(*
 Copyright (C) 2003-2005 Samuel Mimram

 This file is part of Ocaml-ssl.

 This library is free software; you can redistribute it and/or
 modify it under the terms of the GNU Lesser General Public
 License as published by the Free Software Foundation; either
 version 2.1 of the License, or (at your option) any later version.

 This library is distributed in the hope that it will be useful,
 but WITHOUT ANY WARRANTY; without even the implied warranty of
 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 Lesser General Public License for more details.

 You should have received a copy of the GNU Lesser General Public
 License along with this library; if not, write to the Free Software
 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 *)

type protocol =
  | SSLv23
  | SSLv3
  | TLSv1
  | TLSv1_1
  | TLSv1_2
  | TLSv1_3

type context

type certificate

type socket

type ssl_error =
  | Error_none
  | Error_ssl
  | Error_want_read
  | Error_want_write
  | Error_want_x509_lookup
  | Error_syscall
  | Error_zero_return
  | Error_want_connect
  | Error_want_accept

type verify_error =
  | Error_v_unable_to_get_issuer_cert
  | Error_v_unable_to_get_ctl
  | Error_v_unable_to_decrypt_cert_signature
  | Error_v_unable_to_decrypt_CRL_signature
  | Error_v_unable_to_decode_issuer_public_key
  | Error_v_cert_signature_failure
  | Error_v_CRL_signature_failure
  | Error_v_cert_not_yet_valid
  | Error_v_cert_has_expired
  | Error_v_CRL_not_yet_valid
  | Error_v_CRL_has_expired
  | Error_v_error_in_cert_not_before_field
  | Error_v_error_in_cert_not_after_field
  | Error_v_error_in_CRL_last_update_field
  | Error_v_error_in_CRL_next_update_field
  | Error_v_out_of_mem
  | Error_v_depth_zero_self_signed_cert
  | Error_v_self_signed_cert_in_chain
  | Error_v_unable_to_get_issuer_cert_locally
  | Error_v_unable_to_verify_leaf_signature
  | Error_v_cert_chain_too_long
  | Error_v_cert_revoked
  | Error_v_invalid_CA
  | Error_v_path_length_exceeded
  | Error_v_invalid_purpose
  | Error_v_cert_untrusted
  | Error_v_cert_rejected
  | Error_v_subject_issuer_mismatch
  | Error_v_akid_skid_mismatch
  | Error_v_akid_issuer_serial_mismatch
  | Error_v_keyusage_no_certsign
  | Error_v_application_verification

type bigarray = (char, Bigarray.int8_unsigned_elt, Bigarray.c_layout) Bigarray.Array1.t

external get_error_string : unit -> string = "ocaml_ssl_get_error_string"

exception Method_error
exception Context_error
exception Certificate_error of string
exception Cipher_error
exception Diffie_hellman_error
exception Ec_curve_error
exception Private_key_error of string
exception Unmatching_keys
exception Invalid_socket
exception Handler_error
exception Connection_error of ssl_error
exception Accept_error of ssl_error
exception Read_error of ssl_error
exception Write_error of ssl_error
exception Verify_error of verify_error

let () =
  Printexc.register_printer (function
    | Method_error -> Some ("SSL: Method error")
    | Context_error -> Some ("SSL: Context error")
    | Certificate_error s -> Some ("SSL: Certificate error: " ^ s)
    | Cipher_error -> Some ("SSL: Cihper error")
    | Diffie_hellman_error -> Some ("SSL: Diffie Hellman error")
    | Ec_curve_error -> Some ("SSL: EC curve error")
    | Private_key_error s -> Some ("SSL: Privte key error: " ^ s)
    | Unmatching_keys -> Some ("SSL: Unmatching keys")
    | Invalid_socket -> Some ("SSL: Invalid socket")
    | Handler_error -> Some ("SSL: Handler error")
    | Connection_error _ -> Some ("SSL connection() error: " ^ (get_error_string()))
    | Accept_error _ -> Some ("SSL accept() error: " ^ (get_error_string()))
    | Read_error _ -> Some ("SSL read() error: " ^ (get_error_string()))
    | Write_error _ -> Some ("SSL write() error: " ^ (get_error_string()))
    | Verify_error _ -> Some ("SSL verify() error: " ^ (get_error_string()))
    | _ -> None)

