// SPDX-License-Identifier: Apache-2.0
// 
// Copyright 2008-2016 Conrad Sanderson (https://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
// https://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 struct running_stat_aux;
  };



struct running_stat_aux
  {
  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);
  };



//! @}
