const { google } = require('googleapis');
const path = require('path');
const fs = require('fs');

const SHEET_ID = process.env.GOOGLE_SHEET_ID;
const SHEET_NAME = 'Orders'; // The tab name in your Google Sheet

// Path to the service account credentials JSON file
const CREDENTIALS_PATH = path.join(__dirname, '../config/samoulla-490417-daa7176c0091.json');

const getAuth = () => {
  // Option 1: Load from environment variable (useful for production like Vercel/Heroku)
  if (process.env.GOOGLE_SERVICE_ACCOUNT_JSON) {
    try {
      const credentials = JSON.parse(process.env.GOOGLE_SERVICE_ACCOUNT_JSON);
      return new google.auth.GoogleAuth({
        credentials,
        scopes: ['https://www.googleapis.com/auth/spreadsheets'],
      });
    } catch (err) {
      console.error('❌ Failed to parse GOOGLE_SERVICE_ACCOUNT_JSON:', err.message);
    }
  }

  // Option 2: Load from file
  if (fs.existsSync(CREDENTIALS_PATH)) {
    return new google.auth.GoogleAuth({
      keyFile: CREDENTIALS_PATH,
      scopes: ['https://www.googleapis.com/auth/spreadsheets'],
    });
  }

  throw new Error(`Google credentials not found (JSON file missing at ${CREDENTIALS_PATH} and no GOOGLE_SERVICE_ACCOUNT_JSON env var)`);
};

/**
 * Appends a new order row to the Google Sheet.
 * Called after a successful order creation — fails silently so it never blocks the user.
 */
const appendOrderToSheet = async (order) => {
    if (!SHEET_ID) {
        console.warn('⚠️  GOOGLE_SHEET_ID not set in env — skipping Google Sheets sync');
        return;
    }

    try {
        const auth = await getAuth();
        const sheets = google.sheets({ version: 'v4', auth });

        const createdAt = order.createdAt
            ? new Date(order.createdAt).toLocaleString('ar-EG', { timeZone: 'Africa/Cairo' })
            : new Date().toLocaleString('ar-EG', { timeZone: 'Africa/Cairo' });

        const row = [
            order.orderNumber || '',                          // A: رقم الطلب
            order.name || '',                                 // B: الاسم
            order.mobile || '',                               // C: الهاتف
            order.address?.governorate || '',                 // D: المحافظة
            order.address?.city || '',                        // E: المدينة
            order.address?.district || '',                    // F: المنطقة
            order.address?.street || '',                      // G: الشارع
            order.totalPrice || 0,                            // H: الإجمالي
            order.shippingPrice || 0,                         // I: الشحن
            order.payment?.method || '',                      // J: طريقة الدفع
            order.payment?.status || '',                      // K: حالة الدفع
            order.orderStatus || 'created',                   // L: حالة الطلب
            order.source || 'direct',                         // M: المصدر
            order.promoCode || '',                            // N: كود الخصم
            order.discountAmount || 0,                        // O: قيمة الخصم
            order.items?.length || 0,                         // P: عدد المنتجات
            order.items?.map(i => `${i.name} (${i.quantity})`).join(' | ') || '',  // Q: المنتجات
            createdAt,                                        // R: التاريخ
        ];

        await sheets.spreadsheets.values.append({
            spreadsheetId: SHEET_ID,
            range: `${SHEET_NAME}!A:R`,
            valueInputOption: 'USER_ENTERED',
            insertDataOption: 'INSERT_ROWS',
            resource: { values: [row] },
        });

        console.log(`✅ Order syncing: Success for #${order.orderNumber}`);
    } catch (error) {
        console.error(`❌ Google Sheets sync FAILED for order #${order.orderNumber || 'unknown'}:`, error.message);
    }
};

module.exports = { appendOrderToSheet };