import { NextRequest } from 'next/server';
import { existsSync, watchFile, readFileSync } from 'fs';

export async function GET(request: NextRequest) {
  const { searchParams } = new URL(request.url);
  const logPath = searchParams.get('logPath') || process.env.LOG_FILE_PATH || './ai-dev-tools/consolidated.log';
  
  if (!existsSync(logPath)) {
    return new Response('Log file not found', { status: 404 });
  }

  const encoder = new TextEncoder();
  let lastSize = 0;

  const stream = new ReadableStream({
    start(controller) {
      // Send initial content
      try {
        const content = readFileSync(logPath, 'utf-8');
        const lines = content.split('\n').filter(line => line.trim());
        lastSize = content.length;
        
        // Send initial lines
        controller.enqueue(encoder.encode(`data: ${JSON.stringify({ lines })}\n\n`));
      } catch (error) {
        controller.enqueue(encoder.encode(`data: ${JSON.stringify({ error: 'Failed to read log' })}\n\n`));
      }

      // Watch for file changes
      const watcher = watchFile(logPath, { interval: 1000 }, () => {
        try {
          const content = readFileSync(logPath, 'utf-8');
          if (content.length > lastSize) {
            const newContent = content.slice(lastSize);
            const newLines = newContent.split('\n').filter(line => line.trim());
            if (newLines.length > 0) {
              controller.enqueue(encoder.encode(`data: ${JSON.stringify({ newLines })}\n\n`));
            }
            lastSize = content.length;
          }
        } catch (error) {
          controller.enqueue(encoder.encode(`data: ${JSON.stringify({ error: 'Failed to read log updates' })}\n\n`));
        }
      });

      // Cleanup on close
      request.signal.addEventListener('abort', () => {
        watcher.unref();
        controller.close();
      });
    },
  });

  return new Response(stream, {
    headers: {
      'Content-Type': 'text/event-stream',
      'Cache-Control': 'no-cache',
      'Connection': 'keep-alive',
    },
  });
}