-module(roadrunner_default_handler).
-moduledoc false.

%% Default `roadrunner_handler` — used when a listener starts with no
%% `routes` opt configured. Returns 404 with a body pointing the
%% operator at the quickstart, so a smoke `curl` against an otherwise-
%% blank listener tells you what to do next instead of silently 200-ing.
%%
%% Operators wire their own handler via the listener's `routes` opt:
%% either a bare module atom (every request goes to that handler) or
%% a list of `{Path, Module, Opts}` tuples (routed dispatch). See
%% `t:roadrunner_listener:opts/0` and the project README.

-behaviour(roadrunner_handler).

-export([handle/1]).

-define(BODY,
    ~"""
    roadrunner: no routes configured for this listener.

    Quickstart:
      roadrunner:start_listener(my_listener, #{
          port => 8080,
          routes => my_handler
      }).

      roadrunner:start_listener(my_listener, #{
          port => 8080,
          routes => [{~"/", my_handler, #{}}]
      }).

    Docs: https://github.com/arizona-framework/roadrunner
    """
).

-spec handle(roadrunner_req:request()) -> roadrunner_handler:result().
handle(Req) ->
    Resp =
        {404,
            [
                {~"content-type", ~"text/plain; charset=utf-8"},
                {~"content-length", integer_to_binary(byte_size(?BODY))}
            ],
            ?BODY},
    {Resp, Req}.