% Author:
% Date: 08.01.2019

printlist([]):- write('========\n').
printlist([X|List]) :-
        write(X),nl,
        printlist(List).
get_word_list(List):-  findall(X,add_word(X),List).

add_word_to_dynamic_predicate([]):- !.
add_word_to_dynamic_predicate([H|T]):- assert(add_word(H)), add_word_to_dynamic_predicate(T).
store_in_local_db(Data):- retractall(add_word(_)),append(List, [_], Data),length(List, Len),((Len =:= 0) -> write('No data !!!'); add_word_to_dynamic_predicate(List)).

write_data([],'y'):- !.
write_data([H|T], 'y'):- open('words.txt', append, OutputStream), string_concat(H,'.',Data) ,write(OutputStream,Data), nl(OutputStream), close(OutputStream), write_data(T,'y').
write_data(_,_):- write('redirecting to home'), start_game().

%CRUD Operation code%
open_file(FileName,OutputStream,Data):- nl(OutputStream),open(FileName,write,OutputStream), write(OutputStream,Data),nl(OutputStream),close(OutputStream).
append_file(FileName,OutputStream,Data):- open(FileName,append,OutputStream), write(OutputStream,Data),nl(OutputStream), close(OutputStream).
read_file(FileName):- open(FileName, read, InputStream),readfile(InputStream,Data),close(InputStream), store_in_local_db(Data),nl.
readfile(Stream,[]) :- at_end_of_stream(Stream).
readfile(Stream,[X|L]) :- \+ at_end_of_stream(Stream), read(Stream,X), readfile(Stream,L).
create_new_file():- open('words.txt',write,OutputStream), nl(OutputStream), close(OutputStream).





%Game Code%

choose_word(Word) :-
    get_word_list(List),
    length(List, Len),
    random(0, Len, Index),
    nth0(Index, List, Word).

create_stars(0,'').
create_stars(N,Str) :-
    M is N-1,
    create_stars(M,Str2),
    string_concat('*',Str2,Str), !.

init_play() :-
    choose_word(Word),
    string_length(Word,N),
    create_stars(N,Stars),
    play(Word,Stars,0).

play(RightWord, GuessedWord, Tries) :-
    writeln(''),
    TriesNext is Tries+1,
    write('Please guess the word: '), writeln(GuessedWord),
    write('Please guess a letter: '),
    get_single_char(C), char_code(Guess,C),
    atom_chars(RightWord, WordCharacters),
    findall(Ind, nth0(Ind,WordCharacters,Guess), Indices),
    replace_str(GuessedWord, Indices, Guess, NewGuessedWord),
    (RightWord=NewGuessedWord ->
        end_play(TriesNext);
        play(RightWord, NewGuessedWord, TriesNext)), !.

replace_str(Str, Ind, Guess, RetStr) :-
    atom_chars(Str, StrChars),
    length(StrChars, Len),
    LastIndex is Len-1,
    replace_list(StrChars, Ind, Guess, LastIndex, RetList),
    atom_chars(RetStr,RetList).

replace_list(_, _, _, -1, []).
replace_list(CharList, Indices, Guess, Index, RetList) :-
     nth0(Index,CharList,Char),
     Index2 is Index-1,
     replace_list(CharList, Indices, Guess, Index2, RetList2),
     (member(Index,Indices) ->
         append(RetList2,[Guess],RetList) ;
         append(RetList2,[Char],RetList )), !.

end_play(Tries) :-
     writeln(''), write('You needed '), write(Tries),  write(' tries. \n'), start_game().


%==========%




dynamic add_word/1.

read_data_from_file():- (exists_file('words.txt')-> read_file('words.txt');create_new_file(), write('No data !!!')), start_game().
list_knowledge_base():- get_word_list(List), length(List,Len), ((Len =:=0) -> write('No data');write('========\n'),printlist(List)), start_game().
add_new_word():- write('Please enter a word: \n'), readln([H|T]), assert(add_word(H)),start_game().
delete_word():-  write('Please enter a word you want to delete: \n'), readln([H|T]), get_word_list(List), ( member(H,List) -> retract(add_word(H)), write('Succefully deleted.\n'); write("Word is not in Databse\n")),start_game().
write_database_file():- get_word_list(List), length(List, Len), ((Len =:= 0) -> write('No data !!!'),create_new_file();
                         write("File will be overridden, press 'y' for yes and 'n' for No."), get_single_char(X), char_code(Char_Code,X),file_utils(List,Char_Code)),start_game().

file_utils(List,'y'):-  create_new_file(),write_data(List,Char_Code),!.
file_utils(List,'n'):-  write_data(List,Char_Code),!.
file_utils(List,_):-  write('Invalid Option  try again\n '),!.

guess_word():- init_play().
end_game():- write('Game Over'), !.

game('r'):- read_data_from_file(),!.
game('l'):- list_knowledge_base(),!.
game('a'):- add_new_word(),!.
game('d'):- delete_word(),!.
game('w'):- write_database_file(),!.
game('g'):- guess_word(),!.
game('e'):- end_game().
game(_):- write('Invalid Chracter \n'), start_game().

start_game():- write('Guess a Word \n  ===================== \n r - read database file \n l - list knowledge base \n a - add a new word \n d - delete a word \n w - write database file \n g - guess a word \n e - end the game'),
               nl,get_single_char(X), char_code(Char_Code,X),game(Char_Code).