload.smtp_password is not None:
        settings.smtp_password_encrypted = encrypt_secret(payload.smtp_password)
    settings.use_tls = payload.use_tls
    settings.use_starttls = payload.use_starttls
    settings.sender_address = str(payload.sender_address) if payload.sender_address else None
    settings.sender_name = payload.sender_name
    return settings


def send_mail(db: Session, to: str, subject: str, body: str) -> None:
    settings = get_mail_settings(db)
    if not settings.smtp_host or not settings.sender_address:
        raise RuntimeError("SMTP is not configured")
    message = EmailMessage()
    message["From"] = f"{settings.sender_name} <{settings.sender_address}>"
    message["To"] = to
    message["Subject"] = subject
    message.set_content(body)
    password = decrypt_secret(settings.smtp_password_encrypted)
    client_cls = smtplib.SMTP_SSL if settings.use_tls and not settings.use_starttls else smtplib.SMTP
    with client_cls(settings.smtp_host, settings.smtp_port, timeout=20) as smtp:
        if settings.use_starttls:
            smtp.starttls()
        if settings.smtp_user and password:
            smtp.login(settings.smtp_user, password)
        smtp.send_message(message)


def invite_body(token: str) -> str:
    link = f"{get_settings().instance_url.rstrip('/')}/accept-invite?token={token}"
    return f"Welcome to NexaPantry.\n\nOpen this invitation link to set your password:\n{link}\n\nThe link expires automatically."