Better stockfish integration

build.sh

@@ -1,3 +1,3 @@
 #!/bin/bash
-mkdir ./bin
-javac -cp ./src -encoding UTF-8 -d ./bin src/*.java
+mkdir -p ./bin
+javac -cp ./lib/org.jfree.svg-5.0.5.jar:./src -encoding UTF-8 -d ./bin src/*.java

run.sh

@@ -1,2 +1,2 @@
 #!/bin/bash
-java -cp ./bin Chess $@
+java -cp ./lib/org.jfree.svg-5.0.5.jar:./bin Chess $@

src/Chess.java

@@ -85,13 +85,20 @@ public class Chess {
 
         JMenuItem toggleAutomaticRandomOpponent = new JMenuItem("Toggle automatic random opponent");
         toggleAutomaticRandomOpponent.addActionListener(l -> {
-            chessboard.getOtherPlayer().toggleAutomaticRandom();
+            Player opponent = chessboard.getOtherPlayer();
+            opponent.toggleAutomaticRandom(!opponent.isAutomaticRandom());
         });
         menuCPU.add(toggleAutomaticRandomOpponent);
 
         JMenuItem toggleAutomaticSmartOpponent = new JMenuItem("Toggle automatic smart opponent");
         toggleAutomaticSmartOpponent.addActionListener(l -> {
-            chessboard.getOtherPlayer().toggleAutomaticSmart();
+            Player opponent = chessboard.getOtherPlayer();
+            if(!opponent.isAutomaticSmart()) {
+                Stockfish stockfish = opponent.getStockfish();
+                opponent.toggleAutomaticSmart(stockfish);
+            } else {
+                opponent.toggleAutomaticSmart(null);
+            }
         });
         menuCPU.add(toggleAutomaticSmartOpponent);
 

src/Player.java

@@ -1,3 +1,5 @@
+import javax.swing.*;
+import java.io.IOException;
 import java.util.ArrayList;
 import java.util.Random;
 import java.util.Timer;
@@ -72,10 +74,8 @@ public class Player {
     }
 
     public boolean smartMove() {
-        if(stockfish == null) {
-            stockfish = new Stockfish();
-            stockfish.startEngine();
-        }
+        stockfish = getStockfish();
+        if(stockfish == null) return false;
         String fen = chessboard.toFEN();
         String bestMove = stockfish.getBestMove(fen, 0, 500);
         PiecePosition fromPos = PiecePosition.fromString(bestMove.substring(0, 2));
@@ -84,9 +84,28 @@ public class Player {
         APiece piece = chessboard.getPiece(fromPos.x, fromPos.y);
         piece.move(toPos);
         chessboard.changeActivePlayer();
+        stockfish.stopEngine();
+        stockfish = null;
         return true;
     }
 
+    public Stockfish getStockfish() {
+        if(stockfish == null) {
+            String binary = Stockfish.findBinary();
+            if(binary == null) {
+                JOptionPane.showMessageDialog(chessboard, "Stockfish engine not found! (stockfishchess.org)\nDownload 'stockfish' or 'stockfish.exe' to the program's folder or the system's path.");
+                return null;
+            }
+            try {
+                stockfish = new Stockfish(binary);
+            } catch (IOException e) {
+                JOptionPane.showMessageDialog(chessboard, "Unable to start Stockfish engine!");
+                e.printStackTrace();
+            }
+        }
+        return stockfish;
+    }
+
     public Chessboard getChessboard() {
         return chessboard;
     }
@@ -119,12 +138,26 @@ public class Player {
         return myPieces;
     }
 
-    public void toggleAutomaticRandom() {
-        automaticRandom = !automaticRandom;
+    public void toggleAutomaticRandom(boolean state) {
+        if(state) automaticSmart = false;
+        automaticRandom = state;
     }
 
-    public void toggleAutomaticSmart() {
-        automaticSmart = !automaticSmart;
+    public boolean isAutomaticRandom() {
+        return automaticRandom;
+    }
+
+    public void toggleAutomaticSmart(Stockfish stockfish) {
+        boolean state = stockfish != null;
+        if(state) {
+            this.stockfish = stockfish;
+            automaticRandom = false;
+        }
+        automaticSmart = state;
+    }
+
+    public boolean isAutomaticSmart() {
+        return automaticSmart;
     }
 
 }

src/Stockfish.java

@@ -1,38 +1,38 @@
-import java.io.BufferedReader;
-import java.io.IOException;
-import java.io.InputStreamReader;
-import java.io.OutputStreamWriter;
+import java.io.*;
+import java.nio.file.Paths;
+import java.util.ArrayList;
 
 public class Stockfish {
 
-    private Process engineProcess;
-    private BufferedReader processReader;
-    private OutputStreamWriter processWriter;
+    private Process process;
+    private BufferedReader reader;
+    private OutputStreamWriter writer;
 
-    private static final String PATH = "./stockfish";
-
-    /**
-     * Starts Stockfish engine as a process and initializes it
-     *
-     * @return True on success. False otherwise
-     */
-    public boolean startEngine() {
-        try {
-            engineProcess = Runtime.getRuntime().exec(PATH);
-            processReader = new BufferedReader(new InputStreamReader(
-                    engineProcess.getInputStream()));
-            processWriter = new OutputStreamWriter(
-                    engineProcess.getOutputStream());
-        } catch (Exception e) {
-            return false;
+    public static String findBinary() {
+        ArrayList<String> paths = new ArrayList<>();
+        paths.add(".");
+        for (String path : System.getenv("PATH").split(":")) {
+            paths.add(path);
         }
-        return true;
+        for (String path : paths) {
+            for (String binary : new String[]{"stockfish", "stockfish.exe"}) {
+                String file = Paths.get(path, binary).toString();
+                if(new File(file).exists()) return file;
+            }
+        }
+        return null;
+    }
+
+    public Stockfish(String binary) throws IOException {
+        process = Runtime.getRuntime().exec(binary);
+        reader = new BufferedReader(new InputStreamReader(process.getInputStream()));
+        writer = new OutputStreamWriter(process.getOutputStream());
     }
 
     public void sendCommand(String command) {
         try {
-            processWriter.write(command + "\n");
-            processWriter.flush();
+            writer.write(command + "\n");
+            writer.flush();
         } catch (IOException e) {
             e.printStackTrace();
         }
@@ -44,7 +44,7 @@ public class Stockfish {
             Thread.sleep(waitTime);
             sendCommand("isready");
             while (true) {
-                String text = processReader.readLine();
+                String text = reader.readLine();
                 if (text.equals("readyok"))
                     break;
                 else
@@ -57,8 +57,8 @@ public class Stockfish {
     }
 
     public String getBestMove(String fen, int skill, int waitTime) {
-        sendCommand("position fen " + fen);
         sendCommand("setoption name Skill Level value " + skill);
+        sendCommand("position fen " + fen);
         sendCommand("go movetime " + waitTime);
         String[] parts = getOutput(waitTime+150).split("bestmove ");
         while(parts.length != 2) {
@@ -70,10 +70,9 @@ public class Stockfish {
     public void stopEngine() {
         try {
             sendCommand("quit");
-            processReader.close();
-            processWriter.close();
-        } catch (IOException e) {
-        }
+            reader.close();
+            writer.close();
+        } catch (IOException e) {}
     }
 
 }