Stage 3.3

src/handlers/handler_event_occurrences.erl

@@ -0,0 +1,141 @@
+-module(handler_event_occurrences).
+-include("records.hrl").
+
+-export([init/2]).
+
+init(Req, Opts) ->
+  handle(Req, Opts).
+
+handle(Req, _Opts) ->
+  case cowboy_req:method(Req) of
+    <<"GET">> -> get_occurrences(Req);
+    <<"DELETE">> -> cancel_occurrence(Req);
+    _ -> send_error(Req, 405, <<"Method not allowed">>)
+  end.
+
+%% GET /v1/events/:id/occurrences - получение вхождений повторяющегося события
+get_occurrences(Req) ->
+  case handler_auth:authenticate(Req) of
+    {ok, UserId, Req1} ->
+      EventId = cowboy_req:binding(id, Req1),
+      Qs = cowboy_req:parse_qs(Req1),
+
+      % Параметры диапазона
+      From = proplists:get_value(<<"from">>, Qs, undefined),
+      To = proplists:get_value(<<"to">>, Qs, undefined),
+
+      case {From, To} of
+        {undefined, _} ->
+          send_error(Req1, 400, <<"Missing 'from' parameter">>);
+        {_, undefined} ->
+          send_error(Req1, 400, <<"Missing 'to' parameter">>);
+        {FromStr, ToStr} ->
+          case {parse_datetime(FromStr), parse_datetime(ToStr)} of
+            {{ok, FromDt}, {ok, ToDt}} ->
+              case logic_event:get_occurrences(UserId, EventId, ToDt) of
+                {ok, Occurrences} ->
+                  % Фильтруем по from
+                  Filtered = filter_from(Occurrences, FromDt),
+                  Response = occurrences_to_json(Filtered),
+                  send_json(Req1, 200, Response);
+                {error, not_recurring} ->
+                  send_error(Req1, 400, <<"Event is not recurring">>);
+                {error, access_denied} ->
+                  send_error(Req1, 403, <<"Access denied">>);
+                {error, not_found} ->
+                  send_error(Req1, 404, <<"Event not found">>);
+                {error, _} ->
+                  send_error(Req1, 500, <<"Internal server error">>)
+              end;
+            _ ->
+              send_error(Req1, 400, <<"Invalid date format. Use ISO 8601">>)
+          end
+      end;
+    {error, Code, Message, Req1} ->
+      send_error(Req1, Code, Message)
+  end.
+
+%% DELETE /v1/events/:id/occurrences/:start_time - отмена вхождения
+cancel_occurrence(Req) ->
+  case handler_auth:authenticate(Req) of
+    {ok, UserId, Req1} ->
+      EventId = cowboy_req:binding(id, Req1),
+      StartTimeStr = cowboy_req:binding(start_time, Req1),
+
+      case parse_datetime(StartTimeStr) of
+        {ok, StartTime} ->
+          case logic_event:cancel_occurrence(UserId, EventId, StartTime) of
+            {ok, cancelled} ->
+              send_json(Req1, 200, #{status => <<"cancelled">>});
+            {error, not_recurring} ->
+              send_error(Req1, 400, <<"Event is not recurring">>);
+            {error, access_denied} ->
+              send_error(Req1, 403, <<"Access denied">>);
+            {error, not_found} ->
+              send_error(Req1, 404, <<"Event not found">>);
+            {error, _} ->
+              send_error(Req1, 500, <<"Internal server error">>)
+          end;
+        {error, _} ->
+          send_error(Req1, 400, <<"Invalid start_time format">>)
+      end;
+    {error, Code, Message, Req1} ->
+      send_error(Req1, Code, Message)
+  end.
+
+%% Вспомогательные функции
+parse_datetime(Str) ->
+  try
+    [DateStr, TimeStr] = string:split(Str, "T"),
+    TimeStrNoZ = string:trim(TimeStr, trailing, "Z"),
+
+    [YearStr, MonthStr, DayStr] = string:split(DateStr, "-", all),
+    [HourStr, MinuteStr, SecondStr] = string:split(TimeStrNoZ, ":", all),
+
+    Year = binary_to_integer(YearStr),
+    Month = binary_to_integer(MonthStr),
+    Day = binary_to_integer(DayStr),
+    Hour = binary_to_integer(HourStr),
+    Minute = binary_to_integer(MinuteStr),
+    Second = binary_to_integer(SecondStr),
+
+    {ok, {{Year, Month, Day}, {Hour, Minute, Second}}}
+  catch
+    _:_ -> {error, invalid_format}
+  end.
+
+filter_from(Occurrences, From) ->
+  lists:filter(fun
+                 ({virtual, Occ}) -> Occ >= From;
+                 ({materialized, Event}) -> Event#event.start_time >= From
+               end, Occurrences).
+
+occurrences_to_json(Occurrences) ->
+  lists:map(fun occurrence_to_json/1, Occurrences).
+
+occurrence_to_json({virtual, Occ}) ->
+  #{
+    start_time => datetime_to_iso8601(Occ),
+    is_virtual => true
+  };
+occurrence_to_json({materialized, Event}) ->
+  #{
+    id => Event#event.id,
+    start_time => datetime_to_iso8601(Event#event.start_time),
+    duration => Event#event.duration,
+    specialist_id => Event#event.specialist_id,
+    is_virtual => false,
+    status => Event#event.status
+  }.
+
+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).
+
+send_error(Req, Status, Message) ->
+  Body = jsx:encode(#{error => Message}),
+  cowboy_req:reply(Status, #{<<"content-type">> => <<"application/json">>}, Body, Req).