-- goofy3.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 introduce users the Tick5's API (AI Programming Interface.)
-- 
-- See the example in script goofy.wz for the very basics of the AI 
-- function tick5think(board).
--
-- See the example in script goofy2.wz, which is simpler than this one. 
--
-- In this example, the AI does more "thinking". Other than picking up
-- a vacant spot which is the same as the example in goofy2.wz, it goofs
-- around to explore the game board. So it can be defeated without any 
-- effort. :-)
-----------------------------------------------------------------------------
function tick5think( board )
   print( "----- start thinking -----" )

   -- mycolor()
   if mycolor() == 1 then
      print( "I play first, 'cause I play black stone." )
   else
      print( "I play white stone. My favorite color." )
   end

   -- check for last move
   last_move( board )

   -- board API
   goof_around( board )

   -- randomly pick a vacant spot 
   return pick_a_vacant_spot( board )
end

-----------------------------------------------
-- Check for the last move the opponent made
-----------------------------------------------
function last_move( board )
   -- validate global variable
   if previousboard == nil then
      return
   end

   -- the upper bound of coordinates
   local bound = board:dimension() - 1

   -- search the difference 
   local x, y
   for x = 0, bound, 1 do
      for y = 0, bound, 1 do
         if not board:isempty(x, y) and previousboard:isempty(x, y) then
            print( "The guy put a stone on (", x, ",", y, ")" ) 
            return
         end
      end
   end
end

-----------------------------------------------
-- Introduce API of board.
-----------------------------------------------
function goof_around( board )
   -- clone()
   local mycopy = board:clone()
   print( "Make a copy, in case I mess it up." )

   -- dimension()
   local dim = mycopy:dimension()
   print( "A ", dim, "x", dim, "board. That is too big!" )

   -- isempty()
   if mycopy:isempty() then
      print( "Why the board is empty?" )
   else
      print( "Why the board is not empty?" )
   end

   -- isfull()
   if mycopy:isfull() then
      print( "Why the board is full?" )
   else
      print( "The board is not full. There's a lot to do." )
   end

   -- getplies()
   print( "There're ", mycopy:getplies(), " stones" )

   -- pcik a spot
   local x = 9
   local y = 9
   print( "Pick up spot (", x, ",", y, ")" )

   -- isempty(x, y)
   if mycopy:isempty(x, y) then
      print( "(", x, ",", y, ") is empty" )
   else
      print( "(", x, ",", y, ") is not empty" )
   end

   -- set(x,y)
   if mycopy:set(x, y, mycolor()) then
      print( "Put a stone on (", x, ",", y, ")" )
   else
      print( "Can't put a stone on (", x, ",", y, ")" )
   end

   -- getstone(x,y)
   if mycopy:getstone(x,y) == mycolor() then
      print( "The stone on (", x, ",", y, ") is mine" )
   else
      print( "The stone on (", x, ",", y, ") is not mine" )
   end

   -- reset(x,y)
   if mycopy:reset(x,y) then
      print( "Remove the stone from (", x, ",", y, ")" )
   else
      print( "Can't remove the stone from (", x, ",", y, ")" )
   end

   -- clean()
   mycopy:clean()
   if mycopy:isempty() then
      print( "Oops, wipe out all stones. Lucky, I already made a copy." )
   else
      print( "Why I can't wipe all stones?" )
   end
end

------------------------------------------------------------------------------
-- Randomly pick up a vacant spot, the same as the example in script goofy2.wz
------------------------------------------------------------------------------
function pick_a_vacant_spot( board )
   print( "Got to make a move." )

   -- 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

   -- put a stone 
   board:set( x, y, mycolor() )
   print( "Got an empty spot (", x, " ", y, ")." )

   -- cache the board using a global variable
   previousboard = board:clone();

   -- return the chosen coordinates
   return x, y
end