<!DOCTYPE html>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../resources/webxr_util.js"></script>
<script src="../resources/webxr_math_utils.js"></script>
<script src="../resources/webxr_test_asserts.js"></script>
<script src="../resources/webxr_test_constants.js"></script>
<script src="../resources/webxr_test_constants_fake_world.js"></script>

<script>

// 1m above world origin.
const VIEWER_ORIGIN_TRANSFORM = {
  position: [0, 1, 0],
  orientation: [0, 0, 0, 1],
};

// 0.25m above world origin.
const FLOOR_ORIGIN_TRANSFORM = {
  position: [0, -0.25, 0],
  orientation: [0, 0, 0, 1],
};

// Start the screen pointer at the same place as the viewer, so it's essentially
// coming straight forward from the middle of the screen.
const SCREEN_POINTER_TRANSFORM = VIEWER_ORIGIN_TRANSFORM;

const screen_controller_init = {
    handedness: "none",
    targetRayMode: "screen",
    pointerOrigin: SCREEN_POINTER_TRANSFORM,  // aka mojo_from_pointer
    profiles: ["generic-touchscreen",]
};

const fakeDeviceInitParams = {
  supportedModes: ["immersive-ar"],
  views: VALID_VIEWS,
  floorOrigin: FLOOR_ORIGIN_TRANSFORM,    // aka floor_from_mojo
  viewerOrigin: VIEWER_ORIGIN_TRANSFORM,  // aka mojo_from_viewer
  supportedFeatures: ALL_FEATURES,
  world: createFakeWorld(5.0, 2.0, 5.0),  // see webxr_test_constants_fake_world.js for details
};

// Generates a test function given the parameters for the transient hit test.
// |ray| - ray that will be used to subscribe to hit test.
// |expectedPoses| - array of expected pose objects. The poses should be expressed in local space.
//                   Null entries in the array mean that the given entry will not be validated.
// |inputFromPointer| - input from pointer transform that will be used as the input source's
//                      inputFromPointer (aka pointer origin) in subsequent rAF.
// |nextFrameExpectedPoses| - array of expected pose objects. The poses should be expressed in local space.
//                            Null entries in the array mean that the given entry will not be validated.
let testFunctionGenerator = function(ray, expectedPoses, inputFromPointer, nextFrameExpectedPoses) {
  const testFunction = function(session, fakeDeviceController, t) {
    let debug = xr_debug.bind(this, 'testFunction');
    return session.requestReferenceSpace('local').then((localRefSpace) => new Promise((resolve, reject) => {

      const input_source_controller = fakeDeviceController.simulateInputSourceConnection(screen_controller_init);

      requestSkipAnimationFrame(session, (time, frame) => {
        debug('rAF 1');
        t.step(() => {
          assert_equals(session.inputSources.length, 1);
        });

        const hitTestOptionsInit = {
          profile: "generic-touchscreen",
          offsetRay: ray,
        };

        session.requestHitTestSourceForTransientInput(hitTestOptionsInit)
               .then((hitTestSource) => {
          t.step(() => {
            assert_not_equals(hitTestSource, null);
          });

          // We got a hit test source, now get the results in subsequent rAFcb:
          session.requestAnimationFrame((time, frame) => {
            debug('rAF 2');
            const results = frame.getHitTestResultsForTransientInput(hitTestSource);

            t.step(() => {
              assert_true(results != null, "Transient input hit tests should not be null");
              assert_equals(results.length, 1, "There should be exactly one group of transient hit test results!");
              assert_equals(results[0].results.length, expectedPoses.length);
              for(const [index, expectedPose] of expectedPoses.entries()) {
                const pose = results[0].results[index].getPose(localRefSpace);
                assert_true(pose != null, "Each hit test result should have a pose in local space");
                if(expectedPose != null) {
                  assert_transform_approx_equals(pose.transform, expectedPose, FLOAT_EPSILON, "before-move-pose: ");
                }
              }
            });

