Maximal palindrome in erlang

-module (palindrome).
-compile ([export_all]).

maximal_palindrome_in (String) ->
    Stack = [],
    Largest = [],
    no_center_found (String, Stack, Largest).

no_center_found (_RemainingInput = [], _Stack, Largest) -> Largest;

no_center_found ([NextChar|RestOfInput], [NextChar|RestOfStack], Largest) ->
    Center = [NextChar, NextChar],
    center_found (RestOfInput, RestOfStack, [NextChar, NextChar|RestOfStack],
          Center, Largest);

no_center_found ([NextChar1, NextChar2|RestOfInput], [NextChar2|RestOfStack],
         Largest) ->
    Center = [NextChar2, NextChar1, NextChar2],
    center_found (RestOfInput, RestOfStack,
          [NextChar2, NextChar1, NextChar2|RestOfStack], Center,
          Largest);

no_center_found ([NextChar|RestOfInput], Stack, Largest) ->
    no_center_found (RestOfInput, [NextChar|Stack], Largest).


center_found (_RemainingInput = [], _Stack = [], _, Center, Largest) ->
    if length (Center) > length (Largest) -> Center;
       true -> Largest
    end;

center_found (_RemainingInput = [], [TopOfStack|RestOfStack], SavedStack, Center,
          Largest) ->
    Last = lists:last (Center),
    case (Last == TopOfStack) and ([Last|Center] == lists:reverse ([Last|Center])) of
        true ->
        NewCenter = [Last|Center],
        if length (NewCenter) > length (Largest) ->
            center_found ([], RestOfStack, SavedStack, NewCenter,
                  NewCenter);
           true -> Largest
        end;
        _ ->
        if length (Center) > length (Largest) -> Center;
           true -> Largest
        end
    end;

center_found (RemainingInput, Stack = [], SavedStack, Center, Largest) ->
    if length (Center) > length (Largest) ->
        no_center_found (RemainingInput, SavedStack, Center);
       true ->
        no_center_found (RemainingInput, SavedStack, Largest)
    end;

center_found ([NextChar|RestOfInput], [NextChar|RestOfStack], SavedStack, Center,
          Largest) ->
    center_found (RestOfInput, RestOfStack,
          [NextChar|SavedStack],
          lists:concat([NextChar|Center],[NextChar]),
          Largest);

center_found ([NextChar|RestOfInput], [TopOfStack|RestOfStack], SavedStack, Center,
          Largest) ->
    Last = lists:last (Center),
    case (NextChar == Last) and ([Last|Center] == lists:reverse ([Last|Center])) of
        true ->
        NewCenter = [Last|Center],
        if length (NewCenter) > length (Largest) ->
            center_found (RestOfInput, [TopOfStack|RestOfStack],
                  [NextChar|SavedStack],
                  NewCenter, NewCenter);
           true ->
            center_found (RestOfInput, [TopOfStack|RestOfStack],
                  [NextChar|SavedStack],
                  NewCenter, Largest)
        end;
        _ ->
        if length (Center) > length (Largest) ->
            no_center_found (RestOfInput, [NextChar|SavedStack], Center);
           true ->
            no_center_found (RestOfInput, [NextChar|SavedStack], Largest)
        end
    end.


test() ->
    io:format("~p ~n", [maximal_palindrome_in ("abcde")]),
    io:format("~p ~n", [maximal_palindrome_in ("abbbaeeeeee")]),
    io:format("~p ~n", [maximal_palindrome_in ("abcdcbaabcdc")]).


1> palindrome:test().
[]
"eeeeee"
"cdcbaabcdc"
ok