(define "Metior"
    (intersection {
        (sites Distance
            from:(from)
            (exact (+ {
                1
                (count Sites in:(intersection {
                    (sites Direction from:(from) (union (directions #1) (directions #2)))
                    (sites Occupied by:Mover)
                }))
                (- (count Sites in:(intersection {
                    (sites Direction from:(from) (union (directions #1) (directions #2)))
                    (sites Occupied by:Next)
                })))
            }))
        )
        (sites Direction
            from:(from)
            (if (is Mover P1)
                (directions #1)
                (directions #2)
            )
        )
    })
)

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

(game "DIFFERO"
    (players 2)

    (equipment {
        (board (tri Hexagon 5) use:Vertex)
        (piece "Disc" Each)
        (regions P1 (sites Top))
        (regions P2 (sites Bottom))
    })

    (rules
        (start {
            (place "Disc1" { "B2" "B3" "B4" "C2" "C4" "D2" "D3" "D4" "E2" "E4" "F3" "F4" "G4" })
            (place "Disc2" { "C6" "D6" "D7" "E6" "E8" "F6" "F7" "F8" "G6" "G8" "H6" "H7" "H8" })
        })

        (play
            (forEach Piece
                (move
                    (from (from))
                    (to (intersection {
                        (union {
                            ("Metior" { Leftward Rightward } { Leftward Rightward })
                            ("Metior" { FL } { BL })
                            ("Metior" { FR } { BR })
                        })
                        (sites Empty)
                    }))
                )
            )
        )

        (end {
            (if (is In (last To) (sites Mover))
                (result Mover Win)
            )

            (if (no Moves Next)
                (result Next Loss)
            )
        })
    )
)

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

(metadata
    (info
        {
            (description "Differo was invented by Kashio Fujii in 2022. It is a two-player abstract strategy game played on a hexagonal board with five spaces per side.")
            (rules "
Goal
Be the first to move any one of your pieces to your goal line, the edge of the board opposite your starting side.

Movement
- On your turn, choose one of your pieces and move it along one of the hexagonal grid's line directions.
- The distance moved is exactly: (your pieces on that line) minus (your opponent's pieces on that line). 'The line' means the full straight line of sites running through the piece's position in the chosen direction.
- If this value is zero or less, the piece cannot move in that direction.
- Pieces may jump over any piece, friend or foe, while moving.
- Pieces cannot move backwards.
- A piece cannot land on a site already occupied by another piece.

Game End
- Reaching your goal line wins immediately.
- A player with no legal move on their turn loses.")
            (source "<a href=\"https://kashio-games.netlify.app/\" target=\"_blank\" class=\"style1\" style=\"color: #0000EE\" />kashio-games.netlify.app</a>")
            (version "1.0")
            (classification "board/race/reach")
            (author "Kashio Fujii")
            (credit "Kashio Fujii")
            (date "2026-05-22")
        }
    )

    (graphics {
        (player Colour P1 (colour White))
        (player Colour P2 (colour VeryDarkGrey))
        (piece Scale 1)
        (board Style Graph)
        (board Colour InnerVertices (colour Grey))
        (board Colour InnerEdges (colour Grey))
        (board Colour OuterVertices (colour Grey))
        (board Colour OuterEdges (colour Grey))
        (region Colour (sites P1) (colour White))
        (region Colour (sites P2) (colour VeryDarkGrey))
        (board Background fillColour:(colour LightGrey))
    })
)