<?php

namespace IQBall\Core\Validation;

/**
 * A simple validator that takes a predicate and an error factory
 */
class SimpleFunctionValidator extends Validator {
    /**
     * @var callable(mixed): bool
     */
    private $predicate;
    /**
     * @var callable(string): ValidationFail[]
     */
    private $errorFactory;

    /**
     * @param callable(mixed): bool $predicate a function predicate with signature: `(string) => bool`, to validate the given string
     * @param callable(string): ValidationFail[] $errorsFactory a factory function with signature `(string) => array` to emit failures when the predicate fails
     */
    public function __construct(callable $predicate, callable $errorsFactory) {
        $this->predicate = $predicate;
        $this->errorFactory = $errorsFactory;
    }

    public function validate(string $name, $val): array {
        if (!call_user_func_array($this->predicate, [$val])) {
            return call_user_func_array($this->errorFactory, [$name]);
        }
        return [];
    }
}