// -*- mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
// vi: set et ts=4 sw=4 sts=4:
/*
  This file is part of the Open Porous Media project (OPM).

  OPM is free software: you can redistribute it and/or modify
  it under the terms of the GNU General Public License as published by
  the Free Software Foundation, either version 2 of the License, or
  (at your option) any later version.

  OPM is distributed in the hope that it will be useful,
  but WITHOUT ANY WARRANTY; without even the implied warranty of
  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  GNU General Public License for more details.

  You should have received a copy of the GNU General Public License
  along with OPM.  If not, see <http://www.gnu.org/licenses/>.

  Consult the COPYING file in the top-level source directory of this
  module for the precise wording of the license and the list of
  copyright holders.
*/
/*!
 * \file
 *
 * \brief This is the unit test for the 2D tabulation classes.
 *
 * I.e., for the UniformTabulated2DFunction and UniformXTabulated2DFunction classes.
 */
#include "config.h"

#include <opm/material/common/UniformXTabulated2DFunction.hpp>
#include <opm/material/common/UniformTabulated2DFunction.hpp>
#include <opm/material/common/XYTabulated2DFunction.hpp>

#include <dune/common/parallel/mpihelper.hh>

#include <memory>
#include <cmath>
#include <iostream>


template <class ScalarT>
struct Test
{
typedef ScalarT  Scalar;

static Scalar testFn1(Scalar x, Scalar /* y */)
{ return x; }

static Scalar testFn2(Scalar /* x */, Scalar y)
{ return y; }

static Scalar testFn3(Scalar x, Scalar y)
{ return x*y; }

template <class Fn>
std::shared_ptr<Opm::UniformTabulated2DFunction<Scalar> >
createUniformTabulatedFunction(Fn& f)
{
    Scalar xMin = -2.0;
    Scalar xMax = 3.0;
    unsigned m = 50;

    Scalar yMin = -1/2.0;
    Scalar yMax = 1/3.0;
    unsigned n = 40;

    auto tab = std::make_shared<Opm::UniformTabulated2DFunction<Scalar>>(
        xMin, xMax, m,
        yMin, yMax, n);
    for (unsigned i = 0; i < m; ++i) {
        Scalar x = xMin + Scalar(i)/(m - 1) * (xMax - xMin);
        for (unsigned j = 0; j < n; ++j) {
            Scalar y = yMin + Scalar(j)/(n - 1) * (yMax - yMin);
            tab->setSamplePoint(i, j, f(x, y));
        }
    }

    return tab;
}

template <class Fn>
std::shared_ptr<Opm::UniformXTabulated2DFunction<Scalar> >
createUniformXTabulatedFunction(Fn& f)
{
    Scalar xMin = -2.0;
    Scalar xMax = 3.0;
    unsigned m = 50;

    Scalar yMin = -1/2.0;
    Scalar yMax = 1/3.0;
    unsigned n = 40;

    auto tab = std::make_shared<Opm::UniformXTabulated2DFunction<Scalar>>();
    for (unsigned i = 0; i < m; ++i) {
        Scalar x = xMin + Scalar(i)/(m - 1) * (xMax - xMin);
        tab->appendXPos(x);
        for (unsigned j = 0; j < n; ++j) {
            Scalar y = yMin + Scalar(j)/(n -1) * (yMax - yMin);
            tab->appendSamplePoint(i, y, f(x, y));
        }
    }

    return tab;
}


template <class Fn>
std::shared_ptr<Opm::UniformXTabulated2DFunction<Scalar> >
createUniformXTabulatedFunction2(Fn& f)
{
    Scalar xMin = -2.0;
    Scalar xMax = 3.0;
    Scalar m = 50;

    Scalar yMin = - 4.0;
    Scalar yMax = 5.0;

    auto tab = std::make_shared<Opm::UniformXTabulated2DFunction<Scalar>>();
    for (unsigned i = 0; i < m; ++i) {
        Scalar x = xMin + Scalar(i)/(m - 1) * (xMax - xMin);
        tab->appendXPos(x);

