/// Utility functions for text processing
class TextUtils {
  /// Convert Vietnamese characters to English (non-accented) characters
  /// Example: "Tuấn" -> "tuan", "Hồ Chí Minh" -> "ho chi minh"
  static String removeVietnameseAccents(String text) {
    if (text.isEmpty) return text;

    // Convert to lowercase for consistent comparison
    String result = text.toLowerCase();

    // Map of Vietnamese characters to their non-accented equivalents
    const vietnameseMap = {
      // a with accents
      'á': 'a', 'à': 'a', 'ả': 'a', 'ã': 'a', 'ạ': 'a',
      'ă': 'a', 'ắ': 'a', 'ằ': 'a', 'ẳ': 'a', 'ẵ': 'a', 'ặ': 'a',
      'â': 'a', 'ấ': 'a', 'ầ': 'a', 'ẩ': 'a', 'ẫ': 'a', 'ậ': 'a',

      // e with accents
      'é': 'e', 'è': 'e', 'ẻ': 'e', 'ẽ': 'e', 'ẹ': 'e',
      'ê': 'e', 'ế': 'e', 'ề': 'e', 'ể': 'e', 'ễ': 'e', 'ệ': 'e',

      // i with accents
      'í': 'i', 'ì': 'i', 'ỉ': 'i', 'ĩ': 'i', 'ị': 'i',

      // o with accents
      'ó': 'o', 'ò': 'o', 'ỏ': 'o', 'õ': 'o', 'ọ': 'o',
      'ô': 'o', 'ố': 'o', 'ồ': 'o', 'ổ': 'o', 'ỗ': 'o', 'ộ': 'o',
      'ơ': 'o', 'ớ': 'o', 'ờ': 'o', 'ở': 'o', 'ỡ': 'o', 'ợ': 'o',

      // u with accents
      'ú': 'u', 'ù': 'u', 'ủ': 'u', 'ũ': 'u', 'ụ': 'u',
      'ư': 'u', 'ứ': 'u', 'ừ': 'u', 'ử': 'u', 'ữ': 'u', 'ự': 'u',

      // y with accents
      'ý': 'y', 'ỳ': 'y', 'ỷ': 'y', 'ỹ': 'y', 'ỵ': 'y',

      // d with stroke
      'đ': 'd',
    };

    // Replace each Vietnamese character with its non-accented equivalent
    vietnameseMap.forEach((vietnamese, english) {
      result = result.replaceAll(vietnamese, english);
    });

    return result;
  }

  /// Normalize text for search (lowercase + remove accents)
  static String normalizeForSearch(String text) {
    return removeVietnameseAccents(text.toLowerCase().trim());
  }

  /// Check if a text contains a search term (Vietnamese-aware, case-insensitive)
  ///
  /// Example:
  /// ```dart
  /// containsVietnameseSearch("Nguyễn Văn Tuấn", "tuan") // returns true
  /// containsVietnameseSearch("tuan@example.com", "TUAN") // returns true
  /// ```
  static bool containsVietnameseSearch(String text, String searchTerm) {
    if (searchTerm.isEmpty) return true;
    if (text.isEmpty) return false;

    final normalizedText = normalizeForSearch(text);
    final normalizedSearch = normalizeForSearch(searchTerm);

    return normalizedText.contains(normalizedSearch);
  }

  /// Check if any of the provided texts contains the search term
  static bool containsVietnameseSearchInAny(
    List<String> texts,
    String searchTerm,
  ) {
    if (searchTerm.isEmpty) return true;

    for (final text in texts) {
      if (containsVietnameseSearch(text, searchTerm)) {
        return true;
      }
    }

    return false;
  }
}