graph TD
    A[Client Request] --> B[Worker: Route + Auth]
    B --> C{Request Type}
    C -->|API| D[Durable Object: buddy-agent]
    C -->|Content| E[KV: Cached Pages]
    C -->|Upload| F[R2: Object Storage]
    C -->|Query| G[D1: SQLite Database]
    D --> H[Workers AI: Inference]
    D --> I[Vectorize: Embeddings]
    G --> J[buddy-brain: Knowledge Base]
    E --> K[blog-engine: Page Serving]
    H --> L[Response to Client]
    I --> L
    J --> L
    K --> L

export default {
  async fetch(request: Request, env: Env): Promise<Response> {
    const url = new URL(request.url);

    if (url.pathname.startsWith("/api/chat")) {
      const id = env.BUDDY_AGENT.idFromName("default");
      const agent = env.BUDDY_AGENT.get(id);
      return agent.fetch(request);
    }

    const cached = await env.PAGE_CACHE.get(url.pathname);
    if (cached) return new Response(cached, {
      headers: { "Content-Type": "text/html", "Cache-Control": "public, max-age=3600" },
    });

    return new Response("Not Found", { status: 404 });
  },
} satisfies ExportedHandler<Env>;

export class BuddyAgent extends DurableObject {
  async fetch(request: Request): Promise<Response> {
    const body = await request.json<{ message: string }>();

    const embedding = await this.env.AI.run("@cf/baai/bge-base-en-v1.5", {
      text: [body.message],
    });

    const similar = await this.env.VECTORIZE.query(embedding.data[0], {
      topK: 5,
      returnMetadata: "all",
    });

    const context = similar.matches.map(m => m.metadata?.text).join("\n");
    const response = await this.env.AI.run("@cf/meta/llama-3.1-8b-instruct", {
      messages: [
        { role: "system", content: `Context: ${context}` },
        { role: "user", content: body.message },
      ],
    });

    return Response.json({ reply: response.response });
  }
}

// wrangler.jsonc
{
  "name": "buddy-agent",
  "main": "src/index.ts",
  "compatibility_date": "2026-04-01",
  "durable_objects": {
    "bindings": [{ "name": "BUDDY_AGENT", "class_name": "BuddyAgent" }]
  },
  "kv_namespaces": [{ "binding": "PAGE_CACHE", "id": "abc123" }],
  "vectorize": [{ "binding": "VECTORIZE", "index_name": "buddy-brain" }],
  "ai": { "binding": "AI" }
}