import express from 'express';
import { MongoClient } from 'mongodb';
import { google } from 'googleapis';
import crypto from 'crypto';
import dotenv from 'dotenv';  // For loading environment variables
import fs from 'fs';  // For reading the Google credentials JSON file

dotenv.config();  // Load .env variables

const app = express();
const port = 3000;

app.use(express.json());

// Mongo URI from .env
const uri = process.env.MONGO_URI;
const client = new MongoClient(uri);
const dbName = 'inventory';
const collectionName = 'items';

// Load Google credentials from the key.json file
const googleCredentialsPath = process.env.GOOGLE_CREDENTIALS_PATH;
const googleApisKey = JSON.parse(fs.readFileSync(googleCredentialsPath, 'utf8'));

// Initialize Google Sheets API authentication
const auth = new google.auth.JWT(
  googleApisKey.client_email,
  null,
  googleApisKey.private_key,
  ['https://www.googleapis.com/auth/spreadsheets']
);

const spreadsheetId = process.env.SPREADSHEET_ID;
const sheets = google.sheets({ version: 'v4', auth });
const range = 'Sheet1!A:H';

// Connect to MongoDB
async function connectDB() {
    try {
        await client.connect();
        console.log('Connected to MongoDB!');
    } catch (err) {
        console.error('Error connecting to MongoDB:', err);
        process.exit(1);
    }
}

connectDB();

// Generate Serial Number
function generateSerialNumber() {
    return `Jadupc${crypto.randomInt(100000, 999999)}`;
}

// Route to upload device details
app.post('/upload', async (req, res) => {
    const { Verient, mac, os, status, customerAddress, customerNumber, customerName } = req.body;
  
    if (!Verient || !mac || !os) {
        return res.status(400).send('Missing required fields: Verient, mac, os, or status');
    }
  
    // Check if device already exists in database
    try {
        const db = client.db(dbName);
        const collection = db.collection(collectionName);
  
        const existingDevice = await collection.findOne({ mac });
  
        if (existingDevice) {
            return res.status(400).send('Device with the same MAC address is already registered');
        }
  
        // Generate serial number
        const serialNumber = generateSerialNumber();
  
        const newItem = {
            serialNumber,
            Verient,
            mac,
            os,
            status: status || 'registered',
            customerAddress,
            customerNumber,
            customerName,
        };
  
        await collection.insertOne(newItem);
        console.log('Item successfully added to MongoDB');
  
        try {
            // Append data to Google Sheets
            const response = await sheets.spreadsheets.values.append({
                spreadsheetId,
                range,
                valueInputOption: 'USER_ENTERED',
                requestBody: {
                    values: [[serialNumber, Verient, mac, os, status, customerAddress, customerNumber, customerName]],
                },
            });
            console.log('Data successfully appended to Google Sheets');
            res.status(200).send('Device uploaded and added to MongoDB and Google Sheets. Serial Number: ' + serialNumber);
        } catch (err) {
            console.error('Error appending to Google Sheets:', err);
            res.status(500).send('Error uploading to Google Sheets');
        }
    } catch (err) {
        console.error('Error inserting item into MongoDB:', err);
        res.status(500).send('Error uploading item to MongoDB');
    }
});

// Route to check device status
app.get('/check-status', async (req, res) => {
    const { mac, serialNumber } = req.query;

    if (!mac && !serialNumber) {
        return res.status(400).send('MAC or Serial Number required');
    }

    try {
        const db = client.db(dbName);
        const collection = db.collection(collectionName);
        const device = await collection.findOne(mac ? { mac } : { serialNumber });

        if (!device) {
            return res.status(200).json({
                serialNumber: null,
                status: 'new'  // Default status if not found
            });
        }

        res.status(200).json({
            serialNumber: device.serialNumber,
            status: device.status  // Default status if missing
        });
    } catch (err) {
        res.status(500).send('Error checking device status');
    }
});

// Start the server
app.listen(port, () => console.log(`Server running on http://localhost:${port}`));