<?php

namespace Drupal\Tests;

use Behat\Mink\Exception\ExpectationException;
use Behat\Mink\WebAssert as MinkWebAssert;
use Behat\Mink\Element\TraversableElement;
use Behat\Mink\Exception\ElementNotFoundException;
use Behat\Mink\Session;
use Drupal\Component\Utility\Html;
use Drupal\Core\Url;

/**
 * Defines a class with methods for asserting presence of elements during tests.
 */
class WebAssert extends MinkWebAssert {

  /**
   * The absolute URL of the site under test.
   *
   * @var string
   */
  protected $baseUrl = '';

  /**
   * Constructor.
   *
   * @param \Behat\Mink\Session $session
   *   The Behat session object;
   * @param string $base_url
   *   The base URL of the site under test.
   */
  public function __construct(Session $session, $base_url = '') {
    parent::__construct($session);
    $this->baseUrl = $base_url;
  }

  /**
   * {@inheritdoc}
   */
  protected function cleanUrl($url) {
    if ($url instanceof Url) {
      $url = $url->setAbsolute()->toString();
    }
    // Strip the base URL from the beginning for absolute URLs.
    if ($this->baseUrl !== '' && strpos($url, $this->baseUrl) === 0) {
      $url = substr($url, strlen($this->baseUrl));
    }
    // Make sure there is a forward slash at the beginning of relative URLs for
    // consistency.
    if (parse_url($url, PHP_URL_HOST) === NULL && strpos($url, '/') !== 0) {
      $url = "/$url";
    }
    return parent::cleanUrl($url);
  }

  /**
   * Checks that specific button exists on the current page.
   *
   * @param string $button
   *   One of id|name|label|value for the button.
   * @param \Behat\Mink\Element\TraversableElement $container
   *   (optional) The document to check against. Defaults to the current page.
   *
   * @return \Behat\Mink\Element\NodeElement
   *   The matching element.
   *
   * @throws \Behat\Mink\Exception\ElementNotFoundException
   *   When the element doesn't exist.
   */
  public function buttonExists($button, TraversableElement $container = NULL) {
    $container = $container ?: $this->session->getPage();
    $node = $container->findButton($button);

    if ($node === NULL) {
      throw new ElementNotFoundException($this->session, 'button', 'id|name|label|value', $button);
    }

    return $node;
  }

  /**
   * Checks that the specific button does NOT exist on the current page.
   *
   * @param string $button
   *   One of id|name|label|value for the button.
   * @param \Behat\Mink\Element\TraversableElement $container
   *   (optional) The document to check against. Defaults to the current page.
   *
   * @throws \Behat\Mink\Exception\ExpectationException
   *   When the button exists.
   */
  public function buttonNotExists($button, TraversableElement $container = NULL) {
    $container = $container ?: $this->session->getPage();
    $node = $container->findButton($button);

    $this->assert(NULL === $node, sprintf('A button "%s" appears on this page, but it should not.', $button));
  }

  /**
   * Checks that specific select field exists on the current page.
   *
   * @param string $select
   *   One of id|name|label|value for the select field.
   * @param \Behat\Mink\Element\TraversableElement $container
   *   (optional) The document to check against. Defaults to the current page.
   *
   * @return \Behat\Mink\Element\NodeElement
   *   The matching element
   *
   * @throws \Behat\Mink\Exception\ElementNotFoundException
   *   When the element doesn't exist.
   */
  public function selectExists($select, TraversableElement $container = NULL) {
    $container = $container ?: $this->session->getPage();
    $node = $container->find('named', array(
      'select',
      $this->session->getSelectorsHandler()->xpathLiteral($select),
    ));

    if ($node === NULL) {
      throw new ElementNotFoundException($this->session, 'select', 'id|name|label|value', $select);
    }

    return $node;
  }

  /**
   * Checks that specific option in a select field exists on the current page.
   *
   * @param string $select
   *   One of id|name|label|value for the select field.
   * @param string $option
   *   The option value.
   * @param \Behat\Mink\Element\TraversableElement $container
   *   (optional) The document to check against. Defaults to the current page.
   *
   * @return \Behat\Mink\Element\NodeElement
   *   The matching option element
   *
   * @throws \Behat\Mink\Exception\ElementNotFoundException
   *   When the element doesn't exist.
   */
  public function optionExists($select, $option, TraversableElement $container = NULL) {
    $container = $container ?: $this->session->getPage();
    $select_field = $container->find('named', array(
      'select',
      $this->session->getSelectorsHandler()->xpathLiteral($select),
    ));

    if ($select_field === NULL) {
      throw new ElementNotFoundException($this->session, 'select', 'id|name|label|value', $select);
    }

