%% The MIT License

%% Copyright (c) 2011 Alisdair Sullivan <alisdairsullivan@yahoo.ca>

%% Permission is hereby granted, free of charge, to any person obtaining a copy
%% of this software and associated documentation files (the "Software"), to deal
%% in the Software without restriction, including without limitation the rights
%% to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
%% copies of the Software, and to permit persons to whom the Software is
%% furnished to do so, subject to the following conditions:

%% The above copyright notice and this permission notice shall be included in
%% all copies or substantial portions of the Software.

%% THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
%% IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
%% FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
%% AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
%% LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
%% OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
%% THE SOFTWARE.


-module(jsx_terms).

-export([to_term/2]).
-export([init/1, handle_event/2]).


-record(opts, {
    labels = binary
}).

-type opts() :: list().


-spec to_term(Source::(binary() | list()), Opts::opts()) -> binary().
    
to_term(Source, Opts) when (is_binary(Source) andalso is_list(Opts))
        orelse (is_list(Source) andalso is_list(Opts)) ->
    (gen_json:parser(?MODULE, Opts, extract_opts(Opts)))(Source).



init(Opts) -> {[], parse_opts(Opts)}.


parse_opts(Opts) -> parse_opts(Opts, #opts{}).

parse_opts([{labels, Val}|Rest], Opts)
        when Val == binary; Val == atom; Val == existing_atom ->
    parse_opts(Rest, Opts#opts{labels = Val});
parse_opts([labels|Rest], Opts) ->
    parse_opts(Rest, Opts#opts{labels = binary});
parse_opts([_|Rest], Opts) ->
    parse_opts(Rest, Opts);
parse_opts([], Opts) ->
    Opts.


extract_opts(Opts) ->
    extract_parser_opts(Opts, []).

extract_parser_opts([], Acc) -> Acc;     
extract_parser_opts([{K,V}|Rest], Acc) ->
    case lists:member(K, [loose_unicode, escape_forward_slash, explicit_end]) of
        true -> extract_parser_opts(Rest, [{K,V}] ++ Acc)
        ; false -> extract_parser_opts(Rest, Acc)
    end;
extract_parser_opts([K|Rest], Acc) ->
    case lists:member(K, [loose_unicode, escape_forward_slash, explicit_end]) of
        true -> extract_parser_opts(Rest, [K] ++ Acc)
        ; false -> extract_parser_opts(Rest, Acc)
    end.


handle_event(end_json, {[Term], _Opts}) -> Term;

handle_event(start_object, {Term, Opts}) -> {[[]|Term], Opts};
handle_event(end_object, {[[]|Term], Opts}) -> {[[{}]|Term], Opts};

handle_event(start_array, {Term, Opts}) -> {[[]|Term], Opts};
handle_event(end_array, {Term, Opts}) -> {Term, Opts}.


%% eunit tests

-ifdef(TEST).
-include_lib("eunit/include/eunit.hrl").

basic_test_() ->
    [
        {"empty object", ?_assert(to_term(<<"{}">>, []) =:= [{}])},
        {"empty array", ?_assert(to_term(<<"[]">>, []) =:= [])}
    ].
    
-endif.