(local tile (require :game.tiles))
(local {: vm : mapw : maph : itile : controlstate} (require :game.defs))

(local {: walkable} tile.flag-to-bit)

(vm:word :movement-dir ; key -- dyx
  (vm:case [(string.byte "I") 0xff00]
           [(string.byte "J") 0x00ff]
           [(string.byte "K") 0x0001]
           [(string.byte "M") 0x0100]
           [:else             0x0000]))

(vm:def :yx+ ; yx yx -- yx
  [:lda vm.TOP :x]
  [:clc] [:adc vm.ST1 :x]
  [:sta vm.ST1 :x]
  [:lda vm.TOPH :x]
  [:clc] [:adc vm.ST1H :x]
  [:sta vm.ST1H :x]
  (vm:drop))

(vm:var :player-yx 0x0a0a)

(vm:word :draw-player ; --
  :player-yx :dup (vm:if [:get :dup 0xffff := (vm:if [:drop] [:yx>screen :player-tile :drawtile])] [:drop]))

(vm:var :noclip)
(vm:word :move-if-clear ; yx -- f
  :noclip :get (vm:if [:drop vm.false] [:movable-player-flag :flag-at? :not]))

(vm:const :movable-player-flag ; -- flag
  walkable)

(vm:word :move-player-to ; yx --
  :player-yx :dup :get :dup 0xffff := (vm:if [:drop] [:drawtile-at])
  :set :draw-player)

(vm:word :move-noop :drop vm.false)
(vm:word :handle-general-move ; yx -- f
  (vm:if-or [[:dup :map-specific-move] [:dup :move-if-clear]]
    [:drop vm.true] [:move-noop]))

(vm:def :yxclip? ; yx -- f
  [:block
    [:lda vm.TOP :x]
    [:cmp mapw]
    [:bcs :clipped]
    [:lda vm.TOPH :x]
    [:cmp maph]
    [:bcs :clipped]
    [:lda 0] [:sta vm.TOP :x] [:sta vm.TOPH :x] (vm:ret)
  :clipped
    [:lda 0xff] [:sta vm.TOP :x] [:sta vm.TOPH :x]])

(vm:word :try-move-player ; dir --
  :player-yx :get :yx+ ; yxnew
  (vm:if-or [[:dup :yxclip?] [:dup :touch-entity] [:dup :handle-general-move]]
    [:drop :player-yx :get])
  ; always "move" so that player can visibly change direction
  ; touch-entity can modify player-yx so we have to refetch
  :move-player-to)

(vm:word :two-frame :tick-count :get 0x1f :& 0x10 :<)
(vm:word :player-tile ; -- ptile
  :two-frame (vm:if [(itile :player-frame1)] [(itile :player-frame1)]))

(vm:word :flag-at? ; yx flag -- f
  :swap :itile-at :lookup-flags :&)

(vm:word :player-key ; key --
  (vm:ifchain
    [:dup (string.byte " ") :=] [:drop :toggle-player]
    [:movement-dir :dup]
    [:player-yx :get :swap ; oldyx dir
     :try-move-player
     :dup :player-yx :get := (vm:if [:drop] [:load-next-level])]
    [:drop]))

(vm:word :full-redraw :drawmap :player-redraw)

(vm:word :player-redraw :draw-player)