%%%-------------------------------------------------------------------
%%% @doc Обработчик пользовательских тикетов (клиентский API).
%%%
%%% GET  – получить список тикетов.
%%%        Администраторы видят все тикеты,
%%%        обычные пользователи – только свои.
%%% POST – создать/дедуплицировать тикет об ошибке через logic_ticket:report_error.
%%% @end
%%%-------------------------------------------------------------------
-module(handler_tickets).
-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).

%%% Swagger metadata
-spec trails() -> [map()].
trails() ->
  [
    #{  % GET list
      path        => <<"/v1/tickets">>,
      method      => <<"GET">>,
      description => <<"List tickets (admin sees all, user sees own)">>,
      tags        => [<<"Tickets">>],
      parameters  => [
        #{name => <<"limit">>,  in => <<"query">>, schema => #{type => integer}, description => <<"Page size">>},
        #{name => <<"offset">>, in => <<"query">>, schema => #{type => integer}, description => <<"Offset">>}
      ],
      responses => #{
        200 => #{
          description => <<"Array of tickets">>,
          content => #{<<"application/json">> => #{schema => #{
            type  => array,
            items => ticket_schema()
          }}}
        },
        401 => #{description => <<"Unauthorized">>}
      }
    },
    #{  % POST create
      path        => <<"/v1/tickets">>,
      method      => <<"POST">>,
      description => <<"Create or bump a ticket (bug report / frontend error)">>,
      tags        => [<<"Tickets">>],
      requestBody => #{
        required => true,
        content  => #{<<"application/json">> => #{schema => #{
          type       => object,
          required   => [<<"error_message">>],
          properties => #{
            error_message => #{type => string},
            stacktrace    => #{type => string},
            context       => #{type => object},
            source        => #{type => string, enum => [<<"frontend">>, <<"manual">>]}
          }
        }}}
      },
      responses => #{
        201 => #{description => <<"Ticket created or updated">>},
        400 => #{description => <<"Missing required fields or invalid JSON">>},
        401 => #{description => <<"Unauthorized">>},
        429 => #{description => <<"Rate limited">>}
      }
    }
  ].

ticket_schema() ->
  #{
    type       => object,
    properties => #{
      id              => #{type => string},
      reporter_id     => #{type => string},
      error_hash      => #{type => string},
      error_message   => #{type => string},
      stacktrace      => #{type => string},
      context         => #{type => string},
      count           => #{type => integer},
      first_seen      => #{type => string, format => <<"date-time">>},
      last_seen       => #{type => string, format => <<"date-time">>},
      status          => #{type => string, enum => [<<"open">>, <<"in_progress">>, <<"resolved">>, <<"closed">>]},
      assigned_to     => #{type => string, nullable => true},
      resolution_note => #{type => string, nullable => true},
      source          => #{type => string, enum => [<<"backend">>, <<"frontend">>, <<"manual">>]}
    }
  }.

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

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

%% @doc GET /v1/tickets — список тикетов.
-spec list_tickets(cowboy_req:req()) -> {ok, binary(), cowboy_req:req()}.
list_tickets(Req) ->
  case handler_utils:auth_user(Req) of
    {ok, UserId, Req1} ->
      case admin_utils:is_admin(UserId) of
        true ->
          Tickets = core_ticket:list_all(),
          handler_utils:send_json(Req1, 200, [handler_utils:ticket_to_json(T) || T <- Tickets]);
        false ->
          Tickets = core_ticket:list_by_user(UserId),
          handler_utils:send_json(Req1, 200, [handler_utils:ticket_to_json(T) || T <- Tickets])
      end;
    {error, Code, Message, Req1} ->
      handler_utils:send_error(Req1, Code, Message)
  end.

%% @doc POST /v1/tickets — создание/дедуп тикета.
-spec create_ticket(cowboy_req:req()) -> {ok, binary(), cowboy_req:req()}.
create_ticket(Req) ->
  case handler_utils:auth_user(Req) of
    {ok, UserId, Req1} ->
      {ok, Body, Req2} = cowboy_req:read_body(Req1),
      try jsx:decode(Body, [return_maps]) of
        #{<<"error_message">> := ErrorMessage} = Data ->
          Stacktrace = maps:get(<<"stacktrace">>, Data, <<>>),
          Source = resolve_source(Data, Stacktrace),
          Context0 = maps:get(<<"context">>, Data, #{}),
          Context = merge_context(Context0, UserId),
          case logic_ticket:report_error(Source, ErrorMessage, Stacktrace, Context) of
            {ok, Ticket} ->
              handler_utils:send_json(Req2, 201, handler_utils:ticket_to_json(Ticket));
            {error, rate_limited} ->
              handler_utils:send_error(Req2, 429, <<"Too many new tickets">>);
            {error, Reason} ->
              handler_utils:send_error(Req2, 500, Reason)
          end;
        _ ->
          handler_utils:send_error(Req2, 400, <<"Missing 'error_message' field">>)
      catch
        _:_ -> handler_utils:send_error(Req2, 400, <<"Invalid JSON">>)
      end;
    {error, Code, Message, Req1} ->
      handler_utils:send_error(Req1, Code, Message)
  end.

resolve_source(#{<<"source">> := <<"frontend">>}, _) -> frontend;
resolve_source(#{<<"source">> := <<"manual">>}, _) -> manual;
resolve_source(#{<<"source">> := <<"backend">>}, _) -> backend;
resolve_source(_, Stacktrace) when is_binary(Stacktrace), Stacktrace =/= <<>> ->
  frontend;
resolve_source(_, _) ->
  manual.

merge_context(Ctx, UserId) when is_map(Ctx) ->
  Ctx#{<<"reporter_id">> => UserId};
merge_context(Ctx, UserId) when is_binary(Ctx) ->
  #{<<"reporter_id">> => UserId, <<"raw">> => Ctx};
merge_context(_, UserId) ->
  #{<<"reporter_id">> => UserId}.