local MEMSIZE=16
if not digiline then
 print("Digilines not found.")
 return
end
local oldprint=print
local function print(...)
 for k,v in ipairs({...}) do
  oldprint("[Test3D:T400] "..tostring(v))
 end
end
print("Loading.")

local function pos2string(pos)
 return tostring(pos.x)..","..tostring(pos.y)..","..tostring(pos.z)
end

local function push(pos,val)
 local meta = minetest.get_meta(pos)
 local sstring = ""
 local sstab = string.split(meta:get_string("stack"),"\n")
 sstab[#sstab+1] = tostring(tonumber(val))
 if #sstab > 16 then
  table.remove(sstab,1)
 end
 for k,v in ipairs(sstab) do
  sstring = sstring .. v .. "\n"
 end
 meta:set_string("stack",sstring)
end
local function pop(pos)
 local meta = minetest.get_meta(pos)
 local sstring = ""
 local sstab = string.split(meta:get_string("stack"),"\n")
 local sval = table.remove(sstab,#sstab)
 for k,v in ipairs(sstab) do
  sstring = sstring .. v .. "\n"
 end
 meta:set_string("stack",sstring)
 if not sval then sval = 0 end
 return sval
end

local function t400_digiline_receive(pos, node, channel, msg)
 print("Digiline: "..tostring(pos.x)..","..tostring(pos.y)..","..tostring(pos.z).."; Channel: "..tostring(channel).."; Message: "..tostring(msg))
 local meta = minetest.get_meta(pos)
 if meta:get_string("state") == "waitingdat" and meta:get_string("waitingfor") == channel then
  push(pos,tonumber(msg))
  meta:set_int("pc",meta:get_int("pc")+1)
  meta:set_string("state","running")
 elseif meta:get_string("state") == "waitingins" and meta:get_string("waitingfor") == channel then
  meta:set_int("ci",tonumber(msg))
  meta:set_string("state","running")
 end
end
print("Created T400 digiline function")

local function t400_set_meta(pos)
 local meta = minetest.get_meta(pos)
 local ms = ""
 for i = 1, MEMSIZE do
  ms = ms .. "0\n"
 end
 meta:set_string("stack",ms)
 meta:set_string("channel","Default")
 meta:set_string("state","running")
 meta:set_string("waitingfor","")
 meta:set_int("pc",0)
 meta:set_int("ci",0)
 meta:set_string("formspec","size[5,5]\nlabel[0.4,0.5;T400 Execution Node]\nfield[0.5,2;4,1;channel;Channel prefix;${channel}]\nfield[0.5,3;4,1;pc;Program Counter;${pc}]field[0.5,4;4,1;state;State;${state}]")
end
minetest.register_node("test3d_t400:t400", {
 description = "T400 Execution Node",
 tiles = {
  {
   image="t400.png",
   animation={
    type = "vertical_frames",
    aspect_w=16,
    aspect_h=16,
    length=18,
    length=1.8,
   },
  },
 },
 on_construct = t400_set_meta,
 groups = {snappy=1,choppy=2,oddly_breakable_by_hand=2,flammable=3},
 digiline = {
  receptor = {},
  effector = {
   action = t400_digiline_receive
  }
 },
 on_receive_fields = function(pos,_,fields,sender)
  if fields.channel == nil then return end
  local meta = minetest.get_meta(pos)
  fields.channel = fields.channel or ""
  meta:set_string("channel",fields.channel)
  meta:set_string("pc",fields.pc)
  meta:set_string("state",fields.state)
 end
})
print("T400 node registered")

minetest.register_abm({
 nodenames={"test3d_t400:t400"},
 interval=0.1,
 chance=1,
 action = function(pos)
  local meta = minetest.get_meta(pos)
  if meta:get_string("state") == "running" then
   local skipnext = false
   print("Attempting to run T400 node at "..pos2string(pos))
   local ci = meta:get_int("ci")
   --[[
    4095 = drop
    4094 = dup
    4093 = swap
    4092 = read
    4091 = write
    4090 = add
    4089 = sup
    4088 = multiply
    4087 = jmp
    4086 = skip if zero
   ]]--
   if ci == 4095 then
    print("Dropped "..tostring(pop(pos)).." from "..tostring(pos.x)..","..tostring(pos.y)..","..tostring(pos.z))
   elseif ci == 4094 then
    local dat = pop(pos)
    push(pos,dat)
    push(pos,dat)
    print("Duplicated "..tostring(dat).." at "..tostring(pos.x)..","..tostring(pos.y)..","..tostring(pos.z))
   elseif ci == 4093 then
    local a = pop(pos)
    local b = pop(pos)
    push(pos,b)
    push(pos,a)
   --[[ I'll write the stuff for reading and writing memory eventually(TM)
   ]]--
   elseif ci == 4092 then
    skipnext = true
    meta:set_string("state","waitingdat")
    meta:set_string("waitingfor",meta:get_string("channel")..string.format("%X",addr))
    local addr = pop(pos)
    digiline:receptor_send(pos,digiline.rules.default,meta:get_string("channel")..string.format("%X",addr),"get")
   elseif ci == 4091 then
    local addr = pop(pos)
    local dat = pop(pos)
    print("Writing "..tostring(dat).." to address "..addr)
    digiline:receptor_send(pos,digiline.rules.default,meta:get_string("channel")..string.format("%X",addr),dat)
   elseif ci == 4090 then
    print("Adding stuff")
    push(pos,pop(pos)+pop(pos))
   elseif ci == 4089 then
    push(pos,pop(pos)-pop(pos))
   elseif ci == 4088 then
    push(pos,pop(pos)*pop(pos))
   elseif ci == 4087 then
    local npc = pop(pos)
    print("Jumping to "..tostring(npc))
    meta:set_int("pc",npc)
   elseif ci == 4086 then
    if pop(pos) == 0 then
     meta:set_int("pc",meta:get_int("pc")+1)
    end
   else
    print("Pushing "..ci.." to "..pos2string(pos))
    push(pos,ci)
   end
   if not skipnext then
    meta:set_int("pc",meta:get_int("pc")+1)
    meta:set_string("state","waitingins")
    meta:set_string("waitingfor",meta:get_string("channel")..string.format("%X",meta:get_int("pc")))
    digiline:receptor_send(pos, digiline.rules.default, meta:get_string("channel")..string.format("%X",meta:get_int("pc")), "get")
   end
  end
 end
})
print("T400 ABM registered")
print("T400 init finished")