"""Email service using aiosmtplib for contact and rental confirmation emails.

Includes a failed-email queue: when SMTP fails and a db session is provided,
the email is persisted to the email_queue table for later retry via APScheduler.
"""
import logging
from email.mime.text import MIMEText
from email.mime.multipart import MIMEMultipart
from typing import Any
from sqlalchemy import select, update
from sqlalchemy.ext.asyncio import AsyncSession
import aiosmtplib
from app.config import get_settings
from app.models.email_queue import EmailQueue

logger = logging.getLogger(__name__)
settings = get_settings()


class EmailService:
    """Send transactional emails via SMTP with failed-email queue support."""

    async def send_email(
        self,
        to_addr: str,
        subject: str,
        html_body: str,
        text_body: str = "",
        reply_to: str | None = None,
        db: AsyncSession | None = None,
    ) -> bool:
        """Send an email via aiosmtplib. Returns True on success.

        If SMTP fails and a db session is provided, the email is saved to
        the email_queue table for later retry.
        """
        msg = MIMEMultipart("alternative")
        msg["From"] = settings.smtp_from
        msg["To"] = to_addr
        msg["Subject"] = subject
        if reply_to:
            msg["Reply-To"] = reply_to
        msg.attach(MIMEText(text_body or html_body, "plain"))
        msg.attach(MIMEText(html_body, "html"))

        try:
            await aiosmtplib.send(
                msg,
                hostname=settings.smtp_host,
                port=settings.smtp_port,
                username=settings.smtp_user,
                password=settings.smtp_password,
                start_tls=True,
            )
            return True
        except Exception as exc:
            logger.error("Email send failed to %s: %s", to_addr, exc)
            if db is not None:
                try:
                    queued = EmailQueue(
                        to_addr=to_addr,
                        subject=subject,
                        html_body=html_body,
                        text_body=text_body,
                        reply_to=reply_to,
                        status="pending",
                        attempts=0,
                    )
                    db.add(queued)
                    await db.commit()
                    logger.info("Email queued for retry: %s", to_addr)
                except Exception as queue_exc:
                    logger.error("Failed to queue email: %s", queue_exc)
            return False

    async def send_contact_email(
        self, contact_data: dict[str, Any], db: AsyncSession | None = None
    ) -> bool:
        """Send contact form data to info@hms-licht-ton.de."""
        html = f"""
        <h2>Neue Kontaktanfrage</h2>
        <p><strong>Name:</strong> {contact_data.get('name', '')}</p>
        <p><strong>Email:</strong> {contact_data.get('email', '')}</p>
        <p><strong>Telefon:</strong> {contact_data.get('phone', '')}</p>
        <p><strong>Nachricht:</strong></p>
        <p>{contact_data.get('message', '')}</p>
        """
        text = (
            f"Neue Kontaktanfrage\n"
            f"Name: {contact_data.get('name', '')}\n"
            f"Email: {contact_data.get('email', '')}\n"
            f"Telefon: {contact_data.get('phone', '')}\n"
            f"Nachricht: {contact_data.get('message', '')}\n"
        )
        return await self.send_email(
            to_addr=settings.smtp_from,
            subject="Neue Kontaktanfrage ueber hms-licht-ton.de",
            html_body=html,
            text_body=text,
            reply_to=contact_data.get("email"),
            db=db,
        )

    async def send_rental_confirmation(
        self,
        to_addr: str,
        reference_number: str,
        event_name: str,
        items: list[dict[str, Any]],
        db: AsyncSession | None = None,
    ) -> bool:
        """Send rental request confirmation to customer."""
        items_html = "".join(
            f"<li>{item.get('equipment_name', 'Unbekannt')} - Menge: {item.get('quantity', 1)}</li>"
            for item in items
        )
        html = f"""
        <h2>Mietanfrage bestätigt – {reference_number}</h2>
        <p>Vielen Dank für Ihre Mietanfrage bei HMS Licht &amp; Ton.</p>
        <p><strong>Veranstaltung:</strong> {event_name}</p>
        <p><strong>Referenznummer:</strong> {reference_number}</p>
        <h3>Artikel:</h3>
        <ul>{items_html}</ul>
        <p>Wir melden uns in Kürze bei Ihnen.</p>
        <p>Ihr HMS Licht &amp; Ton Team</p>
        """
        text = (
            f"Mietanfrage bestaetigt - {reference_number}\n"
            f"Veranstaltung: {event_name}\n"
            f"Referenznummer: {reference_number}\n"
            f"Artikel:\n"
            + "\n".join(
                f"- {item.get('equipment_name', 'Unbekannt')}: {item.get('quantity', 1)}"
                for item in items
            )
        )
        return await self.send_email(
            to_addr=to_addr,
            subject=f"Mietanfrage bestaetigt – {reference_number}",
            html_body=html,
            text_body=text,
            db=db,
        )

    @staticmethod
    async def retry_failed_emails(db: AsyncSession, max_attempts: int = 5) -> int:
        """Retry all pending emails in the queue. Returns count of successfully sent emails."""
        result = await db.execute(
            select(EmailQueue).where(
                EmailQueue.status == "pending",
                EmailQueue.attempts < max_attempts,
            )
        )
        pending = result.scalars().all()
        sent_count = 0

        for item in pending:
            item.attempts += 1
            msg = MIMEMultipart("alternative")
            msg["From"] = settings.smtp_from
            msg["To"] = item.to_addr
            msg["Subject"] = item.subject
            if item.reply_to:
                msg["Reply-To"] = item.reply_to
            msg.attach(MIMEText(item.text_body or item.html_body, "plain"))
            msg.attach(MIMEText(item.html_body, "html"))

            try:
                await aiosmtplib.send(
                    msg,
                    hostname=settings.smtp_host,
                    port=settings.smtp_port,
                    username=settings.smtp_user,
                    password=settings.smtp_password,
                    start_tls=True,
                )
                item.status = "sent"
                sent_count += 1
                logger.info("Retry succeeded for email to %s", item.to_addr)
            except Exception as exc:
                logger.error("Retry failed for email to %s: %s", item.to_addr, exc)
                if item.attempts >= max_attempts:
                    item.status = "failed"

        await db.commit()
        return sent_count