-module(admin_handler_events).
-behaviour(cowboy_handler).

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

-include("records.hrl").

%%%===================================================================
%%% cowboy_handler callback
%%%===================================================================

init(Req, _Opts) ->
  case cowboy_req:method(Req) of
    <<"GET">> -> list_all_events(Req);
    _         -> handler_utils:send_error(Req, 405, <<"Method not allowed">>)
  end.

%%%===================================================================
%%% Swagger metadata
%%%===================================================================

trails() ->
  [
    #{
      path        => <<"/v1/admin/events">>,
      method      => <<"GET">>,
      description => <<"Search and list events (admin)">>,
      tags        => [<<"Events">>],
      parameters  => [
        #{name => <<"from">>,        in => <<"query">>, description => <<"ISO8601 start datetime">>,             required => false, schema => #{type => string}},
        #{name => <<"to">>,          in => <<"query">>, description => <<"ISO8601 end datetime">>,               required => false, schema => #{type => string}},
        #{name => <<"status">>,      in => <<"query">>, description => <<"active, cancelled, completed, or all">>, required => false, schema => #{type => string}},
        #{name => <<"calendar_id">>, in => <<"query">>, description => <<"Filter by calendar ID">>,               required => false, schema => #{type => string}},
        #{name => <<"title">>,       in => <<"query">>, description => <<"Exact title match">>,                  required => false, schema => #{type => string}},
        #{name => <<"q">>,           in => <<"query">>, description => <<"Substring search in title/description">>, required => false, schema => #{type => string}},
        #{name => <<"limit">>,       in => <<"query">>, description => <<"Page size (max 200)">>,                 required => false, schema => #{type => integer}},
        #{name => <<"offset">>,      in => <<"query">>, description => <<"Offset">>,                              required => false, schema => #{type => integer}},
        #{name => <<"sort">>,        in => <<"query">>, description => <<"created_at, start_time, title, status">>, required => false, schema => #{type => string}},
        #{name => <<"order">>,       in => <<"query">>, description => <<"asc or desc">>,                         required => false, schema => #{type => string, enum => [<<"asc">>, <<"desc">>]}}
      ],
      responses => #{
        200 => #{
          description => <<"Array of events with Content-Range header">>,
          content     => #{<<"application/json">> => #{schema => #{
            type  => array,
            items => event_schema()
          }}}
        },
        405 => #{description => <<"Method not allowed">>}
      }
    }
  ].

event_schema() ->
  #{
    type       => object,
    properties => #{
      id              => #{type => string},
      calendar_id     => #{type => string},
      title           => #{type => string},
      description     => #{type => string},
      event_type      => #{type => string, enum => [<<"single">>, <<"recurring">>]},
      start_time      => #{type => string, format => <<"date-time">>},
      duration        => #{type => integer},
      recurrence      => #{type => object, nullable => true},
      master_id       => #{type => string, nullable => true},
      is_instance     => #{type => boolean},
      specialist_id   => #{type => string, nullable => true},
      location        => #{type => object, nullable => true},
      tags            => #{type => array, items => #{type => string}},
      capacity        => #{type => integer, nullable => true},
      online_link     => #{type => string, nullable => true},
      status          => #{type => string, enum => [<<"active">>, <<"cancelled">>, <<"completed">>]},
      reason          => #{type => string, nullable => true},
      rating_avg      => #{type => number, format => float},
      rating_count    => #{type => integer},
      attachments     => #{type => array, items => #{type => string}, nullable => true},
      edit_history    => #{type => array, items => #{type => object}, nullable => true},
      created_at      => #{type => string, format => <<"date-time">>},
      updated_at      => #{type => string, format => <<"date-time">>}
    }
  }.

%%%===================================================================
%%% Internal functions
%%%===================================================================

list_all_events(Req) ->
  case handler_utils:auth_admin(Req) of
    {ok, _AdminId, Req1} ->
      Params = parse_admin_event_search(Req1),
      {ok, Total, Events} = logic_event:search_events(Params),
      Json = [handler_utils:event_to_json(E) || E <- Events],
      Limit  = maps:get(limit, Params, 50),
      Offset = maps:get(offset, Params, 0),
      RangeEnd = min(Offset + Limit - 1, Total - 1),
      Headers = #{
        <<"content-type">>                  => <<"application/json">>,
        <<"content-range">>                 => iolist_to_binary(io_lib:format("items ~B-~B/~B", [Offset, RangeEnd, Total])),
        <<"x-total-count">>                 => integer_to_binary(Total),
        <<"access-control-expose-headers">> => <<"Content-Range, X-Total-Count">>
      },
      handler_utils:send_json(Req1, 200, Json, Headers);
    {error, Code, Msg, Req1} ->
      handler_utils:send_error(Req1, Code, Msg)
  end.

parse_admin_event_search(Req) ->
  Qs = cowboy_req:parse_qs(Req),
  #{
    from        => handler_utils:parse_datetime_qs(proplists:get_value(<<"from">>, Qs)),
    to          => handler_utils:parse_datetime_qs(proplists:get_value(<<"to">>, Qs)),
    status      => proplists:get_value(<<"status">>, Qs, undefined),
    calendar_id => proplists:get_value(<<"calendar_id">>, Qs, undefined),
    title       => proplists:get_value(<<"title">>, Qs, undefined),
    q           => proplists:get_value(<<"q">>, Qs, undefined),
    limit       => handler_utils:parse_int_qs(proplists:get_value(<<"limit">>, Qs), 50),
    offset      => handler_utils:parse_int_qs(proplists:get_value(<<"offset">>, Qs), 0),
    sort        => proplists:get_value(<<"sort">>, Qs, <<"created_at">>),
    order       => proplists:get_value(<<"order">>, Qs, <<"desc">>)
  }.