-module(sh).
-export([reduce/0, run/1, sh/1]).

reduce() -> fun({_, Chunk}, Acc) -> [Chunk|Acc] end.

run(Args) ->
    erlang:open_port({spawn_executable, os:find_executable("sh")},
        [stream, in, out, eof, use_stdio, stderr_to_stdout, binary, exit_status,
            {args, ["-c",Args]}, {cd, element(2,file:get_cwd())}, {env, []}]).

sh(Port) -> sh(Port, reduce(), []).
sh(Port, Fun, Acc) ->
    receive
        {Port, {exit_status, Status}} -> {done, Status, iolist_to_binary(lists:reverse(Acc))};
        {Port, {data, {eol, Line}}}   -> sh(Port, Fun, Fun({eol,   Line}, Acc));
        {Port, {data, {noeol, Line}}} -> sh(Port, Fun, Fun({noeol, Line}, Acc));
        {Port, {data, Data}} ->
           case {binary:match(Data,  <<"Sign the certificate? [y/n]:">>) =/= nomatch,
                 binary:match(Data,  <<"requests certified, commit?">>)  =/= nomatch} of
                {true,_}   -> Port ! {self(),{command,<<"y\n">>}};
                {_,true}   -> Port ! {self(),{command,<<"y\n">>}};
                {_,_}      -> skip
           end,
           sh(Port, Fun, Fun({data,Data}, Acc))
    end.