#!/usr/bin/env python3
import os
import sqlite3
import smtplib
import logging
from email.message import EmailMessage
from datetime import datetime, timezone

# ─── Environment & Logging ─────────────────────────────────────────────────────
DB_PATH = os.getenv("DB_PATH", "/data/sync_state.db")

# SMTP config from env; convert TLS/STARTTLS flags to real booleans
SMTP_HOST          = os.getenv("SMTP_HOST")
SMTP_PORT          = int(os.getenv("SMTP_PORT", "25"))
SMTP_USERNAME      = os.getenv("SMTP_USERNAME")
SMTP_PASSWORD      = os.getenv("SMTP_PASSWORD")
SMTP_USE_SSL       = os.getenv("SMTP_USE_TLS", "false").lower() in ("1","true","yes")
SMTP_USE_STARTTLS  = os.getenv("SMTP_USE_STARTTLS", "false").lower() in ("1","true","yes")

EMAIL_FROM         = os.getenv("EMAIL_FROM")
EMAIL_TO           = os.getenv("EMAIL_TO")
EMAIL_SUBJECT_PREFIX = os.getenv("EMAIL_SUBJECT_PREFIX", "")

logging.basicConfig(
    level=logging.INFO,
    format="%(asctime)s [%(levelname)s] %(message)s"
)
logger = logging.getLogger(__name__)

# ─── Email sender ──────────────────────────────────────────────────────────────
def send_email(subject: str, body: str, to_addrs: str):
    # 1) Choose SSL socket or plain
    if SMTP_USE_SSL:
        server = smtplib.SMTP_SSL(SMTP_HOST, SMTP_PORT)
    else:
        server = smtplib.SMTP(SMTP_HOST, SMTP_PORT)
        if SMTP_USE_STARTTLS:
            server.ehlo()
            server.starttls()
            server.ehlo()

    # 2) Login if creds provided
    if SMTP_USERNAME and SMTP_PASSWORD:
        server.login(SMTP_USERNAME, SMTP_PASSWORD)

    # 3) Build & send
    msg = EmailMessage()
    msg["Subject"] = subject
    msg["From"]    = EMAIL_FROM
    msg["To"]      = to_addrs
    msg.set_content(body)

    server.send_message(msg)
    server.quit()

# ─── Dispatch loop ─────────────────────────────────────────────────────────────
def dispatch():
    conn = sqlite3.connect(DB_PATH)
    c    = conn.cursor()

    now_iso = datetime.now(timezone.utc).isoformat()
    c.execute("""
        SELECT id, event_uid, trigger_dt, summary, description
          FROM reminders
         WHERE trigger_dt <= ? AND sent_flag = 0
    """, (now_iso,))
    rows = c.fetchall()

    for rid, uid, trigger_dt, summary, description in rows:
        subject = f"{EMAIL_SUBJECT_PREFIX} {summary}"
        body = (
            f"{summary}\n\n"
            f"{description}\n\n"
            f"Scheduled at: {trigger_dt}"
        )
        try:
            send_email(subject, body, EMAIL_TO)
            c.execute("UPDATE reminders SET sent_flag = 1 WHERE id = ?", (rid,))
            conn.commit()
            logger.info(f"Sent reminder {rid} ({uid})")
        except Exception as e:
            logger.error(f"Failed to send reminder {rid}: {e}")

    conn.close()

if __name__ == "__main__":
    dispatch()