#!/usr/bin/env node

import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import { z } from "zod";
import { chromium, type Browser } from "playwright";

const server = new McpServer({
  name: "{{PROJECT_NAME}}",
  version: "{{VERSION}}",
});

// ── Browser management ───────────────────────────────────
// Reuse a single browser instance across tool calls for performance.

let browser: Browser | null = null;

async function getBrowser(): Promise<Browser> {
  if (!browser || !browser.isConnected()) {
    browser = await chromium.launch({ headless: true });
  }
  return browser;
}

async function withPage<T>(
  url: string,
  fn: (page: import("playwright").Page) => Promise<T>,
  options: { timeoutMs?: number } = {}
): Promise<T> {
  const { timeoutMs = 30000 } = options;
  const b = await getBrowser();
  const context = await b.newContext({
    userAgent:
      "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36",
  });
  const page = await context.newPage();
  page.setDefaultTimeout(timeoutMs);

  try {
    await page.goto(url, { waitUntil: "networkidle" });
    return await fn(page);
  } finally {
    await context.close();
  }
}

// ── Example: Scrape page content ─────────────────────────
// This template shows how to build a Playwright-based MCP server.
// Use this for sites that require JavaScript rendering.

server.tool(
  "scrape_page",
  "Load a page in a real browser and extract text content, title, and metadata",
  {
    url: z.string().url().describe("URL to scrape"),
    selector: z
      .string()
      .optional()
      .describe("CSS selector to extract (defaults to body)"),
  },
  async ({ url, selector }) => {
    try {
      const result = await withPage(url, async (page) => {
        const title = await page.title();
        const target = selector || "body";
        const text = await page
          .locator(target)
          .first()
          .innerText()
          .catch(() => "Element not found");

        const meta: Record<string, string> = {};
        const metaTags = await page.locator("meta[name], meta[property]").all();
        for (const tag of metaTags.slice(0, 20)) {
          const name =
            (await tag.getAttribute("name")) ||
            (await tag.getAttribute("property")) ||
            "";
          const content = (await tag.getAttribute("content")) || "";
          if (name && content) meta[name] = content.slice(0, 200);
        }

        return { url, title, text: text.slice(0, 5000), meta };
      });

      return {
        content: [{ type: "text", text: JSON.stringify(result, null, 2) }],
      };
    } catch (e: any) {
      return {
        content: [{ type: "text", text: `Error scraping ${url}: ${e.message}` }],
      };
    }
  }
);

server.tool(
  "screenshot",
  "Take a screenshot of a webpage",
  {
    url: z.string().url().describe("URL to screenshot"),
    full_page: z
      .boolean()
      .optional()
      .default(false)
      .describe("Capture full page or just viewport"),
  },
  async ({ url, full_page }) => {
    try {
      const buffer = await withPage(url, async (page) => {
        return await page.screenshot({ fullPage: full_page });
      });

      return {
        content: [
          {
            type: "image",
            data: buffer.toString("base64"),
            mimeType: "image/png",
          },
        ],
      };
    } catch (e: any) {
      return {
        content: [
          { type: "text", text: `Error taking screenshot of ${url}: ${e.message}` },
        ],
      };
    }
  }
);

// ── Cleanup on exit ──────────────────────────────────────

process.on("SIGINT", async () => {
  if (browser) await browser.close();
  process.exit(0);
});

// ── Start server ─────────────────────────────────────────

async function main() {
  const transport = new StdioServerTransport();
  await server.connect(transport);
}

main().catch(console.error);