#include "m_pd.h"
#include "d_delay.c"


/* ----------------------------- vdc~ ----------------------------- */
static t_class *sigvdc_class;

typedef struct _sigvdc
{
    t_object x_obj;
    t_symbol *x_sym;
    t_float x_sr;       /* samples per msec */
    int x_zerodel;      /* 0 or vecsize depending on read/write order */
    t_float x_f;
} t_sigvdc;

static void *sigvdc_new(t_symbol *s)
{
    t_sigvdc *x = (t_sigvdc *)pd_new(sigvdc_class);
    if (!*s->s_name) s = gensym("vdc~");
    x->x_sym = s;
    x->x_sr = 1;
    x->x_zerodel = 0;
    outlet_new(&x->x_obj, &s_signal);
    x->x_f = 0;
    return (x);
}


static t_int *sigvdc_perform(t_int *w)
{
    t_sample *in = (t_sample *)(w[1]);
    t_sample *out = (t_sample *)(w[2]);
    t_delwritectl *ctl = (t_delwritectl *)(w[3]);
    t_sigvdc *x = (t_sigvdc *)(w[4]);
    int n = (int)(w[5]);

    int nsamps = ctl->c_n;
    t_sample limit = nsamps - n - 1;
    t_sample fn = n-1;
    t_sample *vp = ctl->c_vec, *bp, *wp = vp + ctl->c_phase;
    t_sample zerodel = x->x_zerodel;
    while (n--)
    {
        t_sample delsamps = x->x_sr * *in++ - zerodel, frac;
        int idelsamps;
        t_sample a, b, c, d, cminusb;
        if (delsamps < 1.00001f) delsamps = 1.00001f;
        if (delsamps > limit) delsamps = limit;
        delsamps += fn;
        fn = fn - 1.0f;
        idelsamps = delsamps;
        frac = delsamps - (t_sample)idelsamps;
        bp = wp - idelsamps;
        if (bp < vp + 4) bp += nsamps;
        d = bp[-3];
        c = bp[-2];
        b = bp[-1];
        a = bp[0];
        cminusb = c-b;
        *out++ = b + frac * (
            cminusb - 0.1666667f * (1.-frac) * (
                (d - a - 3.0f * cminusb) * frac + (d + 2.0f*a - 3.0f*b)
            )
        );
    }
    return (w+6);
}

static void sigvdc_dsp(t_sigvdc *x, t_signal **sp)
{
    t_sigdelwrite *delwriter =
        (t_sigdelwrite *)pd_findbyclass(x->x_sym, sigdelwrite_class);
    x->x_sr = sp[0]->s_sr * 0.001;
    if (delwriter)
    {
        sigdelwrite_checkvecsize(delwriter, sp[0]->s_n);
        x->x_zerodel = (delwriter->x_sortno == ugen_getsortno() ?
            0 : delwriter->x_vecsize);
        dsp_add(sigvdc_perform, 5,
            sp[0]->s_vec, sp[1]->s_vec,
                &delwriter->x_cspace, x, sp[0]->s_n);
    }
    else error("vdc~: %s: no such delwrite~",x->x_sym->s_name);
}

void vdc_tilde_setup(void)
{
    sigvdc_class = class_new(gensym("vdc~"), (t_newmethod)sigvdc_new, 0,
        sizeof(t_sigvdc), 0, A_DEFSYM, 0);
    class_addmethod(sigvdc_class, (t_method)sigvdc_dsp, gensym("dsp"), 0);
    CLASS_MAINSIGNALIN(sigvdc_class, t_sigvdc, x_f);
}