%%% @doc hackney_telemetry application supervisor.
%%% @end

-module(hackney_telemetry_sup).

-behaviour(supervisor).

% Supervisor callbacks
-export([init/1]).
% Public API
-export([start_link/0, start_worker/1, stop_worker/1]).

-define(SERVER, ?MODULE).

-include("hackney_telemetry.hrl").

start_link() ->
    supervisor:start_link({local, ?SERVER}, ?MODULE, []).

init([]) ->
    SupFlags =
        #{
            strategy => one_for_one,
            intensity => 0,
            period => 1
        },
    ChildSpecs =
        [
            hackney_telemetry_worker:child_spec([{metric, [hackney, nb_requests]}]),
            hackney_telemetry_worker:child_spec([{metric, [hackney, total_requests]}]),
            hackney_telemetry_worker:child_spec([{metric, [hackney, finished_requests]}])
        ],
    {ok, {SupFlags, ChildSpecs}}.

%%% @doc Start worker for the given metric under this supervisor.

-spec start_worker(hackney_metric()) -> ok.
start_worker(Metric) ->
    ChildSpec = hackney_telemetry_worker:child_spec([{metric, Metric}]),
    supervisor:start_child(?MODULE, ChildSpec),
    ok.

%%% @doc Stop worker associated with the given metric name if it exists.

-spec stop_worker(hackney_metric()) -> ok | undefined.
stop_worker(Metric) ->
    WorkerId = {hackney_telemetry_worker, Metric},
    {global, WorkerName} = hackney_telemetry_worker:worker_name(Metric),
    case global:whereis_name(WorkerName) of
        undefined ->
            undefined;
        _Pid ->
            ok = supervisor:terminate_child(?SERVER, WorkerId),
            ok = supervisor:delete_child(?SERVER, WorkerId),
            ok
    end.