<?php namespace ProcessWire;

/**
 * ProcessWire WireInputData and WireInput
 *
 * WireInputData and the WireInput class together form a simple 
 * front end to PHP's $_GET, $_POST, and $_COOKIE superglobals.
 * 
 * ProcessWire 3.x, Copyright 2016 by Ryan Cramer
 * https://processwire.com
 *
 */

/**
 * Manages the group of GET, POST, COOKIE and whitelist vars, each of which is a WireInputData object.
 * 
 * #pw-summary Provides a means to get user input from URLs, GET, POST, and COOKIE variables and more.
 *
 * @link https://processwire.com/api/ref/wire-input/ Offical $input API variable Documentation
 * 
 * @property array|string[] $urlSegments Retrieve all URL segments (array). This requires url segments are enabled on the template of the requested page. You can turn it on or off under the url tab when editing a template. #pw-group-URL-segments
 * @property WireInputData $post POST variables
 * @property WireInputData $get GET variables
 * @property WireInputDataCookie $cookie COOKIE variables
 * @property WireInputData $whitelist Whitelisted variables
 * @property int $pageNum Current page number (where 1 is first) #pw-group-URLs
 * @property string $urlSegmentsStr String of current URL segments, separated by slashes, i.e. a/b/c  #pw-internal
 * @property string $urlSegmentStr Alias of urlSegmentsStr #pw-group-URL-segments
 * @property string $url Current requested URL including page numbers and URL segments, excluding query string. #pw-group-URLs
 * @property string $httpUrl Like $url but includes the scheme/protcol and hostname. #pw-group-URLs
 * @property string $queryString Current query string #pw-group-URLs
 * @property string $scheme Current scheme/protcol, i.e. http or https #pw-group-URLs
 * 
 * @property string $urlSegment1 First URL segment #pw-group-URL-segments
 * @property string $urlSegment2 Second URL segment #pw-group-URL-segments
 * @property string $urlSegment3 Third URL segment, and so on... #pw-group-URL-segments
 * @property string $urlSegmentLast Last URL segment (since 3.0.155) #pw-group-URL-segments
 * @property string $urlSegmentFirst Alias of $urlSegment1 (since 3.0.155) #pw-group-URL-segments
 * 
 * @method string|int|bool urlSegment1($get = '') Same as urlSegment() method but apply only to 1st URL segment. (since 3.0.155) #pw-group-URL-segments
 * @method string|int|bool urlSegment2($get = '') Same as urlSegment() method but apply only to 2nd URL segment. (since 3.0.155) #pw-group-URL-segments
 * @method string|int|bool urlSegment3($get = '') Same as urlSegment() method but apply only to 3rd URL segment. (since 3.0.155) #pw-group-URL-segments
 * @method string|int|bool urlSegmentLast($get = '') Same as urlSegment() method but apply only to last URL segment. (since 3.0.155) #pw-group-URL-segments
 * @method string|int|bool urlSegmentFirst($get = '') Same as urlSegment() method but apply only to first URL segment. (since 3.0.155) #pw-group-URL-segments
 * 
 * Note that properties and methods that end with numbers 1-3 above (like urlSegment1, urlSegment1(), etc.)
 * continue for as many numbers as the system supports, so you may go beyond 3 where supported. 
 *
 */
class WireInput extends Wire {

	/**
	 * @var WireInputData|null
	 * 
	 */
	protected $getVars = null;
	
	/**
	 * @var WireInputData|null
	 *
	 */
	protected $postVars = null;
	
	/**
	 * @var WireInputData|null
	 *
	 */
	protected $cookieVars = null;
	
	/**
	 * @var WireInputData|null
	 *
	 */
	protected $whitelist = null;

	/**
	 * @var array
	 * 
	 */
	protected $urlSegments = array();

	/**
	 * @var int
	 * 
	 */
	protected $pageNum = 1;

	/**
	 * Use lazy loading method for get/post/cookie?
	 * 
	 * @var bool
	 * 
	 */
	protected $lazy = false;

	/**
	 * Recognized regex start/end delimiters 
	 * 
	 * @var array
	 * 
	 */
	protected $regexDelims = array('/', '!', '%', '#', '@');

	/**
	 * @var array
	 * 
	 */
	protected $requestMethods = array(
		'GET' => 'GET',
		'POST' => 'POST',
		'HEAD' => 'HEAD',
		'PUT' => 'PUT',
		'DELETE' => 'DELETE',
		'OPTIONS' => 'OPTIONS',
		'PATCH' => 'PATCH',
		'CONNECT' => 'CONNECT',
		'TRACE' => 'TRACE',
	);

