<?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\CssSelector;

/**

 * XPathExpr represents an XPath expression.

 *

 * This component is a port of the Python lxml library,

 * which is copyright Infrae and distributed under the BSD license.

 *

 * @author Fabien Potencier <fabien@symfony.com>

 */

class XPathExpr

{

    private $prefix;

    private $path;

    private $element;

    private $condition;

    private $starPrefix;

    /**

     * Constructor.

     *

     * @param string  $prefix     Prefix for the XPath expression.

     * @param string  $path       Actual path of the expression.

     * @param string  $element    The element in the expression.

     * @param string  $condition  A condition for the expression.

     * @param Boolean $starPrefix Indicates whether to use a star prefix.

     */

    public function __construct($prefix = null, $path = null, $element = '*', $condition = null, $starPrefix = false)

    {

        $this->prefix = $prefix;

        $this->path = $path;

        $this->element = $element;

        $this->condition = $condition;

        $this->starPrefix = $starPrefix;

    }

    /**

     * Gets the prefix of this XPath expression.

     *

     * @return string

     */

    public function getPrefix()

    {

        return $this->prefix;

    }

    /**

     * Gets the path of this XPath expression.

     *

     * @return string

     */

    public function getPath()

    {

        return $this->path;

    }

    /**

     * Answers whether this XPath expression has a star prefix.

     *

     * @return Boolean

     */

    public function hasStarPrefix()

    {

        return $this->starPrefix;

    }

    /**

     * Gets the element of this XPath expression.

     *

     * @return string

     */

    public function getElement()

    {

        return $this->element;

    }

    /**

     * Gets the condition of this XPath expression.

     *

     * @return string

     */

    public function getCondition()

    {

        return $this->condition;

    }

    /**

     * Gets a string representation for this XPath expression.

     *

     * @return string

     */

    public function __toString()

    {

        $path = '';

        if (null !== $this->prefix) {

            $path .= $this->prefix;

        }

        if (null !== $this->path) {

            $path .= $this->path;

        }

        $path .= $this->element;

        if ($this->condition) {

            $path .= sprintf('[%s]', $this->condition);

        }

        return $path;

    }

    /**

     * Adds a condition to this XPath expression.

     * Any pre-existent condition will be ANDed to it.

     *

     * @param string $condition The condition to add.

     */

    public function addCondition($condition)

    {

        if ($this->condition) {

            $this->condition = sprintf('%s and (%s)', $this->condition, $condition);

        } else {

            $this->condition = $condition;

        }

    }

    /**

     * Adds a prefix to this XPath expression.

     * It will be prepended to any pre-existent prefixes.

     *

     * @param string $prefix  The prefix to add.

     */

    public function addPrefix($prefix)

    {

        if ($this->prefix) {

            $this->prefix = $prefix.$this->prefix;

        } else {

            $this->prefix = $prefix;

        }

    }

    /**

     * Adds a condition to this XPath expression using the name of the element

     * as the desired value.

     * This method resets the element to '*'.

     */

    public function addNameTest()

    {

        if ($this->element == '*') {

            // We weren't doing a test anyway

            return;

        }

        $this->addCondition(sprintf('name() = %s', XPathExpr::xpathLiteral($this->element)));

        $this->element = '*';

    }

    /**

     * Adds a star prefix to this XPath expression.

     * This method will prepend a '*' to the path and set the star prefix flag

     * to true.

     */

    public function addStarPrefix()

    {

        /*

        Adds a /* prefix if there is no prefix.  This is when you need

        to keep context's constrained to a single parent.

        */

        if ($this->path) {

            $this->path .= '*/';

        } else {

            $this->path = '*/';

        }

        $this->starPrefix = true;

    }

    /**

     * Joins this XPath expression with $other (another XPath expression) using

     * $combiner to join them.

     *

     * @param string    $combiner The combiner string.

     * @param XPathExpr $other    The other XPath expression to combine with

     *                            this one.

     */

    public function join($combiner, $other)

    {

        $prefix = (string) $this;

        $prefix .= $combiner;

        $path = $other->getPrefix().$other->getPath();

        /* We don't need a star prefix if we are joining to this other

             prefix; so we'll get rid of it */

        if ($other->hasStarPrefix() && '*/' == $path) {

            $path = '';

        }

        $this->prefix = $prefix;

        $this->path = $path;

        $this->element = $other->getElement();

        $this->condition = $other->GetCondition();

    }

    /**

     * Gets an XPath literal for $s.

     *

     * @param  mixed $s Can either be a Node\ElementNode or a string.

     *

     * @return string

     */

    static public function xpathLiteral($s)

    {

        if ($s instanceof Node\ElementNode) {

            // This is probably a symbol that looks like an expression...

            $s = $s->formatElement();

        } else {

            $s = (string) $s;

        }

        if (false === strpos($s, "'")) {

            return sprintf("'%s'", $s);

        }

        if (false === strpos($s, '"')) {

            return sprintf('"%s"', $s);

        }

        $string = $s;

        $parts = array();

        while (true) {

            if (false !== $pos = strpos($string, "'")) {

                $parts[] = sprintf("'%s'", substr($string, 0, $pos));

                $parts[] = "\"'\"";

                $string = substr($string, $pos + 1);

            } else {

                $parts[] = "'$string'";

                break;

            }

        }

        return sprintf('concat(%s)', implode($parts, ', '));

    }

}