;;;; examples/09-ghoulspree.lisp

(defpackage #:ww.examples/9
  (:use #:cl)
  (:export #:start)
  (:import-from #:defclass-std #:defclass/std))

(in-package #:ww.examples/9)

;;; CLASSES

(defclass/std  ghoulspree (ww::application)
  ((ghouls-per-click :std 50)))

(defclass/std ghoul (ww:bitmap)
  ((dx dy dr :std)))

;;; UTILITY FUNCTIONS

(defun make-ghoul (x y)
  (make-instance 'ghoul :texture (ww:get-asset "Fezghoul.png")
                        :x x :y y
                        :dr (random-velocity)
                        :dx (random-velocity 5)
                        :dy (random-velocity 5)))

(defun out-of-bounds-p (ghoul)
  (not
   (and
    (< -50 (ww:x ghoul) 850)
    (< -50 (ww:y ghoul) 650))))

(defun random-velocity (&optional (size 1.0))
  (* size (if (< 0.5 (random 1.0))
              (random 1.0)
              (* -1 (random 1.0)))))

(defun advance-pos (thing)
  (with-accessors ((dr dr) (dx dx) (dy dy) (x ww::x) (y ww::y) (r ww::rotation)) thing
    (incf x dx)
    (incf y dy)
    (incf r dr))) ;; rotation diminishes every round, just aesthetic.

(defun clamp (lo val hi)
  "Returns VAL if (< LO VAL HI), otherwise returns LO or HI depending
on which boundary VAL is outside of."
  (max lo (min val hi)))

(ww:defhandler moveghouls
    (ww:on-perframe (app)
      (loop for ghoul in (ww:container-units app)
            do (advance-pos ghoul)
            when (out-of-bounds-p ghoul)
              do (ww:drop-unit ghoul))))

(ww:defhandler add-ghouls
    (ww:on-mousedown (app x y)
      (loop repeat (ghouls-per-click app)
            do (ww:add-unit app (make-ghoul x y)))))


(defmethod ww::boot ((app ghoulspree))
  "Adds the intro text and sets up the start button handler."
  (ww:add-handler app #'add-ghouls)
  (ww:add-handler app #'moveghouls))

(defun start ()
  (ww::start
   (make-instance
    'ghoulspree
    :fps 60
    :width 800
    :height 600
    :refocus-on-mousedown-p nil
    :title "Click to add ghouls"
    :asset-root
    (merge-pathnames
     "examples/"
     (asdf:system-source-directory :wheelwork)))))