rem -- Uses @chr(227) for checkers, @chr(196) for kings --

  rem -- Look for a sound file under 50k in size --
  LIST CREATE, 1
  LIST FILELIST, 1, @windir()\media\*.wav
  if @greater(@count(1), 0)
    REPEAT 
      if @greater(50000, @file(@item(1, %x), Z))
        %%wavfile = @item(1, %x)
      end 
      %x = @succ(%x)
    UNTIL %%wavfile @equal(%x, @count(1))
  end 
  LIST CLOSE, 1

  OPTION SCALE, 96
  OPTION DECIMALSEP, "."
  TITLE By Mac
  rem -- Don't show main, it's use is to create/recreate child dialog --
  DIALOG CREATE,"Main Checker Dialog",0,0,0,0

  rem -- Holds possible moves for a single piece --
  LIST CREATE, 8

  rem -- Holds all possible moves for all computer pieces --
  LIST CREATE, 7

:Start/Restart
  DIALOG CREATE,Checkers By Mac,-1,0,500,400
  DIALOG ADD,STYLE,Style1,,,,YELLOW
  DIALOG ADD,STYLE,Style2,Symbol,36,BC,,CYAN
  DIALOG ADD,STYLE,Style3,Arial,12,B,,LTBLUE
  DIALOG ADD,STYLE,Style4,MS Sans Serif,8,B
  DIALOG ADD,STYLE,Empty1,Symbol,28,BC,BROWN,LTGREEN
  DIALOG ADD,STYLE,Empty,Symbol,28,BC,BROWN,BROWN
  DIALOG ADD,STYLE,Red,Symbol,28,B,BROWN,RED
  DIALOG ADD,STYLE,Black,Symbol,28,B,BROWN,BLACK

  DIALOG ADD,TEXT,GameInfo,5,405,,,"Your Turn...",Style3
  DIALOG ADD,BUTTON,NewGame,30,405,90,20,"New Game",Style4
  DIALOG ADD,TEXT,Instructions,60,405,90,160,"Click red checker to activate it (3 dots), then click a destination square (you can multiple jump). Clicking it again deactivates it so the computer can play. It has very basic AI, so don't cheat!"

  DIALOG ADD,TEXT,Board,0,0,400,400,,Style1

  rem -- Squares numbers, their XY, who's piece/type if occupied --
  rem -- BC = black checker, RC = red checker, NO = No checker --
  rem -- BK = black king, RK = red king --
  %x = 50
  %y = 0
  %n = 1
  REPEAT 
    if @greater(10, %n)
      %n = 0%n
    end 
    rem -- Background squares to see where checker moved from --
    DIALOG ADD,TEXT,B%n,%y,%x,50,50,"*",Empty1

    rem -- Black checkers --
    if @greater(13, %n)
      DIALOG ADD,TEXT,S%n,%y,%x,50,50," "@chr(227)" "|%n|%x|%y|BC,Black,CLICK
    end 
    rem -- Blank Squares --
    if @both(@greater(%n, 12), @greater(21, %n))
      DIALOG ADD,TEXT,S%n,%y,%x,50,50,|%n|%x|%y|NO,Empty,CLICK
    end 
    rem -- Red checkers --
    if @greater(%n, 20)
      DIALOG ADD,TEXT,S%n,%y,%x,50,50," "@chr(227)" "|%n|%x|%y|RC,Red,CLICK
    end 
    %n = @succ(%n)
    %x = @sum(%x, 100)
    if @greater(%x, 350)
      %y = @sum(%y, 50)
      %x = 0
      if @equal(%y, 100)@equal(%y, 200)@equal(%y, 300)
        %x = 50
      end 
    end 
  UNTIL @greater(%n, 32)

  rem -- Dots to highlight player active piece --
  DIALOG ADD,TEXT,HL,0,0,50,50,@chr(188),TRANSPARENT,Style2,CLICK
  DIALOG HIDE,HL
  DIALOG SHOW

  rem -- Total checkers --
  %%playernum = 12
  %%compnum = 12

  rem -- Active player checker --
  %%checker = ""

  if %%wavfile
    PLAY %%wavfile
  end 

:EVLOOP
  rem -- Let everything catch up --
  WAIT .2
  WAIT EVENT
  %e = @event()
  if @equal(@substr(%e, 1), "S")
    goto ClickSquare
  end 
  goto %e

