class InvoiceItem {
  final int? id;
  final int? invoiceId;
  final int? productId;
  final int? inventoryItemId;
  final String? productName;
  final String? categoryName;
  final String? commodityCode;
  final String? sku;
  final String? huid;
  final String? hsnCode;
  final String? description;
  final double quantity;
  final double? weight;
  final double unitPrice; // metal rate
  final double makingCharge;
  final String makingChargesType; // PER_GRAM, PER_PIECE, PERCENTAGE
  final double taxRate;
  final double cgst;
  final double sgst;
  final double igst;
  final double discount;
  final double otherCharges;
  final String? photoUrl;
  final String? localPhotoPath;
  final double total;

  InvoiceItem({
    this.id,
    this.invoiceId,
    this.productId,
    this.inventoryItemId,
    this.productName,
    this.categoryName,
    this.commodityCode,
    this.hsnCode,
    this.sku,
    this.huid,
    this.description,
    required this.quantity,
    this.weight,
    required this.unitPrice,
    this.makingCharge = 0.0,
    this.makingChargesType = 'PER_GRAM',
    this.taxRate = 0.0,
    this.cgst = 0.0,
    this.sgst = 0.0,
    this.igst = 0.0,
    this.discount = 0.0,
    this.otherCharges = 0.0,
    this.photoUrl,
    this.localPhotoPath,
    required this.total,
  });

  InvoiceItem copyWith({
    int? id,
    int? invoiceId,
    int? productId,
    int? inventoryItemId,
    String? productName,
    String? categoryName,
    String? commodityCode,
    String? hsnCode,
    String? sku,
    String? huid,
    String? description,
    double? quantity,
    double? weight,
    double? unitPrice,
    double? makingCharge,
    String? makingChargesType,
    double? taxRate,
    double? cgst,
    double? sgst,
    double? igst,
    double? discount,
    double? otherCharges,
    String? photoUrl,
    String? localPhotoPath,
    double? total,
  }) {
    return InvoiceItem(
      id: id ?? this.id,
      invoiceId: invoiceId ?? this.invoiceId,
      productId: productId ?? this.productId,
      inventoryItemId: inventoryItemId ?? this.inventoryItemId,
      productName: productName ?? this.productName,
      categoryName: categoryName ?? this.categoryName,
      commodityCode: commodityCode ?? this.commodityCode,
      hsnCode: hsnCode ?? this.hsnCode,
      sku: sku ?? this.sku,
      huid: huid ?? this.huid,
      description: description ?? this.description,
      quantity: quantity ?? this.quantity,
      weight: weight ?? this.weight,
      unitPrice: unitPrice ?? this.unitPrice,
      makingCharge: makingCharge ?? this.makingCharge,
      makingChargesType: makingChargesType ?? this.makingChargesType,
      taxRate: taxRate ?? this.taxRate,
      cgst: cgst ?? this.cgst,
      sgst: sgst ?? this.sgst,
      igst: igst ?? this.igst,
      discount: discount ?? this.discount,
      otherCharges: otherCharges ?? this.otherCharges,
      photoUrl: photoUrl ?? this.photoUrl,
      localPhotoPath: localPhotoPath ?? this.localPhotoPath,
      total: total ?? this.total,
    );
  }

  factory InvoiceItem.fromJson(Map<String, dynamic> json) {
    return InvoiceItem(
      id: json['id'],
      invoiceId: json['invoiceId'] ?? json['invoice_id'],
      productId: json['productId'] ?? json['product_id'],
      inventoryItemId: json['inventoryItemId'] ?? json['inventory_item_id'],
      productName: json['productName'] ?? json['product_name'],
      categoryName: json['categoryName'] ?? json['category_name'],
      commodityCode: json['commodityCode'] ?? json['commodity_code'],
      hsnCode: json['hsnCode'] ?? json['hsn_code'],
      sku: json['sku'],
      huid: json['huid'],
      description: json['description'],
      quantity: (json['quantity'] as num?)?.toDouble() ?? 1.0,
      weight: (json['weight'] as num?)?.toDouble(),
      unitPrice: (json['unitPrice'] ?? json['unit_price'] as num?)?.toDouble() ?? 0.0,
      makingCharge: (json['makingCharge'] ?? json['making_charge'] as num?)?.toDouble() ?? 0.0,
      makingChargesType: json['makingChargesType'] ?? json['making_charges_type'] ?? 'PER_GRAM',
      taxRate: (json['taxRate'] ?? json['tax_rate'] as num?)?.toDouble() ?? 0.0,
      cgst: (json['cgst'] as num?)?.toDouble() ?? 0.0,
      sgst: (json['sgst'] as num?)?.toDouble() ?? 0.0,
      igst: (json['igst'] as num?)?.toDouble() ?? 0.0,
      discount: (json['discount'] as num?)?.toDouble() ?? 0.0,
      otherCharges: (json['otherCharges'] ?? json['other_charges'] as num?)?.toDouble() ?? 0.0,
      photoUrl: json['photoUrl'] ?? json['photo_url'],
      total: (json['total'] as num?)?.toDouble() ?? 0.0,
    );
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = {};
    if (id != null) data['id'] = id;
    if (invoiceId != null) data['invoiceId'] = invoiceId;
    if (productId != null) data['productId'] = productId;
    if (inventoryItemId != null) data['inventoryItemId'] = inventoryItemId;
    if (productName != null) data['productName'] = productName;
    if (categoryName != null) data['categoryName'] = categoryName;
    if (commodityCode != null) data['commodityCode'] = commodityCode;
    if (hsnCode != null) data['hsnCode'] = hsnCode;
    if (sku != null) data['sku'] = sku;
    if (huid != null) data['huid'] = huid;
    if (description != null) data['description'] = description;
    data['quantity'] = quantity;
    if (weight != null) data['weight'] = weight;
    data['unitPrice'] = unitPrice;
    data['makingCharge'] = makingCharge;
    data['makingChargesType'] = makingChargesType;
    data['taxRate'] = taxRate;
    data['cgst'] = cgst;
    data['sgst'] = sgst;
    data['igst'] = igst;
    data['discount'] = discount;
    data['otherCharges'] = otherCharges;
    if (photoUrl != null) data['photoUrl'] = photoUrl;
    data['total'] = total;
    return data;
  }
}

