// socialcrawl-langchain.ts
// Run with: SOCIALCRAWL_API_KEY=sc_... ANTHROPIC_API_KEY=... npx tsx socialcrawl-langchain.ts
import { tool } from "@langchain/core/tools";
import { ChatAnthropic } from "@langchain/anthropic";
import { HumanMessage, ToolMessage } from "@langchain/core/messages";
import { z } from "zod";

const API_KEY = process.env.SOCIALCRAWL_API_KEY;
if (!API_KEY) throw new Error("Set SOCIALCRAWL_API_KEY");

const socialcrawl = tool(
  async ({ platform, resource, params }) => {
    const url = new URL(`https://www.socialcrawl.dev/v1/${platform}/${resource}`);
    for (const [key, value] of Object.entries(params ?? {})) {
      url.searchParams.set(key, String(value));
    }
    const res = await fetch(url, { headers: { "x-api-key": API_KEY } });
    const json = await res.json();
    // Return a string so the model can read it back as a ToolMessage.
    return JSON.stringify(json);
  },
  {
    name: "socialcrawl",
    description:
      "Fetch live social media, commerce, and review data from SocialCrawl. " +
      "Covers TikTok, Instagram, YouTube, LinkedIn, Reddit, Amazon and more. " +
      "Set `platform` (e.g. 'tiktok'), `resource` (e.g. 'profile'), and `params` " +
      "(the endpoint's query fields, e.g. { handle: 'charlidamelio' }).",
    schema: z.object({
      platform: z.string().describe("Platform slug, e.g. 'tiktok' or 'youtube'"),
      resource: z.string().describe("Endpoint resource, e.g. 'profile' or 'search'"),
      params: z
        .record(z.string(), z.union([z.string(), z.number()]))
        .describe("Query parameters for the endpoint"),
    }),
  },
);

const model = new ChatAnthropic({ model: "claude-sonnet-4-5" }).bindTools([
  socialcrawl,
]);

// One round trip: ask, let the model call the tool, feed the result back.
const messages = [
  new HumanMessage("How many followers does @charlidamelio have on TikTok?"),
];
const first = await model.invoke(messages);
messages.push(first);

for (const call of first.tool_calls ?? []) {
  const output = await socialcrawl.invoke(call.args as never);
  messages.push(new ToolMessage({ content: output, tool_call_id: call.id! }));
}

const final = await model.invoke(messages);
console.log(final.text);

npm install langchain @langchain/core @langchain/anthropic zod