config/
  perplexity/
    base.ts           # OpenAI client + base URL
    development.ts    # Dev: sonar only, low limits
    staging.ts        # Staging: sonar only, moderate limits
    production.ts     # Prod: full model access
    index.ts          # Environment resolver

// config/perplexity/base.ts
import OpenAI from "openai";

export const PERPLEXITY_BASE_URL = "https://api.perplexity.ai";

export function createPerplexityClient(apiKey: string): OpenAI {
  if (!apiKey) throw new Error("Perplexity API key is required");
  if (!apiKey.startsWith("pplx-")) throw new Error("Invalid Perplexity API key format");

  return new OpenAI({ apiKey, baseURL: PERPLEXITY_BASE_URL });
}

// config/perplexity/development.ts
export const devConfig = {
  apiKey: process.env.PERPLEXITY_API_KEY!,
  defaultModel: "sonar" as const,
  deepModel: "sonar" as const,       // No sonar-pro in dev (cost)
  maxTokens: 512,
  maxConcurrentRequests: 1,
  cacheTTLMs: 24 * 3600_000,         // Long cache in dev
};

// config/perplexity/staging.ts
export const stagingConfig = {
  apiKey: process.env.PERPLEXITY_API_KEY_STAGING!,
  defaultModel: "sonar" as const,
  deepModel: "sonar" as const,       // Keep sonar in staging
  maxTokens: 1024,
  maxConcurrentRequests: 2,
  cacheTTLMs: 4 * 3600_000,
};

// config/perplexity/production.ts
export const productionConfig = {
  apiKey: process.env.PERPLEXITY_API_KEY_PROD!,
  defaultModel: "sonar" as const,    // Fast queries use sonar
  deepModel: "sonar-pro" as const,   // Research queries use sonar-pro
  maxTokens: 4096,
  maxConcurrentRequests: 10,
  cacheTTLMs: 1 * 3600_000,          // Shorter cache in prod (freshness)
};

// config/perplexity/index.ts
import { createPerplexityClient } from "./base";
import { devConfig } from "./development";
import { stagingConfig } from "./staging";
import { productionConfig } from "./production";

type SearchDepth = "quick" | "deep";

const configs = {
  development: devConfig,
  staging: stagingConfig,
  production: productionConfig,
};

export function getConfig() {
  const env = process.env.NODE_ENV || "development";
  const config = configs[env as keyof typeof configs];
  if (!config) throw new Error(`Unknown environment: ${env}`);
  if (!config.apiKey) throw new Error(`PERPLEXITY_API_KEY not set for ${env}`);
  return config;
}

export function getClient() {
  return createPerplexityClient(getConfig().apiKey);
}

export function getModelForDepth(depth: SearchDepth): string {
  const cfg = getConfig();
  return depth === "deep" ? cfg.deepModel : cfg.defaultModel;
}

// lib/search.ts
import { getClient, getModelForDepth, getConfig } from "../config/perplexity";

export async function search(query: string, depth: "quick" | "deep" = "quick") {
  const client = getClient();
  const model = getModelForDepth(depth);
  const config = getConfig();

  const result = await client.chat.completions.create({
    model,
    messages: [
      { role: "system", content: "Provide accurate, well-sourced answers." },
      { role: "user", content: query },
    ],
    max_tokens: depth === "deep" ? config.maxTokens : Math.min(512, config.maxTokens),
  });

  return {
    answer: result.choices[0].message.content,
    citations: (result as any).citations || [],
    model,
    environment: process.env.NODE_ENV,
    usage: result.usage,
  };
}

set -euo pipefail
# Google Cloud Secret Manager
gcloud secrets create perplexity-api-key-prod \
  --data-file=<(echo -n "$PERPLEXITY_API_KEY_PROD")

# AWS Secrets Manager
aws secretsmanager create-secret \
  --name perplexity/api-key-prod \
  --secret-string "$PERPLEXITY_API_KEY_PROD"

# HashiCorp Vault
vault kv put secret/perplexity api_key="$PERPLEXITY_API_KEY_PROD"