modrinth: support datapack retrieval

src/main/java/me/itzg/helpers/modrinth/Loader.java

@@ -14,7 +14,8 @@ public enum Loader {
     pufferfish("plugins", paper),
     purpur("plugins", paper),
     bungeecord("plugins", null),
-    velocity("plugins", null);
+    velocity("plugins", null),
+    datapack(null, null);
 
     private final String type;
     private final Loader compatibleWith;

src/main/java/me/itzg/helpers/modrinth/ModrinthApiClient.java

@@ -125,8 +125,11 @@ public Mono<List<ResolvedProject>> bulkGetProjects(Stream<ProjectRef> projectRef
     public Mono<Version> resolveProjectVersion(Project project, ProjectRef projectRef,
                                                @Nullable Loader loader, String gameVersion,
                                                VersionType defaultVersionType) {
+
+        final Loader loaderToQuery = projectRef.isDatapack() ? Loader.datapack : loader;
+
         if (projectRef.hasVersionName()) {
-            return getVersionsForProject(project.getId(), loader, gameVersion)
+            return getVersionsForProject(project.getId(), loaderToQuery, gameVersion)
                 .flatMap(versions ->
                     Mono.justOrEmpty(versions.stream()
                         .filter(version ->
@@ -137,12 +140,12 @@ public Mono<Version> resolveProjectVersion(Project project, ProjectRef projectRe
                     ));
         }
         if (projectRef.hasVersionType()) {
-            return getVersionsForProject(project.getId(), loader, gameVersion)
+            return getVersionsForProject(project.getId(), loaderToQuery, gameVersion)
                 .mapNotNull(versions -> pickVersion(project, versions, projectRef.getVersionType()));
         } else if (projectRef.hasVersionId()) {
             return getVersionFromId(projectRef.getVersionId());
         } else {
-            return getVersionsForProject(project.getId(), loader, gameVersion)
+            return getVersionsForProject(project.getId(), loaderToQuery, gameVersion)
                     .mapNotNull(versions -> pickVersion(project, versions, defaultVersionType));
         }
     }
@@ -190,7 +193,7 @@ public Mono<List<Version>> getVersionsForProject(String projectIdOrSlug,
                 );
     }
 
-    private List<String> expandCompatibleLoaders(Loader loader) {
+    private List<String> expandCompatibleLoaders(@Nullable Loader loader) {
         if (loader == null) {
             return null;
         }

src/main/java/me/itzg/helpers/modrinth/ModrinthCommand.java

@@ -26,6 +26,7 @@
 import me.itzg.helpers.http.Fetch;
 import me.itzg.helpers.http.SharedFetchArgs;
 import me.itzg.helpers.json.ObjectMappers;
+import me.itzg.helpers.modrinth.model.Constants;
 import me.itzg.helpers.modrinth.model.DependencyType;
 import me.itzg.helpers.modrinth.model.Project;
 import me.itzg.helpers.modrinth.model.ProjectType;
@@ -42,6 +43,7 @@
 @Slf4j
 public class ModrinthCommand implements Callable<Integer> {
 
+    public static final String DATAPACKS_SUBDIR = "datapacks";
     @Option(names = "--projects", description = "Project ID or Slug",
         split = SPLIT_COMMA_NL, splitSynopsisLabel = SPLIT_SYNOPSIS_COMMA_NL,
         paramLabel = "id|slug"
@@ -78,6 +80,11 @@ public enum DownloadDependencies {
     )
     String baseUrl;
 
+    @Option(names = "--world-directory", defaultValue = "${env:LEVEL:-world}",
+        description = "Used for datapacks, a path relative to the output directory or an absolute path\nDefault: ${DEFAULT-VALUE}"
+    )
+    Path worldDirectory;
+
     @ArgGroup(exclusive = false)
     SharedFetchArgs sharedFetchArgs = new SharedFetchArgs();
 
