class Silo < Actor
  collides_as :silo
  attr_accessor :stock

  def initialize(opts={})
    super
    set_image 'silo-b.png', opts
    @factor = @width / @image.width
    @y = $lotu.height - @height/2
    @z = ZOrder::Silo

    @platform = []
    # How many missiles in stock?
    @stock = opts[:stock]
    # How many missiles on platform?
    @platform_capacity = Float(opts[:platform_capacity])
    # Load one missile every n seconds
    @load_time = opts[:load_time]

    # Missiles configuration
    @missile_conf = {
      :force => opts[:missile_force] || 1000,
      :speed => opts[:missile_speed] || 1000,
      :mass => opts[:missile_mass] || 10
    }

    # If negative, it adds some initial delay
    @elapsed_time = -2

    # Platform configuration in pixels
    @left_padding = 13 * @factor
    @right_padding = 24 * @factor
    @bottom_padding = 18 * @factor

    @missile_image_width = 26
    @missile_animation_width = @missile_image_width * 20 / 15

    @slot_width = platform_width/@platform_capacity
  end

  def collision_radius
    50
  end

  def platform_width
    @width - @left_padding - @right_padding
  end

  def update
    super
    load_platform
    place_missiles
  end

  def load_platform
    if @platform.length < @platform_capacity && @stock > 0
      @elapsed_time += dt
      while @platform.length < @platform_capacity && @elapsed_time >= @load_time && @stock > 0
        @elapsed_time -= @load_time
        @platform.push(new_missile)
        @stock -= 1
      end
    end
  end

  def new_missile
    missile = PlayerMissile.new(:mass => @missile_conf[:mass],
                          :max_force => @missile_conf[:force],
                          :max_speed => @missile_conf[:speed],
                          :width => @missile_image_width*@factor)
    missile.x = initial_place(missile)
    missile.y = @y + @height/2 - missile.height/2 - @bottom_padding
    missile.interpolate(missile, :y, :init => missile.y+20, :end => missile.y, :duration => 0.5)
    missile
  end

  def initial_place(missile)
    res = @x - @width/2 + @left_padding + missile.width/2 + (@platform_capacity - 1) * @slot_width
    res += (@slot_width - missile.width)
    res -= @elapsed_time / @load_time * @slot_width
    res
  end

  def place_missiles
    @platform.each_with_index do |missile, i|
      place_to_be = @x - @width/2 + @left_padding + missile.width/2 + i * @slot_width
      place_to_be += i/(@platform_capacity-1) * (@slot_width - missile.width)
      if missile.x > initial_place(missile)
        missile.x = initial_place(missile)
      end
      if missile.x > place_to_be
        missile.x -= @slot_width * dt / @load_time
      end
      if missile.x <= place_to_be
        missile.x = place_to_be
      end
    end
  end

  def launch_missile(x, y)
    if m = @platform.shift
      m.save_init_pos
      m.stop_interpolations
      target = Vector2d.new(x,y)
      m.align_to target
      m.target = target
      m.play_animation('missile.png', :width => @missile_animation_width*@factor)
    end
  end

  def to_s
    ["@platform.length: #{@platform.length}",
     "Missiles in stock: #{@stock}",
     "Missiles on platform: #{@platform.length}",
     "Elapsed loading time: #{format '%.2f', @elapsed_time}",
     "Loading next missile in: #{format('%.2f', @load_time - @elapsed_time)}"]
  end
end