from __future__ import annotations
from datetime import datetime
from email.message import EmailMessage
import smtplib

from app.extensions import db
from app.models.invoice import Invoice, MailDelivery
from app.services.pdf_service import PdfService
from app.services.settings_service import SettingsService


class MailService:
    def __init__(self, company_id=None):
        self.company_id = company_id

    def _smtp_config(self):
        security_mode = (SettingsService.get_effective('mail.security_mode', '', company_id=self.company_id) or '').strip().lower()
        if security_mode not in {'tls', 'ssl', 'none'}:
            security_mode = 'tls' if str(SettingsService.get_effective('mail.tls', 'true', company_id=self.company_id)).lower() == 'true' else 'none'
        return {
            'server': (SettingsService.get_effective('mail.server', '', company_id=self.company_id) or '').strip(),
            'port': int(SettingsService.get_effective('mail.port', '587', company_id=self.company_id) or 587),
            'username': (SettingsService.get_effective('mail.username', '', company_id=self.company_id) or '').strip(),
            'password': (SettingsService.get_effective_secret('mail.password', '', company_id=self.company_id) or '').strip(),
            'sender': (SettingsService.get_effective('mail.sender', '', company_id=self.company_id) or '').strip(),
            'security_mode': security_mode,
        }

    def send_invoice(self, invoice: Invoice, recipient: str, subject: str | None = None, body: str | None = None):
        subject = subject or f'Faktura {invoice.invoice_number}'
        body = body or f'W załączeniu faktura {invoice.invoice_number}.'

        delivery = MailDelivery(invoice_id=invoice.id, recipient=recipient, subject=subject, status='queued')
        db.session.add(delivery)
        db.session.flush()

        pdf_bytes, path = PdfService().render_invoice_pdf(invoice)

        try:
            self.send_mail(
                recipient,
                subject,
                body,
                [(path.name, 'application/pdf', pdf_bytes)]
            )
            delivery.status = 'sent'
            delivery.sent_at = datetime.utcnow()
        except Exception as exc:
            delivery.status = 'error'
            delivery.error_message = str(exc)

        db.session.commit()
        return delivery

    def send_mail(self, recipient: str, subject: str, body: str, attachments=None):
        cfg = self._smtp_config()
        attachments = attachments or []

        if not cfg['server']:
            raise RuntimeError('SMTP server not configured')

        sender = cfg['sender'] or cfg['username']
        if not sender:
            raise RuntimeError('SMTP sender not configured')

        message = EmailMessage()
        message['Subject'] = subject
        message['From'] = sender
        message['To'] = recipient
        message.set_content(body)

        for filename, mime, data in attachments:
            maintype, subtype = mime.split('/', 1)
            message.add_attachment(data, maintype=maintype, subtype=subtype, filename=filename)

        if cfg['security_mode'] == 'ssl':
            smtp = smtplib.SMTP_SSL(cfg['server'], cfg['port'])
        else:
            smtp = smtplib.SMTP(cfg['server'], cfg['port'])

        with smtp:
            smtp.ehlo()

            if cfg['security_mode'] == 'tls':
                smtp.starttls()
                smtp.ehlo()

            if cfg['username']:
                smtp.login(cfg['username'], cfg['password'])

            smtp.send_message(message)

        return {'status': 'sent'}

    def send_test_mail(self, recipient: str):
        return self.send_mail(
            recipient,
            'KSeF Manager - test SMTP',
            'To jest testowa wiadomość z aplikacji KSeF Manager.'
        )

    def retry_delivery(self, delivery_id):
        delivery = db.session.get(MailDelivery, delivery_id)
        return self.send_invoice(delivery.invoice, delivery.recipient, delivery.subject)