//**** Defines used to model the castling Moves. ****
(define "HasNeverMoved"
    (= (state at:(mapEntry #1 (mover))) 1) 
)

(define "PieceHasMoved"
    (set State at:#1 0) 
)

(define "RememberPieceHasMoved"
    (then 
        (if 
            (= (state at:(last To)) 1) 
            ("PieceHasMoved" (last To))
        ) 
    ) 
)

(define "KingNotCheckedAndToEmpty"
    (and 
        (is Empty (to)) 
        (not ("IsInCheck" "King" Mover at:(to)))
    ) 
)

(define "DecideToCastle"
    (move Slide 
        (from (mapEntry #1 (mover))) 
        #2 
        (between 
            (exact #3) 
            if:#4
        ) 
        (to 
            if:True
            (apply ("PieceHasMoved" (from)))
        )
        #5
    )
)

(define "CastleRook"
    (slide 
        (from (mapEntry #1 (mover))) 
        #2 
        (between 
            (exact #3) 
            if:#4
        ) 
        (to 
            if:True
            (apply ("PieceHasMoved" (from)))
        )
    )
)

(define "SmallCastling"
    ("DecideToCastle" "King" E 2 "KingNotCheckedAndToEmpty" (then ("CastleRook" "RookRight" W 2 True)))
)

(define "BigCastling"
    ("DecideToCastle" "King" W 2 "KingNotCheckedAndToEmpty" (then ("CastleRook" "RookLeft" E 3 True)))
)

//**** Defines used to model the extra Pawn moves. ****
(define "SetEnPassantLocation"
    (then 
        (set Pending (ahead (last To) Backward))
    )
)

(define "InLocationEnPassant"
    (and 
        (is Pending) 
        (= (to) (value Pending)) 
    )
)

(define "EnPassant"
    (move Step 
        (directions {FR FL}) 
        (to if:"InLocationEnPassant") 
        (then 
            (remove 
                (ahead (last To) Backward)
            )
        )
    )
)

(define "InitialPawnMove"
    (if (is In (from) (sites Start (piece (what at:(from)))))
        ("DoubleStepForwardToEmpty" "SetEnPassantLocation")
    )
)

//------------------------------------------------------------------------------

(game "Official Football Chess" 
    ("TwoPlayersNorthSouth") 
    (equipment { 
        (board (square 8)) 
        
        ("ChessPawn" "Pawn"
            (or 
                "InitialPawnMove"
                "EnPassant"
            )
            (then 
                (and
                    ("ReplayInMovingOn" (sites Mover "Promotion"))
                    (set Counter)
                )
            )
        )
        
        ("ChessRook" "Rook" (then (set Counter)) ("RememberPieceHasMoved"))
        ("ChessKing" "King" (then (set Counter)) ("RememberPieceHasMoved"))
        ("ChessBishop" "Bishop" (then (set Counter)))
        ("ChessKnight" "Knight" (then (set Counter)))
        ("ChessQueen" "Queen" (then (set Counter)))
        
        (map "King" {(pair 1 "D1") (pair 2 "D8")})
        (map "RookLeft" {(pair 1 "A1") (pair 2 "A8")})
        (map "RookRight" {(pair 1 "H1") (pair 2 "H8")})
        (regions "Promotion" P1 (sites Top))
        (regions "Promotion" P2 (sites Bottom))
    }) 
    (rules 
        (start { 
            (place "Pawn1" (sites {"B2" "C2" "E2" "F2"}))
            (place "Pawn2" (sites {"B7" "C7" "E7" "F7"}))
            (place "Rook1" {"A1" "H1"} state:1) (place "Knight1" {"D2"}) (place "Bishop1" {"A2" "H2"}) (place "Queen1" coord:"E1") (place "King1" coord:"D1" state:1) 
            (place "Rook2" {"A8" "H8"} state:1) (place "Knight2" {"D7"}) (place "Bishop2" {"A7" "H7"}) (place "Queen2" coord:"E8") (place "King2" coord:"D8" state:1) 
        })
        
        (play 
            (if "SameTurn"
                (move Promote (last To) (piece {"Queen" "Knight" "Bishop" "Rook"}) Mover)
                (do 
                    (or 
                        (forEach Piece)
                        (if (and 
                                ("HasNeverMoved" "King")
                                (not ("IsInCheck" "King" Mover)) 
                            )
                            (or
                                (if (and 
                                        ("HasNeverMoved" "RookLeft")
                                        (can Move ("CastleRook" "RookLeft" E 3 (is Empty (to))))
                                    )
                                    "BigCastling"
                                )
                                (if (and 
                                        ("HasNeverMoved" "RookRight")
                                        (can Move ("CastleRook" "RookRight" W 2 (is Empty (to))))
                                    )
                                    "SmallCastling"
                                )
                            )
                        )
                    )
                    ifAfterwards:(not ("IsInCheck" "King" Mover))
                )
            )
        )
        
        (end {
            ("Checkmate" "King")
            (if (or (no Moves Mover) (= (counter) 99)) (result Mover Draw)) 
        })
    )
)

//------------------------------------------------------------------------------

(metadata 
    
    (info
        {
        (description "In 1967, an US game company called Diversified Creations marketed a chess variant called Official Football Chess. ")
        (rules "Same rules as Chess, just a different setup.")
        (id "1792")
        (source "<a href=\"https://www.chessvariants.com/diffsetup.dir/officialfootball.html\" target=\"_blank\" class=\"style1\" style=\"color: #0000EE\" />www.chessvariants.com</a>")
        (version "1.3.12")
        (classification "board/war/replacement/checkmate/chess")
        (credit "Eric Piette")
        (date "1967")
        }
    )
    
    (graphics {
        (show Check "King")
        (piece Scale "Pawn" 0.825)
        (piece Families {"Defined" "Microsoft" "Pragmata" "Symbola"})
        (board Style Chess)
    })
    
    (ai
        "Official Football Chess_ai"
    )
)