// SPDX-License-Identifier: BSD-3-Clause
// Copyright Contributors to the OpenColorIO Project.


#ifndef OPENCOLORIO_GPU_UNITTEST_H
#define OPENCOLORIO_GPU_UNITTEST_H

#include <functional>
#include <string>
#include <vector>

#include "CPUInfoConfig.h"

class OCIOGPUTest;

using OCIOTestFuncCallback = std::function<void(OCIOGPUTest & test)>;


// Test harness for comparing GPU results to CPU results.
//
// By default, the framework compares the GPU results to the CPU results
// using an automatically generated neutral ramp for the standard range [0, 1].
// 
class OCIOGPUTest
{
    public:
        // The structure holds color values to check.
        struct CustomValues
        {
            typedef std::vector<float> Values;
            Values m_inputValues;

            // Keeping the original input value size allows 
            // to avoid manipulating padded values added to fit
            // the predefined GPU texture size.
            size_t m_originalInputValueSize{ 0 };
        };

    public:
        OCIOGPUTest(const std::string& testgroup, const std::string& testname, OCIOTestFuncCallback test);

        ~OCIOGPUTest() = default;

        inline const std::string& group() const  { return m_group; }
        inline const std::string& name() const  { return m_name; }

        void setProcessor(OCIO_NAMESPACE::ConstConfigRcPtr config,
                          OCIO_NAMESPACE::TransformRcPtr transform);

        void setProcessor(OCIO_NAMESPACE::TransformRcPtr transform);

        void setProcessor(OCIO_NAMESPACE::ConstProcessorRcPtr processor);
    
        void setShadingLanguage(OCIO_NAMESPACE::GpuLanguage gpuShadingLanguage)
        {
            m_gpuShadingLanguage = gpuShadingLanguage;
        }

        inline OCIO_NAMESPACE::ConstProcessorRcPtr & getProcessor() { return m_processor; }
        OCIO_NAMESPACE::GpuShaderDescRcPtr & getShaderDesc();

        // Set TestWideRange to true to use test values on [-1,2] rather than [0,1].
        inline bool getTestWideRange() const { return m_testWideRange; }
        inline void setTestWideRange(bool use) { m_testWideRange = use; }

        // Set TestNaN to true to include NaNs in each channel of the test values.
        inline bool getTestNaN() const { return m_testNaN; }
        inline void setTestNaN(bool use) { m_testNaN = use; }

        // Set TestInfinity to true to include positive and negative infinity
        // in each channel of the test values.
        inline bool getTestInfinity() const { return m_testInfinity; }
        inline void setTestInfinity(bool use) { m_testInfinity = use; }

        // Provide a set of RGBA values to test (otherwise a neutral ramp will be used).
        // TestWideRange, TestNaN & TestInfinity are used when m_inputValues is empty. 
        inline void setCustomValues(CustomValues & values) { m_values = values; }
        inline CustomValues & getCustomValues() { return m_values; }

        inline float getErrorThreshold() const { return m_errorThreshold; }
        inline void setErrorThreshold(float error) { m_errorThreshold = error; }

        inline bool getRelativeComparison() const { return m_performRelativeComparison; }
        inline void setRelativeComparison(bool relCompare) { m_performRelativeComparison = relCompare; }

        // This is the lower bound for the value that is divided into the absolute error 
        // to obtain the relative error.
        inline float getExpectedMinimalValue() const { return m_expectedMinimalValue; }
        inline void setExpectedMinimalValue(float minValue) { m_expectedMinimalValue = minValue; }

        // Dump or not the gpu shader program
        inline void setVerbose(bool verbose) { m_verbose = verbose; }
        inline bool isVerbose() const { return m_verbose; }

        inline void setLegacyShader(bool legacy) { m_legacyShader = legacy; }
        inline bool isLegacyShader() const { return m_legacyShader; }

        inline void setLegacyShaderLutEdge(unsigned lutEdge) { m_legacyShaderLutEdge = lutEdge; }
        inline unsigned getLegacyShaderLutEdge() const { return m_legacyShaderLutEdge; }

        inline void setup() { m_function(*this); }

        inline bool isValid() { return (bool)m_processor; }

        inline void disable() { m_enabled = false; }
        inline bool isEnabled() const { return m_enabled; }

        // Testing dynamic properties requires to run several times the same
        // unit test with the same shader code with some dynamic property
        // value changes. Registering n callbacks (i.e. each callback changing
        // a value for example) would run 1+n times the unit test.
        // Test runs, then for each callback, it is called and test runs again.
        // See ECOps_test.cpp for an example.
        typedef std::function<void()> RetestSetupCallback;
        inline void addRetest(RetestSetupCallback & retest)
        {
            m_retests.push_back(retest);
        }

        inline size_t getNumRetests() const
        {
            return m_retests.size();
        }

        void retestSetup(size_t idx);

        inline void updateMaxDiff(float maxDiff, size_t idxDiff)
        {
            if (maxDiff > m_maxDiff)
            {
                m_maxDiff = maxDiff;
                m_idxDiff = idxDiff;
            }
        }
        inline float getMaxDiff() const
        {
            return m_maxDiff;
        }
        inline size_t getMaxDiffIndex() const
        {
            return m_idxDiff;
        }

    private:
        const std::string m_group, m_name;
        OCIOTestFuncCallback m_function;
        OCIO_NAMESPACE::ConstProcessorRcPtr m_processor;
        OCIO_NAMESPACE::GpuShaderDescRcPtr m_shaderDesc;
        float m_errorThreshold;
        float m_expectedMinimalValue{ 1e-6f };
        float m_maxDiff{ 0.f };
        size_t m_idxDiff{ 0 };
        bool m_testWideRange{ true };
        bool m_testNaN{ true };
        bool m_testInfinity{ true };
        bool m_performRelativeComparison{ false };
        bool m_verbose{ false };
        bool m_enabled{ true };
        bool m_legacyShader{ false };
        unsigned m_legacyShaderLutEdge{ 32 };
        CustomValues m_values;
        OCIO_NAMESPACE::GpuLanguage m_gpuShadingLanguage {OCIO_NAMESPACE::GPU_LANGUAGE_GLSL_1_2};

        std::vector<RetestSetupCallback> m_retests;

};

typedef std::shared_ptr<OCIOGPUTest> OCIOGPUTestRcPtr;
typedef std::vector<OCIOGPUTestRcPtr> UnitTests;

UnitTests& GetUnitTests();

struct AddTest { explicit AddTest(OCIOGPUTestRcPtr test); };


// Use this macro to declare a test and provide a setup function for the test.
// Note: Add a SonarCloud tag to suppress all warnings for the following method.
#define OCIO_ADD_GPU_TEST(group, name)                                    \
    static void ocio_gputest_##group##_##name(OCIOGPUTest & test);        \
    AddTest ocio_##group##_##name(                                        \
        std::make_shared<OCIOGPUTest>(#group,                             \
                                      #name,                              \
                                      ocio_gputest_##group##_##name));    \
    /* @SuppressWarnings('all') */                                        \
    static void ocio_gputest_##group##_##name(OCIOGPUTest & test)

// Use this macro inside OCIO_ADD_GPU_TEST function to disable the test.
// The remaining of the function implementation will be skipped.
#define OCIO_DISABLE_GPU_TEST() \
    test.disable();             \
    if (!test.isEnabled()) return; // Test to avoid unreachable code warning.

#endif /* OPENCOLORIO_GPU_UNITTEST_H */