open StdLabels

let identifier = "escaped_string"
let description = "Check for unnecessary use of expression encoded in string"
let is_global = false
let active = ref true

type context = unit

let initialize = Fun.id
let finalize () = []

module TypeBuilder = Compose.Expression (Get_type)

module Expression = TypeBuilder.Make (struct
  type t = Report.t list
  type t' = Report.t list

  let v : Get_type.t Lazy.t * t -> t' = snd

  (** Identify the expressions reprented as string. That’s here that the report
      are added. 

      All the rest of the module only push thoses warning to the top level. *)
  let literal :
      S.pos -> (Get_type.t Lazy.t * t) T.literal list -> Get_type.t Lazy.t -> t
      =
   fun pos content _type_of ->
    match content with
    | [ T.Expression (t', _); T.Text "" ] -> (
        match Get_type.get_type (Lazy.force t') with
        | Get_type.Integer -> []
        | _ ->
            let msg = Report.debug pos "This expression can be simplified" in
            [ msg ])
    | _ -> []

  let ident :
      (S.pos, Get_type.t Lazy.t * t) S.variable -> Get_type.t Lazy.t -> t =
   fun variable _type_of ->
    match variable.index with None -> [] | Some (_, t) -> t

  let integer : S.pos -> string -> Get_type.t Lazy.t -> t =
   fun pos t _type_of ->
    ignore pos;
    ignore t;
    []

  let function_ :
      S.pos ->
      T.function_ ->
      (Get_type.t Lazy.t * t) list ->
      Get_type.t Lazy.t ->
      t =
   fun pos f expressions _type_of ->
    ignore pos;
    ignore f;
    let exprs =
      List.fold_left ~init:[] expressions ~f:(fun acc el ->
          List.rev_append (snd el) acc)
    in
    exprs

  let uoperator :
      S.pos -> T.uoperator -> Get_type.t Lazy.t * t -> Get_type.t Lazy.t -> t =
   fun pos op r _type_of ->
    ignore op;
    ignore pos;
    snd r

  let boperator :
      S.pos ->
      T.boperator ->
      Get_type.t Lazy.t * t ->
      Get_type.t Lazy.t * t ->
      Get_type.t Lazy.t ->
      t =
   fun pos op (_, r1) (_, r2) _type_of ->
    ignore pos;
    ignore op;
    r1 @ r2
end)

module Instruction :
  S.Instruction with type t' = Report.t list and type expression = Expression.t' =
struct
  type t = Report.t list
  (** Internal type used in the evaluation *)

  type t' = t

  let v : t -> t' = Fun.id

  type expression = Expression.t'

  let call : S.pos -> T.keywords -> expression list -> t =
   fun pos k exprs ->
    ignore pos;
    ignore k;
    List.concat exprs

  let location : S.pos -> string -> t = fun _ _ -> []
  let comment : S.pos -> t = fun _ -> []
  let expression : expression -> t = Fun.id

  let act : S.pos -> label:expression -> t list -> t =
   fun pos ~label instructions ->
    ignore pos;
    List.concat (label :: instructions)

  let fold_clause : (expression, t) S.clause -> t =
   fun (_pos1, expression, ts) -> List.concat (expression :: ts)

  let if_ :
      S.pos ->
      (expression, t) S.clause ->
      elifs:(expression, t) S.clause list ->
      else_:(S.pos * t list) option ->
      t =
   fun pos clause ~elifs ~else_ ->
    ignore pos;

    let init =
      match else_ with
      | None -> fold_clause clause
      | Some (_, ts) -> List.rev_append (fold_clause clause) (List.concat ts)
    in

    List.fold_left elifs ~init ~f:(fun t clause ->
        List.rev_append (fold_clause clause) t)

  let assign :
      S.pos ->
      (S.pos, expression) S.variable ->
      T.assignation_operator ->
      expression ->
      t =
   fun pos variable op expression ->
    ignore pos;
    ignore op;
    match variable.index with
    | None -> expression
    | Some v -> List.rev_append v expression

  let for_ :
      S.pos ->
      (S.pos, Expression.t') S.variable ->
      start:Expression.t' ->
      to_:Expression.t' ->
      step:Expression.t' option ->
      t list ->
      t =
   fun pos variable ~start ~to_ ~step statements ->
    ignore variable;
    ignore start;
    ignore to_;
    ignore step;
    ignore pos;
    List.concat statements
end

module Location = struct
  type t = Report.t list
  type instruction = Instruction.t'

  let v = Fun.id

  let location : unit -> S.pos -> instruction list -> t =
   fun () pos intructions ->
    ignore pos;
    List.concat intructions
end