(local asm (require :asm.asm))
(local VM (require :asm.vm))
(local Prodos (require :asm.prodos))
(local util (require :lib.util))
(local {: lo : hi} util)

(fn org-loader [org]
  (local srclabel (.. :loader- org.addr))
  ; this will always copy full pages, because it simplifies the code and we don't actually care if a little extra
  ; garbage is tacked on to the end.
  ; We copy the pages in reverse order, because this allows us to safely move from 0x2000 to higher memory, and we
  ; never want to overlap with 0x2000 from lower memory, so either direction is safe
  (local dstpage-first (hi org.addr))
  (local dstpage-last (hi (+ org.addr (length org.bytes) -1)))
  [:block
    [:computed :srchi #(+ ($1:lookup-addr :ld-src) 2)]
    [:computed :dsthi #(+ ($1:lookup-addr :st-dst) 2)]
    [:computed :src-last #(+ ($1:lookup-addr srclabel) (* (- dstpage-last dstpage-first) 0x100))]
    [:computed :dst-last #(+ org.addr (* (- dstpage-last dstpage-first) 0x100))]
    [:ldx 0]
  :ld-src [:lda :src-last :x]
  :st-dst [:sta :dst-last :x]
    [:inx]
    [:bne :ld-src]

    [:lda :dsthi]
    [:cmp dstpage-first]
    [:beq :done]
    [:dec :srchi]
    [:dec :dsthi]
    [:bne :ld-src]
  :done])

(fn create-sys-loader [disk filename game]
  (local blocks [])
  (local prg (asm.new game))
  (local org (prg:org 0x2000))
  (org:append :loader-main)
  (set prg.start-symbol :loader-main)
  (each [_ block (pairs game.org-to-block)]
    (table.insert blocks block))
  (table.sort blocks #(< $1.addr $2.addr))
  (each [_ block (ipairs blocks)]
    (org:append (org-loader block)))
  (org:append [:jmp game.start-symbol])
  (each [_ block (ipairs blocks)]
    (org:append (.. :loader- block.addr) [:bytes block.bytes]))
  (prg:assemble)
  (disk:add-file (.. filename ".SYSTEM") Prodos.file-type.SYS 0x2000 org.block.bytes))

(fn create-loader [disk game]
  (local boot (asm.new game))
  (set boot.start-symbol :boot)
  (local vm (VM.new boot {:org 0xc00}))
  (disk.install-words vm)
  (vm:def :hires
    [:sta :0xc050]
    [:sta :0xc057]
    [:sta :0xc052]
    [:sta :0xc054])
  (vm:word :loadfile ; length addr filename --
    0xbb00 :open :read :drop :close)

  (disk:add-file "TITLE.SCREEN" Prodos.file-type.BIN 0x2000 (: (util.readjson "game/title.screen") :fromhex))
  (vm.code:append
    :boot
    [:jsr :reset]
    [:jsr :interpret]
    [:vm :hires
      0x2000 0x2000 (vm:pstr "TITLE.SCREEN") :loadfile])
  (local files [])
  (each [_ block (pairs game.org-to-block)]
    (local filename (.. "STUFF." (length files)))
    (table.insert files filename)
    (disk:add-file filename Prodos.file-type.BIN block.addr block.bytes)
    (vm.code:append [:vm (length block.bytes) block.addr :lit (.. :filename (length files)) :loadfile]))
  (vm.code:append
    [:vm :native]
    [:jmp game.start-symbol])
  (each [i filename (ipairs files)]
    (vm.code:append (.. :filename i) (disk.str filename)))
  (boot:assemble)
  boot)

(local disk (Prodos "ProDOS_Blank.dsk"))
(local game (util.reload :game))
(local loader (create-loader disk game))
(create-sys-loader disk :NEUT loader)
(disk:update-volume-header {:name "NEUT.TOWER"})
(disk:write "NeutTower.dsk")