%% This Source Code Form is subject to the terms of the Mozilla Public
%% License, v. 2.0. If a copy of the MPL was not distributed with this
%% file, You can obtain one at https://mozilla.org/MPL/2.0/.
%%
%% Copyright (c) 2007-2020 VMware, Inc. or its affiliates.  All rights reserved.
%%

-module(rabbit_mgmt_wm_aliveness_test).

-export([init/2, to_json/2, content_types_provided/2, is_authorized/2]).
-export([resource_exists/2]).
-export([variances/2]).

-include("rabbit_mgmt.hrl").
-include_lib("rabbitmq_management_agent/include/rabbit_mgmt_records.hrl").
-include_lib("amqp_client/include/amqp_client.hrl").

-define(QUEUE, <<"aliveness-test">>).

%%--------------------------------------------------------------------

init(Req, _State) ->
    {cowboy_rest, rabbit_mgmt_headers:set_common_permission_headers(Req, ?MODULE), #context{}}.

variances(Req, Context) ->
    {[<<"accept-encoding">>, <<"origin">>], Req, Context}.

content_types_provided(ReqData, Context) ->
    {rabbit_mgmt_util:responder_map(to_json), ReqData, Context}.

resource_exists(ReqData, Context) ->
    {case rabbit_mgmt_util:vhost(ReqData) of
            not_found -> false;
            _ -> true
        end, ReqData, Context}.

to_json(ReqData, Context) ->
    rabbit_mgmt_util:with_channel(
        rabbit_mgmt_util:vhost(ReqData),
        ReqData,
        Context,
        fun(Ch) ->
            #'queue.declare_ok'{queue = ?QUEUE} = amqp_channel:call(Ch, #'queue.declare'{
                queue = ?QUEUE
            }),
            ok = amqp_channel:call(Ch, #'basic.publish'{routing_key = ?QUEUE}, #amqp_msg{
                payload = <<"test_message">>
            }),
            case amqp_channel:call(Ch, #'basic.get'{queue = ?QUEUE, no_ack = true}) of
                {#'basic.get_ok'{}, _} ->
                    %% Don't delete the queue. If this is pinged every few
                    %% seconds we don't want to create a mnesia transaction
                    %% each time.
                    rabbit_mgmt_util:reply([{status, ok}], ReqData, Context);
                #'basic.get_empty'{} ->
                    Reason = <<"aliveness-test queue is empty">>,
                    failure(Reason, ReqData, Context);
                Error ->
                    Reason = rabbit_data_coercion:to_binary(Error),
                    failure(Reason, ReqData, Context)
            end
        end
    ).

failure(Reason, ReqData0, Context0) ->
    Body = #{status => failed, reason => Reason},
    {Response, ReqData1, Context1} = rabbit_mgmt_util:reply(Body, ReqData0, Context0),
    {stop, cowboy_req:reply(?HEALTH_CHECK_FAILURE_STATUS, #{}, Response, ReqData1), Context1}.

is_authorized(ReqData, Context) ->
    rabbit_mgmt_util:is_authorized_vhost(ReqData, Context).
