-module(nitro_conv).

-description('N2O Formatter: JSON, BERT').

-author('Maxim Sokhatsky').

-compile(export_all).

-include_lib("nitro/include/nitro.hrl").

% WF to_atom to_list to_binary

-define(IS_STRING(Term),
        is_list(Term) andalso
            Term /= [] andalso is_integer(hd(Term))).

-ifndef(N2O_JSON).

-define(N2O_JSON,
        application:get_env(n2o, json, jsone)).

-endif.

to_list(L) when ?IS_STRING(L) -> L;
to_list(L) when is_list(L) ->
    SubLists = [inner_to_list(X) || X <- L],
    lists:flatten(SubLists);
to_list(A) -> inner_to_list(A).

inner_to_list(A) when is_atom(A) -> atom_to_list(A);
inner_to_list(B) when is_binary(B) -> binary_to_list(B);
inner_to_list(I) when is_integer(I) ->
    integer_to_list(I);
inner_to_list(L) when is_tuple(L) ->
    lists:flatten(io_lib:format("~p", [L]));
inner_to_list(L) when is_list(L) -> L;
inner_to_list(F) when is_float(F) ->
    float_to_list(F, [{decimals, 9}, compact]).

to_atom(A) when is_atom(A) -> A;
to_atom(B) when is_binary(B) ->
    to_atom(binary_to_list(B));
to_atom(I) when is_integer(I) ->
    to_atom(integer_to_list(I));
to_atom(F) when is_float(F) ->
    to_atom(float_to_list(F, [{decimals, 9}, compact]));
to_atom(L) when is_list(L) ->
    list_to_atom(binary_to_list(list_to_binary(L))).

to_binary(A) when is_atom(A) ->
    atom_to_binary(A, latin1);
to_binary(B) when is_binary(B) -> B;
to_binary(T) when is_tuple(T) -> term_to_binary(T);
to_binary(I) when is_integer(I) ->
    to_binary(integer_to_list(I));
to_binary(F) when is_float(F) ->
    float_to_binary(F, [{decimals, 9}, compact]);
to_binary(L) when is_list(L) -> iolist_to_binary(L).

to_integer(A) when is_atom(A) ->
    to_integer(atom_to_list(A));
to_integer(B) when is_binary(B) ->
    to_integer(binary_to_list(B));
to_integer(I) when is_integer(I) -> I;
to_integer([]) -> 0;
to_integer(L) when is_list(L) -> list_to_integer(L);
to_integer(F) when is_float(F) -> round(F).

% HTML encode/decode

html_encode(L, Fun) when is_function(Fun) -> Fun(L);
html_encode(L, EncType) when is_atom(L) ->
    html_encode(nitro:to_list(L), EncType);
html_encode(L, EncType) when is_integer(L) ->
    html_encode(integer_to_list(L), EncType);
html_encode(L, EncType) when is_float(L) ->
    html_encode(float_to_list(L, [{decimals, 9}, compact]),
                EncType);
html_encode(L, false) -> L;
html_encode(L, true) -> L;
html_encode(L, whites) ->
    html_encode_whites(nitro:to_list(lists:flatten([L]))).

html_encode(<<>>) -> <<>>;
html_encode([]) -> [];
html_encode(B) when is_binary(B) ->
    html_encode(binary_to_list(B));
html_encode([$\n | T]) -> "<br>" ++ html_encode(T);
html_encode([H | T]) ->
    case H of
        $< -> "&lt;" ++ html_encode(T);
        $> -> "&gt;" ++ html_encode(T);
        $" -> "&quot;" ++ html_encode(T);
        $` -> "&#39;" ++ html_encode(T);
        $' -> "&#39;" ++ html_encode(T);
        $& -> "&amp;" ++ html_encode(T);
        BigNum when is_integer(BigNum) andalso BigNum > 255 ->
            %% Any integers above 255 are converted to their HTML encode equivilant,
            %% Example: 7534 gets turned into &#7534;
            [$&, $# | nitro:to_list(BigNum)] ++
                ";" ++ html_encode(T);
        Tup when is_tuple(Tup) ->
            throw({html_encode, encountered_tuple, Tup});
        _ -> [H | html_encode(T)]
    end.

html_encode_whites([]) -> [];
html_encode_whites([H | T]) ->
    case H of
        $\s -> "&nbsp;" ++ html_encode_whites(T);
        $\t ->
            "&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;" ++
                html_encode_whites(T);
        $< -> "&lt;" ++ html_encode_whites(T);
        $> -> "&gt;" ++ html_encode_whites(T);
        $" -> "&quot;" ++ html_encode_whites(T);
        $' -> "&#39;" ++ html_encode_whites(T);
        $` -> "&#39;" ++ html_encode_whites(T);
        $& -> "&amp;" ++ html_encode_whites(T);
        $\n -> "<br>" ++ html_encode_whites(T);
        _ -> [H | html_encode_whites(T)]
    end.

%% URL encode/decode

url_encode(S) -> quote_plus(S).

url_decode(S) -> unquote(S).

-define(PERCENT, 37).  % $\%

-define(FULLSTOP, 46). % $\.

-define(IS_HEX(C),
        C >= $0 andalso C =< $9 orelse
            C >= $a andalso C =< $f orelse C >= $A andalso C =< $F).