	/**
	 * Construct
	 * 
	 */
	public function __construct() {
		parent::__construct();
		$this->useFuel(false);
		$this->unregisterGLOBALS();
	}

	/**
	 * Set for lazy loading
	 * 
	 * Must be called before accessing any get/post/cookie input
	 * 
	 * #pw-internal
	 * 
	 * @param bool $lazy
	 * 
	 */
	public function setLazy($lazy = true) {
		$this->lazy = (bool) $lazy;
	}
	
	/**
	 * Retrieve a named GET variable value, or all GET variables (from URL query string)
	 * 
	 * Always sanitize (and validate where appropriate) any values from user input. 
	 * 
	 * The following optional features are available in ProcessWire version 3.0.125 and newer: 
	 * 
	 * - Provide a sanitization method as the 2nd argument to include sanitization.
	 * - Provide an array of valid values as the 2nd argument to limit input to those values. 
	 * - Provide a callback function that receives the value and returns a validated value. 
	 * - Provide a fallback value as the 3rd argument to use if value not present or invalid.
	 * - Append “[]” to the 1st argument to always force return value to be an array, i.e “colors[]”.
	 *
	 * Note that the `$valid` and `$fallback` arguments are only applicable if a `$key` argument is provided. 
	 * 
	 * ~~~~~
	 * // Retrieve a "q" GET variable, sanitize and output
	 * // Example request URL: domain.com/path/to/page/?q=TEST
	 * $q = $input->get('q'); // retrieve value
	 * $q = $sanitizer->text($q); // sanitize input as 1-line text
	 * echo $sanitizer->entities($q); // sanitize for output, outputs "TEST"
	 * 
	 * // You can also combine $input and one $sanitizer call, replacing
	 * // the "text" method call with any $sanitizer method: 
	 * $q = $input->get->text('q'); 
	 *
	 * // like the previous example, but specify sanitizer method as second argument (3.0.125+):
	 * $q = $input->get('q', 'text'); 
	 * 
	 * // if you want more than one sanitizer, specify multiple in a CSV string (3.0.125+):
	 * $q = $input->get('q', 'text,entities'); 
	 * 
	 * // you can provide a whitelist array of allowed values instead of a sanitizer method (3.0.125+):
	 * $color = $input->get('color', [ 'red', 'blue', 'green' ]); 
	 * 
	 * // an optional 3rd argument lets you specify a fallback value to use if valid value not present or 
	 * // empty in input, and it will return this value rather than null/empty (3.0.125+):
	 * $qty = $input->get('qty', 'int', 1); // return 1 if no qty provided
	 * $color = $input->get('color', [ 'red', 'blue', 'green' ], 'red'); // return red if no color selected
	 * 
	 * // you may optionally provide a callback function to sanitize/validate with (3.0.125+):
	 * $isActive = $input->get('active', function($val) { return $val ? true : false; }); 
	 * ~~~~~
	 * 
	 * @param string $key Name of GET variable you want to retrieve. 
	 *  - If populated, returns the value corresponding to the key or NULL if it doesn’t exist.
	 *  - If blank, returns reference to the WireDataInput containing all GET vars. 
	 * @param array|string|int|callable|null $valid Omit for no validation/sanitization, or provide one of the following (3.0.125+ only):
	 *  - String name of Sanitizer method to to sanitize value with before returning it.
	 *  - CSV string of multiple sanitizer names to process the value, in order. 
	 *  - Array of allowed values (aka whitelist), where input value must be one of these, otherwise null (or fallback value) will returned. 
	 *    Values in the array may be any string or integer.
	 *  - Callback function to sanitize and validate the value. 
	 *  - Integer if a specific number is the only allowed value other than fallback value (i.e. like a checkbox toggle).
	 * @param mixed|null Optional fallback value to return if input value is not present or does not validate (3.0.125+ only). 
	 * @return null|mixed|WireInputData Returns one of the following:
	 *  - If given no `$key` argument, returns `WireInputData` with all unsanitized GET vars.
	 *  - If given no `$valid` argument, returns unsanitized value or NULL if not present. 
	 *  - If given a Sanitizer name for `$valid` argument, returns value sanitized with that Sanitizer method (3.0.125+).
	 *  - If given an array of allowed values for `$valid` argument, returns value from that array if it was in the input, or null if not (3.0.125+).
	 *  - If given a callable function for `$valid` argument, returns the value returned by that function (3.0.125+).
	 *  - If given a `$fallback` argument, returns that value when it would otherwise return null (3.0.125+). 
	 * @throws WireException if given unknown Sanitizer method for $valid argument
	 *
	 */
	public function get($key = '', $valid = null, $fallback = null) {
		if(is_null($this->getVars)) {
			$this->getVars = $this->wire(new WireInputData($_GET, $this->lazy));
			$this->getVars->offsetUnset('it');
		}
		if(!strlen($key)) return $this->getVars;
		if($valid === null && $fallback === null && !strpos($key, '[]')) return $this->getVars->__get($key);
		return $this->getValidInputValue($this->getVars, $key, $valid, $fallback);
	}

