Start work on publication tree data structure

src/lib/data_structures/publication_tree.ts

@@ -0,0 +1,57 @@
+import type { NDKEvent } from "@nostr-dev-kit/ndk";
+
+interface PublicationTreeNode {
+  address: string;
+  parent?: PublicationTreeNode;
+  children?: PublicationTreeNode[];
+}
+
+// TODO: Add public method(s) for event retrieval.
+// TODO: Add methods for DFS and BFS traversal-retrieval.
+export class PublicationTree {
+  private root: PublicationTreeNode;
+  private nodes: Map<string, PublicationTreeNode>;
+  private events: Map<string, NDKEvent>;
+
+  constructor(rootEvent: NDKEvent) {
+    const rootAddress = this.getAddress(rootEvent);
+    this.root = { address: rootAddress, children: [] };
+
+    this.nodes = new Map<string, PublicationTreeNode>();
+    this.nodes.set(rootAddress, this.root);
+
+    this.events = new Map<string, NDKEvent>();
+    this.events.set(rootAddress, rootEvent);
+  }
+
+  addEvent(event: NDKEvent, parentEvent: NDKEvent) {
+    const address = this.getAddress(event);
+    const parentAddress = this.getAddress(parentEvent);
+    const parentNode = this.nodes.get(parentAddress);
+
+    if (!parentNode) {
+      throw new Error(
+        `PublicationTree: Parent node with address ${parentAddress} not found.`
+      );
+    }
+
+    const node = {
+      address,
+      parent: parentNode,
+      children: [],
+    };
+    parentNode.children!.push(node);
+    this.nodes.set(address, node);
+    this.events.set(address, event);
+  }
+
+  private getAddress(event: NDKEvent): string {
+    if (event.kind! < 30000 || event.kind! >= 40000) {
+      throw new Error(
+        "PublicationTree: Invalid event kind. Event kind must be in the range 30000-39999"
+      );
+    }
+
+    return `${event.kind}:${event.pubkey}:${event.dTag}`;
+  }
+}