// Scattered everywhere, no composition, no audit trail
$name   = lcfirst(str_replace('_', '', ucwords($input, '_')));  // camelCase
$price  = 'R$ ' . number_format($price, 2, ',', '.');           // currency
$rank   = $rank . 'th';                                          // ordinal
$cpf    = preg_replace('/\D/', '', $cpf);                        // strip formatting

// No attribute DSL, no pipeline composition, no tracking

use KaririCode\Transformer\Provider\TransformerServiceProvider;

$engine = (new TransformerServiceProvider())->createEngine();

$result = $engine->transform(
    data: [
        'name'  => 'walmir_silva',
        'price' => 1234.5,
        'rank'  => 3,
        'cpf'   => '529.982.247-25',
    ],
    fieldRules: [
        'name'  => ['pascal_case'],
        'price' => [['currency_format', ['prefix' => 'R$ ', 'dec_point' => ',', 'thousands' => '.']]],
        'rank'  => ['ordinal'],
        'cpf'   => ['cpf_to_digits'],
    ],
);

echo $result->get('name');  // "WalmirSilva"
echo $result->get('price'); // "R$ 1.234,50"
echo $result->get('rank');  // "3rd"
echo $result->get('cpf');   // "52998224725"

<?php

require_once __DIR__ . '/vendor/autoload.php';

use KaririCode\Transformer\Provider\TransformerServiceProvider;

$engine = (new TransformerServiceProvider())->createEngine();

$result = $engine->transform(
    data: ['name' => 'walmir_silva', 'price' => 1234.5],
    fieldRules: [
        'name'  => ['camel_case'],
        'price' => [['currency_format', ['prefix' => '$']]],
    ],
);

echo $result->get('name');  // "walmirSilva"
echo $result->get('price'); // "$1,234.50"

use KaririCode\Transformer\Attribute\Transform;

final class ApiResponse
{
    #[Transform('camel_case')]
    public string $fieldName = 'user_first_name';

    #[Transform(['mask', ['keep_start' => 3, 'keep_end' => 2]])]
    public string $cpf = '52998224725';

    #[Transform(['currency_format', ['prefix' => 'R$ ', 'dec_point' => ',', 'thousands' => '.']])]
    public float $price = 1234.5;
}

$transformer = (new TransformerServiceProvider())->createAttributeTransformer();
$result      = $transformer->transform(new ApiResponse());

// $dto->fieldName === 'userFirstName'
// $dto->cpf       === '529******25'
// $dto->price     === 'R$ 1.234,50'

$result = $engine->transform(
    ['a' => 'helloWorld', 'b' => 'hello_world', 'c' => 'Hello World', 'd' => 'hello-world'],
    ['a' => ['snake_case'], 'b' => ['camel_case'], 'c' => ['kebab_case'], 'd' => ['pascal_case']],
);
// a: "hello_world", b: "helloWorld", c: "hello-world", d: "HelloWorld"

// Flatten nested arrays
$result = $engine->transform(
    ['config' => ['a' => ['b' => 1, 'c' => 2], 'd' => 3]],
    ['config' => ['flatten']],
);
// config: {"a.b": 1, "a.c": 2, "d": 3}

// Group by field
$result = $engine->transform(
    ['users' => [
        ['dept' => 'eng', 'name' => 'Alice'],
        ['dept' => 'hr',  'name' => 'Bob'],
        ['dept' => 'eng', 'name' => 'Carol'],
    ]],
    ['users' => [['group_by', ['field' => 'dept']]]],
);
// users: {"eng": [{...Alice}, {...Carol}], "hr": [{...Bob}]}

$result = $engine->transform(
    ['cpf' => '529.982.247-25', 'phone' => '85999991234'],
    ['cpf' => ['cpf_to_digits'], 'phone' => ['phone_format']],
);
// cpf:   "52998224725"
// phone: "(85) 99999-1234"

$engine = (new TransformerServiceProvider())->createEngine();

$result = $engine->transform(
    ['price' => 1234.5, 'name' => 'hello_world'],
    ['price' => [['currency_format', ['prefix' => '$']]], 'name' => ['camel_case']],
);

$result->get('price');              // "$1,234.50"
$result->get('name');               // "helloWorld"
$result->wasTransformed();          // true
$result->transformedFields();       // ['price', 'name']

foreach ($result->transformationsFor('name') as $t) {
    echo "{$t->ruleName}: '{$t->before}' → '{$t->after}'\n";
}
// string.camel_case: 'hello_world' → 'helloWorld'