math.randomseed(os.time())

local cron = require "lib.cron"

local lg = love.graphics

local function Enemy(enemyType)
    self = {}
    self.x = lg.getWidth() + 10
    if enemyType == 'top' then
        self.y = lg.getHeight() * 1/5
    elseif enemyType == 'bottom' then
        self.y = lg.getHeight() * 4/5
    elseif enemyType == 'random' then
        self.y = math.random(10, lg.getHeight() - 10)
    end
    self.w = 20
    self.h = 20
    self.color = {255, 0, 0}
    self.update = function(self, dt)
        self.x = self.x - 960/3 * dt
    end

    return self
end

local enemies = {}

table.insert(enemies, Enemy('top'))
table.insert(enemies, Enemy('bottom'))

local newEnemies = cron.every(1, function()
    table.insert(enemies, Enemy('top'))
    table.insert(enemies, Enemy('bottom'))
end)

local randEnemies

local function randEneesfs()
    for i=0,math.random(2) do
        table.insert(enemies, Enemy('random'))
    end
    randEnemies = cron.after(math.random(5, 22) / 2, randEneesfs)
end

randEnemies = cron.after(3.2, randEneesfs)

function love.update(dt)
    newEnemies:update(dt)
    randEnemies:update(dt)
    for i=1,#enemies do
        if enemies[i].update then
            if enemies[i]:update(dt) then
                --enemies[i] = nil
                --table.remove(enemies, i)
            end
        end
    end
end

function love.draw()
    for i=1,#enemies do
        lg.setColor(enemies[i].color)
        lg.rectangle("fill", enemies[i].x - enemies[i].w / 2, enemies[i].y - enemies[i].h / 2, enemies[i].w, enemies[i].h)
    end
end

function love.keypressed(key, unicode)
    if key == 'escape' then
        love.event.quit()
    end
end