(** Subjective self-reports at a point in time: what the trainee said, not what
    the body did. HD1 grounds two of them. HD1 gauges recovery by time and by
    effect, not by a wider battery of wellness proxies. *)

type level =
  | Worse_than_usual
  | As_usual
  | Better_than_usual
      (** A self-report relative to the trainee's usual baseline, not an
          absolute score. HD1 frames both signals this way — Difficulty is "the
          weights feel much heavier than usual". Three values resist the false
          precision of a finer scale, and match HD1's refusal of a finer
          measurement scale. [Worse_than_usual] is the concerning direction for
          both signals. *)

val pp_level : Format.formatter -> level -> unit

type signal =
  | Motivation of level
  | Difficulty of level
      (** The only self-reports HD1 grounds. Motivation is HD1 chapter 6, and a
          halt in motivation is a recognized overtraining symptom ("with those
          who chronically overtrain, such a disinclination is easy to
          understand"). Difficulty is HD1's "the weights feel much heavier than
          usual" — a depletion symptom. HD1 gauges recovery by time and by
          effect (a stall or decompensation), not by a wider battery of wellness
          proxies. This module models none of the other proxies. *)

type t
type error = Duplicate_signal of signal

exception Invalid of error

val make : reported_at:Recovery.timestamp -> signal list -> t
(** Raises [Invalid] when feedback repeats a signal category. *)

val reported_at : t -> Recovery.timestamp
val signals : t -> signal list