import 'package:intl/intl.dart';
import '../../inventory/domain/product.dart';
import '../../inventory/domain/inventory_item.dart';
import '../domain/label_document.dart';

class TemplateDataResolver {
  static final NumberFormat _currencyFormatter = NumberFormat('#,##,##0.##');

  /// Resolves a single field value from a Product (and optional InventoryItem)
  static String? resolveFieldValue({
    required String source,
    required String fieldKey,
    Product? product,
    InventoryItem? inventoryItem,
  }) {
    if (product == null && inventoryItem == null) return null;

    if (source == 'product' && product != null) {
      switch (fieldKey) {
        case 'name':
          return product.name;
        case 'sku':
          return product.sku ?? (inventoryItem?.tagNumber ?? 'SKU-001');
        case 'barcode':
          return (product.barcode != null && product.barcode!.isNotEmpty)
              ? product.barcode
              : (inventoryItem?.tagNumber ?? product.sku ?? '8901234567890');
        case 'sellingPrice':
          final price = product.sellingPrice ?? product.mrp;
          return price != null ? _currencyFormatter.format(price) : null;
        case 'mrp':
          final price = product.mrp ?? product.sellingPrice;
          return price != null ? _currencyFormatter.format(price) : null;
        case 'weightInG':
          final wt = inventoryItem?.grossWeight ?? product.weightInG;
          return wt?.toStringAsFixed(2);
        case 'hsnCode':
          return product.hsnCode;
        case 'gstRate':
          return product.gstRate != null ? product.gstRate!.toStringAsFixed(0) : '3';
        case 'brandName':
          return product.brandName;
        case 'material':
          return product.material;
        case 'size':
          return product.size;
        case 'color':
          return product.color;
        case 'manufacturerCode':
          return inventoryItem?.huid ?? product.manufacturerCode;
        case 'purityFactor':
          if (inventoryItem?.purity != null) return inventoryItem!.purity;
          return product.purityFactor != null
              ? '${(product.purityFactor! * 100).toStringAsFixed(1)}%'
              : null;
        case 'currentStock':
          return product.currentStock?.toString();
        case 'description':
          return product.description;
        default:
          return null;
      }
    }

    if (source == 'inventory' && inventoryItem != null) {
      switch (fieldKey) {
        case 'tagNumber':
          return inventoryItem.tagNumber;
        case 'huid':
          return inventoryItem.huid;
        case 'grossWeight':
          return inventoryItem.grossWeight?.toStringAsFixed(3);
        case 'netWeight':
          return inventoryItem.netWeight?.toStringAsFixed(3);
        case 'purity':
          return inventoryItem.purity;
        default:
          return null;
      }
    }

    return null;
  }

  /// Resolves an entire LabelDocument against sample data, returning a resolved copy
  static LabelDocument resolveDocument({
    required LabelDocument document,
    Product? product,
    InventoryItem? inventoryItem,
  }) {
    if (product == null && inventoryItem == null) {
      return document;
    }

    final resolvedElements = <LabelElement>[];

    for (final elem in document.elements) {
      if (elem is DynamicTextElement) {
        final rawVal = resolveFieldValue(
          source: elem.source,
          fieldKey: elem.fieldKey,
          product: product,
          inventoryItem: inventoryItem,
        );
        final formattedText = elem.formatValue(rawVal);
        resolvedElements.add(
          TextElement(
            id: elem.id,
            xMm: elem.xMm,
            yMm: elem.yMm,
            widthMm: elem.widthMm,
            heightMm: elem.heightMm,
            rotation: elem.rotation,
            isLocked: elem.isLocked,
            zIndex: elem.zIndex,
            text: formattedText,
            fontFamily: elem.fontFamily,
            fontSizePt: elem.fontSizePt,
            isBold: elem.isBold,
            isItalic: elem.isItalic,
            alignment: elem.alignment,
            borderWidthMm: elem.borderWidthMm,
            paddingMm: elem.paddingMm,
          ),
        );
      } else if (elem is BarcodeElement) {
        if (elem.valueType == 'dynamic') {
          final resolvedVal = resolveFieldValue(
            source: elem.source,
            fieldKey: elem.fieldKey,
            product: product,
            inventoryItem: inventoryItem,
          ) ?? elem.staticValue;

          final effectiveBarcode = (resolvedVal.isNotEmpty ? resolvedVal : (product?.sku ?? '8901234567890'))
              .replaceAll(RegExp(r'[^a-zA-Z0-9\-]'), '');

          resolvedElements.add(
            elem.copyWithPosition(
              valueType: 'static',
              staticValue: effectiveBarcode.isNotEmpty ? effectiveBarcode : '8901234567890',
            ),
          );
        } else {
          resolvedElements.add(elem);
        }
      } else if (elem is QrCodeElement) {
        if (elem.valueType == 'dynamic') {
          final resolvedVal = resolveFieldValue(
            source: elem.source,
            fieldKey: elem.fieldKey,
            product: product,
            inventoryItem: inventoryItem,
          ) ?? elem.staticValue;

          final effectiveQr = resolvedVal.isNotEmpty ? resolvedVal : (product?.sku ?? '8901234567890');

          resolvedElements.add(
            elem.copyWithPosition(
              valueType: 'static',
              staticValue: effectiveQr,
            ),
          );
        } else {
          resolvedElements.add(elem);
        }
      } else {
        resolvedElements.add(elem);
      }
    }

    return document.copyWith(elements: resolvedElements);
  }
}