// Copyright 2019 The MediaPipe Authors.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

#include "mediapipe/examples/desktop/autoflip/quality/piecewise_linear_function.h"

#include <stddef.h>

#include <memory>

#include "mediapipe/framework/port/gtest.h"
#include "mediapipe/framework/port/status.h"

namespace {

using mediapipe::autoflip::PiecewiseLinearFunction;

// It should be OK to pass a spec that's out of order as it gets sorted.
TEST(PiecewiseLinearFunctionTest, ReordersSpec) {
  PiecewiseLinearFunction f;
  // This defines the line y = x between 0 and 5
  f.AddPoint(0, 0);
  f.AddPoint(1, 1);
  f.AddPoint(2, 2);
  f.AddPoint(3, 3);
  f.AddPoint(5, 5);

  // Should be 0 as -1 is less than the smallest x value in the spec so it
  // should saturate.
  ASSERT_EQ(0, f.Evaluate(-1));

  // These shoud all be on the line y = x
  ASSERT_EQ(0, f.Evaluate(0));
  ASSERT_EQ(0.5, f.Evaluate(0.5));
  ASSERT_EQ(4.5, f.Evaluate(4.5));
  ASSERT_EQ(5, f.Evaluate(5));

  // Saturating on the high end.
  ASSERT_EQ(5, f.Evaluate(6));
}

TEST(PiecewiseLinearFunctionTest, TestAddPoints) {
  PiecewiseLinearFunction function;
  function.AddPoint(0.0, 0.0);
  function.AddPoint(1.0, 1.0);
  EXPECT_DOUBLE_EQ(0.0, function.Evaluate(-1.0));
  EXPECT_DOUBLE_EQ(0.0, function.Evaluate(0.0));
  EXPECT_DOUBLE_EQ(0.25, function.Evaluate(0.25));
}

TEST(PiecewiseLinearFunctionTest, AddPointsDiscontinuous) {
  PiecewiseLinearFunction function;
  function.AddPoint(-1.0, 0.0);
  function.AddPoint(0.0, 0.0);
  function.AddPoint(0.0, 1.0);
  function.AddPoint(1.0, 1.0);
  EXPECT_DOUBLE_EQ(0.0, function.Evaluate(-1.0));
  EXPECT_DOUBLE_EQ(0.0, function.Evaluate(0.0));
  EXPECT_DOUBLE_EQ(1.0, function.Evaluate(1e-12));
  EXPECT_DOUBLE_EQ(1.0, function.Evaluate(3.14));
}

}  // namespace