-module( roman_numerals ).

-export( [encode_from_integer/1]).

-record( encode_acc, {n, romans=""} ).

encode_from_integer( N ) when N > 0 ->
        #encode_acc{romans=Romans} = lists:foldl( fun encode_from_integer/2, #encode_acc{n=N}, map() ),
        Romans.


encode_from_integer( _Map, #encode_acc{n=0}=Acc ) -> Acc;
encode_from_integer( {_Roman, Value}, #encode_acc{n=N}=Acc ) when N < Value -> Acc;
encode_from_integer( {Roman, Value}, #encode_acc{n=N, romans=Romans} ) ->
        Times = N div Value,
        New_roman = lists:flatten( lists:duplicate(Times, Roman) ),
        #encode_acc{n=N - (Times * Value), romans=Romans ++ New_roman}.

map() -> [{"M",1000}, {"CM",900}, {"D",500}, {"CD",400}, {"C",100}, {"XC",90}, {"L",50}, {"XL",40}, {"X",10}, {"IX",9}, {"V",5}, {"IV",4}, {"I\
",1}].