Enemy = {}
Enemy.__index = Enemy

function Enemy.new(name, hitpoints, attack)
    local self = setmetatable({}, Enemy)
    self.name = name
    self.hitpoints = hitpoints
    self.attack = attack
    return self
end

function Enemy.takeHit(self, damage)
    self.hitpoints = self.hitpoints - damage
    if self.hitpoints <= 0 then
        if self.onDeath ~= nil then
            self.onDeath()
        end
    end
end

function Enemy.setDeathEvent(self, onDeathCallback)
    self.onDeath = onDeathCallback
end

function Enemy.isDead(self)
    return self.hitpoints <= 0
end