%%--------------------------------------------------------------------
%% Copyright (c) 2020-2021 EMQ Technologies Co., Ltd. All Rights Reserved.
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.
%%--------------------------------------------------------------------

-module(emqx_modules_schema).

-include_lib("typerefl/include/types.hrl").

-behaviour(hocon_schema).

-export([ namespace/0
        , roots/0
        , fields/1]).

namespace() -> modules.

roots() ->
    ["delayed",
     "telemetry",
     "event_message",
     array("rewrite"),
     array("topic_metrics")].

fields("telemetry") ->
    [ {enable, hoconsc:mk(boolean(), #{default => false})}
    ];

fields("delayed") ->
    [ {enable, hoconsc:mk(boolean(), #{default => false})}
    , {max_delayed_messages, sc(integer(), #{})}
    ];

fields("rewrite") ->
    [ {action, sc(hoconsc:enum([subscribe, publish, all]), #{desc => "Action", example => publish})}
    , {source_topic, sc(binary(), #{desc => "Origin Topic", example => "x/#"})}
    , {dest_topic, sc(binary(), #{desc => "Destination Topic", example => "z/y/$1"})}
    , {re, fun regular_expression/1 }
    ];


fields("event_message") ->
    [ {"$event/client_connected", sc(boolean(), #{default => false})}
    , {"$event/client_disconnected", sc(boolean(), #{default => false})}
    , {"$event/client_subscribed", sc(boolean(), #{default => false})}
    , {"$event/client_unsubscribed", sc(boolean(), #{default => false})}
    , {"$event/message_delivered", sc(boolean(), #{default => false})}
    , {"$event/message_acked", sc(boolean(), #{default => false})}
    , {"$event/message_dropped", sc(boolean(), #{default => false})}
    ];

fields("topic_metrics") ->
    [{topic, sc(binary(), #{})}].

regular_expression(type) -> binary();
regular_expression(desc) -> "Regular expressions";
regular_expression(example) -> "^x/y/(.+)$";
regular_expression(validator) -> fun is_re/1;
regular_expression(_) -> undefined.

is_re(Bin) ->
    case re:compile(Bin) of
        {ok, _} -> ok;
        {error, Reason} -> {error, {Bin, Reason}}
    end.

array(Name) -> {Name, hoconsc:array(hoconsc:ref(?MODULE, Name))}.

sc(Type, Meta) -> hoconsc:mk(Type, Meta).