	/**
	 * Retrieve a named POST variable value, or all POST variables
	 * 
	 * Always sanitize (and validate where appropriate) any values from user input.
	 * 
	 * The following optional features are available in ProcessWire version 3.0.125 and newer:
	 *
	 * - Provide a sanitization method as the 2nd argument to include sanitization.
	 * - Provide an array of valid values as the 2nd argument to limit input to those values.
	 * - Provide a callback function that receives the value and returns a validated value.
	 * - Provide a fallback value as the 3rd argument to use if value not present or invalid.
	 * - Append “[]” to the 1st argument to always force return value to be an array, i.e “colors[]”.
	 *
	 * Note that the `$valid` and `$fallback` arguments are only applicable if a `$key` argument is provided.
	 * 
	 * 
	 * ~~~~~
	 * // Retrieve a "comments" POST variable, sanitize and output it
	 * $comments = $input->post('comments'); 
	 * $comments = $sanitizer->textarea($comments); // sanitize input as multi-line text with no HTML
	 * echo $sanitizer->entities($comments); // sanitize for output
	 * 
	 * // You can also combine $input and one $sanitizer call like this,
	 * // replacing "text" with name of any $sanitizer method: 
	 * $comments = $input->post->textarea('comments');
	 * 
	 * // like the previous example, but specify sanitizer method as second argument (3.0.125+):
	 * $comments = $input->post('comments', 'textarea');
	 *
	 * // if you want more than one sanitizer, specify multiple in a CSV string (3.0.125+):
	 * $comments = $input->post('comments', 'textarea,entities');
	 *
	 * // you can provide a whitelist array of allowed values instead of a sanitizer method (3.0.125+):
	 * $color = $input->post('color', [ 'red', 'blue', 'green' ]);
	 *
	 * // an optional 3rd argument lets you specify a fallback value to use if valid value not present or
	 * // empty in input, and it will return this value rather than null/empty (3.0.125+):
	 * $qty = $input->post('qty', 'int', 1); // return 1 if no qty provided
	 * $color = $input->post('color', [ 'red', 'blue', 'green' ], 'red'); // return red if no color selected
	 *
	 * // you may optionally provide a callback function to sanitize/validate with (3.0.125+):
	 * $isActive = $input->post('active', function($val) { return $val ? true : false; }); 
	 * ~~~~~
	 * 
	 * @param string $key Name of POST variable you want to retrieve. 
	 *  - If populated, returns the value corresponding to the key or NULL if it doesn't exist.
	 *  - If blank, returns reference to the WireDataInput containing all POST vars.
	 * @param array|string|int|callable|null $valid Omit for no validation/sanitization, or provide one of the following:
	 *  - String name of Sanitizer method to to sanitize value with before returning it.
	 *  - CSV string of multiple sanitizer names to process the value, in order.
	 *  - Array of allowed values (aka whitelist), where input value must be one of these, otherwise null (or fallback value) will returned.
	 *    Values in the array may be any string or integer.
	 *  - Callback function to sanitize and validate the value.
	 *  - Integer if a specific number is the only allowed value other than fallback value (i.e. like a checkbox toggle).
	 * @param mixed|null Optional Fallback value to return if input value is not present or does not validate.
	 * @return null|mixed|WireInputData Returns one of the following:
	 *  - If given no `$key` argument, returns `WireInputData` with all unsanitized POST vars.
	 *  - If given no `$valid` argument, returns unsanitized value or NULL if not present.
	 *  - If given a Sanitizer name for `$valid` argument, returns value sanitized with that Sanitizer method (3.0.125+).
	 *  - If given an array of allowed values for `$valid` argument, returns value from that array if it was in the input, or null if not (3.0.125+).
	 *  - If given a callable function for `$valid` argument, returns the value returned by that function (3.0.125+).
	 *  - If given a `$fallback` argument, returns that value when it would otherwise return null (3.0.125+).
	 * @throws WireException if given unknown Sanitizer method for $valid argument
	 *
	 */
	public function post($key = '', $valid = null, $fallback = null) {
		if(is_null($this->postVars)) $this->postVars = $this->wire(new WireInputData($_POST, $this->lazy));
		if(!strlen($key)) return $this->postVars;
		if($valid === null && $fallback === null && !strpos($key, '[]')) return $this->postVars->__get($key);
		return $this->getValidInputValue($this->postVars, $key, $valid, $fallback);
	}

