Velar/Backend/index.js

require('dotenv').config(); 
const express = require('express');
const mongoose = require('mongoose');
const axios = require('axios');
const cors = require('cors');

const app = express();
app.use(express.json()); 
app.use(cors({
  origin: process.env.CORS_ORIGIN || '*'
}));
// Prediction route
const predictRoute = require('./predict');
app.use('/api/predict', predictRoute);

// MongoDB connection
mongoose.connect('mongodb://localhost:27017/chat', {
  useNewUrlParser: true,
  useUnifiedTopology: true,
});



// Define schema and model
const transactionSchema = new mongoose.Schema({
  description: String,
  amount: Number,

  category: String,
  date: { type: Date, default: Date.now },
});

const Transaction = mongoose.model('Transaction', transactionSchema);



// POST endpoint to add transaction with auto-categorization
app.post('/api/transaction/add', async (req, res) => {
  try {
    const { description, amount } = req.body;

    // Call your AI prediction endpoint
    const predictRes = await axios.post('http://10.231.26.23:5000/api/predict', {
      description,
    });

    const category = predictRes.data.category || 'Other';

    const newTransaction = new Transaction({
      description,
      amount,
      category,
    });

    await newTransaction.save();

    res.status(200).json({
      message: '✅ Transaction saved with category',
      data: newTransaction,
    });
  } catch (err) {
    console.error('❌ Error adding transaction:', err.message);
    res.status(500).json({ error: err.message });
  }
});

app.post('/api/transaction/update', async (req, res) => {
  try {
    const { budget } = req.body;
    // Save to database or wherever you store budgets
    await BudgetModel.updateOne({}, { amount: budget }, { upsert: true });
    res.status(200).json({ success: true });
  } catch (error) {
    res.status(500).json({ error: 'Failed to update budget' });
  }
});
// GET transactions by category
app.get('/api/transactions', async (req, res) => {
  try {
    const category = req.query.category;

    let query = {};
    if (category && category !== 'All') {
      query.category = category;
    }

    const transactions = await Transaction.find(query).sort({ date: -1 });

    res.status(200).json({
      success: true,
      data: transactions.map(tx => ({
        id: tx._id,
        description: tx.description,
        amount: tx.amount,
        category: tx.category,
        date: tx.date,
      })),
    });
  } catch (err) {
    res.status(500).json({ error: err.message });
  }
});
// Get 5 most recent transactions
app.get('/api/transactions/recent', async (req, res) => {
  try {
    const transactions = await Transaction.find({})
      .sort({ date: -1 })
      .limit(5); // 👈 limit to 5

    res.status(200).json({
      success: true,
      data: transactions.map(tx => ({
        id: tx._id,
        description: tx.description,
        amount: tx.amount,
        category: tx.category,
        date: tx.date,
      })),
    });
  } catch (err) {
    res.status(500).json({ error: err.message });
  }
});

app.post('/api/transactions/voice', async (req, res) => {
  try {
    const { voiceInput } = req.body;

    if (!voiceInput) {
      return res.status(400).json({ error: 'No voice input provided' });
    }

    // Step 1: Use regex to extract amount
    const amountMatch = voiceInput.match(/(?:\₹|\$)?(\d+(?:\.\d{1,2})?)/);
    const amount = amountMatch ? parseFloat(amountMatch[1]) : null;

    // Step 2: Extract description (rough logic: remove common verbs + amount)
    const cleaned = voiceInput
      .toLowerCase()
      .replace(/(bought|added|paid|spent|for|on)/g, '')
      .replace(/₹?\d+/, '')
      .trim();

    const description = cleaned || 'misc';

    // Step 3: Predict category using your Flask API
    const predictRes = await axios.post('http://10.231.26.23:5000/api/predict', {
      description,
    });

    const category = predictRes.data?.category || 'Other';

    // Step 4: Save to DB
    const newTransaction = new Transaction({
      description,
      amount,
      category,
    });

    await newTransaction.save();

    res.status(200).json({
      message: '✅ Voice transaction saved',
      data: newTransaction,
    });
  } catch (err) {
    console.error('❌ Voice transaction error:', err.message);
    res.status(500).json({ error: 'Server error during voice transaction' });
  }
});


//server
const HOST = process.env.HOST || '0.0.0.0';  // listen on all interfaces
const PORT = process.env.PORT || 3000;
app.listen(PORT, HOST, () => {
  console.log(`🚀 Server running on http://${HOST}:${PORT}`);
});