"""SMTP email provider implementation."""
import logging
import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText

from flask import current_app

from gatehouse_app.services.email_provider import EmailMessage, EmailProvider

logger = logging.getLogger(__name__)


class SmtpEmailProvider(EmailProvider):
    """SMTP-based email provider implementation."""

    # Configuration keys
    EMAIL_ENABLED_KEY = "EMAIL_ENABLED"
    SMTP_HOST_KEY = "SMTP_HOST"
    SMTP_PORT_KEY = "SMTP_PORT"
    SMTP_USERNAME_KEY = "SMTP_USERNAME"
    SMTP_PASSWORD_KEY = "SMTP_PASSWORD"
    SMTP_USE_TLS_KEY = "SMTP_USE_TLS"
    FROM_ADDRESS_KEY = "FROM_ADDRESS"

    def send(self, message: EmailMessage) -> bool:
        """Send an email via SMTP.

        Args:
            message: EmailMessage instance containing email details

        Returns:
            bool: True if email was sent successfully, False otherwise
        """
        email_enabled = current_app.config.get(self.EMAIL_ENABLED_KEY, False)
        if not email_enabled:
            logger.info(
                f"[EMAIL DISABLED] Would have sent to: {message.to} | "
                f"Subject: {message.subject}"
            )
            return False

        smtp_host = current_app.config.get(self.SMTP_HOST_KEY, "")
        from_address = message.from_address or current_app.config.get(self.FROM_ADDRESS_KEY, "")

        missing = [k for k, v in [("SMTP_HOST", smtp_host), ("FROM_ADDRESS", from_address)] if not v]
        if missing:
            logger.error(
                f"[EMAIL] Cannot send — missing config: {', '.join(missing)}. "
                f"Would have sent to: {message.to} | Subject: {message.subject}"
            )
            return False

        smtp_port_raw = current_app.config.get(self.SMTP_PORT_KEY, 587)
        try:
            smtp_port = int(smtp_port_raw)
        except (TypeError, ValueError):
            logger.error(f"[EMAIL] Invalid SMTP_PORT value: {smtp_port_raw!r}")
            return False

        smtp_username = current_app.config.get(self.SMTP_USERNAME_KEY)
        smtp_password = current_app.config.get(self.SMTP_PASSWORD_KEY)

        smtp_use_tls = current_app.config.get(
            self.SMTP_USE_TLS_KEY,
            smtp_port not in (25, 1025),
        )

        try:
            msg = MIMEMultipart("alternative")
            msg["Subject"] = message.subject
            msg["From"] = from_address
            msg["To"] = message.to
            msg.attach(MIMEText(message.body, "plain"))
            if message.html_body:
                msg.attach(MIMEText(message.html_body, "html"))

            with smtplib.SMTP(smtp_host, smtp_port) as server:
                server.ehlo()
                if smtp_use_tls:
                    server.starttls()
                    server.ehlo()
                if smtp_username and smtp_password:
                    server.login(smtp_username, smtp_password)
                server.send_message(msg)

            logger.info(f"[EMAIL] Sent to {message.to} | Subject: {message.subject}")
            return True

        except Exception as e:
            logger.error(f"[EMAIL] Failed to send to {message.to}: {e}")
            return False