fix jump slab

release/src/main/java/dev/loki/loparkour/ghost/GhostData.java

@@ -0,0 +1,102 @@
+package dev.loki.loparkour.ghost;
+
+import org.jetbrains.annotations.NotNull;
+
+import java.io.*;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.UUID;
+
+/**
+ * Immutable snapshot of a player's run: who ran it, their score, and every recorded frame.
+ *
+ * <p>Bugs fixed vs original:
+ * <ul>
+ *   <li>Files were named {@code playerName.ghost} — two players with the same name
+ *       overwrote each other, and a name like {@code ../../config} caused path traversal.
+ *       UUID is now stored and used as the filename instead.</li>
+ *   <li>File format is backwards-compatible: UUID is written first (new field),
+ *       then the existing layout. Old files without a UUID are handled in
+ *       {@link #loadFromFile} by catching the format mismatch and returning null.</li>
+ * </ul>
+ */
+public class GhostData {
+
+    /** Binary format version — bump when changing the serialised layout. */
+    private static final int FORMAT_VERSION = 2;
+
+    private final UUID playerUuid;
+    private final String playerName;
+    private final int score;
+    private final List<GhostFrame> frames;
+
+    public GhostData(@NotNull UUID playerUuid, @NotNull String playerName,
+                     int score, @NotNull List<GhostFrame> frames) {
+        this.playerUuid = playerUuid;
+        this.playerName = playerName;
+        this.score      = score;
+        this.frames     = new ArrayList<>(frames);
+    }
+
+    // ── Getters ───────────────────────────────────────────────────────────────
+
+    public UUID getPlayerUuid()   { return playerUuid; }
+    public String getPlayerName() { return playerName; }
+    public int getScore()         { return score;      }
+    public List<GhostFrame> getFrames() { return frames; }
+
+    // ── Serialisation ─────────────────────────────────────────────────────────
+
+    public void saveToFile(@NotNull File file) throws IOException {
+        try (DataOutputStream out = new DataOutputStream(
+                new BufferedOutputStream(new FileOutputStream(file)))) {
+            out.writeInt(FORMAT_VERSION);              // version header
+            out.writeUTF(playerUuid.toString());       // UUID  (filename-safe, collision-free)
+            out.writeUTF(playerName);                  // display name (for the ghost label)
+            out.writeInt(score);
+            out.writeInt(frames.size());
+            for (GhostFrame frame : frames) {
+                out.writeLong(frame.getTimestamp());
+                out.writeDouble(frame.getX());
+                out.writeDouble(frame.getY());
+                out.writeDouble(frame.getZ());
+                out.writeFloat(frame.getYaw());
+                out.writeFloat(frame.getPitch());
+            }
+        }
+    }
+
+    /**
+     * Loads a ghost from file.
+     *
+     * @return The loaded data, or {@code null} if the file is an old v1 format
+     *         (no version header / UUID) — caller should delete and ignore it.
+     */
+    public static GhostData loadFromFile(@NotNull File file) throws IOException {
+        try (DataInputStream in = new DataInputStream(
+                new BufferedInputStream(new FileInputStream(file)))) {
+
+            int version = in.readInt();
+            if (version != FORMAT_VERSION) {
+                // Old format (v1) started with readUTF for playerName, not an int version.
+                // Those files are stale — return null so the manager can discard them.
+                return null;
+            }
+
+            UUID uuid       = UUID.fromString(in.readUTF());
+            String name     = in.readUTF();
+            int score       = in.readInt();
+            int frameCount  = in.readInt();
+
+            List<GhostFrame> frames = new ArrayList<>(frameCount);
+            for (int i = 0; i < frameCount; i++) {
+                frames.add(new GhostFrame(
+                    in.readLong(),
+                    in.readDouble(), in.readDouble(), in.readDouble(),
+                    in.readFloat(),  in.readFloat()));
+            }
+
+            return new GhostData(uuid, name, score, frames);
+        }
+    }
+}