            input_source_controller.setPointerOrigin(inputFromPointer, false);

            session.requestAnimationFrame((time, frame) => {
              debug('rAF 3');
              const results = frame.getHitTestResultsForTransientInput(hitTestSource);

              t.step(() => {
                assert_equals(results[0].results.length, nextFrameExpectedPoses.length);
                for(const [index, expectedPose] of nextFrameExpectedPoses.entries()) {
                  const pose = results[0].results[index].getPose(localRefSpace);
                  assert_true(pose != null, "Each hit test result should have a pose in local space");
                  if(expectedPose != null) {
                    assert_transform_approx_equals(pose.transform, expectedPose, FLOAT_EPSILON, "after-move-pose: ");
                  }
                }
              });

              debug('resolving');
              resolve();
            });
          });
        });
      });
    }));
  };

  return testFunction;
};


// Pose of the first expected hit test result - straight ahead of the input source, viewer-facing.
const pose_1 = {
  position: {x: 0.0, y: 1.0, z: -2.5, w: 1.0},
  orientation: {x: 0.0, y: -0.707, z: -0.707, w: 0.0},
    // Hit test API will set Y axis to the surface normal at the intersection point,
    // Z axis towards the ray origin and X axis to cross product of Y axis & Z axis.
    // If the surface normal and Z axis would be parallel, the hit test API
    // will attempt to use `up` vector ([0, 1, 0]) as the Z axis, and if it so happens that Z axis
    // and the surface normal would still be parallel, it will use the `right` vector ([1, 0, 0]) as the Z axis.
    // In this particular case, `up` vector will work so the resulting pose.orientation
    // becomes a rotation around [0, 1, 1] vector by 180 degrees.
};

xr_session_promise_test("Ensures subscription to transient hit test works with an XRSpace from input source - no move",
  testFunctionGenerator(new XRRay(), [pose_1], SCREEN_POINTER_TRANSFORM, [pose_1]),
  fakeDeviceInitParams,
  'immersive-ar', { 'requiredFeatures': ['hit-test'] });

const moved_pointer_transform_1 = {
  position: [0, 1, 0],
  orientation: [ 0.707, 0, 0, 0.707 ] // 90 degrees around X axis = facing up
};

xr_session_promise_test("Ensures subscription to transient hit test works with an XRSpace from input source - after move - no results",
  testFunctionGenerator(new XRRay(), [pose_1], moved_pointer_transform_1, []),
  fakeDeviceInitParams,
  'immersive-ar', { 'requiredFeatures': ['hit-test'] });

const pose_2 = {
  position: {x: -1.443, y: 1.0, z: -2.5, w: 1.0},
    // Intersection point will be on the same height as the viewer, on the front
    // wall. Distance from the front wall to viewer is 2.5m, and we are rotating
    // to the left, so X coordinate of the intersection point will be negative
    // & equal to -2.5 * tan(30 deg) ~= 1.443m.
  orientation: {x: 0.5, y: 0.5, z: 0.5, w: 0.5 },
    // See comment for pose_1.orientation for details.
    // In this case, the hit test pose will have Y axis facing towards world's
    // positive Z axis ([0,0,1]), Z axis to the right ([1,0,0]) and X axis
    // towards world's Y axis ([0,1,0]).
    // This is equivalent to the rotation around [1, 1, 1] vector by 120 degrees.
};

const moved_pointer_transform_2 = {
  position: [0, 1, 0],
  orientation: [ 0, 0.2588, 0, 0.9659 ] // 30 degrees around Y axis = to the left,
                                        // creating 30-60-90 triangle with the front wall
};

xr_session_promise_test("Ensures subscription to transient hit test works with an XRSpace from input source - after move - 1 result",
  testFunctionGenerator(new XRRay(), [pose_1], moved_pointer_transform_2, [pose_2]),
  fakeDeviceInitParams,
  'immersive-ar', { 'requiredFeatures': ['hit-test'] });

</script>