	/**
	 * Retrieve a named COOKIE variable value or all COOKIE variables
	 * 
	 * Please see the [cookie API reference page](https://processwire.com/api/ref/wire-input-data-cookie/) for 
	 * additional documentation on how to get and set cookies and cookie options. 
	 * 
	 * ~~~~~
	 * // setting cookies
	 * $input->cookie->foo = 'bar'; // set with default options (expires with session)
	 * $input->cookie->set('foo', 'bar'); // same as above
	 * $input->cookie->set('foo', bar', 86400); // expire after 86400 seconds (1 day)
	 * $input->cookie->set('foo', 'bar', [ 'age' => 86400, 'path' => $page->url ]); 
	 * 
	 * // getting cookies
	 * $val = $input->cookie->foo;
	 * $val = $input->cookie->get('foo'); // same as above
	 * $val = $input->cookie->text('foo'); // get and use text sanitizer
	 * 
	 * // removing cookies
	 * $input->cookie->remove('foo'); 
	 * 
	 * // getting cookie options
	 * $array = $input->cookie->options();
	 * print_r($array); // see all options
	 * 
	 * // setting cookie options (to use in next $input->cookie->set call)
	 * $input->cookie->options('age', 86400); // set default age to 1 day
	 * $input->cookie->options([ // set multiple options
	 *   'age' => 86400, 
	 *   'path' => $page->url, 
	 *   'domain' => 'www.domain.com',
	 * ]); 
	 * 
	 * // setting default options (in /site/config.php):
	 * $config->cookieOptions = [
	 *   'age' => 604800, // 1 week
	 *   'httponly' => true, // make visible to PHP but not JS
	 *    // and so on
	 * ]; 
	 * ~~~~~
	 * 
	 * Cookies are a form of user input, so always sanitize (and validate where appropriate) any values. 
	 * 
	 * The following optional features are available in ProcessWire version 3.0.125 and newer:
	 *
	 * - Provide a sanitization method as the 2nd argument to include sanitization.
	 * - Provide an array of valid values as the 2nd argument to limit input to those values.
	 * - Provide a callback function that receives the value and returns a validated value.
	 * - Provide a fallback value as the 3rd argument to use if value not present or invalid.
	 * - Append “[]” to the 1st argument to always force return value to be an array, i.e “colors[]”.
	 *
	 * Note that the `$valid` and `$fallback` arguments are only applicable if a `$key` argument is provided.
	 * See the `WireInput::get()` method for usage examples (get method works the same as cookie method).
	 *
	 * @param string $key Name of the COOKIE variable you want to retrieve. 
	 *  - If populated, returns the value corresponding to the key or NULL if it doesn't exist.
	 *  - If blank, returns reference to the WireDataInput containing all COOKIE vars.
	 * @param array|string|int|callable|null $valid Omit for no validation/sanitization, or provide one of the following:
	 *  - String name of Sanitizer method to to sanitize value with before returning it.
	 *  - CSV string of multiple sanitizer names to process the value, in order.
	 *  - Array of allowed values (aka whitelist), where input value must be one of these, otherwise null (or fallback value) will returned.
	 *    Values in the array may be any string or integer.
	 *  - Callback function to sanitize and validate the value.
	 *  - Integer if a specific number is the only allowed value other than fallback value (i.e. like a checkbox toggle).
	 * @param mixed|null Optional Fallback value to return if input value is not present or does not validate.
	 * @return null|mixed|WireInputData Returns one of the following:
	 *  - If given no `$key` argument, returns `WireInputData` with all unsanitized COOKIE vars.
	 *  - If given no `$valid` argument, returns unsanitized value or NULL if not present.
	 *  - If given a Sanitizer name for `$valid` argument, returns value sanitized with that Sanitizer method (3.0.125+).
	 *  - If given an array of allowed values for `$valid` argument, returns value from that array if it was in the input, or null if not (3.0.125+).
	 *  - If given a callable function for `$valid` argument, returns the value returned by that function (3.0.125+).
	 *  - If given a `$fallback` argument, returns that value when it would otherwise return null (3.0.125+).
	 * @throws WireException if given unknown Sanitizer method for $valid argument
	 *
	 */
	public function cookie($key = '', $valid = null, $fallback = null) {
		if($this->cookieVars === null) {
			$this->cookieVars = $this->wire(new WireInputDataCookie($_COOKIE, $this->lazy));
			$this->cookieVars->init();
		}
		if(!strlen($key)) return $this->cookieVars;
		if($valid === null && $fallback === null && !strpos($key, '[]')) return $this->cookieVars->get($key);
		return $this->getValidInputValue($this->cookieVars, $key, $valid, $fallback);
	}

