"""FlowDeck — Email notifications via SMTP (v4.9.0).

If SMTP is not configured (smtp_host empty) this is a safe no-op, so the
application works locally out of the box while still logging intent.
"""
from __future__ import annotations

import logging
import smtplib
from email.message import EmailMessage

from app.config import settings

logger = logging.getLogger(__name__)


def _configured() -> bool:
    return bool(settings.smtp_host)


def _html_body(body_text: str, cta_url: str = "") -> str:
    cta = ""
    if cta_url:
        cta = (
            '<p style="margin:24px 0 0;">'
            f'<a href="{cta_url}" '
            'style="background:#2383E2;color:#fff;text-decoration:none;'
            'padding:10px 20px;border-radius:8px;display:inline-block;'
            'font-weight:600;">Open in FlowDeck &rarr;</a></p>'
        )
    return f"""<div style="font-family:-apple-system,'Segoe UI',Roboto,sans-serif;
background:#191919;color:#e0e0e0;padding:32px;">
<div style="max-width:520px;margin:0 auto;background:#252525;border:1px solid #333;
border-radius:12px;padding:24px;">
<div style="font-size:18px;font-weight:700;color:#fff;margin-bottom:8px;">FlowDeck</div>
<p style="color:#e0e0e0;line-height:1.6;white-space:pre-wrap;">{body_text}</p>
{cta}
<p style="margin-top:24px;font-size:12px;color:#999;">You received this because your
notifications preferences in FlowDeck allow it.</p>
</div></div>"""


def send_email(to_email: str, subject: str, body_text: str, cta_url: str = "") -> bool:
    """Send an email. Returns True on success, False if skipped or failed."""
    if not to_email or not _configured():
        return False
    try:
        msg = EmailMessage()
        msg["Subject"] = subject
        msg["From"] = settings.smtp_from
        msg["To"] = to_email
        msg.set_content(body_text)
        msg.add_alternative(_html_body(body_text, cta_url), subtype="html")

        with smtplib.SMTP(settings.smtp_host, settings.smtp_port, timeout=15) as server:
            if settings.smtp_use_tls:
                server.starttls()
            if settings.smtp_user:
                server.login(settings.smtp_user, settings.smtp_password)
            server.send_message(msg)
        logger.info("Email sent to %s: %s", to_email, subject)
        return True
    except Exception as e:  # never break the request on mail failure
        logger.warning("Email send failed to %s: %s", to_email, e)
        return False


def notify_user(
    user_id: int,
    subject: str,
    body_text: str,
    cta_url: str = "",
    prefs_key: str = "mentions",
) -> bool:
    """Resolve a user's email + preferences and send an email notification."""
    from app.db import get_conn
    from app.services import notifications

    with get_conn() as conn:
        row = conn.execute("SELECT id, email FROM users WHERE id=?", (user_id,)).fetchone()
    if not row or not row["email"]:
        return False
    prefs = notifications.get_user_prefs(user_id)
    if not prefs.get(prefs_key, True):
        return False
    return send_email(row["email"], subject, body_text, cta_url)