<?php
/**
 * Number 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 a number field holds a number inside its configured range.
 *
 * @since 1.0.0
 */
final class NumberRule implements ValidationRule {

	/**
	 * Determines whether this rule applies to a field.
	 *
	 * @param Field $field Field being validated.
	 */
	public function supports( Field $field ): bool {
		return FieldTypes::NUMBER === $field->type();
	}

	/**
	 * Checks the number and its range.
	 *
	 * @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 {
		if ( ! is_numeric( $value ) ) {
			return new ValidationError(
				'',
				'invalid_number',
				__( 'Please enter a number.', 'devplugins-custom-form-builder' )
			);
		}

		$number = (float) $value;
		$min    = $field->setting( 'min', '' );
		$max    = $field->setting( 'max', '' );

		if ( '' !== $min && is_numeric( $min ) && $number < (float) $min ) {
			return new ValidationError(
				'',
				'number_too_small',
				sprintf(
					/* translators: %s: Smallest accepted number. */
					__( 'Please enter a value of %s or more.', 'devplugins-custom-form-builder' ),
					(string) $min
				),
				array( 'min' => (float) $min )
			);
		}

		if ( '' !== $max && is_numeric( $max ) && $number > (float) $max ) {
			return new ValidationError(
				'',
				'number_too_large',
				sprintf(
					/* translators: %s: Largest accepted number. */
					__( 'Please enter a value of %s or less.', 'devplugins-custom-form-builder' ),
					(string) $max
				),
				array( 'max' => (float) $max )
			);
		}

		/*
		 * The step was saved and handed to the browser, but nothing on the server
		 * read it, so a request could send 2.5 to a field that counts in whole
		 * units. Measured from the minimum, as the browser measures it.
		 */
		$step = $field->setting( 'step', '' );

		if ( is_numeric( $step ) && (float) $step > 0 ) {
			$base  = ( '' !== $min && is_numeric( $min ) ) ? (float) $min : 0.0;
			$steps = ( $number - $base ) / (float) $step;

			if ( abs( $steps - round( $steps ) ) > 1e-9 * max( 1.0, abs( $steps ) ) ) {
				return new ValidationError(
					'',
					'number_off_step',
					sprintf(
						/* translators: %s: Step between accepted numbers. */
						__( 'Please enter a value in steps of %s.', 'devplugins-custom-form-builder' ),
						(string) $step
					),
					array( 'step' => (float) $step )
				);
			}
		}

		return null;
	}
}