        Scalar n = i + 10;

        for (unsigned j = 0; j < n; ++j) {
            Scalar y = yMin + Scalar(j)/(n -1) * (yMax - yMin);
            tab->appendSamplePoint(i, y, f(x, y));
        }
    }

    return tab;
}


template <class Fn>
std::shared_ptr<Opm::XYTabulated2DFunction<Scalar> >
createXYTabulated2DFunction(Fn& f)
{
    const Scalar xMin = -2.0;
    const Scalar xMax = 3.0;
    const unsigned m = 50;

    const Scalar yMin = -1/2.0;
    const Scalar yMax = 1/3.0;
    const unsigned n = 40;

    std::vector<Scalar> x_samples(m);
    std::vector<Scalar> y_samples(n);
    std::vector<std::vector<Scalar>> data(m, std::vector<Scalar>(n));

    for (unsigned i = 0; i < m; ++i) {
        x_samples[i] = xMin + Scalar(i)/(m - 1) * (xMax - xMin);

        for (unsigned j = 0; j < n; ++j) {
            y_samples[j] = yMin + Scalar(j)/(n -1) * (yMax - yMin);
            data[i][j] = f(x_samples[i], y_samples[j]);
        }
    }

    auto tab = std::make_shared<Opm::XYTabulated2DFunction<Scalar>>(x_samples, y_samples, data, true, true);

    return tab;
}

template <class Fn, class Table>
bool compareTableWithAnalyticFn(const Table& table,
                                Scalar xMin,
                                Scalar xMax,
                                unsigned numX,

                                Scalar yMin,
                                Scalar yMax,
                                unsigned numY,

                                Fn& f,
                                Scalar tolerance = 1e-8)
{
    // make sure that the tabulated function evaluates to the same thing as the analytic
    // one (modulo tolerance)
    for (unsigned i = 1; i <= numX; ++i) {
        Scalar x = xMin + Scalar(i)/numX*(xMax - xMin);

        for (unsigned j = 0; j < numY; ++j) {
            Scalar y = yMin + Scalar(j)/numY*(yMax - yMin);
            if (std::abs(table->eval(x, y) - f(x, y)) > tolerance) {
                std::cerr << __FILE__ << ":" << __LINE__ << ": table->eval("<<x<<","<<y<<") != f("<<x<<","<<y<<"): " << table->eval(x,y) << " != " << f(x,y) << "\n";
                return false;
            }
        }
    }

    return true;
}

template <class Fn, class Table>
bool compareTableWithAnalyticFn2(const Table& table,
                                 const Scalar xMin,
                                 const Scalar xMax,
                                 unsigned numX,
                                 const Scalar yMin,
                                 const Scalar yMax,
                                 unsigned numY,

                                 Fn& f,
                                 Scalar tolerance = 1e-8)
{
    // make sure that the tabulated function evaluates to the same thing as the analytic
    // one (modulo tolerance)
    for (unsigned i = 1; i <= numX; ++i) {
        Scalar x = xMin + Scalar(i)/numX*(xMax - xMin);

        for (unsigned j = 0; j < numY; ++j) {
            Scalar y = yMin + Scalar(j)/numY*(yMax - yMin);
            Scalar result;
            table->eval(x, y, result);
            if (std::abs(result - f(x, y)) > tolerance) {
                std::cerr << __FILE__ << ":" << __LINE__ << ": table->eval("<<x<<","<<y<<") != f("<<x<<","<<y<<"): " << result << " != " << f(x,y) << "\n";
                return false;
            }
        }
    }

    return true;
}

template <class UniformTablePtr, class UniformXTablePtr, class Fn>
bool compareTables(const UniformTablePtr uTable,
                   const UniformXTablePtr uXTable,
                   Fn& f,
                   Scalar tolerance = 1e-8)
{
    // make sure the uniform and the non-uniform tables exhibit the same dimensions
    if (std::abs(uTable->xMin() - uXTable->xMin()) > tolerance) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->xMin() != uXTable->xMin(): " << uTable->xMin() << " != " << uXTable->xMin() << "\n";
        return false;
    }
    if (std::abs(uTable->xMax() - uXTable->xMax()) > tolerance) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->xMax() != uXTable->xMax(): " << uTable->xMax() << " != " << uXTable->xMax() << "\n";
        return false;
    }
    if (uTable->numX() != uXTable->numX()) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->numX() != uXTable->numX(): " << uTable->numX() << " != " << uXTable->numX() << "\n";
        return false;
    }

