server/src/models/Invoice.js

const mongoose = require('mongoose');

const invoiceSchema = new mongoose.Schema(
  {
    invoiceNumber: {
      type: String,  // e.g., "INV-2026-001"
      unique: true,
      required: true,
    },
    bookingId: {
      type: mongoose.Schema.Types.ObjectId,
      ref: 'Booking',
      required: true,
    },
    photographerId: {
      type: mongoose.Schema.Types.ObjectId,
      ref: 'Photographer',
      required: true,
    },
    customerId: {
      type: mongoose.Schema.Types.ObjectId,
      ref: 'User',
      required: true,
    },
    issueDate: {
      type: Date,
      default: Date.now,
    },
    dueDate: {
      type: Date,
    },
    items: [
      {
        description: String,
        quantity: Number,
        unitPrice: Number,
        total: Number,
      },
    ],
    subtotal: {
      type: Number,
      required: true,
    },
    tax: {
      type: Number,
      default: 0,
    },
    taxRate: {
      type: Number,
      default: 18, // 18% GST in India
    },
    discount: {
      type: Number,
      default: 0,
    },
    totalAmount: {
      type: Number,
      required: true,
    },
    paymentStatus: {
      type: String,
      enum: ['pending', 'paid', 'overdue'],
      default: 'pending',
    },
    paidAt: {
      type: Date,
      default: null,
    },
    notes: {
      type: String,
      default: '',
    },
    pdfUrl: {
      type: String,
      default: null, // URL to generated PDF
    },
  },
  { timestamps: true }
);

module.exports = mongoose.model('Invoice', invoiceSchema);