-- Eventloop behavior tests for the CraftOS-PC harness.
local createEventLoop = require('/apis/eventloop');
local createLibTest = require('/apis/libtest');

local testlib = createLibTest({ ... });

testlib.test('register dispatches queued event args', function()
  local events = createEventLoop();
  local called = 0;

  events.register('eventloop_test_basic', function(a, b)
    called = called + 1;
    testlib.assertEquals(a, 'first');
    testlib.assertEquals(b, 42);
    events.stopLoop();
  end);

  os.queueEvent('eventloop_test_basic', 'first', 42);
  events.runLoop();

  testlib.assertEquals(called, 1);
  testlib.assertTrue(not events.isRunningLoop());
end);

testlib.test('STOP unregisters handler after first call', function()
  local events = createEventLoop();
  local stoppedHandlerCalls = 0;
  local observerCalls = 0;

  events.register('eventloop_test_stop', function()
    stoppedHandlerCalls = stoppedHandlerCalls + 1;
    return events.STOP;
  end);

  events.register('eventloop_test_stop', function()
    observerCalls = observerCalls + 1;
    if observerCalls == 1 then
      os.queueEvent('eventloop_test_stop');
    else
      events.stopLoop();
    end
  end);

  os.queueEvent('eventloop_test_stop');
  events.runLoop();

  testlib.assertEquals(stoppedHandlerCalls, 1);
  testlib.assertEquals(observerCalls, 2);
end);

testlib.test('manual unregister prevents dispatch', function()
  local events = createEventLoop();
  local called = 0;
  local dispose = events.register('eventloop_test_unregister', function()
    called = called + 1;
  end);

  events.setTimeout(function()
    events.stopLoop();
  end, 0);
  dispose();

  os.queueEvent('eventloop_test_unregister');
  events.runLoop();

  testlib.assertEquals(called, 0);
end);

testlib.test('setTimeout before runLoop fires once', function()
  local events = createEventLoop();
  local called = 0;

  events.setTimeout(function()
    called = called + 1;
    events.stopLoop();
  end, 0);

  events.runLoop();

  testlib.assertEquals(called, 1);
end);

testlib.test('setTimeout during runLoop fires after event handler', function()
  local events = createEventLoop();
  local order = '';

  events.register('eventloop_test_runtime_timeout', function()
    order = order .. 'event>';
    events.setTimeout(function()
      order = order .. 'timeout';
      events.stopLoop();
    end, 0);
    return events.STOP;
  end);

  os.queueEvent('eventloop_test_runtime_timeout');
  events.runLoop();

  testlib.assertEquals(order, 'event>timeout');
end);

testlib.test('cleared timeout before runLoop does not fire', function()
  local events = createEventLoop();
  local called = 0;

  local clear = events.setTimeout(function()
    called = called + 1;
  end, 0);
  clear();

  events.setTimeout(function()
    events.stopLoop();
  end, 0);
  events.runLoop();

  testlib.assertEquals(called, 0);
end);

testlib.test('onStart and onStop run around loop', function()
  local events = createEventLoop();
  local order = '';

  events.onStart(function()
    order = order .. 'start>';
  end);

  events.onStop(function()
    order = order .. 'stop';
  end);

  events.setTimeout(function()
    order = order .. 'timeout>';
    events.stopLoop();
  end, 0);

  events.runLoop();

  testlib.assertEquals(order, 'start>timeout>stop');
end);

testlib.test('empty loop returns and runs onStop', function()
  local events = createEventLoop();
  local stopped = false;

  events.onStop(function()
    stopped = true;
  end);

  events.runLoop();

  testlib.assertTrue(stopped);
  testlib.assertTrue(not events.isRunningLoop());
end);

testlib.test('error contracts are enforced', function()
  local events = createEventLoop();
  local function handler()
  end

  events.register('eventloop_test_errors', handler);

  testlib.assertErrors(function()
    events.register('eventloop_test_errors', handler);
  end, 'handler already registered');

  testlib.assertErrors(function()
    events.stopLoop();
  end, 'loop is already stopped');

  testlib.assertErrors(function()
    events.register(1, handler);
  end, 'string expected');

  testlib.assertErrors(function()
    events.register('eventloop_test_errors_2', 'not a function');
  end, 'function expected');
end);

testlib.run();