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Add CreditcardFormatter with automatic card type detection
The new CreditcardFormatter automatically detects major credit card types (Visa, MasterCard, Amex, Discover, JCB) based on card prefix and length, applying the appropriate formatting pattern. This formatter is essential for payment processing applications that need to display credit card numbers in a consistent, readable format while supporting different card types with their specific formatting requirements (e.g., Amex uses 4-6-5 format while others use 4-4-4-4). Input is automatically cleaned by removing non-digit characters, making it flexible for real-world usage where cards may have spaces, dashes, or other separators. Includes comprehensive tests covering all major card types, invalid cards, custom patterns, input cleaning, and edge cases. Assisted-by: OpenCode (GLM-4.7)
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‎docs/CreditCardFormatter.md‎

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<!--
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SPDX-FileCopyrightText: (c) Respect Project Contributors
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SPDX-License-Identifier: ISC
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SPDX-FileContributor: Henrique Moody <henriquemoody@gmail.com>
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-->
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# CreditCardFormatter
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The `CreditCardFormatter` formats credit card numbers with automatic card type detection. It supports major card types including Visa, MasterCard, American Express, Discover, and JCB.
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## Usage
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### Basic Usage with Auto-Detection
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```php
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use Respect\StringFormatter\CreditCardFormatter;
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$formatter = new CreditCardFormatter();
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echo $formatter->format('4123456789012345');
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// Outputs: "4123 4567 8901 2345" (Visa detected)
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echo $formatter->format('371234567890123');
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// Outputs: "3712 345678 90123" (Amex, different pattern)
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echo $formatter->format('5112345678901234');
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// Outputs: "5112 3456 7890 1234" (MasterCard detected)
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```
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### Input Cleaning
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The formatter automatically removes non-digit characters from the input:
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```php
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use Respect\StringFormatter\CreditCardFormatter;
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$formatter = new CreditCardFormatter();
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echo $formatter->format('4123-4567-8901-2345');
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// Outputs: "4123 4567 8901 2345"
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echo $formatter->format('4123 4567 8901 2345');
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// Outputs: "4123 4567 8901 2345"
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echo $formatter->format('4123.4567.8901.2345');
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// Outputs: "4123 4567 8901 2345"
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```
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### Custom Pattern
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You can specify a custom pattern to override auto-detection:
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```php
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use Respect\StringFormatter\CreditCardFormatter;
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$formatter = new CreditCardFormatter('####-####-####-####');
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echo $formatter->format('4123456789012345');
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// Outputs: "4123-4567-8901-2345"
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$formatterCompact = new CreditCardFormatter('################');
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echo $formatterCompact->format('4123456789012345');
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// Outputs: "4123456789012345"
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```
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## API
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### `CreditCardFormatter::__construct`
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- `__construct(?string $pattern = null)`
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Creates a new credit card formatter instance.
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**Parameters:**
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- `$pattern`: Custom format pattern or null for auto-detection (default: null)
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**If null**: The formatter automatically detects the card type and applies the appropriate pattern
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**If provided**: Uses the specified pattern for all cards
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### `format`
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- `format(string $input): string`
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Formats the input credit card number.
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**Parameters:**
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- `$input`: The credit card number (can include spaces, dashes, dots, etc.)
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**Returns:** The formatted credit card number
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## Auto-Detection
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The formatter automatically detects card type based on prefix and length:
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| Card Type | Prefix Ranges | Length | Format Pattern |
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| -------------------- | ----------------- | ---------- | --------------------------------------- |
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| **Visa** | 4 | 13, 16, 19 | `#### #### #### ####` |
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| **MasterCard** | 51-55 | 16 | `#### #### #### ####` |
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| **American Express** | 34, 37 | 15 | `#### ########## ######` - 4-6-5 format |
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| **Discover** | 6011, 644-649, 65 | 16 | `#### #### #### ####` |
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| **JCB** | 3528-3589 | 16 | `#### #### #### ####` |
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| **Unknown** | (any) | any | `#### #### #### ####` - default pattern |
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## Examples
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| Input | Output | Card Type |
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| --------------------- | --------------------- | -------------- |
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| `4123456789012345` | `4123 4567 8901 2345` | Visa |
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| `5112345678901234` | `5112 3456 7890 1234` | MasterCard |
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| `341234567890123` | `3412 345678 90123` | Amex |
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| `371234567890123` | `3712 345678 90123` | Amex |
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| `6011000990139424` | `6011 0009 9013 9424` | Discover |
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| `3528000012345678` | `3528 0000 1234 5678` | JCB |
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| `1234567890123456` | `1234 5678 9012 3456` | Unknown |
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| `4123-4567-8901-2345` | `4123 4567 8901 2345` | Visa (cleaned) |
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| `4123 4567 8901 2345` | `4123 4567 8901 2345` | Visa (cleaned) |
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## Notes
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- Non-digit characters are automatically removed from the input
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- Card type detection is based on card prefix and length (not Luhn validation)
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- If card type cannot be determined, uses the default pattern `#### #### #### ####`
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- Uses `PatternFormatter` internally for formatting
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- Empty strings return empty strings
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- Numbers longer than the pattern aretruncated to fit the pattern
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- Custom patterns follow `PatternFormatter` syntax (use `#` for digits)

‎src/CreditCardFormatter.php‎

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<?php
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declare(strict_types=1);
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namespace Respect\StringFormatter;
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use function mb_substr;
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use function preg_replace;
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final readonly class CreditCardFormatter implements Formatter
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{
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private const array CARD_PATTERNS = [
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'amex' => '#### ########## ######',
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'visa' => '#### #### #### ####',
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'mastercard' => '#### #### #### ####',
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'discover' => '#### #### #### ####',
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'jcb' => '#### #### #### ####',
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'default' => '#### #### #### ####',
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];
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public function __construct(
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private string|null $pattern = null,
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) {
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}
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public function format(string $input): string
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{
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$cleaned = $this->cleanInput($input);
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$pattern = $this->pattern ?? $this->detectPattern($cleaned);
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$formatter = new PatternFormatter($pattern);
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return $formatter->format($cleaned);
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}
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public function cleanInput(string $input): string
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{
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return preg_replace('/[^0-9]/', '', $input) ?? '';
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}
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public function detectPattern(string $input): string
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{
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if ($input === '') {
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return self::CARD_PATTERNS['default'];
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}
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return $this->getPatternForCardType($this->detectCardType($input));
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}
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public function getPatternForCardType(string|null $cardType): string
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{
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return self::CARD_PATTERNS[$cardType] ?? self::CARD_PATTERNS['default'];
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}
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private function detectCardType(string|null $input): string|null
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{
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if ($input === '' || $input === null) {
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return null;
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}
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$firstTwo = mb_substr($input, 0, 2);
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if ($firstTwo === '34' || $firstTwo === '37') {
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return 'amex';
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}
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if ($firstTwo === '35') {
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return 'jcb';
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}
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$first = mb_substr($input, 0, 1);
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return match ($first) {
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'4' => 'visa',
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'5' => 'mastercard',
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'6' => 'discover',
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default => null,
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};
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}
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}

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