fromFile static method

Future<Country> fromFile(String csvFile)

Creates a Country instance by reading and parsing a CSV file.

The csvFile parameter is the full path to the country information CSV file.

Implementation

static Future<Country> fromFile(String csvFile) async {
  final country = Country._();

  final file = File(csvFile);
  if (!await file.exists()) {
    throw Exception('The CSV file $csvFile is not found.');
  }

  final contents = await file.readAsString();
  if (contents.trim().isEmpty) {
    throw Exception('Unable to read $csvFile.');
  }

  final rows = const CsvToListConverter().convert(contents);

  if (rows.isEmpty) {
    throw Exception('Invalid country information CSV file.');
  }

  // First row should be headers
  final headers = rows.first.map((h) => h.toString()).toList();
  final countryCodeIndex = headers.indexOf('country_code');

  if (countryCodeIndex == -1) {
    throw Exception('Invalid country information CSV file.');
  }

  for (var i = 1; i < rows.length; i++) {
    final row = rows[i];
    final rowMap = <String, String>{};

    for (var j = 0; j < headers.length; j++) {
      rowMap[headers[j]] = row[j]?.toString() ?? '';
    }

    country._records[rowMap['country_code'] ?? ''] = rowMap;
  }

  return country;
}