/*
 * React Server Components (RSCs) execute on the server, demanding a different debugging approach.
 * Traditional browser developer tools are ineffective for server-side logic.
 * We must leverage Node.js runtime capabilities and terminal-based inspection.
 */

// Example of a basic React Server Component (RSC)
// This component fetches data directly on the server.
// Path: app/page.tsx (or similar, depending on framework like Next.js App Router)

interface Post {
  id: number;
  title: string;
  body: string;
}

async function getPosts(): Promise<Post[]> {
  // In a real application, this would fetch from a database or external API.
  // Errors or unexpected data here are only visible server-side.
  const response = await fetch('https://jsonplaceholder.typicode.com/posts?_limit=5');
  if (!response.ok) {
    throw new Error(`Failed to fetch posts: ${response.statusText}`);
  }
  const data: Post[] = await response.json();
  console.log('Server: Posts fetched successfully.', data.map(p => p.title)); // Server-side log
  return data;
}

export default async function HomePage() {
  let posts: Post[] = [];
  try {
    posts = await getPosts();
  } catch (error: any) {
    console.error('Server: Error fetching posts for HomePage:', error.message); // Server-side error log
    // In a real app, render an error state or fallback UI.
    return (
      <div>
        <h1>Error Loading Posts</h1>
        <p>A problem occurred while retrieving data. Please try again later.</p>
      </div>
    );
  }

  return (
    <div>
      <h1>Server-Rendered Posts</h1>
      <ul>
        {posts.map(post => (
          <li key={post.id}>
            <strong>{post.title}</strong>
            <p>{post.body.substring(0, 100)}...</p>
          </li>
        ))}
      </ul>
    </div>
  );
}

/*
 * To debug React Server Components effectively, we must leverage Node.js's built-in V8 Inspector.
 * This allows external debugging tools (like VS Code's debugger) to attach to the server process.
 */

// 1. Modify your package.json scripts to enable the Node.js inspector.
//    This example assumes a Next.js project, but the principle applies to any Node.js server.
//    `--inspect` starts the inspector on a default port (usually 9229).
//    `--inspect-brk` pauses execution on the first line, allowing you to set breakpoints before code runs.

// package.json (example for Next.js)
{
  "name": "my-rsc-app",
  "version": "0.1.0",
  "private": true,
  "scripts": {
    "dev": "NODE_OPTIONS='--inspect' next dev",
    "dev:debug-brk": "NODE_OPTIONS='--inspect-brk' next dev",
    "build": "next build",
    "start": "next start",
    "lint": "next lint"
  },
  // ... other dependencies
}

/*
 * How to use with VS Code:
 * 1. Start your application using one of the new debug scripts (e.g., `npm run dev:debug-brk`).
 * 2. In VS Code, open the "Run and Debug" view (Ctrl+Shift+D or Cmd+Shift+D).
 * 3. Click "Create a launch.json file" if you don't have one.
 * 4. Choose "Node.js". VS Code often auto-generates a suitable configuration.
 *    A typical `launch.json` entry for attaching to an inspect port looks like this:
 */

// .vscode/launch.json
{
  "version": "0.2.0",
  "configurations": [
    {
      "name": "Attach to Node.js via Port",
      "type": "node",
      "request": "attach",
      "port": 9229, // Default Node.js inspector port
      "skipFiles": [
        "<node_internals>/**"
      ]
    }
  ]
}

/*
 * Steps to debug:
 * a. Run `npm run dev:debug-brk` in your terminal.
 * b. Open your project in VS Code.
 * c. Navigate to the "Run and Debug" panel.
 * d. Select "Attach to Node.js via Port" from the dropdown.
 * e. Click the green play button to start debugging.
 * f. Set breakpoints in your RSC files (e.g., `app/page.tsx`, server actions).
 * g. Navigate to your application in the browser. The debugger should hit your breakpoints.
 */

/*
 * When interactive debugging isn't feasible or for production environments,
 * strategic logging becomes paramount for understanding RSC behavior.
 * We also need to inspect the 'flight' payload sent from server to client.
 */

// 1. Enhanced Console Logging in RSCs
//    Use structured logging for better readability and filtering.

