const express = require('express');
const fs = require('fs');
const path = require('path');
const Docxtemplater = require('docxtemplater');
const PizZip = require('pizzip');

const app = express();

// Enable JSON parsing for incoming requests
app.use(express.json());
app.use(express.urlencoded({ extended: false }));

// Endpoint to generate the document
app.post('/generate-doc', (req, res) => {
  try {
    // Load your DOCX template (ensure the template is in the same directory)
    const content = fs.readFileSync(path.resolve(__dirname, 'template.docx'), 'binary');
    const zip = new PizZip(content);
    const doc = new Docxtemplater(zip, { paragraphLoop: true, linebreaks: true });

    // Set your template variables from the request body
    doc.setData(req.body);

    // Render the document (this only replaces placeholders, preserving your formatting)
    doc.render();

    // Generate the updated document as a buffer
    const buf = doc.getZip().generate({ type: 'nodebuffer' });

    res.set({
      'Content-Type': 'application/vnd.openxmlformats-officedocument.wordprocessingml.document',
      'Content-Disposition': 'attachment; filename=output.docx'
    });
    res.send(buf);
  } catch (error) {
    console.error('Error during document generation:', error);
    res.status(500).send('An error occurred while generating the document.');
  }
});

const PORT = process.env.PORT || 3000;
app.listen(PORT, () => {
  console.log(`Docxtemplater service listening on port ${PORT}`);
});