miss.ml

let add_missing_hours
  : Date.t -> (Time.t * 'a) list -> (Time.t * 'a) list
  = fun date hourly_counts ->
    let gen_day_hours ~start =
      List.map (List.range 0 24) (fun hr -> Time.add start (Time.Span.create ~hr ())) in
    let day_hours = gen_day_hours
        ~start:(Time.of_date_ofday date Core.Ofday.start_of_day Core.Zone.utc) in
    List.fold day_hours ~init:hourly_counts
      ~f:(fun hourly_counts' hour ->
          if List.Assoc.mem hourly_counts' hour then hourly_counts'
          else List.Assoc.add hourly_counts' hour 0)