/*******************************************************
 * Copyright (c) 2014, ArrayFire
 * All rights reserved.
 *
 * This file is distributed under 3-clause BSD license.
 * The complete license agreement can be obtained at:
 * http://arrayfire.com/licenses/BSD-3-Clause
 ********************************************************/

#include <gtest/gtest.h>
#include <arrayfire.h>
#include <af/dim4.hpp>
#include <af/traits.hpp>
#include <string>
#include <vector>
#include <ctime>
#include <algorithm>
#include <testHelpers.hpp>

using std::string;
using std::vector;
using namespace af;

template<typename T>
class Covariance : public ::testing::Test
{
    public:
        virtual void SetUp() {}
};

// create a list of types to be tested
typedef ::testing::Types<float, double, int, uint, intl, uintl, uchar, short, ushort> TestTypes;

// register the type list
TYPED_TEST_CASE(Covariance, TestTypes);

template<typename T>
struct f32HelperType {
   typedef typename cond_type<is_same_type<T, double>::value,
                                             double,
                                             float>::type type;
};

template<typename T>
struct c32HelperType {
   typedef typename cond_type<is_same_type<T, cfloat>::value,
                                             cfloat,
                                             typename f32HelperType<T>::type >::type type;
};

template<typename T>
struct elseType {
   typedef typename cond_type< is_same_type<T, uintl>::value ||
                               is_same_type<T, intl> ::value,
                                              double,
                                              T>::type type;
};

template<typename T>
struct covOutType {
   typedef typename cond_type< is_same_type<T, float>   ::value ||
                               is_same_type<T, int>     ::value ||
                               is_same_type<T, uint>    ::value ||
                               is_same_type<T, uchar>   ::value ||
                               is_same_type<T, short>   ::value ||
                               is_same_type<T, ushort>  ::value ||
                               is_same_type<T, char>    ::value,
                                              float,
                              typename elseType<T>::type>::type type;
};

template<typename T>
void covTest(string pFileName, bool isbiased=false)
{
    typedef typename covOutType<T>::type outType;
    if (noDoubleTests<T>()) return;
    if (noDoubleTests<outType>()) return;

    vector<af::dim4>      numDims;
    vector<vector<int> >        in;
    vector<vector<float> >   tests;

    readTestsFromFile<int,float>(pFileName, numDims, in, tests);

    af::dim4 dims1 = numDims[0];
    af::dim4 dims2 = numDims[1];
    vector<T> input1(in[0].begin(), in[0].end());
    vector<T> input2(in[1].begin(), in[1].end());

    array a(dims1, &(input1.front()));
    array b(dims2, &(input2.front()));

    array c = cov(a, b, isbiased);

    vector<outType> currGoldBar(tests[0].begin(), tests[0].end());

    size_t nElems    = currGoldBar.size();
    std::vector<outType> outData(nElems);

    c.host((void*)outData.data());

    for (size_t elIter=0; elIter<nElems; ++elIter) {
        ASSERT_NEAR(::real(currGoldBar[elIter]), ::real(outData[elIter]), 1.0e-3)<< "at: " << elIter<< std::endl;
        ASSERT_NEAR(::imag(currGoldBar[elIter]), ::imag(outData[elIter]), 1.0e-3)<< "at: " << elIter<< std::endl;
    }
}

TYPED_TEST(Covariance, Vector)
{
    covTest<TypeParam>(string(TEST_DIR "/covariance/vec_size60.test"), false);
}

TYPED_TEST(Covariance, Matrix)
{
    covTest<TypeParam>(string(TEST_DIR "/covariance/matrix_65x121.test"), false);
}

TEST(Covariance, c32)
{
    array a = constant(cfloat(1.0f, -1.0f), 10, c32);
    array b = constant(cfloat(2.0f, -1.0f), 10, c32);
    ASSERT_THROW(cov(a, b), af::exception);
}

TEST(Covariance, c64)
{
    if (noDoubleTests<double>()) return;
    array a = constant(cdouble(1.0, -1.0), 10, c64);
    array b = constant(cdouble(2.0, -1.0), 10, c64);
    ASSERT_THROW(cov(a, b), af::exception);
}
