feat: Add item overlay index

Author: lineargraph

src/main/java/io/github/moulberry/repo/data/ItemOverlays.java

@@ -0,0 +1,69 @@
+package io.github.moulberry.repo.data;
+
+import io.github.moulberry.repo.IReloadable;
+import io.github.moulberry.repo.NEURepoFile;
+import io.github.moulberry.repo.NEURepository;
+import io.github.moulberry.repo.NEURepositoryException;
+import io.github.moulberry.repo.util.NEUId;
+import lombok.Cleanup;
+import lombok.Getter;
+import lombok.Value;
+
+import java.util.List;
+import java.util.Map;
+import java.util.Objects;
+import java.util.function.Function;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
+import java.util.stream.Collectors;
+import java.util.stream.Stream;
+
+@Getter
+public class ItemOverlays implements IReloadable {
+
+    List<ItemOverlayFile> overlays;
+
+    public static ItemOverlays forRepo(NEURepository repository) {
+        ItemOverlays overlays = new ItemOverlays();
+        repository.registerReloadListener(overlays);
+        return overlays;
+    }
+
+    @Override
+    public void reload(NEURepository repository) throws NEURepositoryException {
+        @Cleanup Stream<NEURepoFile> files = repository.tree("itemsOverlay");
+        overlays = files
+                .filter(NEURepoFile::isFile)
+                .map(file -> {
+                    Matcher matcher = PATH_PATTERN.matcher(file.getPath());
+                    if (matcher.matches()) {
+                        int version = Integer.parseInt(matcher.group(1));
+                        String name = matcher.group(2);
+                        return new ItemOverlayFile(file, version, name);
+                    }
+                    return null;
+                })
+                .filter(Objects::nonNull)
+                .collect(Collectors.toList());
+    }
+
+    /**
+     * @param version the highest supported version
+     * @return a map of item ids to their most up-to-date overlay file that is still readable.
+     */
+    public Map<@NEUId String, ItemOverlayFile> getMostUpToDateCompatibleWith(int version) {
+        return overlays.stream()
+                .filter(it -> it.version <= version)
+                .collect(Collectors.toMap(ItemOverlayFile::getItemId, Function.identity(), (a, b) -> a.version > b.version ? a : b));
+    }
+
+    @Value
+    public static class ItemOverlayFile {
+        NEURepoFile file;
+        int version;
+        @NEUId
+        String itemId;
+    }
+
+    private static final Pattern PATH_PATTERN = Pattern.compile("itemsOverlay/([0-9]+)/(.+)\\.snbt");
+}

src/test/java/io/github/moulberry/repo/NEURepoParserTest.java

@@ -12,6 +12,7 @@
 public class NEURepoParserTest {
     private static final NEURepository repository = NEURepository.of(Paths.get("NotEnoughUpdates-REPO"));
     private static final NEURecipeCache recipes = NEURecipeCache.forRepo(repository);
+    private static final ItemOverlays overlay = ItemOverlays.forRepo(repository);
 
     @BeforeAll
     static void beforeAll() throws NEURepositoryException {
@@ -21,6 +22,13 @@ static void beforeAll() throws NEURepositoryException {
         repository.reload();
     }
 
+    @Test
+    void testOverlayFiles() {
+        Assertions.assertTrue(overlay.getMostUpToDateCompatibleWith(4324).isEmpty());
+        Assertions.assertEquals(4325, overlay.getMostUpToDateCompatibleWith(4326).get("BAMBOO").getVersion());
+        Assertions.assertEquals("BAMBOO", overlay.getMostUpToDateCompatibleWith(4325).get("BAMBOO").getItemId());
+    }
+
     @Test
     void testBazaarStocks() {
         Assertions.assertEquals("SHARD_SALMON", repository.getConstants().getBazaarStocks().getBazaarStockOrDefault("ATTRIBUTE_SHARD_LOST_AND_FOUND;1"));