:NewGameBUTTON
  if @ask(Abandon this game?@tab())
    DIALOG SELECT, 1
    DIALOG CLOSE
    goto Start/Restart
  end 
  goto EVLOOP

:HLCLICK
  %%checker = ""
  DIALOG HIDE, HL
  if %%playermoved
    goto ComputerPlay
  end 
  goto EVLOOP

:ClickSquare
  %%square = @substr(%e, 1, 3)
  PARSE ";%%SQnum;%%SQx;%%SQy;%%SQstatus", @dlgtext(%%square)
  rem -- If red piece --
  if @equal(%%SQstatus, RC)@equal(%%SQstatus, RK)
    %%checker = %%square
    PARSE ";%%startSQ;%%startSQx;%%startSQy;%%caller", @dlgtext(%%checker)
    DIALOG SHOW, HL
    DIALOG SETPOS, HL, %%startSQy, %%startSQx
  end 
  rem -- If empty square --
  if @equal(%%SQstatus, NO)
    if %%checker
      GOSUB CheckBoard
      if @greater(@count(8), 0)
        LIST SEEK, 8, 0
        if @match(8, %%square)
          GOSUB MovePiece
          %%playermoved = 1
        else 
          INFO You cannot move there!@tab()
        end 
      else 
        INFO You cannot move there!@tab()
      end 
    end 
  end 
  goto EVLOOP

:ComputerPlay
  DIALOG SET, GameInfo, "Thinking..."
  WAIT 
  LIST CLEAR, 7
  rem -- Check all computer pieces for possible moves --
  %x = 1
  REPEAT 
    if @greater(10, %x)
      %x = 0%x
    end 
    PARSE ";%%startSQ;%%startSQx;%%startSQy;%%caller", @dlgtext(S%x)
    if @equal(%%caller, "BC")@equal(%%caller, "BK")
      GOSUB CheckBoard
    end 
    %x = @succ(%x)
  UNTIL @greater(%x, 32)
  rem -- Check jumps or multiple jumps --
  if @greater(@count(7), 0)
    %j = ""
    :CheckJumps 
    %%OK = ""
    if @greater(@count(7), 0)
      LIST ASSIGN, 8, 7
      LIST SEEK, 8, 0
      %x = 0
      REPEAT 
        if @greater(@pos("JUMP", @item(8,%x)), 0)
          %%OK = 1
          %j = 1
          %%randompick = @item(8, %x)
          PARSE "%%square;%%start", %%randompick
          PARSE ";%%startSQ;%%startSQx;%%startSQy;%%caller", @dlgtext(%%start)
          rem -- Kill multiple jumps if this jump makes a king --
          if @both(@equal(%%caller, BC), @greater(@substr(%%square, 2, 3), 28))
            %%OK = ""
          end 
          GOSUB MovePiece
          LIST CLEAR, 7
          GOSUB CheckBoard
          %x = @pred(@count(8))
        end 
        %x = @succ(%x)
      UNTIL @equal(%x, @count(8))
    end 
    if %%OK
      goto CheckJumps
    end 
    if %j
      goto ComputerPlayEnd
    end 

    rem -- If can't jump, try to make a king --
    %x = 0
    %k = ""
    REPEAT 
      PARSE "%a" , @item(8, %x)
      if @equal(%a, S29)@equal(%a, S30)@equal(%a, S31)@equal(%a, S32)
        %%randompick = @item(8, %x)
        PARSE "%%square;%%start", %%randompick
        PARSE ";%%startSQ;%%startSQx;%%startSQy;%%caller", @dlgtext(%%start)
        if @equal(%%caller, "BC")
          GOSUB MovePiece
          %x = @pred(@count(8))
          %k = 1
        end 
      end 
      %x = @succ(%x)
    UNTIL @equal(%x, @count(8))
    if %k
      goto ComputerPlayEnd
    end 

    rem -- Just pick a random move --
    %x = 0
    REPEAT 
      %%randompick = @item(8, %x)
      %r = @datetime()
      rem -- get last digit (use as random number)
      %r = @substr(%r, @len(%r))
      %x = @succ(%x)
      if @equal(%x, @count(8))
        %x = 0
      end 
    UNTIL @equal(%r, 5)
    PARSE "%%square;%%start", %%randompick
    PARSE ";%%startSQ;%%startSQx;%%startSQy;%%caller", @dlgtext(%%start)
    GOSUB MovePiece
  end 
  :ComputerPlayEnd 
  if %%wavfile
    PLAY %%wavfile
  end 
  DIALOG SET, GameInfo, "Your Turn..."
  %%playermoved = ""
  goto EVLOOP