class Invoice {
  final int? id;
  final int? customerId;
  final String invoiceNumber;
  final DateTime issueDate;
  final DateTime? dueDate;
  final double subtotal;
  final double taxTotal;
  final double cgstTotal;
  final double sgstTotal;
  final double igstTotal;
  final double discountTotal;
  final double totalAmount;
  final double amountPaid;
  final DateTime? nextPaymentDate;
  final String? paymentMethod;
  final int? paymentWalletId;
  final String status;
  final String? notes;
  final String? invoiceUrl;
  final bool isEmi;
  final double? emiAmount;
  final String? emiCycle;
  final DateTime? emiStartDate;
  final int? salesChannelId;
  final String? salesChannel;
  final String? marketplaceOrderId;
  final int? placeOfSupplyStateId;
  final String? placeOfSupply;
  final List<InvoiceItem> items;
  final List<InvoicePayment>? payments;

  Invoice({
    this.id,
    this.customerId,
    required this.invoiceNumber,
    required this.issueDate,
    this.dueDate,
    required this.subtotal,
    this.taxTotal = 0.0,
    this.cgstTotal = 0.0,
    this.sgstTotal = 0.0,
    this.igstTotal = 0.0,
    this.discountTotal = 0.0,
    required this.totalAmount,
    this.amountPaid = 0.0,
    this.nextPaymentDate,
    this.paymentMethod,
    this.paymentWalletId,
    this.status = 'DRAFT',
    this.notes,
    this.invoiceUrl,
    this.isEmi = false,
    this.emiAmount,
    this.emiCycle,
    this.emiStartDate,
    this.salesChannelId,
    this.salesChannel,
    this.marketplaceOrderId,
    this.placeOfSupplyStateId,
    this.placeOfSupply,
    this.items = const [],
    this.payments,
  });

