<?php declare(strict_types=1);

/*

 * This file is part of PHPUnit.

 *

 * (c) Sebastian Bergmann <sebastian@phpunit.de>

 *

 * For the full copyright and license information, please view the LICENSE

 * file that was distributed with this source code.

 */

namespace PHPUnit\Framework\Constraint;



use function count;



/**

 * @no-named-arguments Parameter names are not covered by the backward compatibility promise for PHPUnit

 */

abstract class UnaryOperator extends Operator

{

    /**

     * @var Constraint

     */

    private $constraint;



    /**

     * @param Constraint|mixed $constraint

     */

    public function __construct($constraint)

    {

        $this->constraint = $this->checkConstraint($constraint);

    }



    /**

     * Returns the number of operands (constraints).

     */

    public function arity(): int

    {

        return 1;

    }



    /**

     * Returns a string representation of the constraint.

     */

    public function toString(): string

    {

        $reduced = $this->reduce();



        if ($reduced !== $this) {

            return $reduced->toString();

        }



        $constraint = $this->constraint->reduce();



        if ($this->constraintNeedsParentheses($constraint)) {

            return $this->operator() . '( ' . $constraint->toString() . ' )';

        }



        $string = $constraint->toStringInContext($this, 0);



        if ($string === '') {

            return $this->transformString($constraint->toString());

        }



        return $string;

    }



    /**

     * Counts the number of constraint elements.

     */

    public function count(): int

    {

        return count($this->constraint);

    }



    /**

     * Returns the description of the failure.

     *

     * The beginning of failure messages is "Failed asserting that" in most

     * cases. This method should return the second part of that sentence.

     *

     * @param mixed $other evaluated value or object

     *

     * @throws \SebastianBergmann\RecursionContext\InvalidArgumentException

     */

    protected function failureDescription($other): string

    {

        $reduced = $this->reduce();



        if ($reduced !== $this) {

            return $reduced->failureDescription($other);

        }



        $constraint = $this->constraint->reduce();



        if ($this->constraintNeedsParentheses($constraint)) {

            return $this->operator() . '( ' . $constraint->failureDescription($other) . ' )';

        }



        $string = $constraint->failureDescriptionInContext($this, 0, $other);



        if ($string === '') {

            return $this->transformString($constraint->failureDescription($other));

        }



        return $string;

    }



    /**

     * Transforms string returned by the memeber constraint's toString() or

     * failureDescription() such that it reflects constraint's participation in

     * this expression.

     *

     * The method may be overwritten in a subclass to apply default

     * transformation in case the operand constraint does not provide its own

     * custom strings via toStringInContext() or failureDescriptionInContext().

     *

     * @param string $string the string to be transformed

     */

    protected function transformString(string $string): string

    {

        return $string;

    }



    /**

     * Provides access to $this->constraint for subclasses.

     */

    final protected function constraint(): Constraint

    {

        return $this->constraint;

    }



    /**

     * Returns true if the $constraint needs to be wrapped with parentheses.

     */

    protected function constraintNeedsParentheses(Constraint $constraint): bool

    {

        $constraint = $constraint->reduce();



        return $constraint instanceof self || parent::constraintNeedsParentheses($constraint);

    }

}

