(ns topdown2d.demoscene
  (:require
    [topdown2d.collision :as collision]
    [topdown2d.input :as input]
    [topdown2d.sprites :as sprites]))

(defn init [gamestate scenedata]
  (assoc scenedata
    :data {
      :player {
        :x (- (/ (get-in gamestate [:dimensions :w]) 2) 32)
        :y (- (/ (get-in gamestate [:dimensions :h]) 2) 32)
        :w 64 :h 64
        :d :?
        :sprite {
          :image (.getElementById js/document "demo-player")
          :size 64
          :d :s
          :rows {
            :w 1 :e 3
            :n 0 :s 2
            :? 2
          }
          :cycle {
            :pos 0
            :from 1 :count 8
            :last-cycle 0
            ; seconds per cycle
            :spc 0.08
          }
        }
      }
      :viewport {
        :image (.getElementById js/document "demo-background")
        :keep-in {
          :x 0 :y 0
          :w 2239 :h 2235
        }
        :x 1 :y 1
        :d :?
        :pps 350
        :w (get-in gamestate [:dimensions :w])
        :h (get-in gamestate [:dimensions :h])
      }
    }))

(defn update-player [gamestate player dir]
  (let [player-dir (get-in player [:sprite :d])
        sprite-dir (if (= :? dir) player-dir dir)]
    (as-> player p
      (assoc-in p
        [:sprite :d]
        sprite-dir)
      (if-not (= :? dir)
        (sprites/proc-cycle gamestate p)
        p))))

(defn update-viewport [gamestate viewport dir]
  (collision/move-inside
    (assoc viewport :d dir)
    (:keep-in viewport)
    (collision/pps->px gamestate viewport)))

(defn update-scene [gamestate scenedata]
  (let [player (get-in scenedata [:data :player])
        viewport (get-in scenedata [:data :viewport])
        dir (input/dirinput)]
    (-> scenedata
      (assoc-in [:data :player]
        (update-player gamestate player dir))
      (assoc-in [:data :viewport]
        (update-viewport gamestate viewport dir)))))

(defn draw-scene [gamestate scenedata]
  (let [viewport (get-in scenedata [:data :viewport])
        {:keys [x y w h background]} viewport]
    (.drawImage
      (:ctx gamestate)
      (:image viewport)
      x y w h
      0 0 w h))
  (sprites/draw
    gamestate
    (get-in scenedata [:data :player])))