// SPDX-License-Identifier: Apache-2.0
//
// Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
// Copyright 2008-2016 National ICT Australia (NICTA)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ------------------------------------------------------------------------

//! \addtogroup running_stat
//! @{

template <typename eT>
class arma_counter {
 public:
  inline ~arma_counter();
  inline arma_counter();

  inline const arma_counter& operator++();
  inline void operator++(int);

  inline void reset();
  inline eT value() const;
  inline eT value_plus_1() const;
  inline eT value_minus_1() const;

 private:
  arma_aligned eT d_count;
  arma_aligned uword i_count;
};

//! Class for keeping statistics of a continuously sampled process / signal.
//! Useful if the storage of individual samples is not necessary or desired.
//! Also useful if the number of samples is not known beforehand or exceeds
//! available memory.
template <typename eT>
class running_stat {
 public:
  typedef typename get_pod_type<eT>::result T;

  inline ~running_stat();
  inline running_stat();

  inline void operator()(const T sample);
  inline void operator()(const std::complex<T>& sample);

  inline void reset();

  inline eT mean() const;

  inline T var(const uword norm_type = 0) const;
  inline T stddev(const uword norm_type = 0) const;

  inline eT min() const;
  inline eT max() const;
  inline eT range() const;

  inline T count() const;

  //
  //

 private:
  arma_aligned arma_counter<T> counter;

  arma_aligned eT r_mean;
  arma_aligned T r_var;

  arma_aligned eT min_val;
  arma_aligned eT max_val;

  arma_aligned T min_val_norm;
  arma_aligned T max_val_norm;

  friend class running_stat_aux;
};

class running_stat_aux {
 public:
  template <typename eT>
  inline static void update_stats(running_stat<eT>& x, const eT sample,
                                  const typename arma_not_cx<eT>::result* junk = nullptr);

  template <typename eT>
  inline static void update_stats(running_stat<eT>& x, const std::complex<eT>& sample,
                                  const typename arma_not_cx<eT>::result* junk = nullptr);

  template <typename eT>
  inline static void update_stats(
      running_stat<eT>& x, const typename eT::value_type sample,
      const typename arma_cx_only<eT>::result* junk = nullptr);

  template <typename eT>
  inline static void update_stats(
      running_stat<eT>& x, const eT& sample,
      const typename arma_cx_only<eT>::result* junk = nullptr);
};

//! @}
