1 files changed, 98 insertions, 0 deletions
diff --git a/app/src/main/java/com/jopek/pai_fillo_nai/Bot.java b/app/src/main/java/com/jopek/pai_fillo_nai/Bot.java
new file mode 100644
index 0000000..4b04a55
--- /dev/null
+++ b/app/src/main/java/com/jopek/pai_fillo_nai/Bot.java
@@ -0,0 +1,98 @@
+package com.jopek.pai_fillo_nai;
+
+import java.util.Arrays;
+
+public class Bot {
+    static int meTheBot, opponent;
+    static int[] board;
+
+    static boolean isntBoardFull() {
+        for (int j : board)
+            if (j == -1)
+                return true;
+        return false;
+    }
+
+    static int goodOrBad() {
+        int[][] possibilities = new int[][]{
+                {0, 1, 2}, {3, 4, 5}, {6, 7, 8},
+                {0, 3, 6}, {1, 4, 7}, {2, 5, 8},
+                {0, 4, 8}, {2, 4, 6}
+        };
+        for (int[] poss : possibilities) {
+            if (chkTriEqOnGB(poss[0], poss[1], poss[2])) {
+                if (board[poss[0]] == meTheBot) return +10;
+                else return -10;
+            }
+        }
+
+        return 0;
+    }
+
+    static int minimax(int depth, Boolean isMax) {
+        int score = goodOrBad();
+
+        if (score == 10)
+            return score;
+
+        if (score == -10)
+            return score;
+
+        if (isntBoardFull() == false)
+            return 0;
+
+        int best;
+        if (isMax) {
+            best = -1000;
+
+            for (int i = 0; i < board.length; i++) {
+                if (board[i] == -1) {
+                    board[i] = meTheBot;
+                    best = Math.max(best, minimax(depth + 1, !isMax));
+                    board[i] = -1;
+                }
+            }
+        } else {
+            best = 1000;
+
+            for (int i = 0; i < board.length; i++) {
+                if (board[i] == -1) {
+                    board[i] = opponent;
+                    best = Math.min(best, minimax(depth + 1, !isMax));
+                    board[i] = -1;
+                }
+            }
+        }
+        return best;
+    }
+
+    static int getBestMove(int[] board, int bot, int opp) {
+        Bot.board = board;
+        Bot.meTheBot = bot;
+        Bot.opponent = opp;
+        int bestVal = -1000;
+        int bestMove = -1;
+
+        if(Arrays.stream(board).filter(c -> c == -1).count() == 9) return 4;
+
+        for (int i = 0; i < board.length; i++) {
+            if (board[i] == -1) {
+                board[i] = meTheBot;
+                int moveVal = minimax(0, false);
+                board[i] = -1;
+
+                if (moveVal > bestVal) {
+                    bestMove = i;
+                    bestVal = moveVal;
+                }
+            }
+        }
+
+        return bestMove;
+    }
+
+    // CheckTripleEqualityOnGameBoard
+    public static boolean chkTriEqOnGB(int a, int b, int c) {
+        return board[a] == board[b] && board[b] == board[c] && board[a] != -1;
+    }
+}