let () =
  Callback.register_exception "ssl_exn_method_error" Method_error;
  Callback.register_exception "ssl_exn_context_error" Context_error;
  Callback.register_exception "ssl_exn_certificate_error" (Certificate_error "");
  Callback.register_exception "ssl_exn_cipher_error" Cipher_error;
  Callback.register_exception "ssl_exn_diffie_hellman_error" Diffie_hellman_error;
  Callback.register_exception "ssl_exn_ec_curve_error" Ec_curve_error;
  Callback.register_exception "ssl_exn_private_key_error" (Private_key_error "");
  Callback.register_exception "ssl_exn_unmatching_keys" Unmatching_keys;
  Callback.register_exception "ssl_exn_invalid_socket" Invalid_socket;
  Callback.register_exception "ssl_exn_handler_error" Handler_error;
  Callback.register_exception "ssl_exn_connection_error" (Connection_error Error_none);
  Callback.register_exception "ssl_exn_accept_error" (Accept_error Error_none);
  Callback.register_exception "ssl_exn_read_error" (Read_error Error_none);
  Callback.register_exception "ssl_exn_write_error" (Write_error Error_none);
  Callback.register_exception "ssl_exn_verify_error" (Verify_error Error_v_application_verification)

let thread_safe = ref false

external init : bool -> unit = "ocaml_ssl_init"

let ts = thread_safe
let init ?thread_safe () =
  let thread_safe =
    match thread_safe with
      | Some b -> b
      | None -> !ts
  in
  init thread_safe

type context_type =
  | Client_context
  | Server_context
  | Both_context

external create_context : protocol -> context_type -> context = "ocaml_ssl_create_context"

external use_certificate : context -> string -> string -> unit = "ocaml_ssl_ctx_use_certificate"

external use_certificate_from_string : context -> string -> string -> unit = "ocaml_ssl_ctx_use_certificate_from_string"

external set_password_callback : context -> (bool -> string) -> unit = "ocaml_ssl_ctx_set_default_passwd_cb"

external embed_socket : Unix.file_descr -> context -> socket = "ocaml_ssl_embed_socket"

external disable_protocols : context -> protocol list -> unit = "ocaml_ssl_disable_protocols"

external set_cipher_list : context -> string -> unit = "ocaml_ssl_ctx_set_cipher_list"

external honor_cipher_order : context -> unit = "ocaml_ssl_ctx_honor_cipher_order"

external init_dh_from_file : context -> string -> unit = "ocaml_ssl_ctx_init_dh_from_file"

external init_ec_from_named_curve : context -> string -> unit = "ocaml_ssl_ctx_init_ec_from_named_curve"

external load_verify_locations : context -> string -> string -> unit = "ocaml_ssl_ctx_load_verify_locations"

external set_default_verify_paths : context -> bool = "ocaml_ssl_ctx_set_default_verify_paths"

external get_verify_result : socket -> int = "ocaml_ssl_get_verify_result"

external get_verify_error_string : int -> string = "ocaml_ssl_get_verify_error_string"

type verify_mode =
  | Verify_peer
  | Verify_fail_if_no_peer_cert
  | Verify_client_once

type verify_callback

external get_client_verify_callback_ptr : unit -> verify_callback = "ocaml_ssl_get_client_verify_callback_ptr"

let client_verify_callback = get_client_verify_callback_ptr ()

external set_client_verify_callback_verbose : bool -> unit = "ocaml_ssl_set_client_verify_callback_verbose"

external set_verify : context -> verify_mode list -> verify_callback option -> unit = "ocaml_ssl_ctx_set_verify"

external set_verify_depth : context -> int -> unit = "ocaml_ssl_ctx_set_verify_depth"

external set_client_CA_list_from_file : context -> string -> unit = "ocaml_ssl_ctx_set_client_CA_list_from_file"

external set_context_alpn_protos : context -> string list -> unit = "ocaml_ssl_ctx_set_alpn_protos"

external set_context_alpn_select_callback : context -> (string list -> string option) -> unit = "ocaml_ssl_ctx_set_alpn_select_callback"

external version : socket -> protocol = "ocaml_ssl_version"

type cipher

external get_cipher : socket -> cipher = "ocaml_ssl_get_current_cipher"

external get_cipher_description : cipher -> string = "ocaml_ssl_get_cipher_description"

