#include "m_pd.h"

static t_class *zeroxpos_tilde_class;

typedef struct _zeroxpos_control
{
  t_float *c_input;
  t_int final_pol;
} t_zeroxpos_control;

typedef struct _zeroxpos_tilde 
{
  t_object x_obj;
  t_zeroxpos_control x_ctl;
  t_float f_num, f_dummy;
  t_int i_bang, i_pol, i_count, i_ndx;
  t_outlet *f_pos, *f_pol;
} t_zeroxpos_tilde;

t_int *zeroxpos_tilde_perform(t_int *w) 
{
  t_zeroxpos_tilde     *x =   (t_zeroxpos_tilde *)(w[1]);
  t_zeroxpos_control *ctl = (t_zeroxpos_control *)(w[2]);  
  int                   n =                  (int)(w[3]);
  t_float            *in = ctl->c_input;
  int number = (int)x->f_num;
  int count = x->i_count;
  int polarity = 1;
  int i = 0;
  x->i_pol = 0;
  x->i_ndx = -1;
  int prev = ctl->final_pol == 0 ? in[0] : ctl->final_pol;

  for(i=0;i<n;i++)
    {
      polarity = in[i] >= 0 ? 1 : -1;
      if((polarity < prev || polarity > prev) && count == number && x->i_bang == 1)
	{
	  x->i_ndx = i;
	  x->i_pol = polarity;
	  count += 1e+06;
	  x->i_bang = 0;
	  outlet_float(x->f_pol, (float)x->i_pol);
	  outlet_float(x->f_pos, (float)x->i_ndx);
	}
      if((polarity < prev || polarity > prev) && count < number) count++;
      if(i==n-1)
	{
	  ctl->final_pol = polarity;
	  x->i_count = count;
	}
      prev = polarity;
    }
  return(w+4);
}

void zeroxpos_tilde_bang(t_zeroxpos_tilde *x)
{
  x->i_bang = 1;
  x->i_count = 0;
}

void *zeroxpos_tilde_dsp(t_zeroxpos_tilde *x, t_signal **sp) 
{
  x->x_ctl.c_input = sp[0]->s_vec;
  dsp_add(zeroxpos_tilde_perform, 3, x, &x->x_ctl, sp[0]->s_n);
  return (void *)x;
}

void *zeroxpos_tilde_new(t_floatarg f) 
{
  t_zeroxpos_tilde *x = (t_zeroxpos_tilde *)pd_new(zeroxpos_tilde_class);
  x->f_num = f > 0 ? f : 1; 
  x->x_ctl.final_pol = 1;
  x->i_count = 0;
  floatinlet_new (&x->x_obj, &x->f_num);
  x->f_pos = outlet_new(&x->x_obj, gensym("float"));
  x->f_pol = outlet_new(&x->x_obj, gensym("float"));
  return (void *)x;
}

void zeroxpos_tilde_setup(void) 
{
  zeroxpos_tilde_class = class_new(gensym("zeroxpos~"), 
  (t_newmethod)zeroxpos_tilde_new, 
  0, sizeof(t_zeroxpos_tilde),
  CLASS_DEFAULT, A_DEFFLOAT, 0);

  post("|¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬zeroxpos~``````````````````````|");
  post("|find 1st, 2nd or 3rd etc zero crossing point in frame|");
  post("|````edward¬¬¬¬¬¬¬¬¬¬¬¬kelly``````````````````2005¬¬¬¬|");

  class_sethelpsymbol(zeroxpos_tilde_class, gensym("help-zeroxpos~"));
  class_addbang(zeroxpos_tilde_class, zeroxpos_tilde_bang);
  class_addmethod(zeroxpos_tilde_class, (t_method)zeroxpos_tilde_dsp, gensym("dsp"), 0);
  CLASS_MAINSIGNALIN(zeroxpos_tilde_class, t_zeroxpos_tilde, f_dummy);
}