//+------------------------------------------------------------------+
//|                                                      StdBase.mqh |
//|                                             Copyright 2026, Leo. |
//|                                             https://www.mql5.com |
//+------------------------------------------------------------------+
#property copyright "Copyright 2026, Leo."
#property link      "https://www.mql5.com/en/users/nique_372"
#property strict

#ifndef SCALERBYLEO_SRC_SCALER_STD_STDBASE_MQH
#define SCALERBYLEO_SRC_SCALER_STD_STDBASE_MQH

//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
#include "..\\ScalerBase.mqh"

//+------------------------------------------------------------------+
//|                                                                  |
//+------------------------------------------------------------------+
namespace TSN
{
//+------------------------------------------------------------------+
//|               Standardization Scaler                             |
//+------------------------------------------------------------------+
template<typename TFlt>
class StandardizationScalerBase : public ScalerBase
 {
protected:
  vector             m_mean, m_std, m_std_inv;
  virtual bool       OnLoad() { return true; }

public:
                     StandardizationScalerBase() : ScalerBase() { m_prefix_file = "_mean_std.csv"; }

  //---
  bool               Save(string prefix_name, int extra_file_flags = FILE_COMMON);
  bool               LoadByFile(string prefix_name, int extra_file_flags = FILE_COMMON);
  bool               LoadByArr(const string &arr[]) override;

  //---
  bool               Fit(const matrix<TFlt> &X);
 };

//+------------------------------------------------------------------+
//| Save / Load                                                      |
//+------------------------------------------------------------------+
template<typename TFlt>
bool StandardizationScalerBase::Save(string prefix_name, int extra_file_flags = FILE_COMMON)
 {
//---
  m_file_name_out = prefix_name + m_prefix_file;
  FileDelete(m_file_name_out);
  ResetLastError();

//---
  const int handle = FileOpen(m_file_name_out, FILE_WRITE | FILE_CSV | extra_file_flags);
  if(handle == INVALID_HANDLE)
   {
    m_last_err = SCALERBYLEO_ERR_FILE_OPEN;
    return false;
   }

//---
  FileWrite(handle, vector_to_string(m_std));
  FileWrite(handle, vector_to_string(m_mean));
  FileWrite(handle, m_i_start);
  FileWrite(handle, m_i_count);

//---
  FileClose(handle);
  return true;
 }

//+------------------------------------------------------------------+
template<typename TFlt>
bool StandardizationScalerBase::LoadByFile(string prefix_name, int extra_file_flags = FILE_COMMON)
 {
//---
  m_file_name_out = prefix_name + m_prefix_file;

//---
  ResetLastError();
  const int handle = FileOpen(m_file_name_out, FILE_READ | FILE_CSV | extra_file_flags, "\n");
  if(handle == INVALID_HANDLE)
   {
    m_last_err = SCALERBYLEO_ERR_FILE_OPEN;
    return false;
   }

//---
  CStringFunc::ToVector<double, CStringConvert>(FileReadString(handle), m_std, ',');
  CStringFunc::ToVector<double, CStringConvert>(FileReadString(handle), m_mean, ',');
  m_i_start = ulong(FileReadString(handle));
  m_i_count = long(FileReadString(handle));

//---
  m_std_inv = 1.0 / m_std;

//---
  FileClose(handle);
  return (m_loaded_scaler = OnLoad());
 }

//+------------------------------------------------------------------+
template<typename TFlt>
bool StandardizationScalerBase::LoadByArr(const string &arr[])
 {
  if(ArraySize(arr) < 4)
   {
    m_last_err = SCALERBYLEO_ERR_INVALID_DATA;
    return false;
   }

//---
  int p = 0;
  CStringFunc::ToVector<double, CStringConvert>(arr[p++], m_std, ',');
  CStringFunc::ToVector<double, CStringConvert>(arr[p++], m_mean, ',');
  m_i_start = ulong(arr[p++]);
  m_i_count = long(arr[p++]);

//---
  m_std_inv = 1.0 / m_std;

//---
  return (m_loaded_scaler = OnLoad());
 }

//+------------------------------------------------------------------+
//| Fit                                                              |
//+------------------------------------------------------------------+
template<typename TFlt>
bool StandardizationScalerBase::Fit(const matrix<TFlt> &X)
 {
//---
  const ulong total_cols = X.Cols();
  const ulong rows = X.Rows();
  if(total_cols == 0 || rows == 0)
   {
    m_last_err = SCALERBYLEO_ERR_EMPTY_INPUT;
    return false;
   }
  if(m_i_start >= total_cols)
   {
    m_last_err = SCALERBYLEO_ERR_INVALID_RANGE;
    return false;
   }

//---
  const ulong fs = SCALERBYLEO_SIZE(total_cols);
  const double rows_inv = 1.0 / double(rows);

//---
  m_mean.Resize(fs);
  m_std.Resize(fs);
  m_std_inv.Resize(fs);

//---
  for(ulong c = 0; c < fs; c++)
   {
    //--- media de la columna c (double, sin importar TFlt)
    double sum = 0.0;
    for(ulong r = 0; r < rows; r++)
      sum += X[r][m_i_start + c];
    const double mean_v = sum * rows_inv;

    //--- varianza de la columna c
    double sq = 0.0;
    for(ulong r = 0; r < rows; r++)
     {
      const double d = X[r][m_i_start + c] - mean_v;
      sq += d * d;
     }
    const double std_v = MathSqrt(sq * rows_inv);

    //---
    if(std_v < SCALER_BASE_MIN_VALUE)
     {
      m_last_err = SCALERBYLEO_ERR_DEGENERATE_SCALE;
      return false;
     }

    //---
    m_mean[c] = mean_v;
    m_std[c] = std_v;
    m_std_inv[c] = 1.0 / std_v;
   }

//---
  return (m_loaded_scaler = OnLoad());
 }
}
#endif // SCALERBYLEO_SRC_SCALER_STD_STDBASE_MQH
//+------------------------------------------------------------------+