// Fill Indicator
//
// fill_indicator - FI
//
// SMA of |C-O|/(H-L)*100, measures candle body fill ratio
//
// Inputs:    4 (OHLC)
// Outputs:   1 (FI)
// Constants: 1 (period)

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

typedef struct {
    uint_t k;
} ts_fill_indicator_params_t;

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

uint_t ts_fill_indicator_offset( ts_constant_t const *c )
{
	( void )c;
	return ( c ? ((ts_fill_indicator_params_t *)c)->k > 0 ? ((ts_fill_indicator_params_t *)c)->k - 1 : 0 : 0 );
}

int ts_fill_indicator(
	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_fill_indicator_p );
	if ( !c ) return -1;
	uint_t k = ((ts_fill_indicator_params_t *)c)->k;
	if (k == 0 || n < k) return -1;

	uint_t xi = 0;
	uint_t yi = k - 1;

	fp_t sum = 0;

	for( ; xi < k; ++xi )
	{
		fp_t range = ts_h( x, xi ) - ts_l( x, xi );
		if (range != 0)
			sum += fabs( ts_c( x, xi ) - ts_o( x, xi ) ) / range * 100;
	}

	y[0][yi] = sum / k;
	++yi;

	for( ; xi < n; ++xi, ++yi )
	{
		fp_t range = ts_h( x, xi ) - ts_l( x, xi );
		fp_t fv = range != 0 ? fabs( ts_c( x, xi ) - ts_o( x, xi ) ) / range * 100 : 0;
		fp_t range_old = ts_h( x, xi - k ) - ts_l( x, xi - k );
		fp_t fo = range_old != 0 ? fabs( ts_c( x, xi - k ) - ts_o( x, xi - k ) ) / range_old * 100 : 0;
		y[0][yi] = y[0][yi - 1] + ( fv - fo ) / k;
	}
	return 0;
}