!7

static DependentCache<S> imageCache = new(f makeChart_fresh, f unixDay);

answer {
  if "visitors chart" ret standardChart();
  
  if (match("visitors chart *", s, m) || match("visitors chart * days", s, m))
    ret makeChart_fresh(m.psi(0));
}

html {
  ret himg(skipToURL(standardChart()));
}

// 7 days
static S standardChart() {
  ret imageCache!;
}

static S makeChart_fresh() {
  ret makeChart_fresh(7);
}

static S makeChart_fresh(int days) {
  print("Making visitors chart for " + days + " days");
  days = max(1, days);
  exceptionToUser {
    L<S> l = toLinesFullTrim(unSlackSnippet(askSelf("visitors last " + (days+1) + " days")));
    
    new L<Integer> data;
    for (S line : l) {
      O o = safeUnstructure(line);
      int n = toInt(get(o, "cookies"));
      data.add(n);
    }
    
    removeLast(data); // drop today's data - it looks bad
    
    ret chartBase("Visitors last " + days + " days (= cookies)", 0, data);
 // base value = 0
  }
}