<?php

/*

 * This file is part of the Symfony package.

 *

 * (c) Fabien Potencier <fabien@symfony.com>

 *

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

 * file that was distributed with this source code.

 */

namespace Symfony\Component\Form\Guess;

/**

 * Base class for guesses made by TypeGuesserInterface implementation

 *

 * Each instance contains a confidence value about the correctness of the guess.

 * Thus an instance with confidence HIGH_CONFIDENCE is more likely to be

 * correct than an instance with confidence LOW_CONFIDENCE.

 *

 * @author Bernhard Schussek <bernhard.schussek@symfony.com>

 */

abstract class Guess

{

    /**

     * Marks an instance with a value that is very likely to be correct

     * @var integer

     */

    const HIGH_CONFIDENCE = 2;

    /**

     * Marks an instance with a value that is likely to be correct

     * @var integer

     */

    const MEDIUM_CONFIDENCE = 1;

    /**

     * Marks an instance with a value that may be correct

     * @var integer

     */

    const LOW_CONFIDENCE = 0;

    /**

     * The list of allowed confidence values

     * @var array

     */

    private static $confidences = array(

        self::HIGH_CONFIDENCE,

        self::MEDIUM_CONFIDENCE,

        self::LOW_CONFIDENCE,

    );

    /**

     * The confidence about the correctness of the value

     *

     * One of HIGH_CONFIDENCE, MEDIUM_CONFIDENCE and LOW_CONFIDENCE.

     *

     * @var integer

     */

    private $confidence;

    /**

     * Returns the guess most likely to be correct from a list of guesses

     *

     * If there are multiple guesses with the same, highest confidence, the

     * returned guess is any of them.

     *

     * @param  array $guesses     A list of guesses

     * @return Guess  The guess with the highest confidence

     */

    static public function getBestGuess(array $guesses)

    {

        usort($guesses, function ($a, $b) {

            return $b->getConfidence() - $a->getConfidence();

        });

        return count($guesses) > 0 ? $guesses[0] : null;

    }

    /**

     * Constructor

     *

     * @param integer $confidence   The confidence

     */

    public function __construct($confidence)

    {

        if (!in_array($confidence, self::$confidences)) {

            throw new \UnexpectedValueException(sprintf('The confidence should be one of "%s"', implode('", "', self::$confidences)));

        }

        $this->confidence = $confidence;

    }

    /**

     * Returns the confidence that the guessed value is correct

     *

     * @return integer  One of the constants HIGH_CONFIDENCE, MEDIUM_CONFIDENCE

     *                  and LOW_CONFIDENCE

     */

    public function getConfidence()

    {

        return $this->confidence;

    }

}