begin
  # In case you use Gosu via RubyGems.
  require 'rubygems'
rescue LoadError
  # In case you don't.
end

require 'gosu'

class Objeto
	def initialize(window, x, y, vel_x = 0, vel_y = 0, imagem = "media/inverse_triangle.bmp")
		@vel_x = vel_x
		@vel_y = vel_y
		@imagem = Gosu::Image.new(window, imagem)
		@x = x
		@y = y
		@w = @imagem.width
		@h = @imagem.height
	end

	def colisao(objeto)
		return true if (@x + @w > objeto.x and @x < objeto.x + objeto.w and @y + @h > objeto.y and @y < objeto.y + objeto.h)
		return false
	end

	def move
		@x += @vel_x
		@y += @vel_y
		@x = 0 if (@x < 0)
		@x = 640 - @w if (@x + @w > 640)
		@y = 0 if (@y < 0)
		@y = 480 - @h if (@y + @h > 480)
	end

	def draw
		@imagem.draw(@x, @y, 1)
	end
	attr_accessor :vel_x, :vel_y, :x, :y, :w, :h
end

class Player < Objeto
	def input(tiros, window)
		if (window.button_down? Gosu::Button::KbLeft or window.button_down? Gosu::Button::GpLeft)
			@vel_x = -5
		elsif (window.button_down? Gosu::Button::KbRight or window.button_down? Gosu::Button::GpRight)
			@vel_x = 5
		else
			@vel_x = 0
		end

		if (window.button_down? Gosu::Button::KbUp or window.button_down? Gosu::Button::GpUp)
			puts "o"
			self.atira(tiros, window)
		end
	end

	def atira(tiros, window)
		tiros.push(Objeto.new(window, @x, @y , 0, - 10, "media/tiro.bmp"))
	end
end

class Inimigo < Objeto
	def atira(tiros, window)
		tiros.push(Objeto.new(window, @x, @y , 0, 10, "media/tiro.bmp"))
	end
end

class GameWindow < Gosu::Window
	def initialize
		super(640, 480, false)
		self.caption = "Space Invaders"
		@background_image = Gosu::Image.new(self, "media/space.png", true)

		@player = Player.new(self, 300, 380, 0, 0, "media/triangle.bmp")
		@tiros_player = Array.new()
		@tiros_inimigos = Array.new()
		@inimigos = Array.new(3) {|i| Array.new(3) {|j| Inimigo.new(self, 50*i ,50*j, 5)}}
		@nave = Inimigo.new(self, 100, 100, 5)
	end

	def update
		@player.input(@tiros_player, self)
		@player.move
		@dir = 0

		@inimigos.flatten.each do |inimigo|
			if ( ((inimigo.x + inimigo.w) + (inimigo.vel_x)) > 640 or (inimigo.x) + (inimigo.vel_x) < 0)
				@dir = 1
			end
		end
		@inimigos.flatten.each { |inimigo| inimigo.vel_x *= -1} if @dir == 1

		@inimigos.flatten.each { |inimigo| inimigo.move }

	end

	def draw
		@background_image.draw(0, 0, 0)
		@player.draw
		@inimigos.flatten.each { |inimigo| inimigo.draw }
	end

	def button_down(id)
		if (id == Gosu::Button::KbEscape)
			close
		end
	end
end

window = GameWindow.new
window.show