#!/usr/bin/ruby

# ****************************************************************************
# *                        VT100 escape sequence                             *
# ****************************************************************************

module VT100
  def cls; print "\e[2J"; end
  def move(x, y); printf("\e[%d;%dH",x, y); end
  def bold; print "\e[1m"; end
  def reset; print "\e[0m"; end
  def sc; print "\e7"; end	# * store cursor *
  def rc; print "\e8"; end	# * restore cursor *
  def d_right; print "\e[0K"; end # * delete right side of the cursor *
end

include VT100

# ****************************************************************************
# *                        Menu class                                        *
# ****************************************************************************

class Menu
  def initialize( table, y0, x0 )
    @table = table
    @y0 = y0
    @x0 = x0
  end

  def display
    cls
    @table.each do |line|
      move(@y0 + line["y"], @x0 + line["x"])
      print line["item"]
    end
  end
  
  def keyin(first, last)
    sc
    while( true )
      key_in = gets
      if key_in =~ /^[0-9]/
        n = key_in.to_i
        if (n >= first && n <= last)
          return n
        end
      end
      rc
      d_right
    end
  end
end

# ****************************************************************************
# *                        menu table                                        *
# ****************************************************************************	

menu_table = [
	{"y" => 0, "x" =>  5, "item" => "Main Menu"		},
	{"y" => 3, "x" =>  0, "item" => "1 Computer (press 1)"	},
	{"y" => 5, "x" =>  0, "item" => "2 Logic    (press 2)"	},
	{"y" => 7, "x" =>  0, "item" => "3 Others   (press 3)"	},
	{"y" => 9, "x" => 0, "item" => "4 Exit     (press 4)"	},
	{"y" => 11, "x" =>  5, "item" => "key in please : "	}
	]

# ****************************************************************************
# *                            main()                                        *
# ****************************************************************************

def task( n )
  rc
  print "item No. #{n} is selected"
  $stdout.flush
  sleep(1)
end

menu = Menu.new( menu_table, 5, 25 )

while true
  menu.display
  item_number = menu.keyin( 1, 4 )

  case item_number
  when 1
	task(1)
  when 2
	task(2)
  when 3
	task(3)
  when 4
	cls; move(1, 1)
        exit
  end
end