local firstArg = ...;
if firstArg == '-version' or firstArg == '--version' then
  print('v' .. require('/apis/libversion')().forSelf());
  return;
end

if firstArg == '-help' or firstArg == '--help' then
  print('Usage: ping [<id|label>]');
  return;
end

local createNet = require('/apis/net');
local net = createNet();

local args = table.pack(...);
local targetComputerId = tonumber(args[1]) or args[1];

local sourceId = os.getComputerID();
local sourceLabel = os.getComputerLabel();

local ok, results, packets = net.callMultiple('ping', 'ping', { destId = targetComputerId });

if not ok and targetComputerId ~= sourceId and targetComputerId ~= sourceLabel then
  error(results);
end

if not ok then return end

for k, message in ipairs(results) do
  if message == 'pong' then
    local packet = packets[k];
    print("=> pong from " .. tostring(packet.sourceId)
      .. (packet.sourceLabel and " (label=" .. tostring(packet.sourceLabel) .. ")" or ""));
  end
end