<?php
declare(strict_types=1);
namespace Butschster\ContextGenerator\Lib\Variable;
use Butschster\ContextGenerator\Application\Logger\LoggerPrefix;
use Butschster\ContextGenerator\Lib\Variable\Provider\VariableProviderInterface;
use Psr\Log\LoggerInterface;
use Spiral\Core\Attribute\Proxy;
/**
* Processor that replaces variable references in text
*
* Supports:
* - ${VAR_NAME} - simple variable reference
* - ${VAR_NAME:-default} - variable with default value
* - {{VAR_NAME}} - alternative syntax
* - {{VAR_NAME:-default}} - alternative syntax with default
*/
final readonly class VariableReplacementProcessor implements VariableReplacementProcessorInterface
{
public function __construct(
#[Proxy]
private VariableProviderInterface $provider,
#[LoggerPrefix(prefix: 'variable-replacement')]
private ?LoggerInterface $logger = null,
) {}
/**
* Process text by replacing variable references
*
* @param string $text Text containing variable references
* @return string Text with variables replaced
*/
public function process(string $text): string
{
// Replace ${VAR_NAME} and ${VAR_NAME:-default} syntax
$result = \preg_replace_callback(
'/\${([a-zA-Z0-9_]+)(?::-([^}]*))?}/',
fn(array $matches) => $this->replaceVariable(
name: $matches[1],
default: $matches[2] ?? null,
format: '${%s}',
),
$text,
);
// Replace {{VAR_NAME}} and {{VAR_NAME:-default}} syntax
return (string) \preg_replace_callback(
'/{{([a-zA-Z0-9_]+)(?::-([^}]*))?}}/',
fn(array $matches) => $this->replaceVariable(
name: $matches[1],
default: $matches[2] ?? null,
format: '{{%s}}',
),
(string) $result,
);
}
/**
* Replace a single variable reference
*
* @param string $name Variable name
* @param string|null $default Default value if variable not found
* @param string $format Format for unreplaced variable
* @return string Variable value, default value, or original reference
*/
private function replaceVariable(string $name, ?string $default, string $format): string
{
if ($this->provider->has($name)) {
$value = $this->provider->get($name);
$this->logger?->debug('Replacing variable', [
'name' => $name,
'value' => $value,
]);
return $value ?? '';
}
// Variable not found - use default if provided
if ($default !== null) {
$this->logger?->debug('Using default value for variable', [
'name' => $name,
'default' => $default,
]);
return $default;
}
// Keep the original reference if not found and no default
return \sprintf($format, $name);
}
}
