import { NextRequest, NextResponse } from 'next/server';
import { LlamaParseReader } from 'llamaindex';
import { writeFile } from 'fs/promises';
import { join } from 'path';
import { existsSync, mkdirSync } from 'fs';

const UPLOAD_DIR = join(process.cwd(), 'uploads');

// Ensure uploads directory exists
if (!existsSync(UPLOAD_DIR)) {
  mkdirSync(UPLOAD_DIR);
}

export async function POST(request: NextRequest) {
  try {
    const formData = await request.formData();
    const file = formData.get('file') as File;
    
    if (!file) {
      return NextResponse.json(
        { error: 'No file uploaded' },
        { status: 400 }
      );
    }

    // Save file temporarily
    const bytes = await file.arrayBuffer();
    const buffer = Buffer.from(bytes);
    const filePath = join(UPLOAD_DIR, file.name);
    await writeFile(filePath, buffer);

    // Extract text using LlamaParser
    const reader = new LlamaParseReader({ resultType: 'markdown' });
    const documents = await reader.loadData(filePath);

    // Combine all document chunks
    const fullText = documents.map(doc => doc.text).join('\n\n');

    // Clean up the temporary file
    await writeFile(filePath, '');

    return NextResponse.json({
      fileName: file.name,
      text: fullText
    });
  } catch (error) {
    console.error('Error processing file:', error);
    return NextResponse.json(
      { error: 'Error processing file' },
      { status: 500 }
    );
  }
}