-module(rumStdlib).

-compile(inline).
-compile({inline_size, 128}).

-export([
   isErrorReport/1,
   is_my_info_report/1
]).
-export([sup_get/2]).
-export([proc_lib_format/2]).

%% From OTP sasl's sasl_report.erl ... These functions aren't
%% exported.
-spec isErrorReport(atom()) -> boolean().
isErrorReport(supervisor_report) -> true;
isErrorReport(crash_report) -> true;
isErrorReport(_) -> false.

-spec is_my_info_report(atom()) -> boolean().
is_my_info_report(progress) -> true;
is_my_info_report(_) -> false.

-spec sup_get(term(), [proplists:property()]) -> term().
sup_get(Tag, Report) ->
   case lists:keysearch(Tag, 1, Report) of
      {value, {_, Value}} ->
         Value;
      _ ->
         ""
   end.

%% From OTP stdlib's proc_lib.erl ... These functions aren't exported.
-spec proc_lib_format([term()], pos_integer()) -> string().
proc_lib_format([OwnReport, LinkReport], FmtMaxBytes) ->
   OwnFormat = format_report(OwnReport, FmtMaxBytes),
   LinkFormat = format_report(LinkReport, FmtMaxBytes),
   %% io_lib:format here is OK because we're limiting max length elsewhere.
   Str = io_lib:format("  crasher:~n~s  neighbours:~n~s", [OwnFormat, LinkFormat]),
   lists:flatten(Str).

format_report(Rep, FmtMaxBytes) when is_list(Rep) ->
   format_rep(Rep, FmtMaxBytes);
format_report(Rep, FmtMaxBytes) ->
   eFmt:formatBin(<<"~p~n">>, [Rep], [{charsLimit, FmtMaxBytes}]).

format_rep([{initial_call, InitialCall} | Rep], FmtMaxBytes) ->
   [format_mfa(InitialCall, FmtMaxBytes) | format_rep(Rep, FmtMaxBytes)];
format_rep([{error_info, {Class, Reason, StackTrace}} | Rep], FmtMaxBytes) ->
   [format_exception(Class, Reason, StackTrace, FmtMaxBytes) | format_rep(Rep, FmtMaxBytes)];
format_rep([{Tag, Data} | Rep], FmtMaxBytes) ->
   [format_tag(Tag, Data, FmtMaxBytes) | format_rep(Rep, FmtMaxBytes)];
format_rep(_, _S) ->
   [].

format_exception(Class, Reason, StackTrace, FmtMaxBytes) ->
   PF = pp_fun(FmtMaxBytes),
   StackFun = fun(M, _F, _A) -> (M =:= erl_eval) or (M =:= ?MODULE) end,
   %% EI = "    exception: ",
   EI = "    ",
   [EI, lib_format_exception(1 + length(EI), Class, Reason,
      StackTrace, StackFun, PF), "\n"].

format_mfa({M, F, Args} = StartF, FmtMaxBytes) ->
   try
      A = length(Args),
      ["    initial call: ", atom_to_list(M), $:, atom_to_list(F), $/,
         integer_to_list(A), "\n"]
   catch
      error:_ ->
         format_tag(initial_call, StartF, FmtMaxBytes)
   end.

pp_fun(FmtMaxBytes) ->
   fun(Term, _I) ->
      eFmt:formatBin(<<"~p">>, [Term], [{charsLimit ,FmtMaxBytes}])
   end.

format_tag(Tag, Data, FmtMaxBytes) ->
   eFmt:formatBin(<<"~p: ~p~n">>, [Tag, Data], [{charsLimit ,FmtMaxBytes}]).

%% From OTP stdlib's lib.erl ... These functions aren't exported.

lib_format_exception(I, Class, Reason, StackTrace, StackFun, FormatFun)
   when is_integer(I), I >= 1, is_function(StackFun, 3),
   is_function(FormatFun, 2) ->
   Str = n_spaces(I - 1),
   {Term, Trace1, Trace} = analyze_exception(Class, Reason, StackTrace),
   Expl0 = explain_reason(Term, Class, Trace1, FormatFun, Str),
   Expl = io_lib:fwrite(<<"~s~s">>, [exited(Class), Expl0]),
   case format_stacktrace1(Str, Trace, FormatFun, StackFun) of
      [] -> Expl;
      Stack -> [Expl, $\n, Stack]
   end.

