feat: add IdentityDB core memory graph APIs

src/queries/topics.ts

@@ -0,0 +1,55 @@
+import type { Kysely, Transaction } from 'kysely';
+
+import type { IdentityDatabaseSchema } from '../types/database';
+import type { TopicRecord } from '../types/domain';
+
+export type DatabaseExecutor = Kysely<IdentityDatabaseSchema> | Transaction<IdentityDatabaseSchema>;
+
+export interface ConnectedTopicRow extends TopicRecord {
+  shared_fact_count: number;
+}
+
+export async function findTopicRowByNormalizedName(
+  executor: DatabaseExecutor,
+  normalizedName: string,
+): Promise<TopicRecord | undefined> {
+  return executor
+    .selectFrom('topics')
+    .selectAll()
+    .where('normalized_name', '=', normalizedName)
+    .executeTakeFirst();
+}
+
+export async function listTopicRows(
+  executor: DatabaseExecutor,
+  limit?: number,
+): Promise<TopicRecord[]> {
+  let query = executor
+    .selectFrom('topics')
+    .selectAll()
+    .orderBy('normalized_name', 'asc');
+
+  if (limit !== undefined) {
+    query = query.limit(limit);
+  }
+
+  return query.execute();
+}
+
+export async function findConnectedTopicRows(
+  executor: DatabaseExecutor,
+  topicId: string,
+): Promise<ConnectedTopicRow[]> {
+  return executor
+    .selectFrom('fact_topics as source_link')
+    .innerJoin('fact_topics as related_link', 'related_link.fact_id', 'source_link.fact_id')
+    .innerJoin('topics', 'topics.id', 'related_link.topic_id')
+    .selectAll('topics')
+    .select((eb) => eb.fn.count<number>('related_link.fact_id').as('shared_fact_count'))
+    .where('source_link.topic_id', '=', topicId)
+    .whereRef('related_link.topic_id', '!=', 'source_link.topic_id')
+    .groupBy('topics.id')
+    .orderBy('shared_fact_count', 'desc')
+    .orderBy('topics.normalized_name', 'asc')
+    .execute() as Promise<ConnectedTopicRow[]>;
+}