"""Email notification service for VoIdea.

Uses aiosmtplib for async SMTP with Jinja2 templates.
Falls back to logging when SMTP is not configured.
"""

import logging
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from pathlib import Path

from jinja2 import Environment, FileSystemLoader, select_autoescape

from app.core.config import get_settings

logger = logging.getLogger(__name__)

TEMPLATES_DIR = Path(__file__).parent.parent / "templates" / "email"
_env = Environment(loader=FileSystemLoader(str(TEMPLATES_DIR)), autoescape=select_autoescape())


def _render(template_name: str, context: dict) -> str:
    """Render an email template.

    Args:
        template_name: Name of the template file (e.g. "welcome.html")
        context: Template variables

    Returns:
        Rendered HTML string, or plain text fallback
    """
    try:
        template = _env.get_template(template_name)
        return template.render(**context)
    except Exception:
        lines = [f"{k}: {v}" for k, v in context.items()]
        return "\n".join(lines)


async def send_email(to: str, subject: str, html: str) -> bool:
    """Send an email via SMTP, or log to console if SMTP not configured.

    Args:
        to: Recipient email
        subject: Email subject
        html: HTML body

    Returns:
        True if sent (or logged) successfully, False on SMTP error
    """
    settings = get_settings()
    if not settings.smtp_host:
        logger.info(
            "SMTP not configured — email logged instead:\n"
            "  To: %s\n  Subject: %s\n  Body:\n%s",
            to, subject, html,
        )
        return True

    try:
        import aiosmtplib

        msg = MIMEMultipart("alternative")
        msg["Subject"] = subject
        msg["From"] = settings.smtp_from
        msg["To"] = to
        msg.attach(MIMEText(html, "html"))

        await aiosmtplib.send(
            msg,
            hostname=settings.smtp_host,
            port=settings.smtp_port,
            username=settings.smtp_user or None,
            password=settings.smtp_pass or None,
            use_tls=settings.smtp_tls,
        )
        return True
    except Exception:
        return False


async def send_welcome_email(to: str, username: str) -> bool:
    """Send welcome email after registration.

    Args:
        to: Recipient email
        username: User display name
    """
    html = _render("welcome.html", {"username": username, "project_name": "VoIdea"})
    return await send_email(to, f"Добро пожаловать в VoIdea!", html)


async def send_notification_email(to: str, subject: str, message: str) -> bool:
    """Send a notification email.

    Args:
        to: Recipient email
        subject: Email subject
        message: Plain text or HTML message
    """
    html = _render("notification.html", {"subject": subject, "message": message})
    return await send_email(to, subject, html)