%% Copyright (c) 2012-2019, DNSimple Corporation
%%
%% Permission to use, copy, modify, and/or distribute this software for any
%% purpose with or without fee is hereby granted, provided that the above
%% copyright notice and this permission notice appear in all copies.
%%
%% THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
%% WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
%% MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
%% ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
%% WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
%% ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
%% OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.

-module(erldns_admin_root_handler).
-moduledoc "Cowboy handler that handles Admin API requests to".

-export([init/2]).
-export([content_types_provided/2, is_authorized/2]).
-export([to_html/2, to_json/2, to_text/2]).

-behaviour(cowboy_rest).

-doc false.
-spec init(cowboy_req:req(), erldns_admin:handler_state()) ->
    {cowboy_rest, cowboy_req:req(), erldns_admin:handler_state()}.
init(Req, State) ->
    {cowboy_rest, Req, State}.

-doc false.
-spec content_types_provided(cowboy_req:req(), erldns_admin:handler_state()) ->
    {[{{binary(), binary(), '*'}, atom()}], cowboy_req:req(), erldns_admin:handler_state()}.
content_types_provided(Req, State) ->
    {
        [
            {{<<"text">>, <<"html">>, '*'}, to_html},
            {{<<"text">>, <<"plain">>, '*'}, to_text},
            {{<<"application">>, <<"json">>, '*'}, to_json}
        ],
        Req,
        State
    }.

-doc false.
-spec is_authorized(cowboy_req:req(), erldns_admin:handler_state()) ->
    {true | {false, iodata()}, cowboy_req:req(), erldns_admin:handler_state()}
    | {stop, cowboy_req:req(), erldns_admin:handler_state()}.
is_authorized(Req, State) ->
    erldns_admin:is_authorized(Req, State).

-doc false.
-spec to_html(cowboy_req:req(), erldns_admin:handler_state()) ->
    {cowboy_req:resp_body(), cowboy_req:req(), erldns_admin:handler_state()}.
to_html(Req, State) ->
    {<<"erldns admin">>, Req, State}.

-doc false.
-spec to_text(cowboy_req:req(), erldns_admin:handler_state()) ->
    {cowboy_req:resp_body(), cowboy_req:req(), erldns_admin:handler_state()}.
to_text(Req, State) ->
    {<<"erldns admin">>, Req, State}.

-doc "Return information about the zones in the cache.".
-spec to_json(cowboy_req:req(), erldns_admin:handler_state()) ->
    {cowboy_req:resp_body(), cowboy_req:req(), erldns_admin:handler_state()}.
to_json(Req, State) ->
    ZoneNamesAndVersionsForJson = lists:map(
        fun({Name, Version}) ->
            #{<<"name">> => Name, <<"version">> => Version}
        end,
        erldns_zone_cache:zone_names_and_versions()
    ),
    Body = json:encode(#{
        <<"erldns">> => #{
            <<"zones">> => #{
                <<"count">> => length(ZoneNamesAndVersionsForJson),
                <<"versions">> => ZoneNamesAndVersionsForJson
            }
        }
    }),
    {Body, Req, State}.