// Accumulation Swing Index
//
// asi - ASI
//
// Cumulative swing indicator using OHLC data to measure buying/selling pressure
//
// Inputs:    4 (OHLC)
// Outputs:   1 (ASI)
// Constants: 0

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


ts_parameter_t const ts_asi_p = { .n_inputs = 4, .n_outputs = 1, .n_constants = 0, .params_size = 0 };

uint_t ts_asi_offset( ts_constant_t const *c )
{
	( void )c;
	return ( 0 );
}

int ts_asi(
	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_asi_p );
	(void)c;
    if( n == 0 ) return -1;

    y[0][0] = 0;

    for( uint_t i = 1; i < n; ++i )
    {
        fp_t term1 = ts_c( x, i ) - ts_c( x, i - 1 );
        fp_t term2 = 0.5 * ( ts_o( x, i ) - ts_o( x, i - 1 ) );
        fp_t term3 = 0.25 * ( ts_c( x, i ) - ts_o( x, i ) + ts_o( x, i - 1 ) - ts_c( x, i - 1 ) );
        fp_t denom = fmax( ts_h( x, i ) - ts_l( x, i - 1 ),
                           fmax( ts_h( x, i - 1 ) - ts_l( x, i ),
                                 ts_h( x, i - 1 ) - ts_l( x, i - 1 ) ) );
        fp_t component2 = denom != 0 ? ( term1 - term2 + term3 ) / denom * ( ts_h( x, i ) - ts_l( x, i ) ) : 0;
        fp_t half_denom = 0.5 * denom;
        fp_t component3 = half_denom != 0 ? ( term1 - term2 + term3 ) / half_denom * 0.5 : 0;

        y[0][i] = y[0][i - 1] + component2 + component3;
    }

	return 0;
}