-module(ephp_const).

-author('manuel@altenwald.com').

-include("ephp.hrl").

%% ------------------------------------------------------------------
%% API Function Exports
%% ------------------------------------------------------------------

-export([start_link/0, is_defined/4, get/4, get/5, get/6, get_ns/1, set/3, set/4, set/5,
         set_bulk/2, set_bulk/3, set_bulk/4, destroy/1, special_consts/0]).

%% ------------------------------------------------------------------
%% API Function Definitions
%% ------------------------------------------------------------------

special_consts() ->
    [<<"__CLASS__">>, <<"__METHOD__">>, <<"__FUNCTION__">>, <<"__NAMESPACE__">>].

start_link() ->
    Ref = make_ref(),
    Init = [{{[], undefined, N}, <<>>} || N <- special_consts()],
    Consts = lists:foldl(fun({K, V}, C) -> dict:store(K, V, C) end, dict:new(), Init),
    erlang:put(Ref, Consts),
    Modules = ephp_config:get(modules, []),
    [set_bulk(Ref, Module:init_const()) || Module <- Modules],
    {ok, Ref}.

is_defined(Ref, NS, ClassName, Name) ->
    Const = erlang:get(Ref),
    dict:is_key({NS, ClassName, Name}, Const).

get(Ref, Name, Line, Context) ->
    get(Ref, undefined, Name, Line, Context).

get(Ref, ClassName, Name, Line, Context) ->
    get(Ref, [], ClassName, Name, Line, Context).

get(Ref, NS, ClassName, Name, Line, Context) ->
    Const = erlang:get(Ref),
    case dict:find({NS, ClassName, Name}, Const) of
        {ok, Value} ->
            Value;
        error when Line =/= false andalso ClassName =:= undefined ->
            File = ephp_context:get_active_file(Context),
            ephp_error:handle_error(Context,
                                    {error, eundefconst, Line, File, ?E_NOTICE, {NS, Name}}),
            Name;
        error when Line =/= false ->
            ephp_error:error({error, enoconst, Line, ?E_ERROR, {NS, Name}});
        error ->
            false
    end.

get_ns(RawConstName) ->
    case binary:split(RawConstName, <<"::">>) of
        [RawClassName, ConstName] ->
            {ClassNS, ClassName} = ephp_ns:parse(RawClassName),
            NS = ephp_ns:normalize(ClassNS),
            {NS, ClassName, ConstName};
        [RawConstName] ->
            {ConstNS, ConstName} = ephp_ns:parse(RawConstName),
            NS = ephp_ns:normalize(ConstNS),
            {NS, undefined, ConstName}
    end.

set_bulk(Ref, Values) ->
    set_bulk(Ref, undefined, Values).

set_bulk(Ref, ClassName, Values) ->
    set_bulk(Ref, [], ClassName, Values).

set_bulk(Ref, NameSpace, ClassName, Values) ->
    erlang:put(Ref,
               lists:foldl(fun({Name, Value}, Const) ->
                              dict:store({NameSpace, ClassName, Name}, Value, Const)
                           end,
                           erlang:get(Ref),
                           Values)).

set(Ref, Name, Value) ->
    set(Ref, undefined, Name, Value).

set(Ref, ClassName, Name, Value) ->
    set(Ref, [], ClassName, Name, Value).

set(Ref, NameSpace, ClassName, Name, Value) ->
    Const = erlang:get(Ref),
    erlang:put(Ref, dict:store({NameSpace, ClassName, Name}, Value, Const)),
    ok.

destroy(Const) ->
    erlang:erase(Const),
    ok.