analyze_exception(error, Term, Stack) ->
   case {is_stacktrace(Stack), Stack, Term} of
      {true, [{_M, _F, As} = MFA | MFAs], function_clause} when is_list(As) ->
         {Term, [MFA], MFAs};
      {true, [{shell, F, A}], function_clause} when is_integer(A) ->
         {Term, [{F, A}], []};
      {true, [{_M, _F, _AorAs} = MFA | MFAs], undef} ->
         {Term, [MFA], MFAs};
      {true, _, _} ->
         {Term, [], Stack};
      {false, _, _} ->
         {{Term, Stack}, [], []}
   end;
analyze_exception(_Class, Term, Stack) ->
   case is_stacktrace(Stack) of
      true ->
         {Term, [], Stack};
      false ->
         {{Term, Stack}, [], []}
   end.

is_stacktrace([]) ->
   true;
is_stacktrace([{M, F, A} | Fs]) when is_atom(M), is_atom(F), is_integer(A) ->
   is_stacktrace(Fs);
is_stacktrace([{M, F, As} | Fs]) when is_atom(M), is_atom(F), length(As) >= 0 ->
   is_stacktrace(Fs);
is_stacktrace(_) ->
   false.

%% ERTS exit codes (some of them are also returned by erl_eval):
explain_reason(badarg, error, [], _PF, _Str) ->
   <<"bad argument">>;
explain_reason({badarg, V}, error = Cl, [], PF, Str) -> % orelse, andalso
   format_value(V, <<"bad argument: ">>, Cl, PF, Str);
explain_reason(badarith, error, [], _PF, _Str) ->
   <<"bad argument in an arithmetic expression">>;
explain_reason({badarity, {Fun, As}}, error, [], _PF, _Str)
   when is_function(Fun) ->
   %% Only the arity is displayed, not the arguments As.
   io_lib:fwrite(<<"~s called with ~s">>,
      [format_fun(Fun), argss(length(As))]);
explain_reason({badfun, Term}, error = Cl, [], PF, Str) ->
   format_value(Term, <<"bad function ">>, Cl, PF, Str);
explain_reason({badmatch, Term}, error = Cl, [], PF, Str) ->
   format_value(Term, <<"no match of right hand side value ">>, Cl, PF, Str);
explain_reason({case_clause, V}, error = Cl, [], PF, Str) ->
   %% "there is no case clause with a true guard sequence and a
   %% pattern matching..."
   format_value(V, <<"no case clause matching ">>, Cl, PF, Str);
explain_reason(function_clause, error, [{F, A}], _PF, _Str) ->
   %% Shell commands
   FAs = io_lib:fwrite(<<"~w/~w">>, [F, A]),
   [<<"no function clause matching call to ">> | FAs];
explain_reason(function_clause, error = Cl, [{M, F, As}], PF, Str) ->
   String = <<"no function clause matching ">>,
   format_errstr_call(String, Cl, {M, F}, As, PF, Str);
explain_reason(if_clause, error, [], _PF, _Str) ->
   <<"no true branch found when evaluating an if expression">>;
explain_reason(noproc, error, [], _PF, _Str) ->
   <<"no such process or port">>;
explain_reason(notalive, error, [], _PF, _Str) ->
   <<"the node cannot be part of a distributed system">>;
explain_reason(system_limit, error, [], _PF, _Str) ->
   <<"a system limit has been reached">>;
explain_reason(timeout_value, error, [], _PF, _Str) ->
   <<"bad receive timeout value">>;
explain_reason({try_clause, V}, error = Cl, [], PF, Str) ->
   %% "there is no try clause with a true guard sequence and a
   %% pattern matching..."
   format_value(V, <<"no try clause matching ">>, Cl, PF, Str);
explain_reason(undef, error, [{M, F, A}], _PF, _Str) ->
   %% Only the arity is displayed, not the arguments, if there are any.
   io_lib:fwrite(<<"undefined function ~s">>,
      [mfa_to_string(M, F, n_args(A))]);
explain_reason({shell_undef, F, A}, error, [], _PF, _Str) ->
   %% Give nicer reports for undefined shell functions
   %% (but not when the user actively calls shell_default:F(...)).
   io_lib:fwrite(<<"undefined shell command ~s/~w">>, [F, n_args(A)]);
%% Exit codes returned by erl_eval only:
explain_reason({argument_limit, _Fun}, error, [], _PF, _Str) ->
   io_lib:fwrite(<<"limit of number of arguments to interpreted function"
   " exceeded">>, []);
explain_reason({bad_filter, V}, error = Cl, [], PF, Str) ->
   format_value(V, <<"bad filter ">>, Cl, PF, Str);
explain_reason({bad_generator, V}, error = Cl, [], PF, Str) ->
   format_value(V, <<"bad generator ">>, Cl, PF, Str);
explain_reason({unbound, V}, error, [], _PF, _Str) ->
   io_lib:fwrite(<<"variable ~w is unbound">>, [V]);
%% Exit codes local to the shell module (restricted shell):
explain_reason({restricted_shell_bad_return, V}, exit = Cl, [], PF, Str) ->
   String = <<"restricted shell module returned bad value ">>,
   format_value(V, String, Cl, PF, Str);
explain_reason({restricted_shell_disallowed, {ForMF, As}},
   exit = Cl, [], PF, Str) ->
   %% ForMF can be a fun, but not a shell fun.
   String = <<"restricted shell does not allow ">>,
   format_errstr_call(String, Cl, ForMF, As, PF, Str);
explain_reason(restricted_shell_started, exit, [], _PF, _Str) ->
   <<"restricted shell starts now">>;
explain_reason(restricted_shell_stopped, exit, [], _PF, _Str) ->
   <<"restricted shell stopped">>;
%% Other exit code:
explain_reason(Reason, Class, [], PF, Str) ->
   PF(Reason, (iolist_size(Str) + 1) + exited_size(Class)).

