Solution: Sunflower vs. Zombies Game Simulation

ZOMBIES_COUNT = 15
DISTANCE = 10

class Sunflower
  attr_accessor :health

  def initialize
    @health = 100
  end

  def exchange_fire(zombie)
    
    if zombie.in_touch_distance? 
      @health -= 5
    else
      @health -= (rand(2) + 1)
    end
    
    if @health <= 0 
      @health = 0
    end
    
    zombie.health -= (rand(31) + 10) # between 10 to 40 damage    
    zombie.die if zombie.health <= 0
  end
  
end


class Zombie
  @@live_count = 0
  attr_accessor :health, :steps
  attr_accessor :moving_speed
  
  def initialize
    @@live_count += 1     
    @health = 100
    @steps = 0
    @moving_speed = rand(10) >= 8  ?  2 : 1 # 80% are jumping zombies
  end
  
  def self.remaining_lives
    @@live_count
  end
  
  def die
    @health = 0
    @@live_count -= 1
  end
  
  def is_dead?
    @health <= 0
  end
  
  def in_touch_distance? 
    @steps == DISTANCE
  end
  
  def move_forward
    @steps += @moving_speed
    if @steps >= DISTANCE
      @steps = DISTANCE
    end
  end
end

print "\nF(100)  ___ ___ ___ ___ ___ ___ ___ ___ ___ ___"

sunflower = Sunflower.new
zombies = []
ZOMBIES_COUNT.times do 
  zombies << Zombie.new
end

active_zombie = nil

while (sunflower.health > 0) do 
  sleep 0.1  # adjust game speed, smaller number, faster
  
  if active_zombie.nil? || active_zombie.is_dead?
    active_zombie = zombies.shift unless zombies.empty?
  end
  
  break if zombies.empty? && (active_zombie.nil? || active_zombie.is_dead?) # no more zombies

  sunflower.exchange_fire(active_zombie)
  active_zombie.move_forward unless active_zombie.is_dead?

  # now print the latest battle field
  flower_health_str = sunflower.health.to_s.rjust(3, " ")
  print "\r"
  print "F(#{flower_health_str})  "
  
  zombie_pos = "Z#{active_zombie.health.to_s.rjust(2, '0')}"
  field = 10.times.collect {|x| 
    if active_zombie.steps == (10 - x)
      zombie_pos
    else
     "___"
    end    
  }.join(" ")
  print field
end

if sunflower.health > 0 
  puts "\n\nYou Win! Flower survived attacks from #{ZOMBIES_COUNT} zombies"
else
  puts "\n\nGame Over! #{Zombie.remaining_lives} zombies left"
end