from datetime import datetime
from decimal import Decimal
import requests

from app.extensions import db
from app.models.company import UserCompanyAccess
from app.models.invoice import NotificationLog
from app.models.user import User
from app.services.mail_service import MailService
from app.services.settings_service import SettingsService


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

    def should_notify(self, invoice):
        if SettingsService.get_effective('notify.enabled', 'false', company_id=self.company_id) != 'true':
            return False
        min_amount = Decimal(SettingsService.get_effective('notify.min_amount', '0', company_id=self.company_id) or '0')
        return Decimal(invoice.gross_amount) >= min_amount

    def _pushover_credentials(self):
        return {
            'token': SettingsService.get_effective_secret('notify.pushover_api_token', '', company_id=self.company_id),
            'user': SettingsService.get_effective('notify.pushover_user_key', '', company_id=self.company_id),
        }

    def _email_recipients(self):
        if not self.company_id:
            return []
        rows = (
            db.session.query(User.email)
            .join(UserCompanyAccess, UserCompanyAccess.user_id == User.id)
            .filter(UserCompanyAccess.company_id == self.company_id, User.is_blocked.is_(False))
            .order_by(User.email.asc())
            .all()
        )
        recipients = []
        seen = set()
        for (email,) in rows:
            email = (email or '').strip().lower()
            if not email or email in seen:
                continue
            seen.add(email)
            recipients.append(email)
        return recipients

    def notify_new_invoice(self, invoice):
        if not self.should_notify(invoice):
            return []
        message = f'Nowa faktura {invoice.invoice_number} / {invoice.contractor_name} / {invoice.gross_amount} PLN'
        logs = [self._send_email_notification(invoice, message)]
        logs.append(self._send_pushover(invoice.id, message))
        return logs

    def log_channel(self, invoice_id, channel, status, message):
        log = NotificationLog(invoice_id=invoice_id, channel=channel, status=status, message=message, sent_at=datetime.utcnow())
        db.session.add(log)
        db.session.commit()
        return log

    def _send_email_notification(self, invoice, message):
        recipients = self._email_recipients()
        if not recipients:
            return self.log_channel(invoice.id, 'email', 'skipped', 'Brak odbiorców e-mail przypisanych do aktywnej firmy')

        mailer = MailService(company_id=self.company_id)
        subject = f'Nowa faktura: {invoice.invoice_number}'
        body = (
            'W systemie KSeF Manager pojawiła się nowa faktura.\n\n'
            f'Numer: {invoice.invoice_number}\n'
            f'Kontrahent: {invoice.contractor_name}\n'
            f'Kwota brutto: {invoice.gross_amount} PLN\n'
        )

        sent = 0
        errors = []
        for recipient in recipients:
            try:
                mailer.send_mail(recipient, subject, body)
                sent += 1
            except Exception as exc:
                errors.append(f'{recipient}: {exc}')

        if sent and not errors:
            return self.log_channel(invoice.id, 'email', 'sent', f'{message} · odbiorców: {sent}')
        if sent and errors:
            return self.log_channel(invoice.id, 'email', 'error', f"Wysłano do {sent}/{len(recipients)} odbiorców. Błędy: {'; '.join(errors[:3])}")
        return self.log_channel(invoice.id, 'email', 'error', 'Nie udało się wysłać powiadomień e-mail: ' + '; '.join(errors[:3]))

    def _send_pushover(self, invoice_id, message):
        creds = self._pushover_credentials()
        if not creds['token'] or not creds['user']:
            return self.log_channel(invoice_id, 'pushover', 'skipped', 'Brak konfiguracji Pushover')
        try:
            response = requests.post('https://api.pushover.net/1/messages.json', data={'token': creds['token'], 'user': creds['user'], 'message': message}, timeout=10)
            response.raise_for_status()
            return self.log_channel(invoice_id, 'pushover', 'sent', message)
        except Exception as exc:
            return self.log_channel(invoice_id, 'pushover', 'error', str(exc))

    def send_test_pushover(self):
        return self._send_pushover(None, 'KSeF Manager - test Pushover')