-- scripts/enemy_rect.lua
-- RectNode: bounces around, changes color on bounce.
-- Try editing vx/vy or the color while the engine is running!

local vx, vy = 180, 130

---@param self RectNode
function on_init(self)
  self.x = 600
  self.y = 300
  -- self.color already set by engine (passed in addRectNode),
  -- but we can override it here.
  self.color = { r = 220, g = 60, b = 60, a = 255 }
end

---@param self RectNode
---@param dt   number
function on_update(self, dt)
  self.x = self.x + vx * dt
  self.y = self.y + vy * dt

  if self.x < 0 or self.x + self.width > 1030 then
    vx = -vx
    self.x = math.max(0, math.min(1030 - self.width, self.x))
    -- Flash yellow on bounce
    self.color = { r = 240, g = 220, b = 50, a = 255 }
  end
  if self.y < 0 or self.y + self.height > 720 then
    vy = -vy
    self.y = math.max(0, math.min(720 - self.height, self.y))
    self.color = { r = 240, g = 220, b = 50, a = 255 }
  end

  -- Fade back to red
  self.color.r = math.min(220, self.color.r + 180 * dt)
  self.color.g = math.max(60, self.color.g - 300 * dt)
  self.color.b = math.max(60, self.color.b - 200 * dt)
end

---@param self RectNode
function on_render(self)
  -- Label over auto-drawn rect
  draw_text("Enemy", self.x + 4, self.y + 18, 13, 255, 210, 210)
  local spd = math.floor(math.sqrt(vx * vx + vy * vy))
  draw_text("v=" .. spd, self.x + 4, self.y + 34, 10, 200, 200, 200)
end