	/**
	 * Get or set a whitelist variable
	 *	
	 * Whitelist variables are used by modules and templates and assumed to be sanitized.
	 * Only place variables in the whitelist that you have already sanitized. 
	 * 
	 * The whitelist is a list of variables specifically set by the application as sanitized for use elsewhere in the application.
	 * This whitelist is not specifically used by ProcessWire unless you populate it from your templates or the API. 
	 * When populated, it is used by the MarkupPagerNav module (for instance) to ensure that sanitized query string (GET) variables 
	 * are maintained across paginations. 
	 * 
	 * ~~~~~
	 * // Retrieve a GET variable, sanitize/validate it, and populate to whitelist
	 * $limit = (int) $input->get('limit'); 
	 * if($limit < 10 || $limit > 100) $limit = 25; // validate
	 * $input->whitelist('limit', $limit); 
	 * ~~~~~
	 * ~~~~~
	 * // Retrieve a variable from the whitelist
	 * $limit = $input->whitelist('limit'); 
	 * ~~~~~
	 *
	 * @param string $key Whitelist variable name that you want to get or set. 
	 *  - If $key is blank, it assumes you are asking to return the entire whitelist. 
	 *  - If $key and $value are populated, it adds the value to the whitelist.
	 *  - If $key is an array, it adds all the values present in the array to the whitelist.
	 *  - If $value is omitted, it assumes you are asking for a value with $key, in which case it returns it. 
	 * @param mixed $value Value you want to set (if setting a value). See explanation for the $key param.
	 * @return null|mixed|WireInputData Returns whitelist variable value if getting a value (null if it doesn't exist).
	 *
	 */
	public function whitelist($key = '', $value = null) {
		if(is_null($this->whitelist)) $this->whitelist = $this->wire(new WireInputData()); 
		if(!$key) return $this->whitelist; 
		if(is_array($key)) return $this->whitelist->setArray($key); 
		if(is_null($value)) return $this->whitelist->__get($key); 
		$this->whitelist->__set($key, $value); 
		return $this->whitelist; 
	}

