#!/usr/bin/env python3
import os, time, smtplib, ssl, base64, sqlite3
from imap_tools import MailBox, AND
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
from datetime import datetime, timedelta, timezone

# --- ENV Variablen ---
imap_host = os.getenv("IMAP_HOST")
imap_user = os.getenv("IMAP_USER")
imap_pass = os.getenv("IMAP_PASS")
smtp_host = os.getenv("SMTP_HOST")
smtp_port = int(os.getenv("SMTP_PORT", "587"))
smtp_user = os.getenv("SMTP_USER", imap_user)
smtp_pass = os.getenv("SMTP_PASS", imap_pass)
poll_seconds = int(os.getenv("POLL_SECONDS", "60"))

# Rebound Zeitraum (Stunden)
rebound_hours = int(os.getenv("REBOUND_HOURS", "24"))

# Ignorier-Muster für Absender
ignore_patterns = [p.strip().lower() for p in os.getenv(
    "IGNORE_ADDRS", "no-reply@,noreply@,donotreply@"
).split(",")]

ctx = ssl.create_default_context()

# --- SQLite DB für Rebound ---
db_path = "/app/logs/replied.db"
os.makedirs("/app/logs", exist_ok=True)
conn = sqlite3.connect(db_path, check_same_thread=False)
c = conn.cursor()
c.execute("""
CREATE TABLE IF NOT EXISTS replied (
    addr TEXT PRIMARY KEY,
    last_reply TIMESTAMP
)
""")
conn.commit()


def log(msg: str):
    print(f"[{datetime.now().strftime('%Y-%m-%d %H:%M:%S')}] {msg}", flush=True)


def already_replied(addr: str) -> bool:
    c.execute("SELECT last_reply FROM replied WHERE addr = ?", (addr,))
    row = c.fetchone()
    if row:
        last = datetime.fromisoformat(row[0])
        if datetime.now() - last < timedelta(hours=rebound_hours):
            return True
    return False


def mark_replied(addr: str):
    c.execute("INSERT OR REPLACE INTO replied (addr, last_reply) VALUES (?, ?)",
              (addr, datetime.now().isoformat()))
    conn.commit()


def send_reply(to_addr, original_subject):
    # Blacklist-Absender ignorieren
    low = to_addr.lower()
    if any(p in low for p in ignore_patterns):
        log(f"[Autoreply] Ignoriere {to_addr} (Blacklist-Match)")
        return

    if already_replied(to_addr):
        log(f"[Autoreply] Überspringe {to_addr}, bereits innerhalb {rebound_hours}h beantwortet")
        return

    msg = MIMEMultipart("alternative")
    msg["Subject"] = "Ihre Mail wurde empfangen"
    msg["From"] = smtp_user
    msg["To"] = to_addr

    # Inline-Logo
    with open("logo.png", "rb") as f:
        logo_b64 = base64.b64encode(f.read()).decode()
    with open("reply.html", "r", encoding="utf-8") as f:
        html = f.read().replace("{{INLINE_LOGO}}", logo_b64)
    msg.attach(MIMEText(html, "html"))

    def _send():
        if smtp_port == 465:
            with smtplib.SMTP_SSL(smtp_host, smtp_port, context=ctx, timeout=20) as s:
                s.set_debuglevel(1)
                s.ehlo()
                s.login(smtp_user, smtp_pass)
                s.sendmail(smtp_user, [to_addr], msg.as_string())
        else:
            with smtplib.SMTP(smtp_host, smtp_port, timeout=20) as s:
                s.set_debuglevel(1)
                s.ehlo()
                s.starttls(context=ctx)
                s.ehlo()
                s.login(smtp_user, smtp_pass)
                s.sendmail(smtp_user, [to_addr], msg.as_string())

    try:
        _send()
        log(f"[Autoreply] Antwort gesendet an {to_addr}")
        mark_replied(to_addr)
    except (smtplib.SMTPServerDisconnected, smtplib.SMTPConnectError) as e:
        log(f"[Autoreply] SMTP Verbindungsfehler ({e}), Retry …")
        try:
            time.sleep(2)
            _send()
            log(f"[Autoreply] Antwort gesendet an {to_addr} (Retry)")
            mark_replied(to_addr)
        except Exception as e2:
            log(f"[Autoreply] SMTP Fehler nach Retry: {e2}")
    except Exception as e:
        log(f"[Autoreply] SMTP Fehler: {e}")


def check_mail():
    try:
        log("Verbinde mit IMAP...")
        with MailBox(imap_host).login(imap_user, imap_pass, initial_folder="INBOX") as mailbox:
            log("IMAP Login OK, prüfe neue Mails...")

            cutoff = datetime.now(timezone.utc) - timedelta(seconds=poll_seconds*2)

            for msg in mailbox.fetch(AND(seen=False), mark_seen=False):
                if msg.date < cutoff:
                    continue  # alte ungelesene überspringen

                # Sicherheitsmaßnahme: falls SEEN gesetzt → zurücksetzen
                try:
                    mailbox.flag(msg.uid, ['\\Seen'], False)
                except Exception as e:
                    log(f"[Autoreply] Warnung: SEEN-Flag konnte nicht zurückgesetzt werden: {e}")

                log(f"Neue Mail von {msg.from_} mit Betreff: {msg.subject}")
                send_reply(msg.from_, msg.subject)
    except Exception as e:
        log(f"IMAP Fehler: {e}")


if __name__ == "__main__":
    log(f"Starte Auto-Reply Service für {imap_user}")
    log(f"Ignoriere Absender-Muster: {ignore_patterns}")
    while True:
        check_mail()
        time.sleep(poll_seconds)