New opening library strategy

src/main/java/com/fathzer/jchess/lichess/AbstractDefaultOpenings.java

@@ -0,0 +1,70 @@
+package com.fathzer.jchess.lichess;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Optional;
+import java.util.function.Supplier;
+import java.util.zip.GZIPInputStream;
+
+import org.json.JSONArray;
+import org.json.JSONObject;
+import org.json.JSONTokener;
+
+import com.fathzer.games.movelibrary.AbstractMoveLibrary;
+import com.fathzer.games.MoveGenerator;
+
+public abstract class AbstractDefaultOpenings<M, B extends MoveGenerator<M>> extends AbstractMoveLibrary<JSONObject, M, B> {
+	//TODO Commonalize with chesslib-uci-engine (probably in an external lichess related library
+	private final JSONObject db;
+
+	protected AbstractDefaultOpenings(Supplier<InputStream> stream, boolean zipped) throws IOException {
+		db = readJSON(stream, zipped);
+		this.setMoveSelector(weightedMoveSelector());
+	}
+
+	private JSONObject readJSON(Supplier<InputStream> stream, boolean zipped) throws IOException {
+		try (InputStream in = zipped ? new GZIPInputStream(stream.get()) : stream.get()) {
+			return new JSONObject(new JSONTokener(in));
+		}
+	}
+
+	private String toReducedXFen(B board) {
+		final String fen = toXFEN(board);
+		int index = fen.lastIndexOf(' ', fen.lastIndexOf(' ')-1);
+		return fen.substring(0, index);
+	}
+
+	@Override
+	protected Optional<List<JSONObject>> getRecord(B board) {
+		final String fen = toReducedXFen(board);
+		final JSONObject theRecord = db.optJSONObject(fen);
+		final JSONArray moves = theRecord==null ? null : theRecord.optJSONArray("moves");
+		if (moves==null) {
+			return Optional.empty();
+		}
+		final List<JSONObject> result = new LinkedList<>();
+		for (int i=0;i<moves.length();i++) {
+			result.add(moves.getJSONObject(i));
+		}
+		return Optional.of(result);
+	}
+
+	@Override
+	protected M toMove(B board, JSONObject move) {
+		return fromUCI(board, getCoord(move));
+	}
+
+	@Override
+	protected long getWeight(JSONObject move) {
+		return move.getLong("count");
+	}
+
+	protected String getCoord(JSONObject move) {
+		return move.getString("coord");
+	}
+
+	protected abstract String toXFEN(B board);
+	protected abstract M fromUCI(B board, String move);
+}

src/main/java/com/fathzer/jchess/lichess/DefaultOpenings.java

@@ -3,24 +3,16 @@
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.UncheckedIOException;
-import java.util.Random;
-import java.util.function.Function;
 import java.util.function.Supplier;
-import java.util.zip.GZIPInputStream;
-
-import org.json.JSONArray;
-import org.json.JSONObject;
-import org.json.JSONTokener;
 
 import com.fathzer.jchess.Board;
 import com.fathzer.jchess.Move;
 import com.fathzer.jchess.fen.FENUtils;
 import com.fathzer.jchess.uci.JChessUCIEngine;
 import com.fathzer.jchess.uci.UCIMove;
 
-public class DefaultOpenings implements Function<Board<Move>, Move> {
-	private static final Random RND = new Random(); 
-	private static final String KNOWN = "/lichess/masters-shrink-full.json.gz";
+public class DefaultOpenings extends AbstractDefaultOpenings<Move, Board<Move>> {
+	private static final String KNOWN = "/lichess/masters-shrink.json.gz";
 
 	public static final DefaultOpenings INSTANCE;
 
@@ -32,36 +24,21 @@ public class DefaultOpenings implements Function<Board<Move>, Move> {
 		}
 	}
 
-	private final JSONObject db;
-
 	private DefaultOpenings() throws IOException {
 		this(() -> DefaultOpenings.class.getResourceAsStream(KNOWN), true);
 	}
 
 	public DefaultOpenings(Supplier<InputStream> stream, boolean zipped) throws IOException {
-		db = readJSON(stream, zipped);
-	}
-
-	private JSONObject readJSON(Supplier<InputStream> stream, boolean zipped) throws IOException {
-		try (InputStream in = zipped ? new GZIPInputStream(stream.get()) : stream.get()) {
-			return new JSONObject(new JSONTokener(in));
-		}
+		super(stream, zipped);
 	}
 
-	private String toFen(Board<Move> board) {
-		String fen = FENUtils.to(board);
-		int index = fen.lastIndexOf(' ', fen.lastIndexOf(' ')-1);
-		return fen.substring(0, index);
+	@Override
+	protected Move fromUCI(Board<Move> board, String move) {
+		return JChessUCIEngine.toMove(board, UCIMove.from(move));
 	}
 
 	@Override
-	public Move apply(Board<Move> board) {
-		final String fen = toFen(board);
-		final JSONArray moves = db.optJSONArray(fen);
-		if (moves==null) {
-			return null;
-		}
-		final String move = moves.getString(RND.nextInt(moves.length()));
-		return JChessUCIEngine.toMove(board, UCIMove.from(move));
+	protected String toXFEN(Board<Move> board) {
+		return FENUtils.to(board);
 	}
 }