    for (unsigned i = 0; i < uTable->numX(); ++i) {
        if (std::abs(uTable->yMin() - uXTable->yMin(i)) > tolerance) {
            std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->yMin() != uXTable->yMin("<<i<<"): " << uTable->yMin() << " != " << uXTable->yMin(i) << "\n";
            return false;
        }

        if (std::abs(uTable->yMax() - uXTable->yMax(i)) > tolerance) {
            std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->yMax() != uXTable->yMax("<<i<<"): " << uTable->yMax() << " != " << uXTable->yMax(i) << "\n";
            return false;
        }

        if (uTable->numY() != uXTable->numY(i)) {
            std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->numY() != uXTable->numY("<<i<<"): " << uTable->numY() << " != " << uXTable->numY(i) << "\n";
            return false;
        }
    }

    // make sure that the x and y values are identical
    for (unsigned i = 0; i < uTable->numX(); ++i) {
        if (std::abs(uTable->iToX(i) - uXTable->iToX(i)) > tolerance) {
            std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->iToX("<<i<<") != uXTable->iToX("<<i<<"): " << uTable->iToX(i) << " != " << uXTable->iToX(i) << "\n";
            return false;
        }

        for (unsigned j = 0; j < uTable->numY(); ++j) {
            if (std::abs(uTable->jToY(j) - uXTable->jToY(i, j)) > tolerance) {
                std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->jToY("<<j<<") != uXTable->jToY("<<i<<","<<j<<"): " << uTable->jToY(i) << " != " << uXTable->jToY(i, j) << "\n";
                return false;
            }
        }
    }

    // check that the appicable range is correct. Note that due to rounding errors it is
    // undefined whether the table applies to the boundary of the tabulated domain or not
    Scalar xMin = uTable->xMin();
    Scalar yMin = uTable->yMin();
    Scalar xMax = uTable->xMax();
    Scalar yMax = uTable->yMax();

    Scalar x = xMin - tolerance;
    Scalar y = yMin - tolerance;
    if (uTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->applies("<<x<<","<<y<<")\n";
        return false;
    }
    if (uXTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uXTable->applies("<<x<<","<<y<<")\n";
        return false;
    }

    x = xMin - tolerance;
    y = yMin + tolerance;
    if (uTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->applies("<<x<<","<<y<<")\n";
        return false;
    }
    if (uXTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uXTable->applies("<<x<<","<<y<<")\n";
        return false;
    }

    x = xMin + tolerance;
    y = yMin - tolerance;
    if (uTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->applies("<<x<<","<<y<<")\n";
        return false;
    }
    if (uXTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uXTable->applies("<<x<<","<<y<<")\n";
        return false;
    }

    x = xMin + tolerance;
    y = yMin + tolerance;
    if (!uTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": !uTable->applies("<<x<<","<<y<<")\n";
        return false;
    }
    if (!uXTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": !uXTable->applies("<<x<<","<<y<<")\n";
        return false;
    }

    x = xMax + tolerance;
    y = yMax + tolerance;
    if (uTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->applies("<<x<<","<<y<<")\n";
        return false;
    }
    if (uXTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uXTable->applies("<<x<<","<<y<<")\n";
        return false;
    }

    x = xMax - tolerance;
    y = yMax + tolerance;
    if (uTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->applies("<<x<<","<<y<<")\n";
        return false;
    }
    if (uXTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uXTable->applies("<<x<<","<<y<<")\n";
        return false;
    }

    x = xMax + tolerance;
    y = yMax - tolerance;
    if (uTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uTable->applies("<<x<<","<<y<<")\n";
        return false;
    }
    if (uXTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": uXTable->applies("<<x<<","<<y<<")\n";
        return false;
    }

    x = xMax - tolerance;
    y = yMax - tolerance;
    if (!uTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": !uTable->applies("<<x<<","<<y<<")\n";
        return false;
    }
    if (!uXTable->applies(x, y)) {
        std::cerr << __FILE__ << ":" << __LINE__ << ": !uXTable->applies("<<x<<","<<y<<")\n";
        return false;
    }

