<?php
/**
 * Validation result.
 *
 * @package FormPilot
 * @since   1.0.0
 */

declare( strict_types = 1 );

namespace FormPilot\Validation;

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Carries the outcome of validating a submission.
 *
 * Holds every reason a field failed rather than only the first, so an API
 * client can show all of them at once, while {@see ValidationResult::errors()}
 * keeps returning one sentence per field for the form UI, which has room for
 * exactly that.
 *
 * @since 1.0.0
 */
final class ValidationResult {

	/**
	 * Accepted values, keyed by field key.
	 *
	 * @var array<string, mixed>
	 */
	private array $values = array();

	/**
	 * Errors, keyed by field key, in the order they were found.
	 *
	 * @var array<string, array<int, ValidationError>>
	 */
	private array $errors = array();

	/**
	 * Stores an accepted value.
	 *
	 * @param string $key   Field key.
	 * @param mixed  $value Sanitised value.
	 */
	public function add_value( string $key, mixed $value ): void {
		$this->values[ $key ] = $value;
	}

	/**
	 * Records a failure.
	 *
	 * @param ValidationError $error Reason the value was refused.
	 */
	public function add( ValidationError $error ): void {
		$key = $error->field();

		if ( '' === $key ) {
			return;
		}

		$this->errors[ $key ][] = $error;

		// A field that failed has no accepted value.
		unset( $this->values[ $key ] );
	}

	/**
	 * Records a failure from its parts.
	 *
	 * Kept for callers that have a message and nothing else, such as an add-on
	 * hooked to `formpilot_validate_submission`.
	 *
	 * @param string               $key     Field key.
	 * @param string               $message Sentence shown to the visitor.
	 * @param string               $code    Optional. Machine readable reason. Default 'invalid'.
	 * @param array<string, mixed> $data    Optional. Values behind the message. Default empty.
	 */
	public function add_error( string $key, string $message, string $code = 'invalid', array $data = array() ): void {
		$this->add( new ValidationError( $key, $code, $message, $data ) );
	}

	/**
	 * Determines whether the submission passed.
	 *
	 * @return bool True when no field reported an error.
	 */
	public function is_valid(): bool {
		return array() === $this->errors;
	}

	/**
	 * Returns the accepted values.
	 *
	 * @return array<string, mixed> Values keyed by field key.
	 */
	public function values(): array {
		return $this->values;
	}

	/**
	 * Returns one message per failed field.
	 *
	 * The shape the form script and the AJAX response expect.
	 *
	 * @return array<string, string> Messages keyed by field key.
	 */
	public function errors(): array {
		$messages = array();

		foreach ( $this->errors as $key => $errors ) {
			$first = reset( $errors );

			if ( $first instanceof ValidationError ) {
				$messages[ $key ] = $first->message();
			}
		}

		return $messages;
	}

	/**
	 * Returns every failure, grouped by field.
	 *
	 * @return array<string, array<int, ValidationError>> Errors keyed by field key.
	 */
	public function all(): array {
		return $this->errors;
	}

	/**
	 * Returns every failure as plain arrays.
	 *
	 * @return array<string, array<int, array<string, mixed>>> Payloads keyed by field key.
	 */
	public function to_array(): array {
		$errors = array();

		foreach ( $this->errors as $key => $list ) {
			foreach ( $list as $error ) {
				$errors[ $key ][] = $error->to_array();
			}
		}

		return $errors;
	}

	/**
	 * Determines whether a specific field failed.
	 *
	 * @param string $key Field key.
	 *
	 * @return bool True when the field has at least one error.
	 */
	public function has_error( string $key ): bool {
		return isset( $this->errors[ $key ] );
	}
}