//  ************************************************************************************************
//
//  BornAgain: simulate and fit reflection and scattering
//
//! @file      Base/Axis/Frame.cpp
//! @brief     Implements class Frame.
//!
//! @homepage  http://www.bornagainproject.org
//! @license   GNU General Public License v3 or higher (see COPYING)
//! @copyright Forschungszentrum Jülich GmbH 2018
//! @authors   Scientific Computing Group at MLZ (see CITATION, AUTHORS)
//
//  ************************************************************************************************

#include "Base/Axis/Frame.h"
#include "Base/Axis/Bin.h"
#include "Base/Axis/IAxis.h"
#include "Base/Util/Assert.h"

Frame::Frame(const std::vector<IAxis*>& axes)
    : m_axes(axes)
{
    m_size = 1;
    for (size_t k = 0; k < rank(); ++k)
        m_size *= axis(k).size();
}

const IAxis& Frame::axis(size_t k_axis) const
{
    return *m_axes.at(k_axis);
}

double Frame::projectedCoord(size_t i_flat, size_t k_axis) const
{
    auto axis_index = projectedIndex(i_flat, k_axis);
    return (*m_axes[k_axis])[axis_index];
}

std::vector<int> Frame::allIndices(size_t i_flat) const
{
    std::vector<int> result(rank());
    for (size_t k = 0; k < rank(); ++k)
        result[k] = projectedIndex(i_flat, k);
    return result;
}

size_t Frame::projectedIndex(size_t i_flat, size_t k_axis) const
{
    if (rank()==1) {
        return i_flat;
    } else if (rank()==2) {
        if (k_axis==0)
            return (i_flat / m_axes[1]->size()) % m_axes[0]->size();
        if (k_axis==1)
            return i_flat  % m_axes[1]->size();
        ASSERT(0);
    }
    ASSERT(0);
    /* // generic code for rank>2 currently unused
    size_t remainder(i_flat);
    for (int k = rank() - 1; k >= 0; --k) {
        size_t result = remainder % m_axes[k]->size();
        if (k_axis == k)
            return result;
        remainder /= m_axes[k]->size();
    }
    */
}

size_t Frame::toGlobalIndex(const std::vector<unsigned>& axes_indices) const
{
    ASSERT(axes_indices.size() == rank());
    size_t result = 0;
    size_t step_size = 1;
    for (int k = rank() - 1; k >= 0; --k) {
        ASSERT(axes_indices[k] < m_axes[k]->size());
        result += axes_indices[k] * step_size;
        step_size *= m_axes[k]->size();
    }
    return result;
}

size_t Frame::findGlobalIndex(const std::vector<double>& coordinates) const
{
    ASSERT(coordinates.size() == rank());
    std::vector<unsigned> axes_indexes;
    axes_indexes.resize(rank());
    for (size_t k = 0; k < rank(); ++k)
        axes_indexes[k] = static_cast<unsigned>(m_axes[k]->findClosestIndex(coordinates[k]));
    return toGlobalIndex(axes_indexes);
}