/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2018 - ROLI Ltd.

   JUCE is an open source library subject to commercial or open-source
   licensing.

   The code included in this file is provided under the terms of the ISC license
   http://www.isc.org/downloads/software-support-policy/isc-license. Permission
   To use, copy, modify, and/or distribute this software for any purpose with or
   without fee is hereby granted provided that the above copyright notice and
   this permission notice appear in all copies.

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

#if JUCE_UNIT_TESTS

template <class SmoothedValueType>
class CommonSmoothedValueTests  : public UnitTest
{
public:
    CommonSmoothedValueTests()
        : UnitTest ("CommonSmoothedValueTests", "SmoothedValues")
    {}

    void runTest() override
    {
        beginTest ("Initial state");
        {
            SmoothedValueType sv;

            auto value = sv.getCurrentValue();
            expectEquals (sv.getTargetValue(), value);

            sv.getNextValue();
            expectEquals (sv.getCurrentValue(), value);
            expect (! sv.isSmoothing());
        }

        beginTest ("Resetting");
        {
            auto initialValue = 15.0f;

            SmoothedValueType sv (initialValue);
            sv.reset (3);
            expectEquals (sv.getCurrentValue(), initialValue);

            auto targetValue = initialValue + 1.0f;
            sv.setTargetValue (targetValue);
            expectEquals (sv.getTargetValue(), targetValue);
            expectEquals (sv.getCurrentValue(), initialValue);
            expect (sv.isSmoothing());

            auto currentValue = sv.getNextValue();
            expect (currentValue > initialValue);
            expectEquals (sv.getCurrentValue(), currentValue);
            expectEquals (sv.getTargetValue(), targetValue);
            expect (sv.isSmoothing());

            sv.reset (5);

            expectEquals (sv.getCurrentValue(), targetValue);
            expectEquals (sv.getTargetValue(),  targetValue);
            expect (! sv.isSmoothing());

            sv.getNextValue();
            expectEquals (sv.getCurrentValue(), targetValue);

            sv.setTargetValue (1.5f);
            sv.getNextValue();

            float newStart = 0.2f;
            sv.setCurrentAndTargetValue (newStart);
            expectEquals (sv.getNextValue(), newStart);
            expectEquals (sv.getTargetValue(), newStart);
            expectEquals (sv.getCurrentValue(), newStart);
            expect (! sv.isSmoothing());
        }

        beginTest ("Sample rate");
        {
            SmoothedValueType svSamples { 3.0f };
            auto svTime = svSamples;

            auto numSamples = 12;

            svSamples.reset (numSamples);
            svTime.reset (numSamples * 2, 1.0);

            for (int i = 0; i < numSamples; ++i)
            {
                svTime.skip (1);
                expectWithinAbsoluteError (svSamples.getNextValue(),
                                           svTime.getNextValue(),
                                           1.0e-7f);
            }
        }

        beginTest ("Block processing");
        {
            SmoothedValueType sv (1.0f);

            sv.reset (12);
            sv.setTargetValue (2.0f);

            const auto numSamples = 15;

            AudioBuffer<float> referenceData (1, numSamples);

            for (int i = 0; i < numSamples; ++i)
                referenceData.setSample (0, i, sv.getNextValue());

            expect (referenceData.getSample (0, 0) > 0);
            expect (referenceData.getSample (0, 10) < sv.getTargetValue());
            expectWithinAbsoluteError (referenceData.getSample (0, 11),
                                       sv.getTargetValue(),
                                       1.0e-7f);

            auto getUnitData = [] (int numSamplesToGenerate)
            {
                AudioBuffer<float> result (1, numSamplesToGenerate);

                for (int i = 0; i < numSamplesToGenerate; ++i)
                    result.setSample (0, i, 1.0f);

                return result;
            };

            auto compareData = [this](const AudioBuffer<float>& test,
                                      const AudioBuffer<float>& reference)
            {
                for (int i = 0; i < test.getNumSamples(); ++i)
                    expectWithinAbsoluteError (test.getSample (0, i),
                                               reference.getSample (0, i),
                                               1.0e-7f);
            };

            auto testData = getUnitData (numSamples);
            sv.setCurrentAndTargetValue (1.0f);
            sv.setTargetValue (2.0f);
            sv.applyGain (testData.getWritePointer (0), numSamples);
            compareData (testData, referenceData);

            testData = getUnitData (numSamples);
            AudioBuffer<float> destData (1, numSamples);
            sv.setCurrentAndTargetValue (1.0f);
            sv.setTargetValue (2.0f);
            sv.applyGain (destData.getWritePointer (0),
                           testData.getReadPointer (0),
                           numSamples);
            compareData (destData, referenceData);
            compareData (testData, getUnitData (numSamples));

            testData = getUnitData (numSamples);
            sv.setCurrentAndTargetValue (1.0f);
            sv.setTargetValue (2.0f);
            sv.applyGain (testData, numSamples);
            compareData (testData, referenceData);
        }

        beginTest ("Skip");
        {
            SmoothedValueType sv;

            sv.reset (12);
            sv.setCurrentAndTargetValue (1.0f);
            sv.setTargetValue (2.0f);

