(** Curated exercises and their permitted relationships. *)

type equipment =
  | Barbell
  | Cable
  | Dumbbell
  | Machine
  | Bodyweight
  | Unspecified

type movement =
  | Fly
  | Crossover
  | Pec_deck
  | Press
  | Lateral_raise
  | French_press
  | Pressdown
  | Dip
  | Pullover
  | Pulldown
  | Row
  | Chin
  | Shrug
  | Hyperextension
  | Deadlift
  | Curl
  | Leg_extension
  | Leg_press
  | Squat
  | Leg_curl
  | Calf_raise
  | Sit_up

type variation =
  | Standard
  | Incline
  | Bent_over
  | Rear_delt
  | Lying
  | Triceps
  | Close_grip_palms_up
  | Straight_arm
  | Preacher

type key = { equipment : equipment; movement : movement; variation : variation }
(** The catalog identity: equipment × movement × variation. *)

type t
(** An opaque catalog entry, only obtainable by lookup. *)

type id = private string
(** A stable serialized identifier for external boundaries. *)

val find : key -> t option
(** Looks up an exercise by structured identity. *)

val find_id : string -> t option
(** Looks up an exercise by stable serialized identifier. *)

val key : t -> key
val id : t -> id
val name : t -> string
val equal : t -> t -> bool
val pp : Format.formatter -> t -> unit

val may_pre_exhaust : isolation:t -> compound:t -> bool
(** Whether the pair shares the isolation's target. *)

val may_substitute : original:t -> candidate:t -> bool
(** Whether [candidate] is author-approved for [original]. *)