-module(handler_booking_by_id).
-include("records.hrl").

-export([init/2]).

init(Req, Opts) ->
  handle(Req, Opts).

handle(Req, _Opts) ->
  case cowboy_req:method(Req) of
    <<"GET">> -> get_booking(Req);
    <<"PUT">> -> update_booking(Req);
    <<"DELETE">> -> cancel_booking(Req);
    _ -> send_error(Req, 405, <<"Method not allowed">>)
  end.

%% GET /v1/bookings/:id - получение бронирования
get_booking(Req) ->
  case handler_auth:authenticate(Req) of
    {ok, UserId, Req1} ->
      BookingId = cowboy_req:binding(id, Req1),
      case logic_booking:get_booking(UserId, BookingId) of
        {ok, Booking} ->
          Response = booking_to_json(Booking),
          send_json(Req1, 200, Response);
        {error, access_denied} ->
          send_error(Req1, 403, <<"Access denied">>);
        {error, not_found} ->
          send_error(Req1, 404, <<"Booking not found">>);
        {error, _} ->
          send_error(Req1, 500, <<"Internal server error">>)
      end;
    {error, Code, Message, Req1} ->
      send_error(Req1, Code, Message)
  end.

%% PUT /v1/bookings/:id - подтверждение/отклонение бронирования (владельцем)
update_booking(Req) ->
  case handler_auth:authenticate(Req) of
    {ok, UserId, Req1} ->
      BookingId = cowboy_req:binding(id, Req1),
      {ok, Body, Req2} = cowboy_req:read_body(Req1),
      try jsx:decode(Body, [return_maps]) of
        Decoded when is_map(Decoded) ->
          case maps:get(<<"action">>, Decoded, undefined) of
            <<"confirm">> ->
              case logic_booking:confirm_booking(UserId, BookingId, confirm) of
                {ok, Booking} ->
                  Response = booking_to_json(Booking),
                  send_json(Req2, 200, Response);
                {error, access_denied} ->
                  send_error(Req2, 403, <<"Access denied">>);
                {error, not_found} ->
                  send_error(Req2, 404, <<"Booking not found">>);
                {error, _} ->
                  send_error(Req2, 500, <<"Internal server error">>)
              end;
            <<"decline">> ->
              case logic_booking:confirm_booking(UserId, BookingId, decline) of
                {ok, Booking} ->
                  Response = booking_to_json(Booking),
                  send_json(Req2, 200, Response);
                {error, access_denied} ->
                  send_error(Req2, 403, <<"Access denied">>);
                {error, not_found} ->
                  send_error(Req2, 404, <<"Booking not found">>);
                {error, _} ->
                  send_error(Req2, 500, <<"Internal server error">>)
              end;
            _ ->
              send_error(Req2, 400, <<"Missing or invalid 'action' field. Use 'confirm' or 'decline'">>)
          end;
        _ ->
          send_error(Req2, 400, <<"Invalid JSON">>)
      catch
        _:_ ->
          send_error(Req2, 400, <<"Invalid JSON format">>)
      end;
    {error, Code, Message, Req1} ->
      send_error(Req1, Code, Message)
  end.

%% DELETE /v1/bookings/:id - отмена бронирования (участником)
cancel_booking(Req) ->
  case handler_auth:authenticate(Req) of
    {ok, UserId, Req1} ->
      BookingId = cowboy_req:binding(id, Req1),
      case logic_booking:cancel_booking(UserId, BookingId) of
        {ok, Booking} ->
          Response = booking_to_json(Booking),
          send_json(Req1, 200, Response);
        {error, access_denied} ->
          send_error(Req1, 403, <<"Access denied">>);
        {error, not_found} ->
          send_error(Req1, 404, <<"Booking not found">>);
        {error, _} ->
          send_error(Req1, 500, <<"Internal server error">>)
      end;
    {error, Code, Message, Req1} ->
      send_error(Req1, Code, Message)
  end.

%% Вспомогательные функции
booking_to_json(Booking) ->
  #{
    id => Booking#booking.id,
    event_id => Booking#booking.event_id,
    user_id => Booking#booking.user_id,
    status => Booking#booking.status,
    confirmed_at => case Booking#booking.confirmed_at of
                      undefined -> null;
                      Dt -> datetime_to_iso8601(Dt)
                    end,
    created_at => datetime_to_iso8601(Booking#booking.created_at),
    updated_at => datetime_to_iso8601(Booking#booking.updated_at)
  }.

datetime_to_iso8601({{Year, Month, Day}, {Hour, Minute, Second}}) ->
  iolist_to_binary(io_lib:format("~4..0B-~2..0B-~2..0BT~2..0B:~2..0B:~2..0BZ",
    [Year, Month, Day, Hour, Minute, Second])).

send_json(Req, Status, Data) ->
  Body = jsx:encode(Data),
  cowboy_req:reply(Status, #{<<"content-type">> => <<"application/json">>}, Body, Req),
  {ok, Body, []}.

send_error(Req, Status, Message) ->
  Body = jsx:encode(#{error => Message}),
  cowboy_req:reply(Status, #{<<"content-type">> => <<"application/json">>}, Body, Req),
  {ok, Body, []}.