From 9144ec823ea141b50cbf0689bbab5401ff187c00 Mon Sep 17 00:00:00 2001
From: Joe Sweeney <joe@joesweeney.org>
Date: Sun, 2 Apr 2017 22:59:12 -0400
Subject: [PATCH] Change behaviors of captures and jump moves

I changed this because of [this](https://piazza.com/class/iy9nmh0fyvc2jx?cid=40) piazza post. Hopefully this is correct.
---
 src/CheckersGameState2.java | 30 ++++++++++-------
 src/Move2.java              | 65 ++++++++++++++++++++++++++++++++++---
 2 files changed, 78 insertions(+), 17 deletions(-)

diff --git a/src/CheckersGameState2.java b/src/CheckersGameState2.java
index 37bbf2b..8a7b57e 100644
--- a/src/CheckersGameState2.java
+++ b/src/CheckersGameState2.java
@@ -118,7 +118,7 @@ public class CheckersGameState2 implements CheckersGameState {
     return neighbors;
   }
 
-  private ArrayList<Move> findJumpMoves(int starting, int current, int[] path, int capture) {
+  private ArrayList<Move> findJumpMoves(int starting, int current, int[] path) {
     ArrayList<Move> moves = new ArrayList<Move>();
     int piece = board[starting];
     int[] neighbors = neighbors(current);
@@ -141,9 +141,12 @@ public class CheckersGameState2 implements CheckersGameState {
         if(next != -1 && board[next] == 0) {
           int [] newPath = Arrays.copyOf(path, path.length+1);
           newPath[path.length] = next;
-          int c = capture == -1 ? neighbors[i] : capture;
-          moves.add(new Move2(newPath, c));
-          moves.addAll(findJumpMoves(starting, next, newPath, c));
+          ArrayList<Move> jumpMoves = findJumpMoves(starting, next, newPath);
+          if(jumpMoves.size() == 0){
+            moves.add(new Move2(newPath));
+          } else {
+            moves.addAll(jumpMoves);
+          }
         }
       }
     }
@@ -155,7 +158,7 @@ public class CheckersGameState2 implements CheckersGameState {
     for(int i = 0; i<32; i++) {
       int piece = board[i];
       if(piece != 0 && correctColor(piece)) {
-        captures.addAll(findJumpMoves(i, i, new int[]{i}, -1));
+        captures.addAll(findJumpMoves(i, i, new int[]{i}));
       }
     }
     return captures;
@@ -170,26 +173,26 @@ public class CheckersGameState2 implements CheckersGameState {
         if(space == 1) {
           // black piece
           if(neighbors[0] != -1 && board[neighbors[0]] == 0) {
-            moves.add(new Move2(i, neighbors[0], -1));
+            moves.add(new Move2(i, neighbors[0]));
           }
           if(neighbors[1] != -1 && board[neighbors[1]] == 0) {
-            moves.add(new Move2(i, neighbors[1], -1));
+            moves.add(new Move2(i, neighbors[1]));
           }
         }
         else if(space == 2) {
           // white piece
           if(neighbors[2] != -1 && board[neighbors[2]] == 0) {
-            moves.add(new Move2(i, neighbors[2], -1));
+            moves.add(new Move2(i, neighbors[2]));
           }
           if(neighbors[3] != -1 && board[neighbors[3]] == 0) {
-            moves.add(new Move2(i, neighbors[3], -1));
+            moves.add(new Move2(i, neighbors[3]));
           }
         }
         else {
           // king
           for(int j = 0; j<4; j++) {
             if(neighbors[j] != -1 && board[neighbors[j]] == 0) {
-              moves.add(new Move2(i, neighbors[j], -1));
+              moves.add(new Move2(i, neighbors[j]));
             }
           }
         }
@@ -213,8 +216,11 @@ public class CheckersGameState2 implements CheckersGameState {
     Move2 move = (Move2) x;
     int[] newBoard = Arrays.copyOf(board, board.length);
     int newPlayer = otherPlayer();
-    if(move.captures != -1) {
-      newBoard[move.captures] = 0;
+    int[] captures = move.captures();
+    if(captures[0] != -1) {
+      for(int i = 0; i<captures.length; i++) {
+        newBoard[captures[i]] = 0;
+      }
     }
     newBoard[move.dest] = newBoard[move.src];
     newBoard[move.src] = 0;
diff --git a/src/Move2.java b/src/Move2.java
index 6dc689a..20e229e 100644
--- a/src/Move2.java
+++ b/src/Move2.java
@@ -4,17 +4,72 @@ public class Move2 implements Move {
   public int[] path;
   public int captures;
 
-  public Move2(int src, int dest, int capture) {
+  public Move2(int src, int dest) {
     this.src = src;
     this.dest = dest;
     path = new int[] {src, dest};
-    this.captures = capture;
   }
-  public Move2(int[] p, int capture) {
+  public Move2(int[] p) {
     src = p[0];
     dest = p[p.length - 1];
     path = p;
-    this.captures = capture;
+  }
+
+  private int[] neighbors(int index) {
+    int[] neighbors = new int[4];
+    int row = (index - index%4)/4;
+    int col = index%4;
+    if (row % 2 == 0) {
+      neighbors[0] = index + 4;
+      neighbors[1] = index + 5;
+      neighbors[2] = index - 4;
+      neighbors[3] = index - 3;
+
+      if(col == 3) {
+        neighbors[1] = -1;
+        neighbors[3] = -1;
+      }
+    }
+    else {
+      neighbors[0] = index + 3;
+      neighbors[1] = index + 4;
+      neighbors[2] = index - 5;
+      neighbors[3] = index - 4;
+
+      if(col == 0) {
+        neighbors[0] = -1;
+        neighbors[2] = -1;
+      }
+    }
+
+    for(int i = 0; i<4; i++) {
+      if(neighbors[i] < 0 || neighbors[i] >=32) {
+        neighbors[i] = -1;
+      }
+    }
+
+    return neighbors;
+  }
+
+  public int[] captures() {
+    int[] captures = new int[path.length-1];
+    for(int i = 0; i<path.length-1; i++) {
+      int[] neighbors = neighbors(path[i]);
+      boolean direct = false;
+      for(int j = 0; j<4; j++) {
+        if(neighbors[j] == path[i+1]){
+          direct = true;
+          break;
+        }
+        else if(neighbors[j] != -1 && neighbors(neighbors[j])[j] == path[i+1]) {
+          captures[i] = neighbors[j];
+        }
+      }
+      if(direct){
+        captures[i] = -1;
+      }
+    }
+    return captures;
   }
 
   private String convert(int position) {
@@ -31,7 +86,7 @@ public class Move2 implements Move {
   public String toString() {
     String output = "";
     for(int i = 0; i<path.length; i++) {
-      if(i!=0){output += ":";}
+      output += i!=0 ? ":" : "";
       output += convert(path[i]);
     }
     return output;