n_spaces(N) ->
   lists:duplicate(N, $\s).

exited_size(Class) ->
   iolist_size(exited(Class)).

exited(error) ->
   <<"exception error: ">>;
exited(exit) ->
   <<"exception exit: ">>;
exited(throw) ->
   <<"exception throw: ">>.

format_stacktrace1(S0, Stack0, PF, SF) ->
   Stack1 = lists:dropwhile(fun({M, F, A}) -> SF(M, F, A)
                            end, lists:reverse(Stack0)),
   S = ["  " | S0],
   Stack = lists:reverse(Stack1),
   format_stacktrace2(S, Stack, 1, PF).

format_stacktrace2(S, [{M, F, A} | Fs], N, PF) when is_integer(A) ->
   [io_lib:fwrite(<<"~s~s ~s">>,
      [sep(N, S), origin(N, M, F, A), mfa_to_string(M, F, A)])
      | format_stacktrace2(S, Fs, N + 1, PF)];
format_stacktrace2(S, [{M, F, As} | Fs], N, PF) when is_list(As) ->
   A = length(As),
   CalledAs = [S, <<"   called as ">>],
   C = format_call("", CalledAs, {M, F}, As, PF),
   [io_lib:fwrite(<<"~s~s ~s\n~s~s">>,
      [sep(N, S), origin(N, M, F, A), mfa_to_string(M, F, A),
         CalledAs, C])
      | format_stacktrace2(S, Fs, N + 1, PF)];
format_stacktrace2(_S, [], _N, _PF) ->
   "".

argss(0) ->
   <<"no arguments">>;
argss(1) ->
   <<"one argument">>;
argss(2) ->
   <<"two arguments">>;
argss(I) ->
   io_lib:fwrite(<<"~w arguments">>, [I]).

format_value(V, ErrStr, Class, PF, Str) ->
   Pre1Sz = exited_size(Class),
   Str1 = PF(V, Pre1Sz + iolist_size([Str, ErrStr]) + 1),
   [ErrStr | case count_nl(Str1) of
                N1 when N1 > 1 ->
                   Str2 = PF(V, iolist_size(Str) + 1 + Pre1Sz),
                   case count_nl(Str2) < N1 of
                      true ->
                         [$\n, Str, n_spaces(Pre1Sz) | Str2];
                      false ->
                         Str1
                   end;
                _ ->
                   Str1
             end].

format_fun(Fun) when is_function(Fun) ->
   {module, M} = erlang:fun_info(Fun, module),
   {name, F} = erlang:fun_info(Fun, name),
   {arity, A} = erlang:fun_info(Fun, arity),
   case erlang:fun_info(Fun, type) of
      {type, local} when F =:= "" ->
         io_lib:fwrite(<<"~w">>, [Fun]);
      {type, local} when M =:= erl_eval ->
         io_lib:fwrite(<<"interpreted function with arity ~w">>, [A]);
      {type, local} ->
         mfa_to_string(M, F, A);
      {type, external} ->
         mfa_to_string(M, F, A)
   end.

