feat(graphql): add top-level query for environmentNodes (#308)

src/main/java/io/cryostat/graphql/EnvironmentNodes.java

@@ -0,0 +1,80 @@
+/*
+ * Copyright The Cryostat Authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.cryostat.graphql;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+import io.cryostat.discovery.DiscoveryNode;
+import io.cryostat.graphql.matchers.LabelSelectorMatcher;
+
+import io.smallrye.graphql.api.Nullable;
+import org.eclipse.microprofile.graphql.Description;
+import org.eclipse.microprofile.graphql.GraphQLApi;
+import org.eclipse.microprofile.graphql.Query;
+
+@GraphQLApi
+public class EnvironmentNodes {
+
+    public static class EnvironmentNodeFilterInput {
+        @Nullable public Long id;
+        @Nullable public String name;
+        @Nullable public List<String> names;
+        @Nullable public String nodeType;
+        @Nullable public List<String> labels;
+    }
+
+    @Query("environmentNodes")
+    @Description("Get all environment nodes in the discovery tree with optional filtering")
+    public List<DiscoveryNode> environmentNodes(EnvironmentNodeFilterInput filter) {
+        DiscoveryNode rootNode = DiscoveryNode.getUniverse();
+        return filterAndTraverse(rootNode, filter);
+    }
+
+    private List<DiscoveryNode> filterAndTraverse(
+            DiscoveryNode node, EnvironmentNodeFilterInput filter) {
+        List<DiscoveryNode> filteredNodes = new ArrayList<>();
+        if (matchesFilter(node, filter)) {
+            filteredNodes.add(node);
+        }
+        if (node.children != null) {
+            for (DiscoveryNode child : node.children) {
+                filteredNodes.addAll(filterAndTraverse(child, filter));
+            }
+        }
+        return filteredNodes;
+    }
+
+    private static boolean matchesFilter(DiscoveryNode node, EnvironmentNodeFilterInput filter) {
+        if (node.target != null) return false;
+        if (filter == null) return true;
+
+        boolean matchesId = filter.id == null || filter.id.equals(node.id);
+        boolean matchesName = filter.name == null || Objects.equals(filter.name, node.name);
+        boolean matchesNames = filter.names == null || filter.names.contains(node.name);
+        boolean matchesLabels =
+                filter.labels == null
+                        || filter.labels.stream()
+                                .allMatch(
+                                        label ->
+                                                LabelSelectorMatcher.parse(label)
+                                                        .test(node.labels));
+        boolean matchesNodeType = filter.nodeType == null || filter.nodeType.equals(node.nodeType);
+
+        return matchesId && matchesName && matchesNames && matchesLabels && matchesNodeType;
+    }
+}