#include <algorithm>
#include <stdexcept>
#include <utility>

#include "interface.hpp"

// =================================================================================================

namespace
{
size_t pose2d_offset(
    size_t view,
    size_t person,
    size_t joint,
    size_t coord,
    size_t max_persons,
    size_t num_joints)
{
    return ((((view * max_persons) + person) * num_joints) + joint) * 3 + coord;
}

size_t pose3d_offset(size_t person, size_t joint, size_t coord, size_t num_joints)
{
    return (((person * num_joints) + joint) * 4) + coord;
}
} // namespace

// =================================================================================================
// =================================================================================================

float &PoseBatch2D::at(size_t view, size_t person, size_t joint, size_t coord)
{
    return data[pose2d_offset(view, person, joint, coord, max_persons, num_joints)];
}

const float &PoseBatch2DView::at(size_t view, size_t person, size_t joint, size_t coord) const
{
    return data[pose2d_offset(view, person, joint, coord, max_persons, num_joints)];
}

const float &PoseBatch3DView::at(size_t person, size_t joint, size_t coord) const
{
    return data[pose3d_offset(person, joint, coord, num_joints)];
}

const float &PoseBatch2D::at(size_t view, size_t person, size_t joint, size_t coord) const
{
    return data[pose2d_offset(view, person, joint, coord, max_persons, num_joints)];
}

PoseBatch2DView PoseBatch2D::view() const
{
    return PoseBatch2DView {data.data(), person_counts.data(), num_views, max_persons, num_joints};
}

PoseBatch2D PoseBatch2D::from_nested(const RaggedPoses2D &poses_2d)
{
    PoseBatch2D batch;
    batch.num_views = poses_2d.size();
    for (const auto &view : poses_2d)
    {
        batch.max_persons = std::max(batch.max_persons, view.size());
        if (!view.empty())
        {
            if (batch.num_joints == 0)
            {
                batch.num_joints = view[0].size();
            }
            else if (batch.num_joints != view[0].size())
            {
                throw std::invalid_argument("All views must use the same joint count.");
            }

            for (const auto &person : view)
            {
                if (person.size() != batch.num_joints)
                {
                    throw std::invalid_argument("All persons must use the same joint count.");
                }
            }
        }
    }

    batch.person_counts.resize(batch.num_views);
    batch.data.assign(batch.num_views * batch.max_persons * batch.num_joints * 3, 0.0f);

    for (size_t view = 0; view < batch.num_views; ++view)
    {
        batch.person_counts[view] = static_cast<uint32_t>(poses_2d[view].size());
        for (size_t person = 0; person < poses_2d[view].size(); ++person)
        {
            for (size_t joint = 0; joint < batch.num_joints; ++joint)
            {
                for (size_t coord = 0; coord < 3; ++coord)
                {
                    batch.at(view, person, joint, coord) = poses_2d[view][person][joint][coord];
                }
            }
        }
    }

    return batch;
}

// =================================================================================================

float &PoseBatch3D::at(size_t person, size_t joint, size_t coord)
{
    return data[pose3d_offset(person, joint, coord, num_joints)];
}

const float &PoseBatch3D::at(size_t person, size_t joint, size_t coord) const
{
    return data[pose3d_offset(person, joint, coord, num_joints)];
}

PoseBatch3DView PoseBatch3D::view() const
{
    return PoseBatch3DView {data.data(), num_persons, num_joints};
}

NestedPoses3D PoseBatch3D::to_nested() const
{
    NestedPoses3D poses_3d(num_persons);
    for (size_t person = 0; person < num_persons; ++person)
    {
        poses_3d[person].resize(num_joints);
        for (size_t joint = 0; joint < num_joints; ++joint)
        {
            for (size_t coord = 0; coord < 4; ++coord)
            {
                poses_3d[person][joint][coord] = at(person, joint, coord);
            }
        }
    }
    return poses_3d;
}

PoseBatch3D PoseBatch3D::from_nested(const NestedPoses3D &poses_3d)
{
    PoseBatch3D batch;
    batch.num_persons = poses_3d.size();
    if (!poses_3d.empty())
    {
        batch.num_joints = poses_3d[0].size();
    }

    batch.data.resize(batch.num_persons * batch.num_joints * 4);
    for (size_t person = 0; person < batch.num_persons; ++person)
    {
        if (poses_3d[person].size() != batch.num_joints)
        {
            throw std::invalid_argument("All 3D poses must use the same joint count.");
        }
        for (size_t joint = 0; joint < batch.num_joints; ++joint)
        {
            for (size_t coord = 0; coord < 4; ++coord)
            {
                batch.at(person, joint, coord) = poses_3d[person][joint][coord];
            }
        }
    }
    return batch;
}