let src = Logs.Src.create "claude.structured_output" ~doc:"Structured output"
module Log = (val Logs.src_log src : Logs.LOG)

type t = {
  json_schema : Jsont.json;
}

let json_to_string json =
  match Jsont_bytesrw.encode_string' Jsont.json json with
  | Ok str -> str
  | Error err -> failwith (Jsont.Error.to_string err)

let of_json_schema schema =
  Log.debug (fun m -> m "Created output format from JSON schema: %s"
    (json_to_string schema));
  { json_schema = schema }

let json_schema t = t.json_schema

(* Codec for serializing structured output format *)
let jsont : t Jsont.t =
  Jsont.Object.map ~kind:"StructuredOutput"
    (fun json_schema -> {json_schema})
  |> Jsont.Object.mem "jsonSchema" Jsont.json ~enc:(fun t -> t.json_schema)
  |> Jsont.Object.finish

let to_json t =
  match Jsont.Json.encode jsont t with
  | Ok json -> json
  | Error msg -> failwith ("Structured_output.to_json: " ^ msg)

let of_json json =
  match Jsont.Json.decode jsont json with
  | Ok t -> t
  | Error msg -> raise (Invalid_argument ("Structured_output.of_json: " ^ msg))

let pp fmt t =
  let schema_str =
    match Jsont_bytesrw.encode_string' ~format:Jsont.Minify Jsont.json t.json_schema with
    | Ok s -> s
    | Error err -> Jsont.Error.to_string err
  in
  let truncated =
    if String.length schema_str > 100 then
      String.sub schema_str 0 97 ^ "..."
    else
      schema_str
  in
  Fmt.pf fmt "@[<2>StructuredOutput { schema = %s }@]" truncated