	/**
	 * Retrieve matching URL segment number or pattern
	 * 
	 * In all ProcessWire versions  this method accepts a 1-based index and returns the 
	 * corresponding URL segment, where 1 is first URL segment, 2 is second, etc.
	 * 
	 * In ProcessWire versions 3.0.155 and newer, this method also does the following:
	 * 
	 * - If given a negative number, it will retrieve from the end of the URL segments. 
	 *   For example, if given -1 it will return the last URL segment, -2 will return second
	 *   to last, and so on. 
	 * 
	 * - If given a full URL segment (i.e. “foo”) it will return the 1-based index at which that
	 *   segment exists, or 0 if not present. 
	 * 
	 * - If given URL segment followed by equals sign, i.e. “foo=” it will return the next URL 
	 *   segment that comes after it. If equals sign comes before URL segment, i.e. “=bar”, it 
	 *   will return the URL segment that came before it. This lets you create “key=value” 
	 *   type relationships with URL segments. For example, an argument of “foo=” would return
	 *   the segment “bar” when applied to URL /path/to/page/foo/bar/.
	 * 
	 * - If given a wildcard string, it will return the first matching URL segment. For example,
	 *   the wildcard string `foo-*` would match the first URL segment to begin with “foo-”, 
	 *   so any of these segments would match & be returned: `foo-bar`, `foo-12345`, `foo-baz123`. 
	 *   A wildcard string of `*bar` would match anything ending with “bar”, i.e. it would match
	 *   and return `foo-bar`, `foobar`, `baz_123bar`, etc.
	 * 
	 * - If given a wildcard string with parenthesis in it, then only the portion in parenthesis 
	 *   is returned for the first matching URL segment. For example, `foo-(*)` would match the
	 *   URL segment `foo-baz123` and would return just the `baz123` portion. 
	 * 
	 * - If given a regular expression (PCRE regex), the behavior is the same as with wildcards, 
	 *   except that your regex is used to perform the match. If there are capturing parenthesis
	 *   in the regex then the first captured text is returned rather than the whole URL segment. 
	 *   To specify a regex, choose one of the following characters as your opening and closing
	 *   delimiters: `/`, `!`, `%`, `#`, `@`. 
	 * 
	 * - If you want to focus any of the above options upon a URL segment at a specific index,
	 *   then you can append the index number to the method name. For example, if you want it to
	 *   just focus on URL segment #1, then call `$input->urlSegment1(…)`, or for URL segment #2
	 *   you would call `$input->urlSegment2(…)`, and so on. 
	 * 
	 * Please also note the following about URL segments: 
	 *   
	 * - URL segments must be enabled in the template settings (for template used by the page).
	 * - When using index numbers, note that it is 1-based. There is no 0 index for URL segments.
	 * - If no arguments are provided, it assumes you ar asking for the first (1) URL segment. 
	 * - The maximum segments allowed can be adjusted in your `$config->maxUrlSegments` setting.
	 * - URL segments are populated by ProcessWire automatically on each request. 
	 * - URL segments are already sanitized as page names. 
	 * - Strongly recommended: throw a 404 when encountering URL segments you do not recognize.
	 * 
	 * ~~~~~
	 * // Get first URL segment and use it to determine output
	 * $action = $input->urlSegment(1); 
	 * if($action == 'photos') {
	 *   // display photos
	 * } else if($action == 'map') {
	 *   // display map
	 * } else if(strlen($action)) {
	 *   // unknown action, throw a 404
	 *   throw new Wire404Exception();
	 * } else {
	 *   // default or display main page
	 * }
	 *
	 * // All following examples require PW 3.0.155+. 
	 * 
	 * // Examples 1-5 below assume current URL is /path/to/page/foo/bar
	 * // and that /foo/bar is the URL segments portion of the URL.
	 * 
	 * // 1. Check if URL segment “foo” is present 
	 * if($input->urlSegment('foo')) {
	 *   // “foo” is present as a URL segment
	 * }
	 * 
	 * // 2. Get index of matching URL segment 
	 * if($input->urlSegment('foo') === 1) {
	 *   // “foo” is first URL segment
	 * }
	 * 
	 * // 3. Get last URL segment 
	 * if($input->urlSegment(-1) === 'bar') {
	 *   // “bar” is last URL segment
	 * }
	 * 
	 * // 4. Get next URL segment
	 * $next = $input->urlSegment('foo='); // returns 'bar'
	 * 
	 * // 5. Get previous URL segment
	 * $prev = $input->urlSegment('=bar'); // returns 'foo'
	 * 
	 * // Examples 6-8 below assume current URL is /path/to/page/sort-date/
	 * // where /sort-date/ is the URL segment. 
	 * 
	 * // 6. Match URL segment using wildcard
	 * $sort = $input->urlSegment('sort-*');
	 * if($sort === 'sort-title') {
	 *   // sort by title
	 * } else if($sort === 'sort-date') {
	 *   // sort by date
	 * } else if(strlen($sort)) {
	 *   // unknown sort value, throw 404 or fallback to default
	 * } else {
	 *   // no sort specified, use default
	 * }
	 * 
	 * // 7. Match using wildcard and parenthesis
	 * $sort = $input->urlSegment('sort-(*)');
	 * if($sort === 'title') {
	 *   // sort by title
	 * } else if($sort === 'date') {
	 *   // sort by date
	 * } else if(strlen($sort)) {
	 *   // unknown sort value, throw 404?
	 * } else {
	 *   // no sort specified, use default
	 * }
	 * 
	 * // 8. Match using regular expression
	 * $sort = $input->urlSegment('/^sort-(.+)$/'); 
	 * if($sort === 'title') {
	 *   // same if statement as example 5...
	 * }
	 * 
	 * // 9. Similar goal to above but with URL /path/to/page/sort/date/
	 * // that uses separate segment for sort value, which is a good 
	 * // example of using the “next” segment feature: 
	 * $sort = $input->urlSegment('sort='); 
	 * if($sort === 'title') {
	 *   // sort by title
	 * } else if($sort === 'date') {
	 *   // sort by date
	 * } else if($sort === '-date') {
	 *   // reverse sort by date
	 * } else {
	 *   // no sort specified, use default
	 * }
	 * ~~~~~
	 * 
	 * #pw-group-URL-segments
	 *
	 * @param int|string $get Specify one of the following
	 *  - Omit argument to simply return 1st URL segment. 
	 *  - Positive integer of n’th URL segment where first is 1.
	 *  - Negative integer of URL segment to match from end where last is -1. (3.0.155+)
	 *  - Full URL segment string to return index for, if present (or 0 if not). (3.0.155+)
	 *  - Full URL segment with equals sign before or after it, to return segment before or after it. (3.0.155+)
	 *  - Wildcard string to match, as described in method description and examples. (3.0.155+)
	 *  - Regular expression string to match, as described in method description and examples. (3.0.155+)
	 * @return string|int Returns one of the following: 
	 *  - URL segment at requested index or blank string if not present. 
	 *  - Index (integer) of matching URL segment when given entire segment to match, or 0 when there is no match. (3.0.155+)
	 *  - Matching URL segment when given wildcard string or regular expression. (3.0.155+)
	 *  - Portion of matching URL segment when given wildcard or regex with parenthesis around pattern to match. (3.0.155+)
	 * @see WireInput::urlSegmentStr()
	 *
	 */
	public function urlSegment($get = 1) {
		
