(*---------------------------------------------------------------------------
  Copyright (c) 2025 Anil Madhavapeddy <anil@recoil.org>. All rights reserved.
  SPDX-License-Identifier: ISC
 ---------------------------------------------------------------------------*)

(** Response limits for HTTP protocol handling

    Configurable limits for response body size, header count, and header length
    to prevent DoS attacks. *)

type t = {
  max_response_body_size : int64;
  max_header_size : int;
  max_header_count : int;
  max_decompressed_size : int64;
  max_compression_ratio : float;
}

let default =
  {
    max_response_body_size = 104_857_600L;
    (* 100MB *)
    max_header_size = 16_384;
    (* 16KB *)
    max_header_count = 100;
    max_decompressed_size = 104_857_600L;
    (* 100MB *)
    max_compression_ratio = 100.0;
    (* 100:1 *)
  }

let v ?(max_response_body_size = 104_857_600L) ?(max_header_size = 16_384)
    ?(max_header_count = 100) ?(max_decompressed_size = 104_857_600L)
    ?(max_compression_ratio = 100.0) () =
  {
    max_response_body_size;
    max_header_size;
    max_header_count;
    max_decompressed_size;
    max_compression_ratio;
  }

let max_response_body_size t = t.max_response_body_size
let max_header_size t = t.max_header_size
let max_header_count t = t.max_header_count
let max_decompressed_size t = t.max_decompressed_size
let max_compression_ratio t = t.max_compression_ratio

let pp fmt t =
  Fmt.pf fmt
    "@[<v 2>Response_limits {@ max_response_body_size: %Ld bytes@ \
     max_header_size: %d bytes@ max_header_count: %d@ max_decompressed_size: \
     %Ld bytes@ max_compression_ratio: %.1f:1@ }@]"
    t.max_response_body_size t.max_header_size t.max_header_count
    t.max_decompressed_size t.max_compression_ratio

let to_string t = Fmt.str "%a" pp t