  factory Invoice.fromJson(Map<String, dynamic> json) {
    return Invoice(
      id: json['id'],
      customerId: json['customerId'] ?? json['customer_id'],
      invoiceNumber: json['invoiceNumber'] ?? json['invoice_number'] ?? '',
      issueDate: json['issueDate'] != null 
          ? DateTime.parse(json['issueDate']) 
          : (json['issue_date'] != null ? DateTime.parse(json['issue_date']) : DateTime.now()),
      dueDate: json['dueDate'] != null ? DateTime.parse(json['dueDate']) : (json['due_date'] != null ? DateTime.parse(json['due_date']) : null),
      subtotal: (json['subtotal'] as num?)?.toDouble() ?? 0.0,
      taxTotal: (json['taxTotal'] ?? json['tax_total'] as num?)?.toDouble() ?? 0.0,
      cgstTotal: (json['cgstTotal'] ?? json['cgst_total'] as num?)?.toDouble() ?? 0.0,
      sgstTotal: (json['sgstTotal'] ?? json['sgst_total'] as num?)?.toDouble() ?? 0.0,
      igstTotal: (json['igstTotal'] ?? json['igst_total'] as num?)?.toDouble() ?? 0.0,
      discountTotal: (json['discountTotal'] ?? json['discount_total'] as num?)?.toDouble() ?? 0.0,
      totalAmount: (json['totalAmount'] ?? json['total_amount'] as num?)?.toDouble() ?? 0.0,
      amountPaid: (json['amountPaid'] ?? json['amount_paid'] as num?)?.toDouble() ?? 0.0,
      nextPaymentDate: json['nextPaymentDate'] != null
          ? DateTime.parse(json['nextPaymentDate'])
          : (json['next_payment_date'] != null ? DateTime.parse(json['next_payment_date']) : null),
      paymentMethod: json['paymentMethod'] ?? json['payment_method'],
      paymentWalletId: json['paymentWalletId'] ?? json['payment_wallet_id'],
      status: json['status'] ?? 'DRAFT',
      notes: json['notes'],
      invoiceUrl: json['invoiceUrl'] ?? json['invoice_url'],
      isEmi: json['isEmi'] ?? json['is_emi'] ?? false,
      emiAmount: (json['emiAmount'] ?? json['emi_amount'] as num?)?.toDouble(),
      emiCycle: json['emiCycle'] ?? json['emi_cycle'],
      emiStartDate: json['emiStartDate'] != null
          ? DateTime.parse(json['emiStartDate'])
          : (json['emi_start_date'] != null ? DateTime.parse(json['emi_start_date']) : null),
      salesChannelId: json['salesChannelId'] ?? json['sales_channel_id'],
      salesChannel: json['salesChannel'] ?? json['sales_channel'],
      marketplaceOrderId: json['marketplaceOrderId'] ?? json['marketplace_order_id'],
      placeOfSupplyStateId: json['placeOfSupplyStateId'] ?? json['place_of_supply_state_id'],
      placeOfSupply: json['placeOfSupply'] ?? json['place_of_supply'],
      items: json['items'] != null
          ? (json['items'] as List).map((i) => InvoiceItem.fromJson(i)).toList()
          : [],
      payments: json['payments'] != null
          ? (json['payments'] as List)
                .map((i) => InvoicePayment.fromJson(i))
                .toList()
          : null,
    );
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = {};
    if (id != null) data['id'] = id;
    if (customerId != null) data['customerId'] = customerId;
    data['invoiceNumber'] = invoiceNumber;
    data['issueDate'] = issueDate.toIso8601String().split('T')[0];
    if (dueDate != null) {
      data['dueDate'] = dueDate!.toIso8601String().split('T')[0];
    }
    data['subtotal'] = subtotal;
    data['taxTotal'] = taxTotal;
    data['cgstTotal'] = cgstTotal;
    data['sgstTotal'] = sgstTotal;
    data['igstTotal'] = igstTotal;
    data['discountTotal'] = discountTotal;
    data['totalAmount'] = totalAmount;
    if (amountPaid > 0) data['amountPaid'] = amountPaid;
    if (nextPaymentDate != null) {
      data['nextPaymentDate'] = nextPaymentDate!.toIso8601String().split('T')[0];
    }
    if (paymentMethod != null) data['paymentMethod'] = paymentMethod;
    if (paymentWalletId != null) data['paymentWalletId'] = paymentWalletId;
    data['status'] = status;
    if (notes != null) data['notes'] = notes;
    if (invoiceUrl != null) data['invoiceUrl'] = invoiceUrl;
    data['isEmi'] = isEmi;
    if (emiAmount != null) data['emiAmount'] = emiAmount;
    if (emiCycle != null) data['emiCycle'] = emiCycle;
    if (emiStartDate != null) {
      data['emiStartDate'] = emiStartDate!.toIso8601String().split('T')[0];
    }
    if (salesChannelId != null) data['salesChannelId'] = salesChannelId;
    if (salesChannel != null) data['salesChannel'] = salesChannel;
    if (marketplaceOrderId != null) data['marketplaceOrderId'] = marketplaceOrderId;
    if (placeOfSupplyStateId != null) data['placeOfSupplyStateId'] = placeOfSupplyStateId;
    if (placeOfSupply != null) data['placeOfSupply'] = placeOfSupply;
    data['items'] = items.map((i) => i.toJson()).toList();
    if (payments != null) {
      data['payments'] = payments!.map((i) => i.toJson()).toList();
    }
    return data;
  }
}

class InvoicePayment {
  final int? id;
  final int? invoiceId;
  final double amount;
  final DateTime? paymentDate;
  final String paymentMethod;
  final int? emiInstallmentNumber;
  final int? walletId;

  InvoicePayment({
    this.id,
    this.invoiceId,
    required this.amount,
    this.paymentDate,
    required this.paymentMethod,
    this.emiInstallmentNumber,
    this.walletId,
  });

  factory InvoicePayment.fromJson(Map<String, dynamic> json) {
    return InvoicePayment(
      id: json['id'],
      invoiceId: json['invoiceId'] ?? json['invoice_id'],
      amount: (json['amount'] as num?)?.toDouble() ?? 0.0,
      paymentDate: json['paymentDate'] != null
          ? DateTime.parse(json['paymentDate'])
          : (json['payment_date'] != null ? DateTime.parse(json['payment_date']) : null),
      paymentMethod: json['paymentMethod'] ?? json['payment_method'] ?? 'Cash',
      emiInstallmentNumber: json['emiInstallmentNumber'] ?? json['emi_installment_number'],
      walletId: json['walletId'] ?? json['wallet_id'],
    );
  }

  Map<String, dynamic> toJson() {
    final Map<String, dynamic> data = {};
    if (id != null) data['id'] = id;
    if (invoiceId != null) data['invoiceId'] = invoiceId;
    data['amount'] = amount;
    if (paymentDate != null) {
      data['paymentDate'] = paymentDate!.toIso8601String().split('T')[0];
    }
    data['paymentMethod'] = paymentMethod;
    if (emiInstallmentNumber != null) {
      data['emiInstallmentNumber'] = emiInstallmentNumber;
    }
    if (walletId != null) data['walletId'] = walletId;
    return data;
  }
}