// Volume Oscillator
//
// volume_oscillator
//
// Volume Oscillator
//
// 
//
// Inputs:    1
// Outputs:   1
// Constants: 2


#include "ts.h"

typedef struct {
    fp_t fast_k;
    fp_t slow_k;
} ts_volume_oscillator_params_t;

ts_parameter_t const ts_volume_oscillator_p = { .n_inputs = 1, .n_outputs = 1, .n_constants = 2, .params_size = sizeof(ts_volume_oscillator_params_t) };

uint_t ts_volume_oscillator_offset( ts_constant_t const *c )
{
	( void )c;
	return ( c ? ((ts_volume_oscillator_params_t *)c)->slow_k > 0 ? (uint_t)(((ts_volume_oscillator_params_t *)c)->slow_k - 1) : 0 : 0 );
}

int ts_volume_oscillator(
	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_volume_oscillator_p );
	if ( !c ) return -1;
    fp_t fast_k = ((ts_volume_oscillator_params_t *)c)->fast_k;
    fp_t slow_k = ((ts_volume_oscillator_params_t *)c)->slow_k;
    if (fast_k == 0 || slow_k == 0) return -1;
    if (n == 0) return -1;

    fp_t fast_a = 2.0 / (fast_k + 1);
    fp_t slow_a = 2.0 / (slow_k + 1);

    fp_t fast_ema = x[0][0];
    fp_t slow_ema = x[0][0];
    y[0][0] = 0;

    for (uint_t i = 1; i < n; ++i)
    {
        fast_ema = fast_ema + fast_a * (x[0][i] - fast_ema);
        slow_ema = slow_ema + slow_a * (x[0][i] - slow_ema);
        y[0][i] = slow_ema != 0 ? (fast_ema - slow_ema) / slow_ema * 100 : 0;
    }
	return 0;
}