(define "AdjacentNotEmptySites"
    (sites Around 
        (to) 
        if:(not (is In (to) (sites Empty)))
    )
)

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

(game "Blue Nile" 
    (players 2) 
    (equipment { 
        (board (hex 5)) 
        (piece "Marker" Neutral) 
    }) 
    
    (rules 
        
        phases:{
        (phase "start" P1 
            (play (move Add (piece (id "Marker0")) (to (sites Empty)))) 
            (nextPhase "play")
        )
        
        (phase "play"  
            (play 
                (move Add 
                    (piece "Marker0") 
                    (to 
                        (sites Around 
                            (last To) 
                            if:(and 
                                (is Empty (to)) 
                                // not adjacent to any other piece except the last one placed.
                                ("NoSites" (difference ("AdjacentNotEmptySites") (last To)))
                            ) 
                        )
                    )
                )
            )
        )
        }
        
        (end ("NoMoves" Loss)) 
    )
)

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

(metadata 
    (info
        {
        (description "Invented by William Daniel Troyka in 2002, Blue Nile is a modern game played on a hexagonal board.")
        (rules "Played on a hexagonal board with five spaces per side. Players take turns placing stones on an empty space. The stone must be adjacent to the last stone played but cannot be adjacent to any other. The last player to be able to make a legal move wins.")
        (source "<a href=\"https://boardgamegeek.com/boardgame/33046/blue-nile\" target=\"_blank\" class=\"style1\" style=\"color: #0000EE\" />BGG</a>")
        (id "381")
        (version "1.3.12")
        (classification "board/space/blocking")
        (author "Dan Troyka")
        (credit "Eric Piette")
        (date "2002")
        }
    )
    
    (ai 
        "Blue Nile_ai"
    )
    
)