36 lines
1.1 KiB
Dart
36 lines
1.1 KiB
Dart
import 'dart:math';
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/// Masks a card number, leaving only the last 4 digits visible.
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/// Returns 'N/A' when the input is null or empty.
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String? maskCardNumber(String? pan) {
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if (pan == null || pan.isEmpty) return null;
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// Strip non-digits to avoid leaking formatting patterns.
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final digits = pan.replaceAll(RegExp(r'\D'), '');
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if (digits.length <= 4) return digits;
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final last4 = digits.substring(digits.length - 4);
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final maskedPrefix = '*' * (digits.length - 4);
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final masked = '$maskedPrefix$last4';
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// Group into blocks of 4 for readability.
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final groups = <String>[];
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for (var i = 0; i < masked.length; i += 4) {
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final end = min(i + 4, masked.length);
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groups.add(masked.substring(i, end));
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}
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return groups.join(' ');
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}
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String? maskAccountEdge(String? value, {int head = 2, int tail = 2}) {
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if (value == null) return null;
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final trimmed = value.replaceAll(RegExp(r'\s+'), '');
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if (trimmed.isEmpty) return null;
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if (trimmed.length <= head + tail) return trimmed;
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final start = trimmed.substring(0, head);
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final end = trimmed.substring(trimmed.length - tail);
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return '$start*****$end';
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}
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