Adds ability to return depth, score & pv in info line before go reply

README.md

@@ -7,7 +7,7 @@
 A partial (but yet usable) java implementation of the [chess UCI protocol](https://www.shredderchess.com/chess-features/uci-universal-chess-interface.html) with pluggable chess engines.
 
 ## How to use it
-This library requires Java 11+ and is available in [Maven central](https://central.sonatype.com/artifact/com.fathzer/jchess-uci).
+This library requires Java 17+ and is available in [Maven central](https://central.sonatype.com/artifact/com.fathzer/jchess-uci).
 
 - First create a class that implements the **com.fathzer.jchess.uci.Engine** interface.  
 Let say this implementation class is **MyEngine**.
@@ -30,6 +30,7 @@ It does not directly support the following commands (but you can add them in an
 - **Dont miss the ShredderChess Annual Barbeque**: This command was in the original specification ... But was a joke.
 - **register**: As a promoter of open source free sofware, I will not encourage you to develop software that requires registration.
 - **ponderhit** is not yet implemented.
+- Only depth, score and pv are implemented in info lines preceeding go reply.
 
 It also does not recognize commands starting with unknown token (to be honest, it's not very hard to implement but seemed a very bad, error prone, idea to me).
 
@@ -90,4 +91,5 @@ If you do not use the *com.fathzer.jchess.uci.extended* and *com.fathzer.jchess.
 
 ## TODO
 * Verify the engine is protected against strange client behavior (like changing the position during a go request).
+* Implement support for multi-PV search.
 * Implement support for pondering.

pom.xml

@@ -9,7 +9,7 @@
 		<version>1.0.8</version>
 	</parent>
 	<artifactId>jchess-uci</artifactId>
-	<version>2.0.1-SNAPSHOT</version>
+	<version>2.0.2-SNAPSHOT</version>
 
 	<properties>
 		<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
@@ -22,7 +22,7 @@
 		<dependency>
 			<groupId>com.fathzer</groupId>
 			<artifactId>games-core</artifactId>
-			<version>0.0.9-SNAPSHOT</version>
+			<version>0.0.10-SNAPSHOT</version>
 		</dependency>
 		<dependency>
 			<groupId>org.junit.jupiter</groupId>

src/main/java/com/fathzer/jchess/uci/GoReply.java

@@ -112,6 +112,10 @@ public GoReply(UCIMove move, UCIMove ponderMove) {
 		this.ponderMove = ponderMove;
 	}
 
+	public void setInfo(Info info) {
+		this.info = info;
+	}
+
 	public Optional<UCIMove> getMove() {
 		return Optional.ofNullable(bestMove);
 	}
@@ -140,7 +144,25 @@ public Optional<String> getMainInfoString() {
 		if (info==null) {
 			return Optional.empty();
 		}
-		//TODO
-		return Optional.of("depth "+info.depth);
+		final StringBuilder builder = new StringBuilder();
+		if (info.depth>0) {
+			builder.append("depth ").append(info.depth);
+		}
+		final Optional<Score> score = info.scoreBuilder.apply(bestMove);
+		if (score.isPresent()) {
+			if (!builder.isEmpty()) {
+				builder.append(' ');
+			}
+			builder.append("score ").append(score.get().toUCI());
+		}
+		final Optional<List<UCIMove>> pv = info.pvBuilder.apply(bestMove);
+		if (pv.isPresent()) {
+			if (!builder.isEmpty()) {
+				builder.append(' ');
+			}
+			final String moves = String.join(" ", pv.get().stream().map(UCIMove::toString).toList());
+			builder.append("multipv 1 pv ").append(moves);
+		}
+		return builder.isEmpty() ? Optional.empty() : Optional.of("info "+builder);
 	}
 }

src/main/java/com/fathzer/jchess/uci/UCI.java

@@ -191,7 +191,12 @@ protected void doGo(Deque<String> tokens) {
 			final Optional<GoParameters> goOptions = parse(GoParameters::new, GoParameters.PARSER, tokens);
 			if (goOptions.isPresent()) {
 				final LongRunningTask<GoReply> task = engine.go(goOptions.get());
-				final boolean started = doBackground(() -> out(task.get().toString()), task::stop);
+				final boolean started = doBackground(() -> {
+					final GoReply goReply = task.get();
+					final Optional<String> mainInfo = goReply.getMainInfoString();
+					mainInfo.ifPresent(this::out);
+					out(goReply.toString());
+				}, task::stop);
 				if (!started) {
 					debug("Engine is already working");
 				}