    // make sure that the function values at the sampling points are identical and that
    // they correspond to the analytic function
    unsigned m2 = uTable->numX()*5;
    unsigned n2 = uTable->numY()*5;
    if (!compareTableWithAnalyticFn(uTable,
                                    xMin, xMax, m2,
                                    yMin, yMax, n2,
                                    f,
                                    tolerance))
        return false;
    if (!compareTableWithAnalyticFn(uXTable,
                                    xMin, xMax, m2,
                                    yMin, yMax, n2,
                                    f,
                                    tolerance))
        return false;

    return true;
}
};


template <class TestType>
inline int testAll( const typename TestType::Scalar tolerance = 1e-6 )
{
    TestType test;
    auto uniformTab = test.createUniformTabulatedFunction(TestType::testFn1);
    auto uniformXTab = test.createUniformXTabulatedFunction(TestType::testFn1);
    if (!test.compareTables(uniformTab, uniformXTab, TestType::testFn1, tolerance))
        return 1;

    uniformTab = test.createUniformTabulatedFunction(TestType::testFn2);
    uniformXTab = test.createUniformXTabulatedFunction(TestType::testFn2);
    if (!test.compareTables(uniformTab, uniformXTab, TestType::testFn2, tolerance))
        return 1;

    uniformTab = test.createUniformTabulatedFunction(TestType::testFn3);
    uniformXTab = test.createUniformXTabulatedFunction(TestType::testFn3);
    if (!test.compareTables(uniformTab, uniformXTab, TestType::testFn3, /*tolerance=*/1e-2))
        return 1;

    uniformXTab = test.createUniformXTabulatedFunction2(TestType::testFn3);
    if (!test.compareTableWithAnalyticFn(uniformXTab,
                                    -2.0, 3.0, 100,
                                    -4.0, 5.0, 100,
                                    TestType::testFn3,
                                    /*tolerance=*/1e-2))
        return 1;

    {
        using ScalarType = typename TestType::Scalar;

        auto xytab = test.createXYTabulated2DFunction(TestType::testFn1);
        const ScalarType xMin = -4.0;
        const ScalarType xMax = 8.0;
        const unsigned m = 250;

        const ScalarType yMin = -2. / 2.0;
        const ScalarType yMax = 3. / 3.0;
        const unsigned n = 170;

        // extrapolation and interpolation involved, the tolerance needs to be bigger
        const ScalarType temp_tolerance = 1000. * tolerance;

        if (!test.compareTableWithAnalyticFn2(xytab, xMin, xMax, m, yMin, yMax, n, TestType::testFn1, temp_tolerance))
            return 1;

        xytab = test.createXYTabulated2DFunction(TestType::testFn2);

        if (!test.compareTableWithAnalyticFn2(xytab, xMin, xMax, m, yMin, yMax, n, TestType::testFn2, temp_tolerance))
            return 1;

        xytab = test.createXYTabulated2DFunction(TestType::testFn3);

        if (!test.compareTableWithAnalyticFn2(xytab, xMin, xMax, m, yMin, yMax, n, TestType::testFn3, temp_tolerance))
            return 1;
    }

    // CSV output for debugging
#if 0
    int m = 100;
    int n = 100;
    Scalar xMin = -3.0;
    Scalar xMax = 4.0;

    Scalar yMin = -1;
    Scalar yMax = 1;
    for (int i = 0; i < m; ++i) {
        Scalar x = xMin + Scalar(i)/m * (xMax - xMin);

        for (int j = 0; j < n; ++j) {
            Scalar y = yMin + Scalar(j)/n * (yMax - yMin);

            std::cout << x << " "
                      << y << " "
                      << uniformXTab->eval(x,y,true) << "\n";
        }
        std::cout << "\n";
    }
#endif
    return 0;
}


int main(int argc, char **argv)
{
    Dune::MPIHelper::instance(argc, argv);

    if (testAll<Test<double> >(1e-12))
        return 1;
    if (testAll<Test<float> >(1e-6))
        return 1;

    return 0;
}