program snake;
uses crt, graph;
var graphicsdriver,graphicsmode:smallint;
    entry,active,n,count,s,r:integer;
    x,y:array of integer;
    b:array[1..2] of integer;

procedure varinit;
begin
  b[1] := 1000;
  b[2] := 600;
end;

procedure opgr;
begin
  active := 1;
  graphicsdriver := detect;
  initgraph(graphicsdriver, graphicsmode,'');
end;

procedure clgr;
begin
  active := 0;
  closegraph;
end;

procedure valout;
begin
  textcolor(lightred);
  write('* Please enter a number within the defined parameters. ');
  textcolor(yellow);
  write('[1..6]');
  writeln();
  textcolor(lightgray);
end;

procedure coordout;
begin
  textcolor(lightred);
  write('* Your entered coordinate is out of the border. ');
  textcolor(yellow);
  write('[',b[1],' x ',b[2],']');
  writeln();
  textcolor(lightgray);
end;

procedure border;
begin
  rectangle(0,0,b[1],b[2]);
end;

procedure xyvals;
begin
  count := n;
  for n := 1 to count do
  begin
    repeat
    textcolor(lightgray);
    write('Please enter the value of ');
    textcolor(white);
    write('x');
    textcolor(yellow);
    write('[',n,']');
    textcolor(lightgray);
    if n = 1 then
    begin
      textcolor(lightgreen);
      write(' (the origin coordinates).');
      textcolor(lightgray);
    end
    else
    begin
      write('.');
    end;
    writeln();
    readln(x[n]);
    if (x[n] < 1) or (x[n] > (b[1]-1)) then
    begin
      coordout;
    end;
    until (x[n] > 0) and (x[n] < b[1]);
    //
    repeat
    textcolor(lightgray);
    write('Please enter the value of ');
    textcolor(white);
    write('y');
    textcolor(yellow);
    write('[',n,']');
    textcolor(lightgray);
    if n = 1 then
    begin
      textcolor(lightgreen);
      write(' (the origin coordinates).');
      textcolor(lightgray);
    end
    else
    begin
      write('.');
    end;
    writeln();
    readln(y[n]);
    if (y[n] < 1) or (y[n] > (b[2]-1)) then
    begin
      coordout;
    end;
    until (y[n] > 0) and (y[n] < b[2])
  end;
end;

procedure tri;
begin
  n := 3;
  setlength(x, n);
  setlength(y, n);
  xyvals;
  opgr;
  border;
  line(x[1],y[1],x[2],y[2]);
  line(x[2],y[2],x[3],y[3]);
  line(x[3],y[3],y[1],y[1]);
  delay(3000);
  clgr;
end;

procedure rect;
begin
  n := 2;
  setlength(x, n);
  setlength(y, n);
  xyvals;
  opgr;
  border;
  rectangle(x[1],y[1],x[2],y[2]);
  delay(3000);
  clgr;
end;

procedure squ;
begin
  n := 1;
  setlength(x, n);
  setlength(y, n);
  xyvals;
  repeat
  writeln('Please enter the side length of the square.');
  readln(s);
  if ((x[1]+s) > (b[1]-1)) or ((y[1])+s > (b[2]-1)) or ((x[1]-s) < 1) or ((y[1]-s) < 1) then
  begin
  textcolor(lightred);
  write('* Your entered side length causes the square to exceed the border. ');
  textcolor(yellow);
  write('[',b[1],' x ',b[2],']');
  writeln();
  textcolor(lightgray);
  end;
  until ((x[1])+s < b[1]) and ((y[1])+s < b[2]) and ((x[1]-s) > 0) and ((y[1]-s) > 0);
  opgr;
  border;
  rectangle(x[1],y[1],x[1]+s,y[1]+s);
  delay(3000);
  clgr;
end;

procedure circ;
begin
  n := 1;
  setlength(x, n);
  setlength(y, n);
  xyvals;
  repeat
  writeln('Please enter the radius of the circle.');
  readln(r);
  if ((x[1]+r) > (b[1]-1)) or ((y[1])+r > (b[2]-1)) or ((x[1]-r) < 1) or ((y[1]-r) < 1) then
  begin
  textcolor(lightred);
  write('* Your entered radius causes the circle to exceed the border. ');
  textcolor(yellow);
  write('[',b[1],' x ',b[2],']');
  writeln();
  textcolor(lightgray);
  end;
  until ((x[1])+r < b[1]) and ((y[1])+r < b[2]) and ((x[1]-r) > 0) and ((y[1]-r) > 0);
  opgr;
  border;
  circle(x[1],y[1],r);
  delay(3000);
  clgr;
end;

procedure scr;
begin

end;

procedure proc;
begin
  case entry of
  1:tri;
  2:rect;
  3:squ;
  4:circ;
  5:scr;
  6:halt(0);
  end;
end;

procedure menu;
begin
  textcolor(lightgray);
  writeln('1. Draw Triangle');
  writeln('2. Draw Rectangle');
  writeln('3. Draw Square');
  writeln('4. Draw Circle');
  writeln('5. Screensaver');
  textcolor(lightmagenta);
  writeln('6. EXIT');
  textcolor(lightgray);
  writeln();
  repeat
  write('Please enter your option ');
  textcolor(lightcyan);
  write('[1..6]');
  writeln();
  textcolor(lightgray);
  readln(entry);
  if (entry < 1) or (entry > 6) then
  begin
    valout;
  end;
  until (entry > 0) and (entry < 7);
end;

begin
  varinit;
  while true do
  begin
    clrscr;
    menu;
    proc;
  end;
end.