-module(acumen@fetch_certificate).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/acumen/fetch_certificate.gleam").
-export([build/3, response/1]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

?MODULEDOC(
    " Fetch an issued certificate from the ACME server.\n"
    "\n"
    " After an order reaches the `Valid` status, use the certificate URL\n"
    " from `order.Valid(certificate_url)` to download the certificate chain\n"
    " in PEM format.\n"
    "\n"
    " ## Example\n"
    "\n"
    " ```gleam\n"
    " import acumen\n"
    " import acumen/fetch_certificate\n"
    " import acumen/order\n"
    "\n"
    " // After the order is valid...\n"
    " let assert order.Valid(certificate_url) = completed_order.status\n"
    "\n"
    " let assert Ok(#(resp, ctx)) = acumen.execute(\n"
    "   ctx,\n"
    "   build: fetch_certificate.build(certificate_url, _, registered_key),\n"
    "   send: httpc.send,\n"
    " )\n"
    "\n"
    " let assert Ok(pem_chain) = fetch_certificate.response(resp)\n"
    " ```\n"
).

-file("src/acumen/fetch_certificate.gleam", 34).
?DOC(" Builds a POST-as-GET request to fetch an issued certificate.\n").
-spec build(acumen@url:url(), acumen:context(), acumen:registered_key()) -> {ok,
        gleam@http@request:request(binary())} |
    {error, acumen:acme_error()}.
build(Url, Context, Key) ->
    _pipe = acumen:build_fetch(Url, Context, Key),
    gleam@result:map(
        _pipe,
        fun(_capture) ->
            gleam@http@request:set_header(
                _capture,
                <<"accept"/utf8>>,
                <<"application/pem-certificate-chain"/utf8>>
            )
        end
    ).

-file("src/acumen/fetch_certificate.gleam", 50).
?DOC(
    " Parses the certificate fetch response.\n"
    "\n"
    " Returns the certificate chain in PEM format.\n"
).
-spec response(gleam@http@response:response(binary())) -> {ok, binary()} |
    {error, acumen:acme_error()}.
response(Resp) ->
    case erlang:element(2, Resp) of
        200 ->
            {ok, erlang:element(4, Resp)};

        _ ->
            {error,
                {invalid_response,
                    acumen@internal@utils:unexpected_status_message(
                        erlang:element(2, Resp)
                    )}}
    end.