-module(

markov

 .
-export([load/1,make_sentence/1]).

clean_unicode([]) ->
    [];

clean_unicode([H|T]) when H >= 127;H < 32 ->
    clean_unicode(T);

clean_unicode([H|T]) ->
    [H|clean_unicode(T)].

%{key,total,word_list}
load_sentence(MTable,[W1|[]]) ->
    W2 = stop,
    case ets:lookup(MTable,W1) of
[] -> ets:insert(MTable,{W1,1,dict:update_counter(W2,1,dict:new())});
[{_,Total,NextDict}] ->
    ets:insert(MTable,
      {W1,Total+1,
dict:update_counter(W2,1,NextDict)})
    end;

load_sentence(MTable,[W1,W2|Rest]) ->
    case ets:lookup(MTable,W1) of
[] -> ets:insert(MTable,{W1,1,dict:update_counter(W2,1,dict:new())});
[{_,Total,NextDict}] ->
    ets:insert(MTable,
      {W1,Total+1,
dict:update_counter(W2,1,NextDict)})
    end,
    load_sentence(MTable,[W2|Rest]).

load_lines(H,MTable,eof) ->
    file:close(H),
    ok;

load_lines(H,MTable,Sentence) ->
    load_sentence(MTable,[start|string:tokens(clean_unicode(Sentence)," "]),
    load_lines(H,MTable,io:get_line(H,'')).

load(FileName) ->
    MTable = ets:new(

markov

 ,[set]),
    {ok,H} = filepen(FileName,read),
    load_lines(H,MTable,io:get_line(H,'')),
    MTable
    .

walk_next([{Key,Value}|[]],_,_) ->
    Key
    ;

walk_next([{Key,Value}|Rest],Height,Sum) when Height =< Sum ->
    Key

markov

 :make_sentence(M).
    ;

walk_next([{Key,Value}|Rest],Height,Sum)->
    %io:format("~s ~w ~n", [Key,Value]),
    walk_next(Rest,Height,Sum+Value)
    .

make_sentence(MTable,Seed) ->
    [{_,Total,NextDict}] = ets:lookup(MTable,Seed),
    Height = random:uniform(Total)-1,
    case walk_next(dict:to_list(NextDict),Height,0) of
stop -> " ";
NextSeed -> NextSeed ++ " " ++ make_sentence(MTable,NextSeed)
    end
    .

make_sentence(MTable) ->
    try
make_sentence(MTable,start)
    catch
error:X -> error
    end.