#!/usr/bin/env ruby

# ArgumentError: wrong kind of argument
# RuntimeError: error due to the value of an argument,
#               or combination of values of more arguments.

# Create custom error type, subclass of RuntimeError
class OutOfScreenError < RuntimeError; end

class Screen
  def initialize(w, h, *args)
    raise ArgumentError, "Width (w) must be a natural > 3" if not (w.is_a? Integer and w > 3)
    raise ArgumentError, "Height (h) must be a natural > 3" if not (h.is_a? Integer and h > 3)

    @w, @h = w - 2, h - 2
    self.clear()
  end

  def clear()
    # @screen = [['='] * @w] * @h # DO NOT: copies by reference
    @screen = Array.new(@h) {[' '] * @w}
  end

  def set(x, y, val='0')
    raise ArgumentError, "X, Y must be natural" if not (x.is_a? Integer and y.is_a? Integer)

    # NOTE: === is not commutative.
    raise OutOfScreenError, "X is out of screen" if not (0...@screen[0].size) === x
    raise OutOfScreenError, "Y is out of screen" if not (0...@screen.size) === y

    @screen[y][x] = val
  end

  def unset(x, y)
    @screen[y][x] = ' '
  end

  def print()
    tmp = ['+' + '-' * @w + '+']
    for row in @screen do
      tmp << '|' + row.join('') + '|'
    end
    tmp << ['+' + '-' * @w + '+']
    puts tmp.join("\n")
  end
end



s = Screen.new(20, 20)
s.set(5,5)

# s.set(25,25)


#http://rubylearning.com/satishtalim/ruby_exceptions.html
x, y = 25, 5
begin
  puts "> In begin body"
  s.set(x, y)

  puts "> Middle of begin body"
  s.set(2.3, y)

  puts "> End of begin body"
rescue ArgumentError
  puts "wat?"

rescue OutOfScreenError
  puts "ops, lets try with different x"
  x = 7
  retry

rescue
  # catch any error

ensure
  puts "This is always printed in the end, no matter what happen"
end