%%%-------------------------------------------------------------------
%%% @doc Административный обработчик конкретной подписки.
%%% GET – получить подписку по ID.
%%% PUT – обновить подписку (статус, план, дата окончания).
%%% DELETE – удалить подписку.
%%% @end
%%%-------------------------------------------------------------------
-module(admin_handler_subscriptions_by_id).
-behaviour(cowboy_handler).
-export([init/2]).
-export([trails/0]).

-include("records.hrl").

-spec init(cowboy_req:req(), any()) -> {ok, cowboy_req:req(), any()}.
init(Req, _Opts) ->
  case cowboy_req:method(Req) of
    <<"GET">> -> get_subscription(Req);
    <<"PUT">> -> update_subscription(Req);
    <<"DELETE">> -> delete_subscription(Req);
    _ -> handler_utils:send_error(Req, 405, <<"Method not allowed">>)
  end.

-spec trails() -> [map()].
trails() ->
  BaseParams = [
    #{name => <<"id">>, in => <<"path">>, description => <<"Subscription ID">>, required => true, schema => #{type => string}}
  ],
  [
    #{ % GET by id
      path => <<"/v1/admin/subscriptions/:id">>,
      method => <<"GET">>,
      description => <<"Get subscription by ID (admin)">>,
      tags => [<<"Subscriptions">>],
      parameters => BaseParams,
      responses => #{
        200 => #{description => <<"Subscription details">>, content => #{<<"application/json">> => #{schema => subscription_schema()}}},
        404 => #{description => <<"Subscription not found">>}
      }
    },
    #{ % PUT update
      path => <<"/v1/admin/subscriptions/:id">>,
      method => <<"PUT">>,
      description => <<"Update subscription (admin)">>,
      tags => [<<"Subscriptions">>],
      parameters => BaseParams,
      requestBody => #{
        required => true,
        content => #{<<"application/json">> => #{schema => subscription_update_schema()}}
      },
      responses => #{
        200 => #{description => <<"Updated subscription">>},
        404 => #{description => <<"Subscription not found">>}
      }
    },
    #{ % DELETE
      path => <<"/v1/admin/subscriptions/:id">>,
      method => <<"DELETE">>,
      description => <<"Delete subscription (admin)">>,
      tags => [<<"Subscriptions">>],
      parameters => BaseParams,
      responses => #{
        200 => #{description => <<"Subscription deleted">>},
        404 => #{description => <<"Subscription not found">>}
      }
    }
  ].

subscription_schema() ->
  #{
    type => object,
    properties => #{
      id => #{type => string},
      user_id => #{type => string},
      plan => #{type => string, enum => [<<"monthly">>, <<"quarterly">>, <<"biannual">>, <<"annual">>]},
      status => #{type => string, enum => [<<"active">>, <<"expired">>, <<"cancelled">>]},
      trial_used => #{type => boolean},
      started_at => #{type => string, format => <<"date-time">>},
      expires_at => #{type => string, format => <<"date-time">>},
      created_at => #{type => string, format => <<"date-time">>},
      updated_at => #{type => string, format => <<"date-time">>}
    }
  }.

subscription_update_schema() ->
  #{
    type => object,
    properties => #{
      plan => #{type => string, enum => [<<"monthly">>, <<"quarterly">>, <<"biannual">>, <<"annual">>]},
      status => #{type => string, enum => [<<"active">>, <<"expired">>, <<"cancelled">>]},
      trial_used => #{type => boolean},
      expires_at => #{type => string, format => <<"date-time">>, description => <<"New expiration date">>}
    }
  }.

%%% Internal functions

get_subscription(Req) ->
  case handler_utils:auth_admin(Req) of
    {ok, _AdminId, Req1} ->
      Id = cowboy_req:binding(id, Req1),
      case core_subscription:get_by_id(Id) of
        {ok, Sub} ->
          handler_utils:send_json(Req1, 200, handler_utils:subscription_to_json(Sub));
        {error, not_found} ->
          handler_utils:send_error(Req1, 404, <<"Subscription not found">>);
        {error, _} ->
          handler_utils:send_error(Req1, 500, <<"Internal server error">>)
      end;
    {error, Code, Msg, Req1} ->
      handler_utils:send_error(Req1, Code, Msg)
  end.

update_subscription(Req) ->
  case handler_utils:auth_admin(Req) of
    {ok, AdminId, Req1} ->
      Id = cowboy_req:binding(id, Req1),
      {ok, Body, Req2} = cowboy_req:read_body(Req1),
      try jsx:decode(Body, [return_maps]) of
        Data when is_map(Data) ->
          case core_subscription:update_subscription(Id, Data) of
            {ok, Updated} ->
              admin_utils:log_admin_action(AdminId, <<"update_subscription">>, <<"subscription">>, Id, Req2),
              handler_utils:send_json(Req2, 200, handler_utils:subscription_to_json(Updated));
            {error, not_found} ->
              handler_utils:send_error(Req2, 404, <<"Subscription not found">>);
            {error, _} ->
              handler_utils:send_error(Req2, 500, <<"Internal server error">>)
          end;
        _ ->
          handler_utils:send_error(Req2, 400, <<"Invalid JSON">>)
      catch
        _:_ -> handler_utils:send_error(Req1, 400, <<"Invalid JSON format">>)
      end;
    {error, Code, Msg, Req1} ->
      handler_utils:send_error(Req1, Code, Msg)
  end.

delete_subscription(Req) ->
  case handler_utils:auth_admin(Req) of
    {ok, AdminId, Req1} ->
      Id = cowboy_req:binding(id, Req1),
      case core_subscription:delete_subscription(Id) of
        {ok, _} ->
          admin_utils:log_admin_action(AdminId, <<"delete_subscription">>, <<"subscription">>, Id, Req1),
          handler_utils:send_json(Req1, 200, #{status => <<"deleted">>});
        {error, not_found} ->
          handler_utils:send_error(Req1, 404, <<"Subscription not found">>);
        {error, _} ->
          handler_utils:send_error(Req1, 500, <<"Internal server error">>)
      end;
    {error, Code, Msg, Req1} ->
      handler_utils:send_error(Req1, Code, Msg)
  end.