feat(Phase 4): Memory & Intelligence — memory, log, summarization, skills (#91)

Co-authored-by: Jason Woltje <jason@diversecanvas.com>
Co-committed-by: Jason Woltje <jason@diversecanvas.com>

packages/memory/src/insights.ts

@@ -0,0 +1,89 @@
+import { eq, and, desc, sql, lt, type Db, insights } from '@mosaic/db';
+
+export type Insight = typeof insights.$inferSelect;
+export type NewInsight = typeof insights.$inferInsert;
+
+export interface SearchResult {
+  insight: Insight;
+  distance: number;
+}
+
+export function createInsightsRepo(db: Db) {
+  return {
+    async findByUser(userId: string, limit = 50): Promise<Insight[]> {
+      return db
+        .select()
+        .from(insights)
+        .where(eq(insights.userId, userId))
+        .orderBy(desc(insights.createdAt))
+        .limit(limit);
+    },
+
+    async findById(id: string): Promise<Insight | undefined> {
+      const rows = await db.select().from(insights).where(eq(insights.id, id));
+      return rows[0];
+    },
+
+    async create(data: NewInsight): Promise<Insight> {
+      const rows = await db.insert(insights).values(data).returning();
+      return rows[0]!;
+    },
+
+    async update(id: string, data: Partial<NewInsight>): Promise<Insight | undefined> {
+      const rows = await db
+        .update(insights)
+        .set({ ...data, updatedAt: new Date() })
+        .where(eq(insights.id, id))
+        .returning();
+      return rows[0];
+    },
+
+    async remove(id: string): Promise<boolean> {
+      const rows = await db.delete(insights).where(eq(insights.id, id)).returning();
+      return rows.length > 0;
+    },
+
+    /**
+     * Semantic search using pgvector cosine distance.
+     * Requires the vector extension and an embedding for the query.
+     */
+    async searchByEmbedding(
+      userId: string,
+      queryEmbedding: number[],
+      limit = 10,
+      maxDistance = 0.8,
+    ): Promise<SearchResult[]> {
+      const embeddingStr = `[${queryEmbedding.join(',')}]`;
+      const rows = await db.execute(sql`
+        SELECT *,
+               (embedding <=> ${embeddingStr}::vector) AS distance
+        FROM insights
+        WHERE user_id = ${userId}
+          AND embedding IS NOT NULL
+          AND (embedding <=> ${embeddingStr}::vector) < ${maxDistance}
+        ORDER BY distance ASC
+        LIMIT ${limit}
+      `);
+
+      return rows as unknown as SearchResult[];
+    },
+
+    /**
+     * Decay relevance scores for old insights that haven't been accessed recently.
+     */
+    async decayOldInsights(olderThan: Date, decayFactor = 0.95): Promise<number> {
+      const result = await db
+        .update(insights)
+        .set({
+          relevanceScore: sql`${insights.relevanceScore} * ${decayFactor}`,
+          decayedAt: new Date(),
+          updatedAt: new Date(),
+        })
+        .where(and(lt(insights.updatedAt, olderThan), sql`${insights.relevanceScore} > 0.1`))
+        .returning();
+      return result.length;
+    },
+  };
+}
+
+export type InsightsRepo = ReturnType<typeof createInsightsRepo>;