%%%-------------------------------------------------------------------
%%% @doc Обработчик маршрута `/v1/events/:id/bookings`.
%%%
%%% POST – Создание бронирования (запись на событие).
%%% GET  – Получение списка бронирований события (для владельца календаря).
%%% @end
%%%-------------------------------------------------------------------
-module(handler_bookings).
-behaviour(cowboy_handler).

-export([init/2]).
-export([trails/0]).

-include("records.hrl").

%%% cowboy_handler callback
-spec init(cowboy_req:req(), any()) -> {ok, cowboy_req:req(), any()}.
init(Req, Opts) ->
  handle(Req, Opts).

-spec handle(cowboy_req:req(), any()) -> {ok, cowboy_req:req(), any()}.
handle(Req, _Opts) ->
  case cowboy_req:method(Req) of
    <<"POST">> -> create_booking(Req);
    <<"GET">>  -> list_bookings(Req);
    _          -> handler_utils:send_error(Req, 405, <<"Method not allowed">>)
  end.

%%% Swagger metadata
-spec trails() -> [map()].
trails() ->
  BookingSchema = booking_schema(),
  [
    #{  % POST
      path        => <<"/v1/events/:id/bookings">>,
      method      => <<"POST">>,
      description => <<"Create a booking for an event">>,
      tags        => [<<"Bookings">>],
      parameters  => [
        #{
          name        => <<"id">>,
          in          => <<"path">>,
          description => <<"Event ID">>,
          required    => true,
          schema      => #{type => string}
        }
      ],
      responses   => #{
        201 => #{
          description => <<"Booking created">>,
          content     => #{<<"application/json">> => #{schema => BookingSchema}}
        },
        400 => #{description => <<"Event is full or not active">>},
        403 => #{description => <<"Access denied">>},
        404 => #{description => <<"Event not found">>},
        409 => #{description => <<"Already booked">>}
      }
    },
    #{  % GET list
      path        => <<"/v1/events/:id/bookings">>,
      method      => <<"GET">>,
      description => <<"List bookings for an event (owner only)">>,
      tags        => [<<"Bookings">>],
      parameters  => [
        #{
          name        => <<"id">>,
          in          => <<"path">>,
          description => <<"Event ID">>,
          required    => true,
          schema      => #{type => string}
        }
      ],
      responses   => #{
        200 => #{
          description => <<"Array of bookings">>,
          content     => #{<<"application/json">> => #{schema => #{
            type  => array,
            items => BookingSchema
          }}}
        },
        403 => #{description => <<"Access denied">>},
        404 => #{description => <<"Event not found">>}
      }
    }
  ].

-spec booking_schema() -> map().
booking_schema() ->
  #{
    type       => object,
    properties => #{
      id            => #{type => string},
      event_id      => #{type => string},
      user_id       => #{type => string},
      status        => #{type => string, enum => [<<"pending">>, <<"confirmed">>, <<"cancelled">>, <<"expired">>]},
      notes         => #{type => string, nullable => true},
      reminder_sent => #{type => boolean},
      confirmed_at  => #{type => string, format => <<"date-time">>, nullable => true},
      created_at    => #{type => string, format => <<"date-time">>},
      updated_at    => #{type => string, format => <<"date-time">>}
    }
  }.

%%%===================================================================
%%% HTTP-методы
%%%===================================================================

%% @doc POST /v1/events/:id/bookings — Создание бронирования.
-spec create_booking(cowboy_req:req()) -> {ok, binary(), cowboy_req:req()}.
create_booking(Req) ->
  case handler_utils:auth_user(Req) of
    {ok, UserId, Req1} ->
      EventId = cowboy_req:binding(id, Req1),
      case logic_booking:create_booking(UserId, EventId) of
        {ok, Booking} ->
          handler_utils:send_json(Req1, 201, booking_to_json(Booking));
        {error, already_booked} ->
          handler_utils:send_error(Req1, 409, <<"Already booked">>);
        {error, full} ->
          handler_utils:send_error(Req1, 400, <<"Event is full">>);
        {error, event_full} ->
          handler_utils:send_error(Req1, 400, <<"Event is full">>);
        {error, event_not_active} ->
          handler_utils:send_error(Req1, 400, <<"Event is not active">>);
        {error, personal_calendar} ->
          handler_utils:send_error(Req1, 403, <<"personal_calendar">>);
        {error, subscription_inactive} ->
          handler_utils:send_error(Req1, 403, <<"subscription_inactive">>);
        {error, own_event} ->
          handler_utils:send_error(Req1, 403, <<"Cannot book own event">>);
        {error, access_denied} ->
          handler_utils:send_error(Req1, 403, <<"Access denied">>);
        {error, not_found} ->
          handler_utils:send_error(Req1, 404, <<"Event not found">>);
        {error, _} ->
          handler_utils:send_error(Req1, 500, <<"Internal server error">>)
      end;
    {error, Code, Message, Req1} ->
      handler_utils:send_error(Req1, Code, Message)
  end.

%% @doc GET /v1/events/:id/bookings — Список бронирований события (для владельца).
-spec list_bookings(cowboy_req:req()) -> {ok, binary(), cowboy_req:req()}.
list_bookings(Req) ->
  case handler_utils:auth_user(Req) of
    {ok, UserId, Req1} ->
      EventId = cowboy_req:binding(id, Req1),
      case logic_booking:list_event_bookings(UserId, EventId) of
        {ok, Bookings} ->
          Response = [booking_to_json(B) || B <- Bookings],
          handler_utils:send_json(Req1, 200, Response);
        {error, access_denied} ->
          handler_utils:send_error(Req1, 403, <<"Access denied">>);
        {error, not_found} ->
          handler_utils:send_error(Req1, 404, <<"Event not found">>);
        {error, _} ->
          handler_utils:send_error(Req1, 500, <<"Internal server error">>)
      end;
    {error, Code, Message, Req1} ->
      handler_utils:send_error(Req1, Code, Message)
  end.

%%%===================================================================
%%% Внутренние функции
%%%===================================================================

%% @private Формирует JSON-представление записи #booking{}.
-spec booking_to_json(#booking{}) -> map().
booking_to_json(Booking) ->
  handler_utils:booking_to_json(Booking).