#!/usr/bin/env python3
"""Serve a sitrep-panel report directory on a free localhost port.

Usage: python3 serve.py <directory> [preferred_port]

Prints exactly one line to stdout on success: `SERVING http://localhost:<port>/`
then blocks, running the HTTP server — launch this with the caller's
background/detached mechanism (e.g. Claude Code's Bash tool with
run_in_background: true). Stdlib only, no dependencies.
"""

from __future__ import annotations

import functools
import http.server
import sys


class QuietHandler(http.server.SimpleHTTPRequestHandler):
    """SimpleHTTPRequestHandler that suppresses per-request access logging,
    so stdout stays to the one clean SERVING line callers parse."""

    def log_message(self, format: str, *args: object) -> None:  # noqa: A002
        pass


def main() -> None:
    if len(sys.argv) < 2:
        print("usage: serve.py <directory> [preferred_port]", file=sys.stderr)
        sys.exit(1)

    directory = sys.argv[1]
    preferred_port = int(sys.argv[2]) if len(sys.argv) > 2 else 8934
    handler = functools.partial(QuietHandler, directory=directory)

    try:
        httpd = http.server.ThreadingHTTPServer(("127.0.0.1", preferred_port), handler)
    except OSError:
        # Preferred port is taken — let the OS assign a free one rather than
        # guessing and racing another process for it.
        httpd = http.server.ThreadingHTTPServer(("127.0.0.1", 0), handler)

    port = httpd.server_address[1]
    print(f"SERVING http://localhost:{port}/", flush=True)
    httpd.serve_forever()


if __name__ == "__main__":
    main()