<?php
/**
 * Choice rule.
 *
 * @package FormPilot
 * @since   1.0.0
 */

declare( strict_types = 1 );

namespace FormPilot\Validation\Rules;

use FormPilot\Contracts\ValidationRule;
use FormPilot\Fields\FieldTypes;
use FormPilot\Models\Field;
use FormPilot\Validation\ValidationError;

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

/**
 * Checks that every submitted choice exists on the field.
 *
 * The browser only offers the options the form rendered, so a value outside
 * that set means the request was assembled by hand. Trusting it would let a
 * visitor write arbitrary text into a column the site treats as a fixed
 * vocabulary.
 *
 * @since 1.0.0
 */
final class ChoiceRule implements ValidationRule {

	/**
	 * Field types that offer a fixed set of choices.
	 */
	private const TYPES = array( FieldTypes::SELECT, FieldTypes::RADIO, FieldTypes::CHECKBOX );

	/**
	 * Determines whether this rule applies to a field.
	 *
	 * @param Field $field Field being validated.
	 */
	public function supports( Field $field ): bool {
		return in_array( $field->type(), self::TYPES, true );
	}

	/**
	 * Checks the submitted choices against the field.
	 *
	 * @param Field $field Field being validated.
	 * @param mixed $value Sanitised value.
	 *
	 * @return ValidationError|null The failure, or null when the value passes.
	 */
	public function validate( Field $field, mixed $value ): ?ValidationError {
		$allowed = array();

		foreach ( $field->options() as $option ) {
			$allowed[] = (string) ( $option['value'] ?? '' );
		}

		foreach ( (array) $value as $item ) {
			if ( ! in_array( (string) $item, $allowed, true ) ) {
				return new ValidationError(
					'',
					'invalid_choice',
					__( 'Please choose one of the available options.', 'devplugins-custom-form-builder' )
				);
			}
		}

		return $this->check_count( $field, (array) $value );
	}

	/**
	 * Checks how many choices were made against the configured limits.
	 *
	 * @param Field             $field    Field being validated.
	 * @param array<int, mixed> $selected Submitted choices.
	 *
	 * @return ValidationError|null The failure, or null when the count is acceptable.
	 */
	private function check_count( Field $field, array $selected ): ?ValidationError {
		$count = count( $selected );
		$min   = (int) $field->setting( 'min_choices', 0 );
		$max   = (int) $field->setting( 'max_choices', 0 );

		if ( $min > 0 && $count < $min ) {
			return new ValidationError(
				'',
				'too_few_choices',
				sprintf(
					/* translators: %s: Smallest number of choices required. */
					_n( 'Please choose at least %s option.', 'Please choose at least %s options.', $min, 'devplugins-custom-form-builder' ),
					number_format_i18n( $min )
				),
				array( 'min' => $min )
			);
		}

		if ( $max > 0 && $count > $max ) {
			return new ValidationError(
				'',
				'too_many_choices',
				sprintf(
					/* translators: %s: Largest number of choices allowed. */
					_n( 'Please choose no more than %s option.', 'Please choose no more than %s options.', $max, 'devplugins-custom-form-builder' ),
					number_format_i18n( $max )
				),
				array( 'max' => $max )
			);
		}

		return null;
	}
}