		if(empty($get)) $get = 1;

		if($get < 0) {
			// retrieve from end
			$get = abs($get)-1;
			$urlSegments = array_reverse($this->urlSegments);
			return isset($urlSegments[$get]) ? $urlSegments[$get] : '';
		}

		if(is_int($get) || ctype_digit($get) || empty($get)) {
			// return URL segment at numbered index $get
			$get = (int) $get;
			if($get < 1) $get = 1;
			return isset($this->urlSegments[$get]) ? $this->urlSegments[$get] : '';
		}
	
		return $this->urlSegmentMatch($get); 
	}
	
	/**
	 * Handles find/match logic for URL segment methods
	 * 
	 * @param string $get URL segment match string
	 * @param int $num Limit only to this URL segment number (default=0 to indicate ignore)
	 * @return string|int|bool
	 * @since 3.0.155
	 * 
	 */
	protected function urlSegmentMatch($get, $num = 0) {
		
		if(empty($get) && $num > 0) {
			return isset($this->urlSegments[$num]) ? $this->urlSegments[$num] : '';
		}
		
		$eqPos = strpos($get, '=');
		if($eqPos !== false) $get = trim($get, '=');
		list($matchBefore, $matchAfter) = array($eqPos === 0, $eqPos > 0);
	
		// check if $get has wildcard or regex
		$regex = $this->patternToRegex($get);
		$match = '';
		$index = 0;

		if($regex) {
			// find matching URL segment and return it
			foreach($this->urlSegments as $index => $segment) {
				if($num > 0 && $index !== $num) continue;
				$match = $this->patternMatchesValue($regex, $segment);
				if($match !== '') break;
			}
			if($match === '') $index = 0;
			
		} else {
			// return index where segment is found
			if($num > 0) {
				// apply only to specific URL segment and return bool
				$match = isset($this->urlSegments[$num]) && $this->urlSegments[$num] === $get;
				$index = $match ? $num : 0;
			} else {
				// search all URL segments and return index
				$match = (int) array_search($get, $this->urlSegments);
				$index = $match;
			}
		}
	
		// adjust to use urlSegment before or after when requested
		if($matchBefore) {
			$match = $index > 1 ? $this->urlSegments[$index-1] : '';
		} else if($matchAfter) {
			$match = isset($this->urlSegments[$index+1]) ? $this->urlSegments[$index+1] : '';
		}

		return $match;
	}

	/**
	 * Retrieve array of all URL segments
	 * 
	 * - URL segments must be enabled in the template settings (for template used by the page).
	 * - The maximum segments allowed can be adjusted in your `$config->maxUrlSegments` setting.
	 * - URL segments are populated by ProcessWire automatically on each request.
	 * - URL segments are already sanitized as page names. 
	 * 
	 * #pw-group-URL-segments
	 * 
	 * @return array Returns an array of strings, or an empty array if no URL segments available.
	 * 
	 */
	public function urlSegments() {
		return $this->urlSegments; 
	}

	/**
	 * Set a URL segment value 
	 *
	 * - This is typically only used by the core. 
	 * - To unset, specify NULL as the value. 
	 * 
	 * #pw-group-URL-segments
	 *
	 * @param int $num Number of this URL segment (1 based)
	 * @param string|null $value Value to set, or NULL to unset. 
	 *
	 */
	public function setUrlSegment($num, $value) {
		$config = $this->wire()->config;
		$sanitizer = $this->wire()->sanitizer;
		$num = (int) $num; 
		$maxLength = $config->maxUrlSegmentLength;
		if($maxLength < 1) $maxLength = 128;
		if(is_null($value)) {
			// unset
			$n = 0;
			$urlSegments = array();
			foreach($this->urlSegments as $k => $v) {
				if($k == $num) continue;
				$urlSegments[++$n] = $v;
			}
			$this->urlSegments = $urlSegments;
		} else {
			// sanitize to standard PW name format
			$urlSegment = $sanitizer->name($value, false, $maxLength);
			// if UTF-8 mode and value changed during name sanitization, try pageNameUTF8 instead
			if($urlSegment !== $value && $config->pageNameCharset == 'UTF8') {
				$urlSegment = $sanitizer->pageNameUTF8($value, $maxLength);
			}
			$this->urlSegments[$num] = $urlSegment;
		}
	}

	/**
	 * Set/replace all URL segments
	 *
	 * #pw-group-URL-segments
	 * #pw-internal
	 *
	 * @param array $urlSegments Regular/non-indexed PHP array where first element is first URL segment
	 * @since 3.0.186
	 *
	 */
	public function setUrlSegments(array $urlSegments) {
		$this->urlSegments = array();
		$n = 1;
		foreach($urlSegments as $urlSegment) {
			$this->setUrlSegment($n, $urlSegment);
			$n++;
		}
	}
	
