import { execFile } from 'node:child_process';
import { promisify } from 'node:util';
const pexec = promisify(execFile);

// Run bluetoothctl non-interactively. Returns combined stdout even on nonzero exit.
async function btctl(args, timeoutSec = 15) {
  try {
    const { stdout } = await pexec('bluetoothctl', args, { timeout: timeoutSec * 1000, maxBuffer: 1 << 20 });
    return stdout;
  } catch (e) {
    return (e.stdout || '') + (e.stderr || '');
  }
}

function parseDevices(out) {
  const res = [];
  for (const line of out.split('\n')) {
    const m = line.match(/Device\s+([0-9A-F:]{17})\s+(.*)/i);
    if (m) res.push({ mac: m[1].toUpperCase(), name: m[2].trim() });
  }
  return res;
}

// Scan for `seconds`, return all discovered devices.
export async function scan(seconds = 10) {
  await btctl(['--timeout', '2', 'power', 'on'], 5);
  await btctl(['--timeout', String(seconds), 'scan', 'on'], seconds + 6);
  return enrich(parseDevices(await btctl(['devices'])));
}

// Known devices with paired/connected status.
export async function knownDevices() {
  return enrich(parseDevices(await btctl(['devices'])));
}

async function enrich(devices) {
  const pairedMacs = new Set(parseDevices(await btctl(['paired-devices'])).map(d => d.mac));
  for (const d of devices) {
    d.paired = pairedMacs.has(d.mac);
    const info = await btctl(['info', d.mac]);
    d.connected = /Connected:\s*yes/i.test(info);
    d.audio = /Icon:\s*audio|UUID:.*(Headset|Handsfree|Audio Sink)/i.test(info);
  }
  return devices;
}

export async function pair(mac) {
  const r1 = await btctl(['--timeout', '25', 'pair', mac], 30);
  const r2 = await btctl(['trust', mac], 5);
  const r3 = await btctl(['--timeout', '15', 'connect', mac], 20);
  const info = await btctl(['info', mac]);
  return { pair: r1.trim(), trust: r2.trim(), connect: r3.trim(), connected: /Connected:\s*yes/i.test(info) };
}

// Full re-pair. realme (and many cheap earbuds) DISCARD their stored bond when
// put back in pairing mode, so the board's kept bond goes stale → plain connect
// or pair fails (AuthenticationFailed). Recipe: drop stale bond, rediscover
// (scan must be its own step), then pair+trust+connect fresh. All via
// bluetoothctl, so the callrec user can run it through the polkit rule.
export async function repair(mac) {
  await btctl(['disconnect', mac], 10);
  await btctl(['remove', mac], 10);
  await btctl(['--timeout', '2', 'power', 'on'], 5);
  await btctl(['--timeout', '12', 'scan', 'on'], 18); // rediscover after removal
  const found = parseDevices(await btctl(['devices'])).some(d => d.mac === mac.toUpperCase());
  if (!found) return { ok: false, step: 'scan', msg: 'Gerät nicht gefunden — im Pairing-Modus?' };
  const r1 = await btctl(['--timeout', '25', 'pair', mac], 30);
  await btctl(['trust', mac], 5);
  const r3 = await btctl(['--timeout', '15', 'connect', mac], 20);
  const info = await btctl(['info', mac]);
  const connected = /Connected:\s*yes/i.test(info);
  return { ok: connected, pair: r1.trim(), connect: r3.trim(), connected };
}

export async function connect(mac) {
  const out = await btctl(['--timeout', '15', 'connect', mac], 20);
  const info = await btctl(['info', mac]);
  return { out: out.trim(), connected: /Connected:\s*yes/i.test(info) };
}

export async function disconnect(mac) {
  return { out: (await btctl(['disconnect', mac], 10)).trim() };
}