src/main/java/com/fathzer/jchess/uci/helper/AbstractEngine.java

@@ -4,15 +4,24 @@
 import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
+import java.util.Optional;
 import java.util.function.Supplier;
 
 import com.fathzer.games.MoveGenerator;
 import com.fathzer.games.MoveGenerator.MoveConfidence;
+import com.fathzer.games.ai.evaluation.EvaluatedMove;
+import com.fathzer.games.ai.evaluation.Evaluation;
+import com.fathzer.games.ai.evaluation.Evaluation.Type;
 import com.fathzer.games.ai.evaluation.Evaluator;
 import com.fathzer.games.ai.iterativedeepening.IterativeDeepeningEngine;
+import com.fathzer.games.ai.iterativedeepening.IterativeDeepeningEngine.BestMove;
 import com.fathzer.games.ai.time.TimeManager;
 import com.fathzer.games.ai.transposition.TranspositionTable;
 import com.fathzer.jchess.uci.GoReply;
+import com.fathzer.jchess.uci.GoReply.CpScore;
+import com.fathzer.jchess.uci.GoReply.Info;
+import com.fathzer.jchess.uci.GoReply.MateScore;
+import com.fathzer.jchess.uci.GoReply.Score;
 import com.fathzer.jchess.uci.Engine;
 import com.fathzer.jchess.uci.LongRunningTask;
 import com.fathzer.jchess.uci.UCIMove;
@@ -120,9 +129,21 @@ public GoReply get() {
 				final UCIEngineSearchConfiguration<M, B> c = new UCIEngineSearchConfiguration<>(timeManager);
 				final UCIEngineSearchConfiguration.EngineConfiguration previous = c.configure(engine, options, board);
 				final List<M> candidates = options.getMoveToSearch().stream().map(AbstractEngine.this::toMove).toList();
-				final M move = engine.getBestMove(board, candidates.isEmpty() ? null : candidates);
+				final Optional<BestMove<M>> best = engine.getBestMove(board, candidates.isEmpty() ? null : candidates);
 				c.set(engine, previous);
-				return new GoReply(move==null ? null : toUCI(move));
+				if (best.isEmpty()) {
+					return new GoReply(null);
+				}
+				final EvaluatedMove<M> move = best.get().move();
+				final GoReply goReply = new GoReply(toUCI(move.getContent()));
+				final Info info = new Info(best.get().depth());
+				info.setScoreBuilder(m -> toScore(toMove(m), move));
+				info.setPvBuilder(m -> {
+					final List<UCIMove> list = engine.getTranspositionTable().collectPV(board, toMove(m), info.getDepth()).stream().map(x -> toUCI(x)).toList();
+					return list.isEmpty() ? Optional.empty() : Optional.of(list);
+				});
+				goReply.setInfo(info);
+				return goReply;
 			}
 
 			@Override
@@ -133,6 +154,25 @@ public void stop() {
 		};
 	}
 
+	private Optional<Score> toScore(M m, EvaluatedMove<M> known) {
+		final Evaluation evaluation = known.getEvaluation();
+		final Type type = evaluation.getType();
+		if (!m.equals(known.getContent()) || type==Type.UNKNOWN) {
+			return Optional.empty();
+		}
+		final Score score;
+		if (type==Type.EVAL) {
+			score = new CpScore(evaluation.getScore());
+		} else if (type==Type.WIN) {
+			score = new MateScore(evaluation.getCountToEnd());
+		} else if (type==Type.LOOSE) {
+			score = new MateScore(-evaluation.getCountToEnd());
+		} else {
+			throw new IllegalArgumentException("Type "+type+" is not supported");
+		}
+		return Optional.of(score); 
+	}
+
 	@SuppressWarnings("unchecked")
 	@Override
 	public B get() {