#!/usr/bin/env python3
"""Serve the built site (public/) on all interfaces so other machines on the
same LAN can reach it. Usage: python3 serve_lan.py [port]   (default 8090)

The site must be built first:      make build index
Then start this:                   python3 serve_lan.py
Address to open from ANOTHER machine on the same network:
    http://<THIS-MACHINE-LAN-IP>:8090/
where the LAN IP is printed at startup (and is also  hostname -I  | head -1).
"""
import functools
import http.server
import socket
import subprocess
import sys

PORT = int(sys.argv[1]) if len(sys.argv) > 1 else 8090

# Serve the built site (public/), NOT the repo root.
handler = functools.partial(http.server.SimpleHTTPRequestHandler, directory="public")
server = http.server.ThreadingHTTPServer(("0.0.0.0", PORT), handler)


def lan_ip() -> str:
    try:
        return subprocess.check_output(["hostname", "-I"], text=True).split()[0]
    except Exception:
        s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
        try:
            s.connect(("8.8.8.8", 80))
            return s.getsockname()[0]
        finally:
            s.close()


ip = lan_ip()
print(f"Serving public/  ->  http://0.0.0.0:{PORT}/", flush=True)
print(f"LAN address      ->  http://{ip}:{PORT}/   (open this from another machine)", flush=True)
print("Press Ctrl+C to stop.", flush=True)
try:
    server.serve_forever()
except KeyboardInterrupt:
    pass
finally:
    server.server_close()