-- goofy2.wz - An example Lua script for Tick5
-- Copyright (C) 2006  XMartin Yao
--
-- This program is free software; you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation; either version 2 of the License, or
-- (at your option) any later version.
-- 
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-- GNU General Public License for more details.
-- 
-- You should have received a copy of the GNU General Public License
-- along with this program; if not, write to the Free Software
-- Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

----------------------------------------------------------------------------
-- This is a simple example of AI engine built using Lua script for Tick5. 
-- It is to teach users how to build an AI engine that can play the game.
-- 
-- See the example in script goofy.wz for the very basics of the AI 
-- function tick5think(board).
--
-- In this example, the AI does "think" a little bit: it randomly 
-- picks up the coordinates of a vacant spot. Although it runs fast,
-- anyone who knows the game rules can defeat it wihtout any effort. 
-- Better to let it beat itself. :-)
----------------------------------------------------------------------------
function tick5think( board )
   -- set random number seed
   math.randomseed( os.time() )

   -- query the game board's dimension
   local dim = board:dimension()

   -- the upper bound of coordinates
   local bound = dim - 1

   -- x and y are random numbers from 0 to bound
   local x = math.random( 0, bound )
   local y = math.random( 0, bound )

   -- generate coordinates until a vacant spot found 
   while not board:isempty( x, y ) do
      x = math.random( 0, bound )
      y = math.random( 0, bound )
   end

   -- return the chosen coordinates
   return x, y
end