// Natr
//
// natr
//
// Normalized ATR
//
// 
//
// Inputs:    4
// Outputs:   1
// Constants: 1


#include <math.h>
#include "ts.h"


typedef struct {
    uint_t k;
} ts_natr_params_t;

ts_parameter_t const ts_natr_p = { .n_inputs = 4, .n_outputs = 1, .n_constants = 1, .params_size = sizeof(ts_natr_params_t) };


uint_t ts_natr_offset( ts_constant_t const *c )
{
	( void )c;
	return ( c ? ((ts_natr_params_t *)c)->k : 0 );
}

int ts_natr(
	fp_t * const *y, uint_t y_n,
	fp_t const * const *x, uint_t x_n,
	uint_t n, ts_constant_t const *c
)
{
	TS_PROLOGUE( ts_natr_p );
	if ( !c ) return -1;
	uint_t k = ((ts_natr_params_t *)c)->k;
	if (k == 0) return -1;
	if (n < k + 1) return -1;

	for( uint_t i = k; i < n; ++i )
	{
		fp_t tr_sum = 0;
		for( uint_t j = 0; j < k; ++j )
		{
			uint_t idx = i - k + 1 + j;
			fp_t tr = fmax( ts_h( x, idx ) - ts_l( x, idx ), fmax( fabs( ts_h( x, idx ) - ts_c( x, idx - 1 ) ), fabs( ts_l( x, idx ) - ts_c( x, idx - 1 ) ) ) );
			tr_sum += tr;
		}
		fp_t atr = tr_sum / (fp_t)k;
		y[0][i] = ts_c( x, i ) != 0 ? atr / ts_c( x, i ) * 100.0 : 0;
	}
	return 0;
}