#include "../sources/OnePoleFilter.h"
#include "catch2/catch.hpp"
#include "cnpy.h"
#include "gsl/gsl-lite.hpp"
#include <string>
#include <filesystem>
#include <algorithm>
using namespace Catch::literals;

template<class Type>
inline bool approxEqual(const std::vector<Type>& lhs, const std::vector<Type>& rhs)
{
    if (lhs.size() != rhs.size())
        return false;

    for (size_t i = 0; i < rhs.size(); ++i)
        if (lhs[i] != Approx(rhs[i]).epsilon(1e-3))
        {
            std::cerr << lhs[i] << " != " << rhs[i] << " at index " << i << '\n';
            return false;
        }

    return true;
}

template<class Type>
void testLowpass(const std::filesystem::path& inputNumpyFile, const std::filesystem::path& outputNumpyFile, Type gain)
{
    const auto input = cnpy::npy_load(inputNumpyFile.string());
    REQUIRE( input.word_size == 8 );
    const auto inputSpan = gsl::make_span(input.data<double>(), input.shape[0]);

    const auto output = cnpy::npy_load(outputNumpyFile.string());
    REQUIRE( output.word_size == 8 );
    const auto outputSpan = gsl::make_span(output.data<double>(), output.shape[0]);
    auto size = std::min(outputSpan.size(), inputSpan.size());
    REQUIRE( size > 0 );

    std::vector<Type> inputData;
    std::vector<Type> expectedData;
    inputData.reserve(size);
    expectedData.reserve(size);
    for (auto& data: inputSpan)
        inputData.push_back(static_cast<Type>(data));
    for (auto& data: outputSpan)
        expectedData.push_back(static_cast<Type>(data));
    
    OnePoleFilter filter { gain };
    std::vector<Type> outputData (size);
    filter.processLowpass(inputData, outputData);
    REQUIRE( approxEqual(outputData, expectedData) );

    filter.reset();
    std::fill(outputData.begin(), outputData.end(), 0.0);
    std::vector<Type> gains(size);
    std::fill(gains.begin(), gains.end(), gain);
    filter.processLowpassVariableGain(inputData, outputData, gains);
    REQUIRE( approxEqual(outputData, expectedData) );
}

template<class Type>
void testHighpass(const std::filesystem::path& inputNumpyFile, const std::filesystem::path& outputNumpyFile, Type gain)
{
    const auto input = cnpy::npy_load(inputNumpyFile.string());
    REQUIRE( input.word_size == 8 );
    const auto inputSpan = gsl::make_span(input.data<double>(), input.shape[0]);

    const auto output = cnpy::npy_load(outputNumpyFile.string());
    REQUIRE( output.word_size == 8 );
    const auto outputSpan = gsl::make_span(output.data<double>(), output.shape[0]);
    auto size = std::min(outputSpan.size(), inputSpan.size());
    REQUIRE( size > 0 );

    std::vector<Type> inputData;
    std::vector<Type> expectedData;
    inputData.reserve(size);
    expectedData.reserve(size);
    for (auto& data: inputSpan)
        inputData.push_back(static_cast<Type>(data));
    for (auto& data: outputSpan)
        expectedData.push_back(static_cast<Type>(data));
    
    OnePoleFilter filter { gain };
    std::vector<Type> outputData (size);
    filter.processHighpass(inputData, outputData);
    REQUIRE( approxEqual(outputData, expectedData) );

    filter.reset();
    std::fill(outputData.begin(), outputData.end(), 0.0);
    std::vector<Type> gains(size);
    std::fill(gains.begin(), gains.end(), gain);
    filter.processHighpassVariableGain(inputData, outputData, gains);
    REQUIRE( approxEqual(outputData, expectedData) );
}

TEST_CASE("[OnePoleFilter] Lowpass Float")
{
    testLowpass<float>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.1.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_low_gain_0.1.npy",
        0.1f
    );
    testLowpass<float>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.3.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_low_gain_0.3.npy",
        0.3f
    );
    testLowpass<float>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.5.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_low_gain_0.5.npy",
        0.5f
    );
    testLowpass<float>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.7.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_low_gain_0.7.npy",
        0.7f
    );
    testLowpass<float>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.9.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_low_gain_0.9.npy",
        0.9f
    );
}

TEST_CASE("[OnePoleFilter] Lowpass Double")
{
    testLowpass<double>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.1.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_low_gain_0.1.npy",
        0.1f
    );
    testLowpass<double>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.3.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_low_gain_0.3.npy",
        0.3f
    );
    testLowpass<double>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.5.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_low_gain_0.5.npy",
        0.5f
    );
    testLowpass<double>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.7.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_low_gain_0.7.npy",
        0.7f
    );
    testLowpass<double>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.9.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_low_gain_0.9.npy",
        0.9f
    );
}

TEST_CASE("[OnePoleFilter] Highpass Float")
{
    testHighpass<float>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.1.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_high_gain_0.1.npy",
        0.1f
    );
    testHighpass<float>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.3.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_high_gain_0.3.npy",
        0.3f
    );
    testHighpass<float>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.5.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_high_gain_0.5.npy",
        0.5f
    );
    testHighpass<float>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.7.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_high_gain_0.7.npy",
        0.7f
    );
    testHighpass<float>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.9.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_high_gain_0.9.npy",
        0.9f
    );
}

TEST_CASE("[OnePoleFilter] Highpass Double")
{
    testHighpass<double>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.1.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_high_gain_0.1.npy",
        0.1f
    );
    testHighpass<double>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.3.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_high_gain_0.3.npy",
        0.3f
    );
    testHighpass<double>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.5.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_high_gain_0.5.npy",
        0.5f
    );
    testHighpass<double>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.7.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_high_gain_0.7.npy",
        0.7f
    );
    testHighpass<double>(
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_input_gain_0.9.npy",
        std::filesystem::current_path() / "tests/TestFiles/OnePoleFilter/OPF_high_gain_0.9.npy",
        0.9f
    );
}