abstk-ox

local abstk = require 'abstk'
local scr = abstk.new_screen("Tic-Tac-Toe v0.1")
local O = {false,false,false,false,false,false,false,false,false}
local X = {false,false,false,false,false,false,false,false,false}
local win = {{1,2,3},
            {4,5,6},
            {7,8,9},
            {1,4,7},
            {2,5,8},
            {3,6,9},
            {1,5,9},
            {3,5,7}}
local rnd = math.random
local max = math.max
local floor = math.floor
local add = table.insert
local unpak = table.unpack
local concat = table.concat
local defMap = "[_][_][_]\n[_][_][_]\n[_][_][_]\n"
local inpLabel1 = "Choose position [1-9]: "
local inpLabel2 = "Bad move: choose position [1-9]: "

function all(t1, t2)
  return t1[t2[1]] and t1[t2[2]] and t1[t2[3]]
end

function any(t1, t2)
  local t = 0
  t = t + (t1[t2[1]] and 1 or 0)
  t = t + (t1[t2[2]] and 1 or 0)
  t = t + (t1[t2[3]] and 1 or 0)
  return t
end

function randomChoice(args)
    return args[rnd(#args)]
end

function checkWin(P)
  for _, w in pairs(win) do
    if all(P, w) then
      return true
    end
  end
  return false
end

function displayOX()
  local map = ""
  for i = 1, 9, 3 do
    map = map .. (O[i] and "[O]" or (X[i] and "[X]" or "[_]"))
    map = map .. (O[i+1] and "[O]" or (X[i+1] and "[X]" or "[_]"))
    map = map .. (O[i+2] and "[O]" or (X[i+2] and "[X]" or "[_]")) .."\n"
  end
  scr:set_value("board",map)
end

function ai()
  local validMove = {true,true,true,true,true,true,true,true,true}
  for i = 1, 9 do
    validMove[i] = not (O[i] or X[i]) and validMove[i]
  end
  for _, w in pairs(win) do
    local cX = any(X,w)
    for _, v in pairs(w) do
      if cX == 2 and validMove[v] then
        return v
      end
    end
  end
  local V = {-100,-100,-100,-100,-100,-100,-100,-100,-100}
  for i, v in ipairs(validMove) do
    if v then
      local tempX, criticalMove = {unpak(X)}, {}
      tempX[i] = v
      V[i], criticalMove = evalOX(O,tempX)
      if #criticalMove > 0 then
        for _, c in pairs(criticalMove) do
          if validMove[c] then
            return c
          end
        end
      end
    end
  end
  local maxV = max(unpak(V))
  local imaxV = {}
  for i, v in pairs(V) do
    if v == maxV then
      add(imaxV,i)
    end
  end
  return randomChoice(imaxV)
end

function evalOX(o,x)
  local SO, SX, criticalMove =calSOX(o,x)
  return (1 + SX - SO), criticalMove
end

function calSOX(o,x)
  local SO, SX = 0, 0
  local criticalMove = {}
  for _, w in pairs(win) do
    local cO = any(o,w)
    local cX = any(x,w)
    if cX == 0 then
      SO = SO + cO
      if cO == 2 then
        scr:set_value("critical", "{".. concat(w,",").."}")
        criticalMove = w
      end
    end
    if cO == 0 then
      SX = SX + cX
    end
  end
  return SO, SX, criticalMove
end

function checkInput(id,opos)
  local o = tonumber(scr:get_value("opoint"))
  if not o or (floor(o) > 9 or o < 1) then
    scr:set_value("inplb", inpLabel2)
  else
    o = floor(o)
    if O[o] or X[o] then
      scr:set_value("inplb", inpLabel2)
    else
      scr:set_value("inplb", inpLabel1)
      main(o)
    end
  end
  scr:set_value("opoint", "")
end

function clear()
  scr:set_value("board",defMap)
end

function main(opos)
  scr:set_value("critical","")
  O[opos] = true
  displayOX()
  local d = true
  for i = 1, 9 do
    d = (O[i] or X[i]) and d
  end
  if d then
    scr:show_message_box("Draw")
    clear()
  elseif checkWin(O) then
    scr:show_message_box("O win")
    clear()
  else
    X[ai()] = true
    displayOX()
    if checkWin(X) then
      scr:show_message_box("X win")
      clear()
    end
  end
end

abstk.set_mode(...)
scr:add_label("board", defMap)
scr:add_label("inplb", inpLabel1)
scr:add_text_input("opoint",nil,nil,nil, checkInput)
scr:add_button("ok", "Ok", nil, checkInput)
scr:add_label("critical","")
scr:run()