// Copyright 2018 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "cc/input/scroll_snap_data.h"

#include "testing/gtest/include/gtest/gtest.h"

namespace cc {

class ScrollSnapDataTest : public testing::Test {};

TEST_F(ScrollSnapDataTest, StartAlignmentCalculation) {
  SnapContainerData container(
      ScrollSnapType(false, SnapAxis::kBoth, SnapStrictness::kMandatory),
      gfx::RectF(10, 10, 200, 300), gfx::ScrollOffset(600, 800));
  SnapAreaData area(ScrollSnapAlign(SnapAlignment::kStart),
                    gfx::RectF(100, 150, 100, 100), false);
  container.AddSnapAreaData(area);
  gfx::ScrollOffset current_position(0, 0);
  gfx::ScrollOffset snap_position;
  EXPECT_TRUE(
      container.FindSnapPosition(current_position, true, true, &snap_position));
  EXPECT_EQ(90, snap_position.x());
  EXPECT_EQ(140, snap_position.y());
}

TEST_F(ScrollSnapDataTest, CenterAlignmentCalculation) {
  SnapContainerData container(
      ScrollSnapType(false, SnapAxis::kBoth, SnapStrictness::kMandatory),
      gfx::RectF(10, 10, 200, 300), gfx::ScrollOffset(600, 800));
  SnapAreaData area(ScrollSnapAlign(SnapAlignment::kCenter),
                    gfx::RectF(100, 150, 100, 100), false);
  container.AddSnapAreaData(area);
  gfx::ScrollOffset current_position(0, 0);
  gfx::ScrollOffset snap_position;
  EXPECT_TRUE(
      container.FindSnapPosition(current_position, true, true, &snap_position));
  EXPECT_EQ(40, snap_position.x());
  EXPECT_EQ(40, snap_position.y());
}

TEST_F(ScrollSnapDataTest, EndAlignmentCalculation) {
  SnapContainerData container(
      ScrollSnapType(false, SnapAxis::kBoth, SnapStrictness::kMandatory),
      gfx::RectF(10, 10, 200, 200), gfx::ScrollOffset(600, 800));
  SnapAreaData area(ScrollSnapAlign(SnapAlignment::kEnd),
                    gfx::RectF(150, 200, 100, 100), false);
  container.AddSnapAreaData(area);
  gfx::ScrollOffset current_position(0, 0);
  gfx::ScrollOffset snap_position;
  EXPECT_TRUE(
      container.FindSnapPosition(current_position, true, true, &snap_position));
  EXPECT_EQ(40, snap_position.x());
  EXPECT_EQ(90, snap_position.y());
}

TEST_F(ScrollSnapDataTest, UnreachableSnapPositionCalculation) {
  SnapContainerData container(
      ScrollSnapType(false, SnapAxis::kBoth, SnapStrictness::kMandatory),
      gfx::RectF(0, 0, 200, 200), gfx::ScrollOffset(100, 100));
  SnapAreaData area(ScrollSnapAlign(SnapAlignment::kStart, SnapAlignment::kEnd),
                    gfx::RectF(200, 0, 100, 100), false);
  container.AddSnapAreaData(area);
  gfx::ScrollOffset current_position(50, 50);
  gfx::ScrollOffset snap_position;
  EXPECT_TRUE(
      container.FindSnapPosition(current_position, true, true, &snap_position));
  // Aligning to start on x would lead the scroll offset larger than max, and
  // aligning to end on y would lead the scroll offset smaller than zero. So
  // we expect these are clamped.
  EXPECT_EQ(100, snap_position.x());
  EXPECT_EQ(0, snap_position.y());
}

TEST_F(ScrollSnapDataTest, FindsClosestSnapPositionIndependently) {
  SnapContainerData container(
      ScrollSnapType(false, SnapAxis::kBoth, SnapStrictness::kMandatory),
      gfx::RectF(0, 0, 200, 200), gfx::ScrollOffset(600, 800));
  SnapAreaData snap_x_only(
      ScrollSnapAlign(SnapAlignment::kStart, SnapAlignment::kNone),
      gfx::RectF(80, 0, 150, 150), false);
  SnapAreaData snap_y_only(
      ScrollSnapAlign(SnapAlignment::kNone, SnapAlignment::kStart),
      gfx::RectF(0, 70, 150, 150), false);
  SnapAreaData snap_on_both(ScrollSnapAlign(SnapAlignment::kStart),
                            gfx::RectF(50, 150, 150, 150), false);
  gfx::ScrollOffset current_position(100, 100);
  container.AddSnapAreaData(snap_x_only);
  container.AddSnapAreaData(snap_y_only);
  container.AddSnapAreaData(snap_on_both);
  gfx::ScrollOffset snap_position;
  EXPECT_TRUE(
      container.FindSnapPosition(current_position, true, true, &snap_position));
  EXPECT_EQ(80, snap_position.x());
  EXPECT_EQ(70, snap_position.y());
}