:CLOSE
  EXIT 
  STOP 

  rem ------------ GOSUB ROUTINES ------------

:CheckBoard
  rem -- Add all possible legal moves to LIST 8 --
  rem -- Uses %%caller, %%startSQ, %%startSQx, %%startSQy --
  LIST CLEAR, 8
  if @equal(%%caller,"BC")
    goto CheckBoardDown
  end 
  :CheckBoardUp 
  rem -- Up left --
  if @both(@greater(%%startSQ, 4), @greater(%%startSQx, 0))
    %%dir = L
    if @equal(@mod(%%startSQy, 100), 0)
      %%up1 = 4
      %%up2 = 5
    else 
      %%up1 = 5
      %%up2 = 4
    end 
    GOSUB CheckUp
  end 
  rem -- Up right --
  if @both(@greater(%%startSQ, 4), @greater(350, %%startSQx))
    %%dir = R
    if @equal(@mod(%%startSQy, 100), 0)
      %%up1 = 3
      %%up2 = 4
    else 
      %%up1 = 4
      %%up2 = 3
    end 
    GOSUB CheckUp
  end 
  if @equal(%%caller,"RC")
    goto CheckBoardEnd
  end 
  :CheckBoardDown 
  rem -- Down left --
  if @both(@greater(29, %%startSQ), @greater(%%startSQx, 0))
    %%dir = L
    if @equal(@mod(%%startSQy, 100), 0)
      %%dn1 = 4
      %%dn2 = 3
    else 
      %%dn1 = 3
      %%dn2 = 4
    end 
    GOSUB CheckDown
  end 
  rem -- Down right --
  if @both(@greater(29, %%startSQ), @greater(350, %%startSQx))
    %%dir = R
    if @equal(@mod(%%startSQy, 100), 0)
      %%dn1 = 5
      %%dn2 = 4
    else 
      %%dn1 = 4
      %%dn2 = 5
    end 
    GOSUB CheckDown
  end 
  :CheckBoardEnd 
  exit 

:CheckUp
  %z = @diff(%%startSQ, %%up1)
  GOSUB FormatZ
  PARSE ";%%tmp;;;%%piece", @dlgtext(S%z)
  if @equal(%%piece, "NO")
    LIST ADD, 8, S%%tmp|dud
    LIST ADD, 7, S%%tmp|S%%startSQ
  else 
    rem -- If opponent is there, check for possible jump --
    if @not(@equal(@substr(%%piece, 1), @substr(%%caller, 1)))
      if @both(@equal(%%dir, "L"), @greater(100, %%startSQx)) @both(@equal(%%dir, "R"), @greater(%%startSQx, 250))
        goto CheckUpEnd 
      end 
      if @greater(%%startSQ, 8)
        %z = @diff(%z, %%up2)
        GOSUB FormatZ
        PARSE ";%%tmp;;;%%piece", @dlgtext(S%z)
        if @equal(%%piece, "NO")
          rem -- List piece to be removed if this move is used --
          %z = @sum(%z, %%up2)
          GOSUB FormatZ
          LIST ADD, 8, S%%tmp|dud|JUMP|%z
          LIST ADD, 7, S%%tmp|S%%startSQ|JUMP|%z
        end 
      end 
    end 
  end 
  :CheckUpEnd 
  exit 