            Array<float> reference;

            for (int i = 0; i < 15; ++i)
                reference.add (sv.getNextValue());

            sv.setCurrentAndTargetValue (1.0f);
            sv.setTargetValue (2.0f);

            expectWithinAbsoluteError (sv.skip (1), reference[0], 1.0e-6f);
            expectWithinAbsoluteError (sv.skip (1), reference[1], 1.0e-6f);
            expectWithinAbsoluteError (sv.skip (2), reference[3], 1.0e-6f);
            sv.skip (3);
            expectWithinAbsoluteError (sv.getCurrentValue(), reference[6], 1.0e-6f);
            expectEquals (sv.skip (300), sv.getTargetValue());
            expectEquals (sv.getCurrentValue(), sv.getTargetValue());
        }

        beginTest ("Negative");
        {
            SmoothedValueType sv;

            auto start = -1.0f, end = -2.0f;
            auto numValues = 12;

            sv.reset (numValues);
            sv.setCurrentAndTargetValue (start);
            sv.setTargetValue (end);

            auto val = sv.skip (3);
            expect (val < start && val > end);

            auto nextVal = sv.getNextValue();
            expect (nextVal < val);

            auto endVal = sv.skip (500);
            expectEquals (endVal, end);
            expectEquals (sv.getNextValue(), end);
            expectEquals (sv.getCurrentValue(), end);

            sv.setCurrentAndTargetValue (start);
            sv.reset (numValues);
            sv.setTargetValue (end);

            SmoothedValueType positiveSv { -start };
            positiveSv.reset (numValues);
            positiveSv.setTargetValue (-end);

            for (int i = 0; i < numValues + 2; ++i)
                expectEquals (sv.getNextValue(), -positiveSv.getNextValue());
        }
    }
};

static CommonSmoothedValueTests <SmoothedValue<float, ValueSmoothingTypes::Linear>> commonLinearSmoothedValueTests;
static CommonSmoothedValueTests <SmoothedValue<float, ValueSmoothingTypes::Multiplicative>> commonMultiplicativeSmoothedValueTests;

class SmoothedValueTests  : public UnitTest
{
public:
    SmoothedValueTests()
        : UnitTest ("SmoothedValueTests", "SmoothedValues")
    {}

    void runTest() override
    {
        beginTest ("Linear moving target");
        {
            SmoothedValue<float, ValueSmoothingTypes::Linear> sv;

            sv.reset (12);
            float initialValue = 0.0f;
            sv.setCurrentAndTargetValue (initialValue);
            sv.setTargetValue (1.0f);

            auto delta = sv.getNextValue() - initialValue;

            sv.skip (6);

            auto newInitialValue = sv.getCurrentValue();
            sv.setTargetValue (newInitialValue + 2.0f);
            auto doubleDelta = sv.getNextValue() - newInitialValue;

            expectWithinAbsoluteError (doubleDelta, delta * 2.0f, 1.0e-7f);
        }

        beginTest ("Multiplicative curve");
        {
            SmoothedValue<double, ValueSmoothingTypes::Multiplicative> sv;

            auto numSamples = 12;
            AudioBuffer<double> values (2, numSamples + 1);

            sv.reset (numSamples);
            sv.setCurrentAndTargetValue (1.0);
            sv.setTargetValue (2.0f);

            values.setSample (0, 0, sv.getCurrentValue());

            for (int i = 1; i < values.getNumSamples(); ++i)
                values.setSample (0, i, sv.getNextValue());

            sv.setTargetValue (1.0f);
            values.setSample (1, values.getNumSamples() - 1, sv.getCurrentValue());

            for (int i = values.getNumSamples() - 2; i >= 0 ; --i)
                values.setSample (1, i, sv.getNextValue());

            for (int i = 0; i < values.getNumSamples(); ++i)
                expectWithinAbsoluteError (values.getSample (0, i), values.getSample (1, i), 1.0e-9);
        }
    }
};

static SmoothedValueTests smoothedValueTests;

#endif

} // namespace juce