-define(QS_SAFE(C),
        C >= $a andalso C =< $z orelse
            C >= $A andalso C =< $Z orelse
                C >= $0 andalso C =< $9 orelse
                    C =:= (?FULLSTOP) orelse
                        C =:= $- orelse C =:= $~ orelse C =:= $_).

quote_plus(Atom) when is_atom(Atom) ->
    quote_plus(atom_to_list(Atom));
quote_plus(Int) when is_integer(Int) ->
    quote_plus(integer_to_list(Int));
quote_plus(Bin) when is_binary(Bin) ->
    quote_plus(binary_to_list(Bin));
quote_plus(String) -> quote_plus(String, []).

quote_plus([], Acc) -> lists:reverse(Acc);
quote_plus([C | Rest], Acc) when ?QS_SAFE(C) ->
    quote_plus(Rest, [C | Acc]);
quote_plus([$\s | Rest], Acc) ->
    quote_plus(Rest, [$+ | Acc]);
quote_plus([C | Rest], Acc) ->
    <<Hi:4, Lo:4>> = <<C>>,
    quote_plus(Rest,
               [digit(Lo), digit(Hi), ?PERCENT | Acc]).

unquote(Binary) when is_binary(Binary) ->
    unquote(binary_to_list(Binary));
unquote(String) -> qs_revdecode(lists:reverse(String)).

unhexdigit(C) when C >= $0, C =< $9 -> C - $0;
unhexdigit(C) when C >= $a, C =< $f -> C - $a + 10;
unhexdigit(C) when C >= $A, C =< $F -> C - $A + 10.

qs_revdecode(S) -> qs_revdecode(S, []).

qs_revdecode([], Acc) -> Acc;
qs_revdecode([$+ | Rest], Acc) ->
    qs_revdecode(Rest, [$\s | Acc]);
qs_revdecode([Lo, Hi, ?PERCENT | Rest], Acc)
    when ?IS_HEX(Lo), ?IS_HEX(Hi) ->
    qs_revdecode(Rest,
                 [unhexdigit(Lo) bor (unhexdigit(Hi) bsl 4) | Acc]);
qs_revdecode([C | Rest], Acc) ->
    qs_revdecode(Rest, [C | Acc]).

%% JavaScript encode/decode

js_escape(undefined) -> [];
js_escape(Value) when is_list(Value) ->
    binary_to_list(js_escape(iolist_to_binary(Value)));
js_escape(Value) -> js_escape(Value, <<>>).

js_escape(<<"\\", Rest/binary>>, Acc) ->
    js_escape(Rest, <<Acc/binary, "\\\\">>);
js_escape(<<"\r", Rest/binary>>, Acc) ->
    js_escape(Rest, <<Acc/binary, "\\r">>);
js_escape(<<"\n", Rest/binary>>, Acc) ->
    js_escape(Rest, <<Acc/binary, "\\n">>);
js_escape(<<"\"", Rest/binary>>, Acc) ->
    js_escape(Rest, <<Acc/binary, "\\\"">>);
js_escape(<<"'", Rest/binary>>, Acc) ->
    js_escape(Rest, <<Acc/binary, "\\'">>);
js_escape(<<"`", Rest/binary>>, Acc) ->
    js_escape(Rest, <<Acc/binary, "\\`">>);
js_escape(<<"<script", Rest/binary>>, Acc) ->
    js_escape(Rest, <<Acc/binary, "<script">>);
js_escape(<<"script>", Rest/binary>>, Acc) ->
    js_escape(Rest, <<Acc/binary, "script>">>);
js_escape(<<C, Rest/binary>>, Acc) ->
    js_escape(Rest, <<Acc/binary, C>>);
js_escape(<<>>, Acc) -> Acc.

% JOIN

join([], _) -> [];
join([Item], _Delim) -> [Item];
join([Item | Items], Delim) ->
    [Item, Delim | join(Items, Delim)].

% Fast HEX

digit(0) -> $0;
digit(1) -> $1;
digit(2) -> $2;
digit(3) -> $3;
digit(4) -> $4;
digit(5) -> $5;
digit(6) -> $6;
digit(7) -> $7;
digit(8) -> $8;
digit(9) -> $9;
digit(10) -> $a;
digit(11) -> $b;
digit(12) -> $c;
digit(13) -> $d;
digit(14) -> $e;
digit(15) -> $f.

hex(Bin) ->
    << <<(digit(A1)), (digit(A2))>>
        || <<A1:4, A2:4>> <= Bin >>.

unhex(Hex) ->
    << <<(erlang:list_to_integer([H1, H2], 16))>>
        || <<H1, H2>> <= Hex >>.

f(S) -> f(S, []).

f(S, Args) -> lists:flatten(io_lib:format(S, Args)).

replace([], _, _) -> [];
replace(String, S1, S2)
    when is_list(String), is_list(S1), is_list(S2) ->
    Length = length(S1),
    case string:substr(String, 1, Length) of
        S1 ->
            S2 ++
                replace(string:substr(String, Length + 1), S1, S2);
        _ -> [hd(String) | replace(tl(String), S1, S2)]
    end.

coalesce({_, Y}) -> Y;
coalesce(false) -> undefined;
coalesce([]) -> undefined;
coalesce([H]) -> H;
coalesce([undefined | T]) -> coalesce(T);
coalesce([[] | T]) -> coalesce(T);
coalesce([H | _]) -> H.

indexof(Key, Fields) -> indexof(Key, Fields, 2).

indexof(_Key, [], _N) -> undefined;
indexof(Key, [Key | _T], N) -> N;
indexof(Key, [_ | T], N) -> indexof(Key, T, N + 1).

config(App, Key, Default) ->
    application:get_env(App, Key, Default).

os_env(Key) -> os_env(Key, "").

os_env(Key, Default) ->
    case os:getenv(Key) of
        false -> Default;
        V -> V
    end.

% base64 encode/decode
pickle(Data) ->
    base64:encode(term_to_binary({Data, os:timestamp()},
                                 [compressed])).

depickle(PickledData) ->
    try {Data, _PickleTime} =
            binary_to_term(base64:decode(nitro:to_binary(PickledData))),
        Data
    catch
        _:_ -> undefined
    end.