    $option_field = $select_field->find('named', array('option', $option));

    if ($option_field === NULL) {
      throw new ElementNotFoundException($this->session, 'select', 'id|name|label|value', $option);
    }

    return $option_field;
  }

  /**
   * Checks that an option in a select field does NOT exist on the current page.
   *
   * @param string $select
   *   One of id|name|label|value for the select field.
   * @param string $option
   *   The option value that shoulkd not exist.
   * @param \Behat\Mink\Element\TraversableElement $container
   *   (optional) The document to check against. Defaults to the current page.
   *
   * @throws \Behat\Mink\Exception\ElementNotFoundException
   *   When the select element doesn't exist.
   */
  public function optionNotExists($select, $option, TraversableElement $container = NULL) {
    $container = $container ?: $this->session->getPage();
    $select_field = $container->find('named', array(
      'select',
      $this->session->getSelectorsHandler()->xpathLiteral($select),
    ));

    if ($select_field === NULL) {
      throw new ElementNotFoundException($this->session, 'select', 'id|name|label|value', $select);
    }

    $option_field = $select_field->find('named', array('option', $option));

    $this->assert($option_field === NULL, sprintf('An option "%s" exists in select "%s", but it should not.', $option, $select));
  }

  /**
   * Pass if the page title is the given string.
   *
   * @param string $expected_title
   *   The string the page title should be.
   *
   * @throws \Behat\Mink\Exception\ExpectationException
   *   Thrown when element doesn't exist, or the title is a different one.
   */
  public function titleEquals($expected_title) {
    $title_element = $this->session->getPage()->find('css', 'title');
    if (!$title_element) {
      throw new ExpectationException('No title element found on the page', $this->session);
    }
    $actual_title = $title_element->getText();
    $this->assert($expected_title === $actual_title, 'Title found');
  }

  /**
   * Passes if a link with the specified label is found.
   *
   * An optional link index may be passed.
   *
   * @param string $label
   *   Text between the anchor tags.
   * @param int $index
   *   Link position counting from zero.
   * @param string $message
   *   (optional) A message to display with the assertion. Do not translate
   *   messages: use strtr() to embed variables in the message text, not
   *   t(). If left blank, a default message will be displayed.
   *
   * @throws \Behat\Mink\Exception\ExpectationException
   *   Thrown when element doesn't exist, or the link label is a different one.
   */
  public function linkExists($label, $index = 0, $message = '') {
    $message = ($message ? $message : strtr('Link with label %label found.', ['%label' => $label]));
    $links = $this->session->getPage()->findAll('named', ['link', $label]);
    $this->assert(!empty($links[$index]), $message);
  }

  /**
   * Passes if a link with the specified label is not found.
   *
   * An optional link index may be passed.
   *
   * @param string $label
   *   Text between the anchor tags.
   * @param string $message
   *   (optional) A message to display with the assertion. Do not translate
   *   messages: use strtr() to embed variables in the message text, not
   *   t(). If left blank, a default message will be displayed.
   *
   * @throws \Behat\Mink\Exception\ExpectationException
   *   Thrown when element doesn't exist, or the link label is a different one.
   */
  public function linkNotExists($label, $message = '') {
    $message = ($message ? $message : strtr('Link with label %label found.', ['%label' => $label]));
    $links = $this->session->getPage()->findAll('named', ['link', $label]);
    $this->assert(empty($links), $message);
  }

  /**
   * Passes if a link containing a given href (part) is found.
   *
   * @param string $href
   *   The full or partial value of the 'href' attribute of the anchor tag.
   * @param int $index
   *   Link position counting from zero.
   * @param string $message
   *   (optional) A message to display with the assertion. Do not translate
   *   messages: use \Drupal\Component\Utility\SafeMarkup::format() to embed
   *   variables in the message text, not t(). If left blank, a default message
   *   will be displayed.
   *
   * @throws \Behat\Mink\Exception\ExpectationException
   *   Thrown when element doesn't exist, or the link label is a different one.
   */
  public function linkByHrefExists($href, $index = 0, $message = '') {
    $xpath = $this->buildXPathQuery('//a[contains(@href, :href)]', [':href' => $href]);
    $message = ($message ? $message : strtr('Link containing href %href found.', ['%href' => $href]));
    $links = $this->session->getPage()->findAll('xpath', $xpath);
    $this->assert(!empty($links[$index]), $message);
  }