TEST_F(ScrollSnapDataTest, FindsClosestSnapPositionOnAxisValueBoth) {
  SnapContainerData container(
      ScrollSnapType(false, SnapAxis::kBoth, SnapStrictness::kMandatory),
      gfx::RectF(0, 0, 200, 200), gfx::ScrollOffset(600, 800));
  SnapAreaData snap_x_only(
      ScrollSnapAlign(SnapAlignment::kStart, SnapAlignment::kNone),
      gfx::RectF(80, 0, 150, 150), false);
  SnapAreaData snap_y_only(
      ScrollSnapAlign(SnapAlignment::kNone, SnapAlignment::kStart),
      gfx::RectF(0, 70, 150, 150), false);
  SnapAreaData snap_on_both(ScrollSnapAlign(SnapAlignment::kStart),
                            gfx::RectF(50, 150, 150, 150), false);
  gfx::ScrollOffset current_position(40, 120);
  container.AddSnapAreaData(snap_x_only);
  container.AddSnapAreaData(snap_y_only);
  container.AddSnapAreaData(snap_on_both);
  gfx::ScrollOffset snap_position;
  EXPECT_TRUE(
      container.FindSnapPosition(current_position, true, true, &snap_position));
  EXPECT_EQ(50, snap_position.x());
  EXPECT_EQ(150, snap_position.y());
}

TEST_F(ScrollSnapDataTest, DoesNotSnapOnNonScrolledAxis) {
  SnapContainerData container(
      ScrollSnapType(false, SnapAxis::kBoth, SnapStrictness::kMandatory),
      gfx::RectF(0, 0, 200, 200), gfx::ScrollOffset(600, 800));
  SnapAreaData snap_x_only(
      ScrollSnapAlign(SnapAlignment::kStart, SnapAlignment::kNone),
      gfx::RectF(80, 0, 150, 150), false);
  SnapAreaData snap_y_only(
      ScrollSnapAlign(SnapAlignment::kNone, SnapAlignment::kStart),
      gfx::RectF(0, 70, 150, 150), false);
  gfx::ScrollOffset current_position(100, 100);
  container.AddSnapAreaData(snap_x_only);
  container.AddSnapAreaData(snap_y_only);
  gfx::ScrollOffset snap_position;
  EXPECT_TRUE(container.FindSnapPosition(current_position, true, false,
                                         &snap_position));
  EXPECT_EQ(80, snap_position.x());
  EXPECT_EQ(100, snap_position.y());
}

TEST_F(ScrollSnapDataTest, DoesNotSnapOnNonVisibleAreas) {
  SnapContainerData container(
      ScrollSnapType(false, SnapAxis::kBoth, SnapStrictness::kMandatory),
      gfx::RectF(0, 0, 200, 200), gfx::ScrollOffset(600, 800));
  SnapAreaData snap_x_only(
      ScrollSnapAlign(SnapAlignment::kStart, SnapAlignment::kNone),
      gfx::RectF(300, 400, 100, 100), false);
  SnapAreaData snap_y_only(
      ScrollSnapAlign(SnapAlignment::kNone, SnapAlignment::kStart),
      gfx::RectF(400, 300, 100, 100), false);
  gfx::ScrollOffset current_position(0, 0);
  container.AddSnapAreaData(snap_x_only);
  container.AddSnapAreaData(snap_y_only);
  gfx::ScrollOffset snap_position;
  EXPECT_FALSE(
      container.FindSnapPosition(current_position, true, true, &snap_position));
}

TEST_F(ScrollSnapDataTest, SnapOnClosestAxisFirstIfVisibilityConflicts) {
  SnapContainerData container(
      ScrollSnapType(false, SnapAxis::kBoth, SnapStrictness::kMandatory),
      gfx::RectF(0, 0, 200, 200), gfx::ScrollOffset(600, 800));
  gfx::ScrollOffset current_position(0, 0);

  // Both the areas are currently visible.
  // However, if we snap to them on x and y independently, none is visible after
  // snapping. So we only snap on the axis that has a closer snap point first.
  // After that, we look for another snap point on y axis which does not
  // conflict with the snap point on x.
  SnapAreaData snap_x(
      ScrollSnapAlign(SnapAlignment::kStart, SnapAlignment::kNone),
      gfx::RectF(150, 0, 100, 100), false);
  SnapAreaData snap_y1(
      ScrollSnapAlign(SnapAlignment::kNone, SnapAlignment::kStart),
      gfx::RectF(0, 180, 100, 100), false);
  SnapAreaData snap_y2(
      ScrollSnapAlign(SnapAlignment::kNone, SnapAlignment::kStart),
      gfx::RectF(250, 80, 100, 100), false);
  container.AddSnapAreaData(snap_x);
  container.AddSnapAreaData(snap_y1);
  container.AddSnapAreaData(snap_y2);
  gfx::ScrollOffset snap_position;
  EXPECT_TRUE(
      container.FindSnapPosition(current_position, true, true, &snap_position));
  EXPECT_EQ(150, snap_position.x());
  EXPECT_EQ(80, snap_position.y());
}

TEST_F(ScrollSnapDataTest, DoesNotSnapToPositionsOutsideProximityRange) {
  SnapContainerData container(
      ScrollSnapType(false, SnapAxis::kBoth, SnapStrictness::kMandatory),
      gfx::RectF(0, 0, 200, 200), gfx::ScrollOffset(600, 800));
  container.set_proximity_range(gfx::ScrollOffset(50, 50));

  gfx::ScrollOffset current_position(100, 100);
  SnapAreaData area(ScrollSnapAlign(SnapAlignment::kStart),
                    gfx::RectF(80, 160, 100, 100), false);
  container.AddSnapAreaData(area);
  gfx::ScrollOffset snap_position;
  EXPECT_TRUE(
      container.FindSnapPosition(current_position, true, true, &snap_position));

  // The snap position on x, 80, is within the proximity range of [50, 150].
  // However, the snap position on y, 160, is outside the proximity range of
  // [50, 150], so we should only snap on x.
  EXPECT_EQ(80, snap_position.x());
  EXPECT_EQ(100, snap_position.y());
}

}  // namespace cc