with ada.Text_IO; use Ada.Text_IO;
with ada.strings.unbounded; use ada.strings.unbounded;
with ada.strings.unbounded.Text_IO; use ada.strings.unbounded.Text_IO;
with ada.directories; use ada.directories;
with imagestr; use imagestr;
with imagepgm; use imagepgm;
with imageprocess; use imageprocess;

procedure image is
   fnameI, fnameO : unbounded_string;
   img0 : imagep;
   opt : character;
   buf : unbounded_string;
   lb,ub : float;
   bit : integer;

   -- Procedure to
   procedure getfilename(fname: out unbounded_string; t: in character) is
      res : character;
      buf : unbounded_string;
   begin
      if t = 'r' then
         loop
            put_line("Enter PGM filename: ");
            get_line(fname);
            exit when exists(to_string(fname));
         end loop;
      elsif t = 'w' then
         loop
            put_line("Enter PGM filename: ");
            get_line(fname);
            if exists(to_string(fname)) then
               put_line("Overwrite? (y/n):");
               buf := get_line;
               res := element(buf,1);
               if res = 'y' then
                  exit;
               end if;
            else
               exit;
            end if;
         end loop;
      end if;
   end getfilename;

begin

   loop
      put_line("        Image Processing");
      new_line;
      put_line(" 1. Read in PGM image from file");
      put_line(" 2. Apply image invertion");
      put_line(" 3. Apply LOG function");
      put_line(" 4. Apply contrast stretching");
      put_line(" 5. Apply histogram equalization");
      put_line(" 6. Write PGM image to file");
      put_line(" 7. Apply reduce grays");
      put_line(" 8. Quit");
      put_line(" Choice? ");
      buf := get_line;
      opt := element(buf,1);

      case opt is
         when '1' => getfilename(fnameI,'r');
                     readpgm(img0,fnameI);
         when '2' => imageinv(img0);
         when '3' => imagelog(img0);
         when '4' => put_line("lower bound:");
                     buf := get_line;
                     lb := float'value(to_string(buf));
                     put_line("upper bound:");
                     buf := get_line;
                     ub := float'value(to_string(buf));
                     imagestretch(img0,lb,ub);
         when '5' => histequal(img0);
         when '6' => getfilename(fnameO,'w');
                     writepgm(img0,fnameO);
         when '7' => put_line("bit value (1-8):");
                     buf := get_line;
                     bit := integer'value(to_string(buf));
                     reducegrays(img0,bit);
         when others => exit;
      end case;

   end loop;

end image;