from __future__ import annotations

import smtplib
from email.message import EmailMessage

from flask import current_app, render_template

from .settings import get_bool_setting, get_int_setting, get_str_setting


class MailService:
    def _settings(self) -> dict:
        security = get_str_setting('smtp_security', '') or ('ssl' if get_bool_setting('smtp_use_ssl', current_app.config.get('MAIL_USE_SSL', True)) else ('starttls' if get_bool_setting('smtp_use_tls', current_app.config.get('MAIL_USE_TLS', False)) else 'plain'))
        return {
            'host': get_str_setting('smtp_host', current_app.config.get('MAIL_SERVER', '')),
            'port': get_int_setting('smtp_port', current_app.config.get('MAIL_PORT', 465)),
            'username': get_str_setting('smtp_username', current_app.config.get('MAIL_USERNAME', '')),
            'password': get_str_setting('smtp_password', current_app.config.get('MAIL_PASSWORD', '')),
            'sender': get_str_setting('smtp_sender', current_app.config.get('MAIL_DEFAULT_SENDER', 'no-reply@example.com')),
            'security': security,
        }

    def is_configured(self) -> bool:
        return bool(self._settings()['host'])

    def send(self, to_email: str, subject: str, body: str, html: str | None = None) -> bool:
        cfg = self._settings()
        if not cfg['host']:
            current_app.logger.info('Mail skipped for %s: %s', to_email, subject)
            return False
        msg = EmailMessage()
        msg['Subject'] = subject
        msg['From'] = cfg['sender']
        msg['To'] = to_email
        msg.set_content(body)
        if html:
            msg.add_alternative(html, subtype='html')
        if cfg['security'] == 'ssl':
            with smtplib.SMTP_SSL(cfg['host'], cfg['port']) as smtp:
                if cfg['username']:
                    smtp.login(cfg['username'], cfg['password'])
                smtp.send_message(msg)
        else:
            with smtplib.SMTP(cfg['host'], cfg['port']) as smtp:
                if cfg['security'] == 'starttls':
                    smtp.starttls()
                if cfg['username']:
                    smtp.login(cfg['username'], cfg['password'])
                smtp.send_message(msg)
        return True

    def send_template(self, to_email: str, subject: str, template_name: str, **context) -> bool:
        html = render_template(f'mail/{template_name}.html', **context)
        text = render_template(f'mail/{template_name}.txt', **context)
        return self.send(to_email, subject, text, html=html)