#!/usr/local/bin/python3

import getpass
import subprocess
from pathlib import Path

LOG = Path("/var/gab/chatlog.txt")
STATE = Path.home() / ".gab-notify.lines"
TO = f"{getpass.getuser()}@texto-plano.xyz"


def format_message(line: str) -> str:
    """Turn 'user >  text' into 'user: text'."""
    user, _, text = line.partition(">")
    return f"{user.strip()}: {text.strip()}"


def main() -> None:
    lines = LOG.read_text(encoding="utf-8", errors="replace").splitlines()
    current = len(lines)

    if not STATE.exists():
        STATE.write_text(str(current))
        return

    previous = int(STATE.read_text())
    STATE.write_text(str(current))

    if current <= previous:
        return

    new_lines = lines[previous:]
    body = "\n- - -\n".join(format_message(line) for line in new_lines)
    subprocess.run(
        ["/usr/bin/mail", "-s", f"gab: {len(new_lines)} mensaje(s) nuevo(s)", TO],
        input=body + "\n",
        text=True,
        check=True,
    )


if __name__ == "__main__":
    main()