<?php
/**
 * PHPUnit
 *
 * Copyright (c) 2001-2014, Sebastian Bergmann <sebastian@phpunit.de>.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   * Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   * Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in
 *     the documentation and/or other materials provided with the
 *     distribution.
 *
 *   * Neither the name of Sebastian Bergmann nor the names of his
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * @package    PHPUnit
 * @subpackage Framework
 * @author     Sebastian Bergmann <sebastian@phpunit.de>
 * @author     Bernhard Schussek <bschussek@2bepublished.at>
 * @copyright  2001-2014 Sebastian Bergmann <sebastian@phpunit.de>
 * @license    http://www.opensource.org/licenses/BSD-3-Clause  The BSD 3-Clause License
 * @link       http://www.phpunit.de/
 * @since      File available since Release 3.0.0
 */

use SebastianBergmann\Exporter\Exporter;

/**
 * Abstract base class for constraints. which are placed upon any value.
 *
 * @package    PHPUnit
 * @subpackage Framework
 * @author     Sebastian Bergmann <sebastian@phpunit.de>
 * @author     Bernhard Schussek <bschussek@2bepublished.at>
 * @copyright  2001-2014 Sebastian Bergmann <sebastian@phpunit.de>
 * @license    http://www.opensource.org/licenses/BSD-3-Clause  The BSD 3-Clause License
 * @link       http://www.phpunit.de/
 * @since      Interface available since Release 3.0.0
 */
abstract class PHPUnit_Framework_Constraint implements Countable, PHPUnit_Framework_SelfDescribing
{
    protected $exporter;

    public function __construct()
    {
        $this->exporter = new Exporter;
    }

    /**
     * Evaluates the constraint for parameter $other
     *
     * If $returnResult is set to false (the default), an exception is thrown
     * in case of a failure. null is returned otherwise.
     *
     * If $returnResult is true, the result of the evaluation is returned as
     * a boolean value instead: true in case of success, false in case of a
     * failure.
     *
     * @param  mixed                                        $other        Value or object to evaluate.
     * @param  string                                       $description  Additional information about the test
     * @param  bool                                         $returnResult Whether to return a result or throw an exception
     * @return mixed
     * @throws PHPUnit_Framework_ExpectationFailedException
     */
    public function evaluate($other, $description = '', $returnResult = false)
    {
        $success = false;

        if ($this->matches($other)) {
            $success = true;
        }

        if ($returnResult) {
            return $success;
        }

        if (!$success) {
            $this->fail($other, $description);
        }
    }

    /**
     * Evaluates the constraint for parameter $other. Returns true if the
     * constraint is met, false otherwise.
     *
     * This method can be overridden to implement the evaluation algorithm.
     *
     * @param  mixed $other Value or object to evaluate.
     * @return bool
     */
    protected function matches($other)
    {
        return false;
    }

    /**
     * Counts the number of constraint elements.
     *
     * @return integer
     * @since  Method available since Release 3.4.0
     */
    public function count()
    {
        return 1;
    }

    /**
     * Throws an exception for the given compared value and test description
     *
     * @param  mixed $other Evaluated value or object.
     * @param  string $description Additional information about the test
     * @param  SebastianBergmann\Comparator\ComparisonFailure $comparisonFailure
     * @throws PHPUnit_Framework_ExpectationFailedException
     */
    protected function fail($other, $description, SebastianBergmann\Comparator\ComparisonFailure $comparisonFailure = null)
    {
        $failureDescription = sprintf(
          'Failed asserting that %s.',
          $this->failureDescription($other)
        );

        $additionalFailureDescription = $this->additionalFailureDescription($other);

        if ($additionalFailureDescription) {
            $failureDescription .= "\n" . $additionalFailureDescription;
        }

        if (!empty($description)) {
            $failureDescription = $description . "\n" . $failureDescription;
        }

        throw new PHPUnit_Framework_ExpectationFailedException(
          $failureDescription,
          $comparisonFailure
        );
    }

    /**
     * Return additional failure description where needed
     *
     * The function can be overridden to provide additional failure
     * information like a diff
     *
     * @param  mixed  $other Evaluated value or object.
     * @return string
     */
    protected function additionalFailureDescription($other)
    {
        return '';
    }

    /**
     * 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.
     *
     * To provide additional failure information additionalFailureDescription
     * can be used.
     *
     * @param  mixed  $other Evaluated value or object.
     * @return string
     */
    protected function failureDescription($other)
    {
        return $this->exporter->export($other) . ' ' . $this->toString();
    }
}
