// Shared "launch/view a student's disposable Lab" logic. Phase 5B extracted this out of
// server.js's original POST /api/environment/launch route body so the new entitlement-gated
// self-paced launch route (selfpaced-routes.js) can reuse the EXACT same Provisioner call and
// response shape instead of a second copy — the underlying disposable-Lab mechanism (Phase
// 2A-4.1) is completely unchanged either way, only who's allowed to reach it differs.

async function publicEnvView(provisioner, env) {
  if (!env) return { status: 'none' };
  const view = { status: env.status };
  if (env.status === 'running') {
    let token = env.routing_token && env.routing_token !== '[redacted]' ? env.routing_token : null;
    if (!token) {
      const { status, body } = await provisioner.getToken(env.environment_id);
      if (status === 200) token = body.routing_token;
    }
    if (token) view.launch_path = `/lab/${token}/`;
  }
  if (env.status === 'error') view.error_reason = 'Lab failed to start. You can try launching again.';
  return view;
}

async function launchEnvironmentForStudent(provisioner, studentId) {
  const existing = await provisioner.listForStudent(studentId);
  const active = existing.body?.find((e) => ['requested', 'provisioning', 'running', 'resetting'].includes(e.status));
  if (active) return { status: 200, body: await publicEnvView(provisioner, active) };

  const { status, body } = await provisioner.provision(studentId);
  if (status === 409) {
    const retry = await provisioner.listForStudent(studentId);
    return { status: 200, body: await publicEnvView(provisioner, retry.body?.[0]) };
  }
  if (status === 503 && body?.code === 'CAPACITY_EXCEEDED') {
    return { status: 503, body: { error: 'capacity_exceeded', message: 'Lab capacity is temporarily full. Try again shortly.' } };
  }
  if (status !== 201) return { status: 502, body: { error: 'provision_failed', message: body?.error } };
  return { status: 200, body: await publicEnvView(provisioner, { environment_id: body.environment_id, status: body.status, routing_token: body.routing_token }) };
}

module.exports = { publicEnvView, launchEnvironmentForStudent };