"""
Diagnostic script for ScrAIbe email (SMTP) connectivity.

Run inside the container to verify:
- Required env vars are set
- SMTP connection
- TLS (if configured)
- Authentication

Output is written to stdout/stderr so it appears in docker logs.
"""

import os
import sys
import smtplib
import logging

logging.basicConfig(
    level=logging.INFO,
    format="DIAG [%(levelname)s] %(message)s",
    stream=sys.stdout,
    force=True,
)
log = logging.getLogger("email_diagnostics")


def main():
    # 1) Check required env vars
    required = [
        "EMAIL_SMTP_HOST",
        "EMAIL_SMTP_PORT",
        "EMAIL_SMTP_USER",
        "EMAIL_SMTP_PASSWORD",
        "EMAIL_FROM_ADDRESS",
    ]
    missing = [v for v in required if not os.getenv(v)]
    if missing:
        log.error("Missing required env vars: %s", ", ".join(missing))
        sys.exit(1)

    smtp_host = os.getenv("EMAIL_SMTP_HOST")
    smtp_port = int(os.getenv("EMAIL_SMTP_PORT"))
    smtp_user = os.getenv("EMAIL_SMTP_USER")
    smtp_password = os.getenv("EMAIL_SMTP_PASSWORD")
    from_address = os.getenv("EMAIL_FROM_ADDRESS")
    use_tls_str = (os.getenv("EMAIL_SMTP_USE_TLS") or "true").strip().lower()
    use_tls = use_tls_str not in ("false", "0", "no")

    log.info("SMTP config:")
    log.info("  host: %s", smtp_host)
    log.info("  port: %s", smtp_port)
    log.info("  user: %s", smtp_user)
    log.info("  from: %s", from_address)
    log.info("  use_tls: %s", use_tls)
    log.info("  password: %s", ("set" if smtp_password else "NOT SET"))

    # 2) Connect to SMTP server
    log.info("Attempting SMTP connection...")
    try:
        if use_tls:
            server = smtplib.SMTP(smtp_host, smtp_port, timeout=15)
            log.info("Connected (SMTP) to %s:%s", smtp_host, smtp_port)
        else:
            server = smtplib.SMTP(smtp_host, smtp_port, timeout=15)
            log.info("Connected (SMTP, no TLS) to %s:%s", smtp_host, smtp_port)
    except Exception as e:
        log.error("SMTP connection failed: %s", e)
        sys.exit(1)

    # 3) EHLO
    log.info("Sending EHLO...")
    try:
        ehlo_resp = server.ehlo()
        log.info("EHLO response code: %s", ehlo_resp[0])
    except Exception as e:
        log.error("EHLO failed: %s", e)
        server.quit()
        sys.exit(1)

    # 4) STARTTLS if configured
    if use_tls:
        log.info("Attempting STARTTLS...")
        try:
            server.starttls()
            server.ehlo()
            log.info("STARTTLS succeeded.")
        except Exception as e:
            log.error("STARTTLS failed: %s", e)
            server.quit()
            sys.exit(1)
    else:
        log.info("TLS not requested; continuing without STARTTLS.")

    # 5) AUTH LOGIN
    log.info("Attempting AUTH LOGIN with user: %s", smtp_user)
    try:
        server.login(smtp_user, smtp_password)
        log.info("AUTH LOGIN succeeded.")
    except smtplib.SMTPAuthenticationError as e:
        log.error("AUTH LOGIN failed (bad credentials?): %s", e)
        server.quit()
        sys.exit(1)
    except Exception as e:
        log.error("AUTH LOGIN failed: %s", e)
        server.quit()
        sys.exit(1)

    # 6) Optional: quick MAIL FROM / RCPT TO / QUIT test (no message sent)
    log.info("Testing MAIL FROM / RCPT TO / RSET...")
    try:
        server.mail(from_address)
        # Use from_address as recipient for test
        server.rcpt(from_address)
        server.reset()
        log.info("MAIL FROM / RCPT TO / RSET succeeded.")
    except Exception as e:
        log.warning("MAIL FROM / RCPT TO / RSET failed (non-critical): %s", e)

    # 7) Quit
    server.quit()
    log.info("All email diagnostics passed. SMTP is reachable and authenticated.")


if __name__ == "__main__":
    main()