@@ -115,7 +122,9 @@ private List<Path> processProjects(List<String> projects) {
                 .defaultIfEmpty(Collections.emptyList())
                 .block()
                 .stream()
-                .flatMap(resolvedProject -> processProject(modrinthApiClient, resolvedProject.getProjectRef(), resolvedProject.getProject()))
+                .flatMap(resolvedProject -> processProject(
+                    modrinthApiClient, resolvedProject.getProjectRef(), resolvedProject.getProject()
+                ))
                 .collect(Collectors.toList());
         }
     }
@@ -201,14 +210,31 @@ private Version pickVersion(List<Version> versions, VersionType versionType) {
         return null;
     }
 
-    private Path download(ProjectType projectType, VersionFile versionFile) {
-        if (projectType != ProjectType.mod) {
-            throw new InvalidParameterException("Only mod project types can be downloaded for now");
-        }
+    private Path download(boolean isDatapack, VersionFile versionFile) {
         final Path outPath;
         try {
-            outPath = Files.createDirectories(outputDirectory.resolve(loader.getType()))
-                .resolve(versionFile.getFilename());
+            if (!isDatapack) {
+                outPath = Files.createDirectories(outputDirectory
+                        .resolve(loader.getType())
+                    )
+                    .resolve(versionFile.getFilename());
+            }
+            else {
+                if (worldDirectory.isAbsolute()) {
+                    outPath = Files.createDirectories(worldDirectory
+                            .resolve(DATAPACKS_SUBDIR)
+                        )
+                        .resolve(versionFile.getFilename());
+                }
+                else {
+                    outPath = Files.createDirectories(outputDirectory
+                            .resolve(worldDirectory)
+                            .resolve(DATAPACKS_SUBDIR)
+                        )
+                        .resolve(versionFile.getFilename());
+                }
+            }
+
         } catch (IOException e) {
             throw new RuntimeException("Creating mods directory", e);
         }
@@ -238,7 +264,14 @@ private List<Version> getVersionsForProject(ModrinthApiClient modrinthApiClient,
 
 
     private Stream<Path> processProject(ModrinthApiClient modrinthApiClient, ProjectRef projectRef, Project project) {
-        log.debug("Starting with projectRef={}", projectRef);
+        if (project.getProjectType() != ProjectType.mod) {
+            throw new InvalidParameterException(
+                String.format("Requested project '%s' is not a mod, but has type %s",
+                    project.getTitle(), project.getProjectType()
+                ));
+        }
+
+        log.debug("Starting with project='{}' slug={}", project.getTitle(), project.getSlug());
 
         if (projectsProcessed.add(project.getId())) {
             final Version version;
@@ -256,13 +289,15 @@ private Stream<Path> processProject(ModrinthApiClient modrinthApiClient, Project
                     throw new GenericException(String.format("Project %s has no files declared", project.getSlug()));
                 }
 
+                final boolean isDatapack = isDatapack(version);
+
                 return Stream.concat(
                         Stream.of(version),
                         expandDependencies(modrinthApiClient, version)
                     )
                     .map(ModrinthApiClient::pickVersionFile)
-                    .map(versionFile -> download(project.getProjectType(), versionFile))
-                    .flatMap(this::expandIfZip);
+                    .map(versionFile -> download(isDatapack, versionFile))
+                    .flatMap(downloadedFile -> !isDatapack ? expandIfZip(downloadedFile) : Stream.empty());
             }
             else {
                 throw new InvalidParameterException(
@@ -274,6 +309,13 @@ private Stream<Path> processProject(ModrinthApiClient modrinthApiClient, Project
         return Stream.empty();
     }
 
+    private boolean isDatapack(Version version) {
+        return
+            version.getLoaders() != null
+            && version.getLoaders().size() == 1
+            && version.getLoaders().get(0).equals(Constants.LOADER_DATAPACK);
+    }
+
     /**
      * If downloadedFile ends in .zip, then expand it, return its files and given file.
      *

src/main/java/me/itzg/helpers/modrinth/ProjectRef.java

@@ -13,29 +13,38 @@
 import lombok.ToString;
 import me.itzg.helpers.errors.InvalidParameterException;
 import me.itzg.helpers.modrinth.model.VersionType;
+import org.jetbrains.annotations.Nullable;
 
