# ==============================================================================
# Formeleon - Multi-tenant Form Generator
# Author: Björn Runden <br@runden.net>
# Module: services/mailer.py
# Description: Service for handling email notifications and autoresponders.
# ==============================================================================

import smtplib
import logging
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
from typing import List, Dict, Any, Optional
from flask import current_app
from jinja2 import Template, TemplateError

logger = logging.getLogger(__name__)

class MailerService:
    """Service class for handling email dispatch."""

    @classmethod
    def is_configured(cls) -> bool:
        """Check if SMTP settings are provided in configuration."""
        server = current_app.config.get('SMTP_SERVER')
        # Wir betrachten den Service als "konfiguriert", wenn entweder ein Server da ist, 
        # oder wir im Dev-Mode sind (um das Terminal-Logging zu erlauben)
        if current_app.config.get('DEV_MODE', False) and not server:
            return True
            
        port = current_app.config.get('SMTP_PORT')
        return bool(server and port)

    @classmethod
    def send_email(cls, to_addresses: List[str], subject: str, body_text: str, reply_to: Optional[str] = None) -> bool:
        """
        Sends an email using the configured SMTP server.
        
        :param to_addresses: List of recipient email addresses
        :param subject: Email subject line
        :param body_text: Plain text email body
        :param reply_to: Optional Reply-To address
        :return: True if successful, False otherwise
        """
        if not cls.is_configured():
            logger.warning("MailerService: Attempted to send email, but SMTP is not configured.")
            return False

        if current_app.config.get('DEV_MODE', False) and not current_app.config.get('SMTP_SERVER'):
            logger.info(f"MailerService [DEV MODE]: Would send email to {to_addresses} | Subject: '{subject}'")
            return True

        smtp_server = current_app.config.get('SMTP_SERVER')
        smtp_port = int(current_app.config.get('SMTP_PORT', 587))
        smtp_user = current_app.config.get('SMTP_USERNAME')
        smtp_pass = current_app.config.get('SMTP_PASSWORD')
        use_tls = str(current_app.config.get('SMTP_USE_TLS', 'true')).lower() == 'true'
        from_address = current_app.config.get('EMAIL_FROM', 'formeleon@localhost')

        msg = MIMEMultipart()
        msg['From'] = from_address
        msg['To'] = ", ".join(to_addresses)
        msg['Subject'] = subject
        if reply_to:
            msg['Reply-To'] = reply_to

        msg.attach(MIMEText(body_text, 'plain', 'utf-8'))

        try:
            with smtplib.SMTP(smtp_server, smtp_port) as server:
                if use_tls:
                    server.starttls()
                if smtp_user and smtp_pass:
                    server.login(smtp_user, smtp_pass)
                
                server.send_message(msg)
            
            logger.info(f"Successfully sent email to {to_addresses}")
            return True
            
        except Exception as e:
            logger.error(f"Failed to send email to {to_addresses}: {str(e)}", exc_info=True)
            return False

    @classmethod
    def render_template(cls, template_string: str, payload: Dict[str, Any]) -> str:
        """
        Renders a Jinja2 template string using the submission payload.
        
        :param template_string: The template string (e.g., "Hello {{ name }}")
        :param payload: Dictionary containing the form submission data
        :return: Rendered string
        """
        try:
            template = Template(template_string)
            return template.render(**payload)
        except TemplateError as e:
            logger.error(f"Template rendering failed: {str(e)}")
            # Fallback: Return original string if rendering fails
            return template_string

    @classmethod
    def send_admin_notification(cls, form_name: str, to_addresses: List[str], payload: Dict[str, Any]) -> bool:
        """
        Sends an alert to the tenant admins about a new submission.
        """
        subject = f"New Submission: {form_name}"
        
        # Build a simple readable key-value body
        body_lines = [f"A new submission was received for the form '{form_name}'.\n", "-" * 40]
        for key, value in payload.items():
            body_lines.append(f"{key}: {value}")
        body_lines.append("-" * 40)
        
        body_text = "\n".join(body_lines)
        return cls.send_email(to_addresses, subject, body_text)

    @classmethod
    def send_autoresponder(cls, to_address: str, subject_template: str, body_template: str, payload: Dict[str, Any]) -> bool:
        """
        Sends a templated autoresponder to the person who submitted the form.
        """
        subject = cls.render_template(subject_template, payload)
        body = cls.render_template(body_template, payload)
        
        return cls.send_email([to_address], subject, body)