// app/actions.ts (Server Action example)
'use server';

export async function submitForm(formData: FormData) {
  const name = formData.get('name');
  const email = formData.get('email');

  console.log('SERVER ACTION: Received form submission.', {
    timestamp: new Date().toISOString(),
    source: 'submitForm',
    data: { name, email },
    actionType: 'form_submission'
  });

  if (!name || !email) {
    console.warn('SERVER ACTION: Missing required fields.', { name, email });
    throw new Error('Name and email are required.');
  }

  // Simulate a database save
  await new Promise(resolve => setTimeout(resolve, 500));
  console.log(`SERVER ACTION: User ${name} saved successfully.`);

  return { success: true, message: 'Form submitted successfully!' };
}

// 2. Inspecting the RSC 'Flight' Payload
//    This payload is the serialized instruction set sent from the server to the client.
//    It is visible in your browser's network tab for requests initiated by React.

/*
 * How to inspect the payload:
 * a. Open your browser's Developer Tools (F12 or Cmd+Option+I).
 * b. Navigate to the 'Network' tab.
 * c. Filter by 'Fetch/XHR' or 'WS' (for WebSockets, if applicable).
 * d. Look for requests initiated by React (often to a special endpoint like /_next/data/ or direct API routes).
 * e. The response will contain the RSC payload. It's often prefixed with a special marker (e.g., `0:` for Next.js).
 * f. Example (simplified JSON-like structure you might see after parsing): 
 *    [
 *      "_RSC",
 *      [
 *        "$L3:",
 *        ["h1", null, "Server-Rendered Posts"],
 *        ["ul", null,
 *          ["li", { "key": 1 }, ["strong", null, "Post Title 1"], ["p", null, "Post body excerpt..."]],
 *          ["li", { "key": 2 }, ["strong", null, "Post Title 2"], ["p", null, "Post body excerpt..."]]
 *        ]
 *      ]
 *    ]
 *
 *    This is a highly optimized, custom format, not standard JSON. You'll need to interpret React's specific serialization.
 *    Tools or browser extensions might assist in visualizing this.
 */

/*
 * Moving beyond basic logging and inspector attachment, we refine our strategy
 * to tackle more complex RSC debugging scenarios, focusing on payload integrity
 * and robust error management.
 */

// 1. Implement Robust Server-Side Error Boundaries for RSCs
//    Next.js (App Router) uses `error.tsx` for this purpose.
//    This catches errors during rendering of server components or data fetching.

// app/error.tsx (Client Component: Must use 'use client')
'use client';

import { useEffect } from 'react';

export default function Error({ error, reset }: { error: Error; reset: () => void }) {
  useEffect(() => {
    // Log the error to an error reporting service
    console.error('CLIENT: Error boundary caught an error:', error.message, error.stack);
    // You might send this error to Sentry, DataDog, etc.
  }, [error]);

  return (
    <div>
      <p>Something went wrong!</p>
      <button onClick={() => reset()}>Try again</button>
      <p>Error details: <strong>{error.message}</strong></p>
      <p>Please check server logs for more specific information.</p>
    </div>
  );
}

// 2. Custom Middleware or Server-Side Hooks for Request/Response Logging (Advanced)
//    In frameworks like Next.js, this might involve custom server implementations or middleware.

// next.config.mjs (example, highly simplified)
// This level of interception is complex and framework-dependent.
// const nextConfig = {
//   async rewrites() {
//     return [
//       {
//         source: '/_next/data/:path*', // Intercept data requests
//         destination: '/api/debug-rsc-payload',
//       },
//     ];
//   },
// };

// Then, create an API route to log the payload before sending it:
// app/api/debug-rsc-payload/route.ts
// export async function GET(request: Request) {
//   const url = new URL(request.url);
//   const originalPath = url.pathname.replace('/api/debug-rsc-payload', '/_next/data');
//   // ... proxy the request to the actual Next.js data endpoint
//   // ... capture and log the response body (RSC payload)
//   // ... return the original response
// }

// 3. Environment-Specific Debugging Configuration
//    Leverage environment variables to control log verbosity.

// package.json (modify 'dev' script)
// {
//   "scripts": {
//     "dev:verbose": "DEBUG_RSC_LEVEL=verbose NODE_OPTIONS='--inspect' next dev"
//   }
// }

// Your RSC code then checks process.env.DEBUG_RSC_LEVEL
// if (process.env.DEBUG_RSC_LEVEL === 'verbose') {
//   console.log('VERBOSE LOG: Detailed data for debugging.');
// }