feat: Pos gets to see neighbours

Author: vincentfrochot

src/main/scala/Move.scala

@@ -359,7 +359,7 @@ object Move {
         Situation.Abalone(m.situationBefore),
         Board.Abalone(m.after),
         m.autoEndTurn,
-        None, // capture. @TODO: Could be the pos of the piece that was on targetSquare described by the move (because line moves are basically just marbles jumping over other ones)
+        None, // capture. @TODO: Could be the pos of the piece that was on targetSquare described by the move (because line moves (and by extension, pushes) are basically just marbles jumping over other ones)
         None,
         None,
         None,

src/main/scala/abalone/Pos.scala

@@ -194,6 +194,8 @@ case class Pos private (index: Int) extends AnyVal {
   @inline def file = File of this // column (as if it was an index in a 1D array)
   @inline def rank = Rank of this // horizontal row, makes sense in a 2D array
 
+  def neighbours: List[Option[Pos]] = List(left, downLeft, upLeft, right, downRight, upRight)
+
   // these 3 below might be handy
   // def touches(other: Pos): Boolean = xDist(other) <= 1 && yDist(other) <= 1
   // def xDist(other: Pos) = abs(file - other.file)

src/main/scala/abalone/variant/Variant.scala

@@ -98,8 +98,8 @@ abstract class Variant private[variant] (
     situation.board.piecesOf(situation.player).flatMap {
       case ((pos, piece)) =>
         Map(pos ->
-          Stone.dirs.flatMap { _(pos) } // if the piece would remain on the board after applying a direction...
-          .filterNot(situation.board.pieces.contains(_)) // ...keep it only if the landing square is free of marble
+          pos.neighbours.flatten // for each direction that would remain on the board...
+          .filterNot(situation.board.pieces.contains(_)) // ...keep the piece only if the landing square is empty
           .map(landingSquare => 
             Move(piece, pos, landingSquare, situation, boardAfter(situation, pos, landingSquare), false)
           )
@@ -123,10 +123,17 @@ abstract class Variant private[variant] (
     //   case ((pos, piece)) => {
     //     Map(pos -> List({
     //       Stone.dirs.flatMap { // if the piece would remain on the board after applying a direction...
-    //         case dir => dir(pos)
+    //         case dir => (dir, dir(pos))
+    //         case _ => None
     //       }.flatMap { // ...check that it would move to square occupied by one of our pieces
-    //         case (landingSquare) if (situation.board.pieces.contains(landingSquare) && situation.board.pieces(landingSquare).player == situation.player) => 
-    //             Some(Move(piece, pos, landingSquare, situation, boardAfter(situation, pos, landingSquare), false))
+    //         case ((dir: Direction, landingSquare: Option[Pos]))
+    //           if (situation.board.pieces.contains(landingSquare) && situation.board.pieces(landingSquare).player == situation.player) => 
+    //             // let's check if the next square is occupied by us too, or empty :
+    //             if(dir(landingSquare))
+    //               Some(Move(piece, pos, landingSquare, situation, boardAfter(situation, pos, landingSquare), false))
+    //             else
+    //               None
+            
     //         case _ => None
     //       }
     //     }).flatten)

src/test/scala/abalone/AbaloneFenTest.scala

@@ -105,7 +105,7 @@ class AbaloneFenTest extends AbaloneTest with ValidatedMatchers {
             pieces.filter(p => p._2.player == P2).size must_== 14
         }
 
-        "has an even number of valid moves, as the position is symetrical" in {
+        "has an even number of valid moves, as the position is symmetrical" in {
             board.variant.validMoves(situation).foldLeft(0)(_ + _._2.size) % 2 must_== 0
         }
     }