DM3BA-Play Game

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*** DM3BA-Play Game ***
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Subordinate design modules:

======= DM4BAA-Logic
FUNCTION LegalMove% (Move AS STRING)
- Given a move such as e2-e4 this returns as follows:
0=Not possible 1=Illegal 2=Allowed

FUNCTION ExistsAValidMove% (c$)
- Given either "White" or "Black" this returns as follows:
-1 = There exists a legal move for that color
0 = There is no legal move

FUNCTION IsInCheck$ (c$)
- Given either "White" or "Black" this returns as follows:
--- = Not in check
N-- = In check by a knight"
-L- = In check on the long diagonal"
-S- = In check on the short diagonal"
--R = In check on the rank"
--F = In check on the file"
-LF = (example multiple checks)"


======= DM4BAB-Make Move
FUNCTION MakeMove%(c$)
- Given either "White" or "Black" this returns as follows:
1 = A move was made
2 = Will move later (wants to exit program)
3 = Game Over

Determine if player has a legal move. If not, determine whether Stalemate or Checkmate

Change any en-passent moves for the player to normal

Show board and prompt for move

Ensure move is valid via LegalMove function. If not, prompt again.

Give proper calls to WindowSub:
Illegal move
Legal Move
Not possible
Pawn gone
Piece gone
White (or Black) cannot move - stalemate!
White (or Black) is in check by a Knight
White (or Black) is in check on the long diagonal
White (or Black) is in check on the short diagonal
White (or Black) is in check on the rank
White (or Black) is in check on the file
White (or Black) loses - checkmate!
White (or Black) promotes
White (or Black) to move with possible pawn capture(s)
White (or Black) to move

Fix Board to show move taken.


======= DM4BAC-InputOutput
SUB SecureEncryptAndWrite (Game$, Key#, pb$, Pw$, Who%)
SUB SecureReadAndDecrypt (Game$, Key#, pb$, Pw$, Who%)
- Given Game$ such as "Don", read or write "Don.ksg"
- Encrypt or Decrypt using FUNCTIONs GetKey, ksgEncrypt, and ksgDecrypt
- Save and Restore shared arrays Board, WBoard and BBoard.
- Save and Restore Pb$ and Pw$ (Password checks for players)
- Save and Restore Who% (Whose turn)


======= DM4BAD-Main
DECLARE SUB RefereeSpeaks (Msg$)
- To be used to capture and replay referee calls.

MAIN
- Control the program according to Whose Turn.
0=Need PasswordB 1=NeedPassW
2=White's move 3=Black's move
4=Black needs to acknowledge game over
5=White needs to acknowledge game over
6=Game Over

On first call (new game)
Get Black's password, initialize Board and set Who%=1
On subsequent calls (old game)
Who%=1: Get White's password, set Who%=2
Who%=2: Verify White's password, let White move
Continue according to MakeMove result
1 = A move was made, set Who%=3
2 = Will move later (wants to exit program), leave with Who%=2
3 = Game Over, Set Who%=4
Who%=3: Verify Black's password, let Black move
Continue according to MakeMove result
1 = A move was made, set Who%=2
2 = Will move later (wants to exit program), leave with Who%=3
3 = Game Over, Set Who%=5
Who%=4: Verify Black's password, set Who%=6
Who%=5: Verify White's password, set Who%=6
Who%=6: Display Whole Board

Normal play:
Player's move. Continue according to MakeMove result
1 = A move was made, it is the other player's move
If the other player is remote,
hit return on password prompt to exit,transfer xxx.ksg
2 = Will move later (wants to exit program)
Start program again to continue
3 = Game Over
Transfer xxx.ksg to other player to acknowledge
When other player acknowledges, show board


======= DM4BAE-Passwords
Note: c$="White" or "Black"

FUNCTION Authorized% (c$, Pw#)
Given Pw$=password verifier, prompt user for password and compute
whether it is valid. Return 0 for no, -1 for yes.

FUNCTION GetInitialPassword# (c$)
Prompt user for password. Compute and return a password verifier.