#include "gtest/gtest.h"

#include "RiaWeightedHarmonicMeanCalculator.h"
#include <cmath>

#include <numeric>

//--------------------------------------------------------------------------------------------------
/// 
//--------------------------------------------------------------------------------------------------
TEST(RiaWeightedHarmonicMeanCalculator, BasicUsage)
{
    {
        RiaWeightedHarmonicMeanCalculator calc;

        EXPECT_DOUBLE_EQ(0.0, calc.aggregatedWeight());
        EXPECT_FALSE(calc.validAggregatedWeight());
    }


    {
        RiaWeightedHarmonicMeanCalculator calc;

        std::vector<double> values {1, 4, 4};
        std::vector<double> weights {1, 1, 1};

        for (size_t i = 0; i< values.size(); i++)
        {
            calc.addValueAndWeight(values[i], weights[i]);
        }

        double expectedValue = 2.0;

        EXPECT_DOUBLE_EQ(3.0, calc.aggregatedWeight());
        EXPECT_NEAR(expectedValue, calc.weightedMean(), 1e-10);
    }
}

//--------------------------------------------------------------------------------------------------
/// 
//--------------------------------------------------------------------------------------------------
TEST(RiaWeightedHarmonicMeanCalculator, WeightedValues)
{
    {
        RiaWeightedHarmonicMeanCalculator calc;

        std::vector<double> values{ 10, 5, 4, 3 };
        std::vector<double> weights{ 10, 5, 4, 3 };

        for (size_t i = 0; i < values.size(); i++)
        {
            calc.addValueAndWeight(values[i], weights[i]);
        }

        double sumWeights = std::accumulate(weights.begin(), weights.end(), 0.0);


        EXPECT_DOUBLE_EQ(sumWeights, calc.aggregatedWeight());
        EXPECT_NEAR(sumWeights / weights.size(), calc.weightedMean(), 1e-8);
    }
    {
        RiaWeightedHarmonicMeanCalculator calc;

        std::vector<double> values{ 2.0, 3.0, 1.0, 4.0 };
        std::vector<double> weights{ 1.0, 2.0, 7.0, 3.0 };
        for (size_t i = 0; i < values.size(); i++)
        {
            calc.addValueAndWeight(values[i], weights[i]);
        }
        double sumWeights = std::accumulate(weights.begin(), weights.end(), 0.0);
        double aggregatedWeightAndValues = 1.0 / 2.0 + 2.0 / 3.0 + 7.0 / 1.0 + 3.0 / 4.0;
        double expectedValue = sumWeights / aggregatedWeightAndValues;
        EXPECT_DOUBLE_EQ(sumWeights, calc.aggregatedWeight());
        EXPECT_NEAR(expectedValue, calc.weightedMean(), 1.0e-8);
    }
}