%%%-------------------------------------------------------------------
%%% @copyright 2009 Anders Nygren
%%% @author Anders Nygren <anders.nygren@gmail.com>
%%% @doc
%%% @end
%%%-------------------------------------------------------------------
-module(abnfc).

%% API
-export([file/1, file/2,
         parse/1, parse/2]).

-export([erlangcode/0]).

-compile(export_all).
%%====================================================================
%% API
%%====================================================================
%%--------------------------------------------------------------------
%% @spec (File::string()) -> {ok, AST, Rest::binary()} | Error
%% @doc Compile an ABNF file.
%% @end
%%--------------------------------------------------------------------
file(File) ->
    file(File,[]).

%%--------------------------------------------------------------------
%% @spec (File::string(), Opts) -> {ok, AST, Rest::binary()} | Error
%% Opts = [Option]
%% Option = OutFile
%% OutFile = string()
%% @doc Compile an ABNF file.
%% @end
%%--------------------------------------------------------------------
file(File, Opts) when is_list(Opts) ->
    {ok, Name, Text} = read_file(File),
    POpts = [],
    GenOpts = gen_opts(Name, Opts),
    COpts = compiler_opts(Opts),
    case parse(Text, POpts) of
        {ok, AST, _Rest} ->
            AST1 = abnfc_ast:ast_to_int_form(AST),
            case proplists:get_bool(verbose,Opts) of
                true -> io:format("~p~n",[AST1]);
                false -> ok
            end,
            {ok, Code} = abnfc_gen:generate(AST1, GenOpts),
            {ok, GenFile} = write_file(Code, GenOpts ++ Opts),
            compile_file(GenFile, COpts, Opts);
        fail ->
            io:format("abnfc: failed~n",[])
    end.

%%--------------------------------------------------------------------
%% @spec (Text) -> {ok, AST, Rest::binary()} | fail
%% Text = list() | binary()
%% @doc Parse a list or binary.
%% @end
%%--------------------------------------------------------------------
parse(Bin) ->
    parse(Bin, []).

%%--------------------------------------------------------------------
%% @spec (Text, Opts) -> {ok, AST, Rest::list()} | fail
%% Text = list() | binary()
%% @doc Parse a list or binary.
%% @end
%%--------------------------------------------------------------------
parse(Bin, Opts) when is_binary(Bin) ->
    parse(binary_to_list(Bin), Opts);

parse(String, Opts) when is_list(String) ->
    Parser = proplists:get_value(parser, parse_opts(Opts)),
    maybe_write("abnfc: parsing with ~p~n", [Parser], Opts),
    case catch Parser:rulelist_dec(String) of
        {ok, _Rulelist, []} = Result ->
            Result;
        Error ->
            Error
    end.

%%--------------------------------------------------------------------
%% @spec () -> list()
%% @doc Scan erlang code.
%% @end
%%--------------------------------------------------------------------
erlangcode() ->
    fun (T) ->
            scan(T)
    end.

scan(Input) ->
    case erl_scan:tokens([], Input, 1) of
        {done, {ok, Toks, _EndLine}, Extra} ->
            %%	    Code = toks_to_list(Toks),
            %%	    {ok, Code, Extra};
            {ok,Abs} = erl_parse:parse_exprs(Toks),
            {ok, Abs, Extra};
        {more, _Cont} ->
            throw(end_of_input)
    end.

%%--------------------------------------------------------------------
%% @private
%% @spec (Tokens) -> list()
%% @doc Convert tokens returned by erl_scan to a string again.
%% @end
%%--------------------------------------------------------------------
toks_to_list(Tokens) ->
    lists:foldl(fun({atom,L,Name},{Line, Acc}) ->
                        {L,["'",Name,"'",sep(L,Line)|Acc]};
                   ({string,L,Name},{Line, Acc}) ->
                        {L,["\"",Name,"\"",sep(L,Line)|Acc]};
                   ({_Type,L,Name},{Line, Acc}) ->
                        {L,[Name,sep(L,Line)|Acc]};
                   ({dot,_L},{_Line,Acc}) ->
                        lists:concat(lists:reverse(Acc));
                   ({Reserved, L},{Line,Acc}) ->
                        {L,[Reserved,sep(L,Line)|Acc]}
                end, {1,[]}, Tokens).

sep(L,L) ->
    " ";
sep(_,_) ->
    "\n".

%%====================================================================
%% Internal functions
%%====================================================================
read_file(File) ->
    case string:tokens(filename:basename(File), ".") of
        [Name,"set","abnf"] ->
            {ok, Files} = file:consult(File),
            {ok, Name, lists:flatten([read_file1(F) || F <- Files])};
        [Name, "abnf"] ->
            {ok, Name, read_file1(File)}
    end.

read_file1(File) ->
    {ok, Bin} = file:read_file(File),
    binary_to_list(Bin).

parse_opts(Opts) ->
    Parser = proplists:get_value(parser, Opts, abnfc_rfc4234),
    [{parser,Parser}].

gen_opts(Name, Opts) ->
    Mod = proplists:get_value(mod, Opts, Name),
    Type = case proplists:get_bool(binary, Opts) of
               true -> binary;
               false -> list
           end,
    Verbose = proplists:get_bool(verbose,Opts),
    [{mod,Mod},{verbose,Verbose},Type].

compiler_opts(Opts) ->
    OutDir = proplists:get_value(o, Opts, "./"),
    IncludeDirs = [{i,Dir}||Dir <- proplists:get_all_values(i, Opts)],
    [report,{outdir,OutDir}|IncludeDirs].

write_file(Code, Opts) ->
    Name = filename:join(proplists:get_value(o, Opts, "."),
                         proplists:get_value(mod, Opts))++".erl",

    maybe_write("abnfc: writing to ~p~n",[Name],Opts),
    ok = file:write_file(Name, Code),
    abnfc_erl_tidy:file(Name,[{paper, 95},{backups,false}]),
    {ok,Name}.

compile_file(File, COpts, MyOpts) ->
    maybe_write("abnfc: compiling ~p opts = ~p~n",[File, COpts],MyOpts),
    case proplists:get_bool(noobj,MyOpts) of
        true -> ok;
        false -> compile:file(File, COpts)
    end.

maybe_write(Fmt,Args,Opts) ->
    case proplists:get_bool(verbose,Opts) of
        true -> io:format(Fmt,Args);
        false -> ok
    end.