:CheckDown
  %z = @sum(%%startSQ, %%dn1)
  GOSUB FormatZ
  PARSE ";%%tmp;;;%%piece", @dlgtext(S%z)
  if @equal(%%piece, "NO")
    LIST ADD, 8, S%%tmp|dud
    LIST ADD, 7, S%%tmp|S%%startSQ
  else 
    rem -- If opponent is there, check for possible jump --
    if @not(@equal(@substr(%%piece, 1), @substr(%%caller, 1)))
      if @both(@equal(%%dir, "L"), @greater(100, %%startSQx)) @both(@equal(%%dir, "R"), @greater(%%startSQx, 250))
        goto CheckDownEnd 
      end 
      if @greater(25, %%startSQ)
        %z = @sum(%z, %%dn2)
        GOSUB FormatZ
        PARSE ";%%tmp;;;%%piece", @dlgtext(S%z)
        if @equal(%%piece, "NO")
          %z = @diff(%z, %%dn2)
          GOSUB FormatZ
          LIST ADD, 8, S%%tmp|dud|JUMP|%z
          LIST ADD, 7, S%%tmp|S%%startSQ|JUMP|%z
        end 
      end 
    end 
  end 
  :CheckDownEnd 
  exit 

:MovePiece
  rem -- Uses %%square, %%caller, %%startSQ, %%startSQx, %%startSQy --
  PARSE ";%%destSQ;%%destx;%%desty", @dlgtext(%%square)
  DIALOG REMOVE, S%%destSQ
  DIALOG REMOVE, S%%startSQ
  rem -- Replace destination square with appropriate checker or king --
  if @equal(%%caller, "RC")@equal(%%caller, "RK")
    DIALOG REMOVE, HL
    if @both(@equal(%%caller, "RC"), @greater(%%desty, 0))
      DIALOG ADD,TEXT,%%square,%%desty,%%destx,50,50," "@chr(227)" "|%%destSQ|%%destx|%%desty|RC,Red,CLICK
    else 
      DIALOG ADD,TEXT,%%square,%%desty,%%destx,50,50," "@chr(196)" "|%%destSQ|%%destx|%%desty|RK,Red,CLICK
    end 
    DIALOG ADD,TEXT,HL,%%desty,%%destx,50,50,@chr(188),TRANSPARENT,Style2,CLICK
  else 
    if @both(@equal(%%caller, BC), @greater(350, %%desty))
      DIALOG ADD,TEXT,%%square,%%desty,%%destx,50,50," "@chr(227)" "|%%destSQ|%%destx|%%desty|BC,Black,CLICK
    else 
      DIALOG ADD,TEXT,%%square,%%desty,%%destx,50,50," "@chr(196)" "|%%destSQ|%%destx|%%desty|BK,Black,CLICK
    end 
  end 
  if %%checker
    %%checker = %%square
    WAIT .1
  else 
    WAIT 
  end 
  rem -- Replace old checker with blank square --
  DIALOG ADD,TEXT,S%%startSQ,%%startSQy,%%startSQx,50,50,|%%startSQ|%%startSQx|%%startSQy|NO,Empty,CLICK
  PARSE ";%%startSQ;%%startSQx;%%startSQy;%%caller", @dlgtext(%%square)
  PARSE "%a;%b;%c;%d", @item(8)
  if %c
    %%remove = S%d
    GOSUB RemoveJumpedPiece
  end 
  exit 

:RemoveJumpedPiece
  PARSE ";%a;%b;%c;%d", @dlgtext(%%remove)
  DIALOG REMOVE, %%remove
  if @equal(%d, BC)@equal(%d, BK)
    %%compnum = @pred(%%compnum)
  else 
    %%playernum = @pred(%%playernum)
  end 
  rem -- Replace checker with blank square --
  DIALOG ADD,TEXT,%%remove,%c,%b,50,50,|%a|%b|%c|NO,Empty,CLICK
  rem -- Check for winner --
  if @equal(%%compnum, 0)
    INFO YOU WON!@cr()@cr()Starting New Game...@tab()
    DIALOG SELECT, 1
    DIALOG CLOSE
    goto Start/Restart
  end 
  if @equal(%%playernum, 0)
    INFO COMPUTER WON...@cr()@cr()Starting New Game...@tab()
    DIALOG SELECT, 1
    DIALOG CLOSE
    goto Start/Restart
  end 
  exit 

:FormatZ
  if @greater(10, %z)
    %z = 0%z
  end 
  exit