 @Getter
 @ToString
 public class ProjectRef {
     private static final Pattern VERSIONS = Pattern.compile("[a-zA-Z0-9]{8}");
-    private final static Pattern MODPACK_PAGE_URL = Pattern.compile(
+    private static final Pattern MODPACK_PAGE_URL = Pattern.compile(
         "https://modrinth.com/modpack/(?<slug>.+?)(/version/(?<versionName>.+))?"
     );
+    private static final Pattern PROJECT_REF = Pattern.compile("(?<datapack>datapack:)?(?<idSlug>[^:]+?)(:(?<version>[^:]+))?");
+
+    private final String idOrSlug;
+    private final boolean datapack;
 
-    final String idOrSlug;
     /**
      * Either a remote URI or a file URI for a locally provided file
      */
-    final URI projectUri;
-    final VersionType versionType;
-    final String versionId;
-    final String versionName;
+    private final URI projectUri;
+    private final VersionType versionType;
+    private final String versionId;
+    private final String versionName;
 
     public static ProjectRef parse(String projectRef) {
-        final String[] projectRefParts = projectRef.split(":", 2);
+        final Matcher m = PROJECT_REF.matcher(projectRef);
+        if (!m.matches()) {
+            throw new InvalidParameterException("Invalid project reference: " + projectRef);
+        }
 
-        return new ProjectRef(projectRefParts[0],
-            projectRefParts.length > 1 ? projectRefParts[1] : null
+        return new ProjectRef(
+            m.group("idSlug"),
+            m.group("version"),
+            m.group("datapack") != null
         );
     }
 
@@ -44,7 +53,15 @@ public static ProjectRef parse(String projectRef) {
      * @param version can be a {@link VersionType}, ID, or name/number
      */
     public ProjectRef(String projectSlug, String version) {
+        this(projectSlug, version, false);
+    }
+
+    /**
+     * @param version  can be a {@link VersionType}, ID, or name/number
+     */
+    public ProjectRef(String projectSlug, @Nullable String version, boolean datapack) {
         this.idOrSlug = projectSlug;
+        this.datapack = datapack;
         this.projectUri = null;
         this.versionType = parseVersionType(version);
         if (this.versionType == null) {
@@ -64,6 +81,7 @@ public ProjectRef(String projectSlug, String version) {
     }
 
     public ProjectRef(URI projectUri, String versionId) {
+        this.datapack = false;
         this.projectUri = projectUri;
 
         final String filename = extractFilename(projectUri);

src/main/java/me/itzg/helpers/modrinth/model/Constants.java

@@ -0,0 +1,7 @@
+package me.itzg.helpers.modrinth.model;
+
+public class Constants {
+
+    public static final String LOADER_DATAPACK = "datapack";
+
+}

src/main/java/me/itzg/helpers/modrinth/model/Version.java

@@ -2,29 +2,31 @@
 
 import com.fasterxml.jackson.databind.PropertyNamingStrategies;
 import com.fasterxml.jackson.databind.annotation.JsonNaming;
-import lombok.Data;
-
 import java.time.Instant;
 import java.util.List;
+import lombok.Data;
 
 @Data
 @JsonNaming(PropertyNamingStrategies.SnakeCaseStrategy.class)
 public class Version {
-  String id;
 
-  String projectId;
+    private String id;
+
+    private String projectId;
+
+    private String name;
 
-  String name;
+    private Instant datePublished;
 
-  Instant datePublished;
+    private String versionNumber;
 
-  String versionNumber;
+    private VersionType versionType;
 
-  VersionType versionType;
+    private List<VersionFile> files;
 
-  List<VersionFile> files;
+    private List<VersionDependency> dependencies;
 
-  List<VersionDependency> dependencies;
+    private List<String> gameVersions;
 
-  List<String> gameVersions;
+    private List<String> loaders;
 }