  /**
   * Passes if a link containing a given href (part) is not found.
   *
   * @param string $href
   *   The full or partial value of the 'href' attribute of the anchor tag.
   * @param string $message
   *   (optional) A message to display with the assertion. Do not translate
   *   messages: use \Drupal\Component\Utility\SafeMarkup::format() to embed
   *   variables in the message text, not t(). If left blank, a default message
   *   will be displayed.
   *
   * @throws \Behat\Mink\Exception\ExpectationException
   *   Thrown when element doesn't exist, or the link label is a different one.
   */
  public function linkByHrefNotExists($href, $message = '') {
    $xpath = $this->buildXPathQuery('//a[contains(@href, :href)]', [':href' => $href]);
    $message = ($message ? $message : strtr('Link containing href %href found.', ['%href' => $href]));
    $links = $this->session->getPage()->findAll('xpath', $xpath);
    $this->assert(empty($links), $message);
  }

  /**
   * Builds an XPath query.
   *
   * Builds an XPath query by replacing placeholders in the query by the value
   * of the arguments.
   *
   * XPath 1.0 (the version supported by libxml2, the underlying XML library
   * used by PHP) doesn't support any form of quotation. This function
   * simplifies the building of XPath expression.
   *
   * @param string $xpath
   *   An XPath query, possibly with placeholders in the form ':name'.
   * @param array $args
   *   An array of arguments with keys in the form ':name' matching the
   *   placeholders in the query. The values may be either strings or numeric
   *   values.
   *
   * @return string
   *   An XPath query with arguments replaced.
   */
  public function buildXPathQuery($xpath, array $args = array()) {
    // Replace placeholders.
    foreach ($args as $placeholder => $value) {
      if (is_object($value)) {
        throw new \InvalidArgumentException('Just pass in scalar values.');
      }
      // XPath 1.0 doesn't support a way to escape single or double quotes in a
      // string literal. We split double quotes out of the string, and encode
      // them separately.
      if (is_string($value)) {
        // Explode the text at the quote characters.
        $parts = explode('"', $value);

        // Quote the parts.
        foreach ($parts as &$part) {
          $part = '"' . $part . '"';
        }

        // Return the string.
        $value = count($parts) > 1 ? 'concat(' . implode(', \'"\', ', $parts) . ')' : $parts[0];
      }

      // Use preg_replace_callback() instead of preg_replace() to prevent the
      // regular expression engine from trying to substitute backreferences.
      $replacement = function ($matches) use ($value) {
        return $value;
      };
      $xpath = preg_replace_callback('/' . preg_quote($placeholder) . '\b/', $replacement, $xpath);
    }
    return $xpath;
  }

  /**
   * Passes if the raw text IS NOT found escaped on the loaded page.
   *
   * Raw text refers to the raw HTML that the page generated.
   *
   * @param string $raw
   *   Raw (HTML) string to look for.
   */
  public function assertNoEscaped($raw) {
    $this->responseNotContains(Html::escape($raw));
  }

  /**
   * Passes if the raw text IS found escaped on the loaded page.
   *
   * Raw text refers to the raw HTML that the page generated.
   *
   * @param string $raw
   *   Raw (HTML) string to look for.
   */
  public function assertEscaped($raw) {
    $this->responseContains(Html::escape($raw));
  }

  /**
   * Asserts a condition.
   *
   * The parent method is overridden because it is a private method.
   *
   * @param bool $condition
   *   The condition.
   * @param string $message
   *   The success message.
   *
   * @throws \Behat\Mink\Exception\ExpectationException
   *   When the condition is not fulfilled.
   */
  public function assert($condition, $message) {
    if ($condition) {
      return;
    }

    throw new ExpectationException($message, $this->session->getDriver());
  }

  /**
   * Checks that a given form field element is disabled.
   *
   * @param string $field
   *   One of id|name|label|value for the field.
   * @param \Behat\Mink\Element\TraversableElement $container
   *   (optional) The document to check against. Defaults to the current page.
   *
   * @return \Behat\Mink\Element\NodeElement
   *   The matching element.
   *
   * @throws \Behat\Mink\Exception\ElementNotFoundException
   * @throws \Behat\Mink\Exception\ExpectationException
   */
  public function fieldDisabled($field, TraversableElement $container = NULL)  {
    $container = $container ?: $this->session->getPage();
    $node = $container->findField($field);

    if ($node === NULL) {
      throw new ElementNotFoundException($this->session->getDriver(), 'field', 'id|name|label|value', $field);
    }

    if (!$node->hasAttribute('disabled')) {
      throw new ExpectationException("Field $field is disabled", $this->session->getDriver());
    }

    return $node;
  }

}