format_errstr_call(ErrStr, Class, ForMForFun, As, PF, Pre0) ->
   Pre1 = [Pre0 | n_spaces(exited_size(Class))],
   format_call(ErrStr, Pre1, ForMForFun, As, PF).

format_call(ErrStr, Pre1, ForMForFun, As, PF) ->
   Arity = length(As),
   [ErrStr |
      case is_op(ForMForFun, Arity) of
         {yes, Op} ->
            format_op(ErrStr, Pre1, Op, As, PF);
         no ->
            MFs = mf_to_string(ForMForFun, Arity),
            I1 = iolist_size([Pre1, ErrStr | MFs]),
            S1 = pp_arguments(PF, As, I1),
            S2 = pp_arguments(PF, As, iolist_size([Pre1 | MFs])),
            Long = count_nl(pp_arguments(PF, [a2345, b2345], I1)) > 0,
            case Long or (count_nl(S2) < count_nl(S1)) of
               true ->
                  [$\n, Pre1, MFs, S2];
               false ->
                  [MFs, S1]
            end
      end].

mfa_to_string(M, F, A) ->
   io_lib:fwrite(<<"~s/~w">>, [mf_to_string({M, F}, A), A]).

mf_to_string({M, F}, A) ->
   case erl_internal:bif(M, F, A) of
      true ->
         io_lib:fwrite(<<"~w">>, [F]);
      false ->
         case is_op({M, F}, A) of
            {yes, '/'} ->
               io_lib:fwrite(<<"~w">>, [F]);
            {yes, F} ->
               atom_to_list(F);
            no ->
               io_lib:fwrite(<<"~w:~w">>, [M, F])
         end
   end;
mf_to_string(Fun, _A) when is_function(Fun) ->
   format_fun(Fun);
mf_to_string(F, _A) ->
   io_lib:fwrite(<<"~w">>, [F]).

n_args(A) when is_integer(A) ->
   A;
n_args(As) when is_list(As) ->
   length(As).

origin(1, M, F, A) ->
   case is_op({M, F}, n_args(A)) of
      {yes, F} -> <<"in operator ">>;
      no -> <<"in function ">>
   end;
origin(_N, _M, _F, _A) ->
   <<"in call from">>.

sep(1, S) -> S;
sep(_, S) -> [$\n | S].

count_nl([E | Es]) ->
   count_nl(E) + count_nl(Es);
count_nl($\n) ->
   1;
count_nl(Bin) when is_binary(Bin) ->
   count_nl(binary_to_list(Bin));
count_nl(_) ->
   0.

is_op(ForMForFun, A) ->
   try
      {erlang, F} = ForMForFun,
      _ = erl_internal:op_type(F, A),
      {yes, F}
   catch error:_ -> no
   end.

format_op(ErrStr, Pre, Op, [A1, A2], PF) ->
   I1 = iolist_size([ErrStr, Pre]),
   S1 = PF(A1, I1 + 1),
   S2 = PF(A2, I1 + 1),
   OpS = atom_to_list(Op),
   Pre1 = [$\n | n_spaces(I1)],
   case count_nl(S1) > 0 of
      true ->
         [S1, Pre1, OpS, Pre1 | S2];
      false ->
         OpS2 = io_lib:fwrite(<<" ~s ">>, [Op]),
         S2_2 = PF(A2, iolist_size([ErrStr, Pre, S1 | OpS2]) + 1),
         case count_nl(S2) < count_nl(S2_2) of
            true ->
               [S1, Pre1, OpS, Pre1 | S2];
            false ->
               [S1, OpS2 | S2_2]
         end
   end.

pp_arguments(PF, As, I) ->
   case {As, io_lib:printable_list(As)} of
      {[Int | T], true} ->
         L = integer_to_list(Int),
         Ll = length(L),
         A = list_to_atom(lists:duplicate(Ll, $a)),
         S0 = binary_to_list(iolist_to_binary(PF([A | T], I + 1))),
         brackets_to_parens([$[, L, string:sub_string(S0, 2 + Ll)]);
      _ ->
         brackets_to_parens(PF(As, I + 1))
   end.

brackets_to_parens(S) ->
   B = iolist_to_binary(S),
   Sz = byte_size(B) - 2,
   <<$[, R:Sz/binary, $]>> = B,
   [$(, R, $)].