#!/usr/bin/env python3
# SPDX-FileCopyrightText: 2026 Echolot contributors
# SPDX-License-Identifier: GPL-3.0-or-later
#
# Tiny rendezvous receiver for the wireless-adb beacon. The phone POSTs its
# current wireless-debug endpoint here; the PC-side connector reads the stored
# file (over SSH) and runs `adb connect`. Dev tooling — not part of the product.
#
#   POST /beacon  { "ip": "...", "port": N }   header: X-Beacon-Secret: <secret>
#   GET  /beacon  -> the last stored JSON (no secret; it's just an ip:port)
#
# Secret comes from ECHOLOT_BEACON_SECRET; stored state goes to STATE_PATH.
# Bind is 0.0.0.0:9099 so the phone can reach it over the internet/VPN.

import json
import os
import time
from http.server import BaseHTTPRequestHandler, ThreadingHTTPServer

STATE_PATH = os.environ.get("STATE_PATH", "/run/echolot-adb-beacon.json")
SECRET = os.environ.get("ECHOLOT_BEACON_SECRET", "")
BIND = os.environ.get("BEACON_BIND", "0.0.0.0")
PORT = int(os.environ.get("BEACON_PORT", "9099"))


class Handler(BaseHTTPRequestHandler):
    def _send(self, code, body=b"", ctype="application/json"):
        self.send_response(code)
        self.send_header("Content-Type", ctype)
        self.send_header("Content-Length", str(len(body)))
        self.end_headers()
        if body:
            self.wfile.write(body)

    def do_GET(self):
        if self.path.rstrip("/") != "/beacon":
            return self._send(404, b'{"error":"not found"}')
        try:
            with open(STATE_PATH, "rb") as f:
                self._send(200, f.read())
        except FileNotFoundError:
            self._send(200, b'{"available":false}')

    def do_POST(self):
        if self.path.rstrip("/") != "/beacon":
            return self._send(404, b'{"error":"not found"}')
        if SECRET and self.headers.get("X-Beacon-Secret") != SECRET:
            return self._send(403, b'{"error":"bad secret"}')
        n = int(self.headers.get("Content-Length", "0"))
        try:
            data = json.loads(self.rfile.read(n) or b"{}")
            ip = str(data["ip"])
            port = int(data["port"])
        except Exception:
            return self._send(400, b'{"error":"need {ip, port}"}')
        record = {"ip": ip, "port": port, "seen_at": int(time.time())}
        tmp = STATE_PATH + ".tmp"
        with open(tmp, "w") as f:
            json.dump(record, f)
        os.replace(tmp, STATE_PATH)
        self._send(200, json.dumps(record).encode())

    def log_message(self, *_):
        pass  # quiet


if __name__ == "__main__":
    print(f"adb-beacon receiver on {BIND}:{PORT} -> {STATE_PATH}", flush=True)
    ThreadingHTTPServer((BIND, PORT), Handler).serve_forever()