// Simple endpoint — add to any Express/Next.js app
import OpenAI from "openai";

const perplexity = new OpenAI({
  apiKey: process.env.PERPLEXITY_API_KEY!,
  baseURL: "https://api.perplexity.ai",
});

app.post("/api/search", async (req, res) => {
  try {
    const response = await perplexity.chat.completions.create({
      model: "sonar",
      messages: [{ role: "user", content: req.body.query }],
      max_tokens: 1024,
    });

    res.json({
      answer: response.choices[0].message.content,
      citations: (response as any).citations || [],
    });
  } catch (err: any) {
    if (err.status === 429) {
      res.status(429).json({ error: "Rate limited. Try again shortly." });
    } else {
      res.status(500).json({ error: "Search unavailable" });
    }
  }
});

import { createHash } from "crypto";
import { LRUCache } from "lru-cache";

const cache = new LRUCache<string, any>({
  max: 5000,
  ttl: 4 * 3600_000,  // 4-hour TTL
});

class CachedSearchService {
  constructor(private client: OpenAI) {}

  async search(query: string, model = "sonar") {
    const key = this.cacheKey(query, model);
    const cached = cache.get(key);
    if (cached) return { ...cached, cached: true };

    const response = await this.client.chat.completions.create({
      model,
      messages: [{ role: "user", content: query }],
      max_tokens: 1024,
    });

    const result = {
      answer: response.choices[0].message.content || "",
      citations: (response as any).citations || [],
      model: response.model,
    };

    cache.set(key, result);
    return { ...result, cached: false };
  }

  private cacheKey(query: string, model: string): string {
    return createHash("sha256")
      .update(`${model}:${query.toLowerCase().trim()}`)
      .digest("hex");
  }

  get stats() {
    return { size: cache.size, max: 5000 };
  }
}

import PQueue from "p-queue";

class ResearchPipeline {
  private queue: PQueue;
  private cache: CachedSearchService;

  constructor(private client: OpenAI) {
    this.queue = new PQueue({
      concurrency: 3,
      interval: 60_000,
      intervalCap: 40,  // 40 RPM (safety margin)
    });
    this.cache = new CachedSearchService(client);
  }

  async researchTopic(topic: string): Promise<{
    overview: string;
    sections: Array<{ question: string; answer: string; citations: string[] }>;
    bibliography: string[];
  }> {
    // Phase 1: Decompose (sonar, fast)
    const decomposition = await this.cache.search(
      `Break "${topic}" into 4 focused research questions. One per line.`,
      "sonar"
    );
    const questions = decomposition.answer.split("\n").filter((q) => q.trim().length > 10);

    // Phase 2: Deep research each question (sonar-pro, queued)
    const sections = await Promise.all(
      questions.slice(0, 5).map((q) =>
        this.queue.add(async () => {
          const result = await this.cache.search(q.trim(), "sonar-pro");
          return { question: q.trim(), ...result };
        })
      )
    );

    // Phase 3: Compile
    const allCitations = new Set<string>();
    for (const s of sections) {
      if (s) s.citations.forEach((url: string) => allCitations.add(url));
    }

    return {
      overview: decomposition.answer,
      sections: sections.filter(Boolean).map((s) => ({
        question: s!.question,
        answer: s!.answer,
        citations: s!.citations,
      })),
      bibliography: [...allCitations],
    };
  }
}

from flask import Flask, request, jsonify
from openai import OpenAI
import os

app = Flask(__name__)
client = OpenAI(api_key=os.environ["PERPLEXITY_API_KEY"], base_url="https://api.perplexity.ai")

@app.route("/api/search", methods=["POST"])
def search():
    query = request.json["query"]
    response = client.chat.completions.create(
        model="sonar",
        messages=[{"role": "user", "content": query}],
        max_tokens=1024,
    )
    raw = response.model_dump()
    return jsonify({
        "answer": response.choices[0].message.content,
        "citations": raw.get("citations", []),
    })

How many queries per day?
├─ <500 → Variant 1 (Direct Widget)
│   └─ Add retry with backoff
├─ 500-5K → Variant 2 (Cached Layer)
│   └─ Add LRU cache with 4-hour TTL
└─ 5K+ → Variant 3 (Research Pipeline)
    └─ Add job queue + sonar-pro for deep queries