% vim: sw=4 ts=4 et ft=erlang
% Nitrogen Web Framework for Erlang
% Copyright (c) 2008-2010 Rusty Klophaus
% See MIT-LICENSE for licensing information.

-module (query_handler).
-include("wf.hrl").
-export ([
    get_value/1,
    get_values/1,
    get_params/0,
    set_websocket_params/1
]).


-callback init(         handler_config(),
                        handler_state()) -> {ok, handler_state()}.
-callback finish(       handler_config(),
                        handler_state()) -> {ok, handler_state()}.
-callback set_websocket_params(Params :: proplist(),
                        handler_config(),
                        handler_state()) -> {ok, handler_state()}.
-callback get_value(    Path :: string() | atom(),
                        handler_config(),
                        handler_state()) -> Value :: string() | binary().
-callback get_values(   Path :: string() | atom(),
                        handler_config(),
                        handler_state()) -> [Value :: string()].
-callback get_params(   handler_config(),
                        handler_state()) -> [{Key :: string(), Value :: string()}].

set_websocket_params(Params) ->
    ok = wf_handler:call(query_handler, set_websocket_params, [Params]).

% get_value(Path, State) -> Value.  Given a path, return the parameter
% value, undefined, or throw an exception if there are too many
% matches. 
get_value(Path) ->
    _Value = wf_handler:call_readonly(query_handler, get_value, [Path]).

% get_value(Path, State) -> [Values].
% Given a path, return a list of values.
get_values(Path) ->
    wf_handler:call_readonly(query_handler, get_values, [Path]).

get_params() ->
    wf_handler:call_readonly(query_handler, get_params, []).