#!/usr/bin/env python3
"""
Send a reply email via SMTP (e.g. Proton Mail Bridge).
Usage: ./gitea-issues/mail-send-reply.sh --to addr@example.com --subject "..." --body "..." [--in-reply-to "<msg-id>" [--references "<refs>"]]
  Or:  echo "body" | ./gitea-issues/mail-send-reply.sh --to addr@example.com --subject "..." [--in-reply-to "<msg-id>"]
"""

from __future__ import annotations

import argparse
import os
import smtplib
import sys
from email.mime.text import MIMEText
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parent))
from mail_common import load_smtp_config, repo_root, imap_ssl_context

DEFAULT_SIGNATURE = """--
Support IA du projet Lecoffre.io
ai.support.lecoffreio@4nkweb.com"""

# Patterns that indicate the body contains a citation of the received message (forbidden).
CITATION_PATTERNS = (
    "From:",
    "Message-ID:",
    "Message-ID :",
    " wrote:",
    " a écrit",
)
CITATION_LINE_START = (">",)  # Quoted line start


def body_contains_citation(body: str) -> bool:
    """Return True if body looks like it contains the received message (citation)."""
    if not body or not body.strip():
        return False
    lines = body.strip().splitlines()
    for line in lines:
        stripped = line.strip()
        if not stripped:
            continue
        for pat in CITATION_PATTERNS:
            if pat in line:
                return True
        for start in CITATION_LINE_START:
            if stripped.startswith(start):
                return True
    return False


def get_reply_signature() -> str:
    sig = os.environ.get("MAIL_REPLY_SIGNATURE", "").strip()
    if sig:
        return "\n\n" + sig.replace("\\n", "\n")
    return "\n\n" + DEFAULT_SIGNATURE


def main() -> None:
    ap = argparse.ArgumentParser(description="Send reply email via Bridge SMTP")
    ap.add_argument("--to", required=True, help="To address")
    ap.add_argument("--subject", required=True, help="Subject")
    ap.add_argument("--body", default="", help="Body (or use stdin)")
    ap.add_argument("--in-reply-to", default="", help="Message-ID of the message we reply to")
    ap.add_argument("--references", default="", help="References header for threading")
    args = ap.parse_args()

    cfg = load_smtp_config()
    if not cfg["user"] or not cfg["password"]:
        root = repo_root()
        env_path = root / ".secrets" / "gitea-issues" / "imap-bridge.env"
        print("[gitea-issues] ERROR: SMTP_USER and SMTP_PASSWORD required.", file=sys.stderr)
        print(f"[gitea-issues] Set env or create {env_path}", file=sys.stderr)
        sys.exit(1)

    body = args.body
    if not body and not sys.stdin.isatty():
        body = sys.stdin.read()
    body = body.rstrip()
    if body_contains_citation(body):
        print(
            "[gitea-issues] ERROR: Body must not contain the received message (no citation, no From:, Message-ID, wrote:, etc.). Send only your reply text.",
            file=sys.stderr,
        )
        sys.exit(1)
    body = (body + get_reply_signature()).strip()

    msg = MIMEText(body, "plain", "utf-8")
    msg["Subject"] = args.subject
    msg["From"] = cfg["user"]
    msg["To"] = args.to
    if args.in_reply_to:
        msg["In-Reply-To"] = args.in_reply_to
    if args.references:
        msg["References"] = args.references

    with smtplib.SMTP(cfg["host"], int(cfg["port"])) as smtp:
        if cfg["use_starttls"]:
            smtp.starttls(context=imap_ssl_context(cfg.get("ssl_verify", True)))
        smtp.login(cfg["user"], cfg["password"])
        smtp.sendmail(cfg["user"], [args.to], msg.as_string())

    print("[gitea-issues] Reply sent.")


if __name__ == "__main__":
    main()