(* TODO: get_cipher_bits *)

external get_cipher_name : cipher -> string = "ocaml_ssl_get_cipher_name"

external get_cipher_version : cipher -> string = "ocaml_ssl_get_cipher_version"

external get_certificate : socket -> certificate = "ocaml_ssl_get_certificate"

external read_certificate : string -> certificate = "ocaml_ssl_read_certificate"

external write_certificate : string -> certificate -> unit = "ocaml_ssl_write_certificate"

external get_issuer : certificate -> string = "ocaml_ssl_get_issuer"

external get_subject : certificate -> string = "ocaml_ssl_get_subject"

external get_start_date : certificate -> Unix.tm = "ocaml_ssl_get_start_date"

external get_expiration_date : certificate -> Unix.tm = "ocaml_ssl_get_expiration_date"

external file_descr_of_socket : socket -> Unix.file_descr = "ocaml_ssl_get_file_descr"

external set_client_SNI_hostname : socket -> string -> unit = "ocaml_ssl_set_client_SNI_hostname"

external set_alpn_protos : socket -> string list -> unit = "ocaml_ssl_set_alpn_protos"

external get_negotiated_alpn_protocol : socket -> string option = "ocaml_ssl_get_negotiated_alpn_protocol"

external connect : socket -> unit = "ocaml_ssl_connect"

external verify : socket -> unit = "ocaml_ssl_verify"

type x509_check_flag =
  | Always_check_subject
  | No_wildcards
  | No_partial_wildcards
  | Multi_label_wildcards
  | Single_label_subdomains

external set_hostflags : socket -> x509_check_flag list -> unit = "ocaml_ssl_set_hostflags"

external set_host : socket -> string -> unit = "ocaml_ssl_set1_host"

external write : socket -> Bytes.t -> int -> int -> int = "ocaml_ssl_write"

external write_substring : socket -> string -> int -> int -> int = "ocaml_ssl_write"

external write_bigarray : socket -> bigarray -> int -> int -> int = "ocaml_ssl_write_bigarray"

external write_bigarray_blocking :
  socket -> bigarray -> int -> int -> int = "ocaml_ssl_write_bigarray_blocking"

external read : socket -> Bytes.t -> int -> int -> int = "ocaml_ssl_read"

external read_into_bigarray :
  socket -> bigarray -> int -> int -> int = "ocaml_ssl_read_into_bigarray"

external read_into_bigarray_blocking :
  socket -> bigarray -> int -> int -> int = "ocaml_ssl_read_into_bigarray_blocking"

external accept : socket -> unit = "ocaml_ssl_accept"

external flush : socket -> unit = "ocaml_ssl_flush"

external shutdown : socket -> unit = "ocaml_ssl_shutdown"

let open_connection_with_context context sockaddr =
  let domain =
    match sockaddr with
      | Unix.ADDR_UNIX _ -> Unix.PF_UNIX
      | Unix.ADDR_INET(_, _) -> Unix.PF_INET
  in
  let sock =
    Unix.socket domain Unix.SOCK_STREAM 0 in
    try
      Unix.connect sock sockaddr;
      let ssl = embed_socket sock context in
        connect ssl; ssl
    with
      | exn -> Unix.close sock; raise exn

let open_connection ssl_method sockaddr =
  open_connection_with_context (create_context ssl_method Client_context) sockaddr

let shutdown_connection = shutdown

let output_string ssl s =
  ignore (write_substring ssl s 0 (String.length s))

let output_char ssl c =
  let tmp = String.make 1 c in
    ignore (write_substring ssl tmp 0 1)

let output_int ssl i =
  let tmp = Bytes.create 4 in
    Bytes.set tmp 0 (char_of_int (i lsr 24));
    Bytes.set tmp 1 (char_of_int ((i lsr 16) land 0xff));
    Bytes.set tmp 2 (char_of_int ((i lsr 8) land 0xff));
    Bytes.set tmp 3 (char_of_int (i land 0xff));
    if write ssl tmp 0 4 <> 4 then failwith "output_int error: all the byte were not sent"

let input_string ssl =
  let bufsize = 1024 in
  let buf = Bytes.create bufsize in
  let ret = ref "" in
  let r = ref 1 in
    while !r <> 0
    do
      r := read ssl buf 0 bufsize;
      ret := !ret ^ (Bytes.sub_string buf 0 !r)
    done;
    !ret

let input_char ssl =
  let tmp = Bytes.create 1 in
    if read ssl tmp 0 1 <> 1 then
      raise End_of_file
    else
      Bytes.get tmp 0

let input_int ssl =
  let i = ref 0 in
  let tmp = Bytes.create 4 in
    ignore (read ssl tmp 0 4);
    i := int_of_char (Bytes.get tmp 0);
    i := (!i lsl 8) + int_of_char (Bytes.get tmp 1);
    i := (!i lsl 8) + int_of_char (Bytes.get tmp 2);
    i := (!i lsl 8) + int_of_char (Bytes.get tmp 3);
    !i