	/**
	 * Get the string of URL segments separated by slashes
	 *
	 * - Note that return value lacks leading or trailing slashes.
	 * - URL segments must be enabled in the template settings (for template used by the page).
	 * - The maximum segments allowed can be adjusted in your `$config->maxUrlSegments` setting.
	 * - URL segments are populated by ProcessWire automatically on each request.
	 * - URL segments are already sanitized as page names. 
	 * - The URL segment string can also be accessed by property: `$input->urlSegmentStr`.
	 * 
	 * ~~~~~
	 * // Adjust output according to urlSegmentStr
	 * // In this case our urlSegmentStr is 2 URL segments
	 * $s = $input->urlSegmentStr();
	 * if($s == 'photos/large') {
	 *   // show large photos
	 * } else if($s == 'photos/small') {
	 *   // show small photos
	 * } else if($s == 'map') {
	 *   // show map
	 * } else if(strlen($s)) {
	 *   // something we don't recognize
	 *   throw new Wire404Exception();
	 * } else {
	 *   // no URL segments present, do some default behavior
	 *   echo $page->body;
	 * }
	 * ~~~~~
	 * 
	 * #pw-group-URL-segments
	 *
	 * @param bool|array $verbose Include pagination number (pageNum) and trailing slashes, when appropriate? (default=false)
	 *  - Use this option for a more link-ready version of the URL segment string (since 3.0.106). 
	 *  - Optionally substitute $options argument for this argument, default for $verbose option remains false (since 3.0.155+).
	 * @param array $options Options to adjust behavior (since 3.0.106):
	 *  - `segments` (array): Optionally specify URL segments to use, rather than those from current request. (default=[])
	 *  - `values` (array): Same as segments option, but associative array converted to /key1/value1/key2/value2/ segment string. (default=[]) 3.0.155+
	 *  - `pageNum` (int): Optionally specify page number to use rather than current. (default=current page number)
	 *  - `page` (Page): Optionally specify Page to use for context. (default=current page)
	 *  - `verbose` (bool): Verbose argument from method, applies only if $options given for $verbose argument. 
	 *  - *NOTE* the `pageNum` and `page` options are not applicable unless the $verbose argument is true. 
	 * @return string URL segment string, i.e. `segment1/segment2/segment3` or blank if none
	 * @see WireInput::urlSegment()
	 *
	 */
	public function urlSegmentStr($verbose = false, array $options = array()) {
		
		if(is_array($verbose)) {
			$options = $verbose;
			$verbose = isset($options['verbose']) ? $options['verbose'] : false;
		}
		
		if(!empty($options['values']) && is_array($options['values'])) {
			$str = '';
			foreach($options['value'] as $key => $value) {
				$str .= "$key/$value/";
			}
			$str = rtrim($str, '/');
		} else if(!empty($options['segments']) && is_array($options['segments'])) {
			$str = implode('/', $options['segments']);
		} else {
			$str = implode('/', $this->urlSegments);
		}
		
		// regular mode exits here
		if(!$verbose) return $str;
	
		// verbose mode takes page number, slash settings, and other $options into account
		$page = isset($options['page']) && $options['page'] instanceof Page ? $options['page'] : $this->wire()->page;
		$template = $page->template; 
		
		if(isset($options['pageNum'])) {
			$pageNum = (int) $options['pageNum']; 
		} else if($template->allowPageNum) {
			$pageNum = $this->pageNum();
		} else {
			$pageNum = 0;
		}
		
		if($pageNum > 1) {
			if(strlen($str)) $str .= '/';
			$str .= $this->pageNumStr($pageNum);
			if($template->slashPageNum) $str .= '/';
		} else if(strlen($str) && (int) $template->slashUrlSegments > -1) {
			$str .= '/';
		}
			
		return $str;
	}

	/**
	 * Return the current pagination/page number (starting from 1)
	 *
	 * - Page numbers must be enabled in the template settings (for template used by the page).
	 * - The current page number affects all paginated page finding operations. 
	 * - First page number is 1 (not 0). 
	 * 
	 * ~~~~~
	 * // Adjust output according to page number
	 * if($input->pageNum == 1) {
	 *   echo $page->body; 
	 * } else {
	 *   echo "<a href='$page->url'>Return to first page</a>";
	 * }
	 * ~~~~~
	 * 
	 * #pw-group-URL-segments
	 *
	 * @return int Current pagination number
	 *
	 */
	public function pageNum() {
		return $this->pageNum; 	
	}
	
	/**
	 * Return the string that represents the page number URL segment
	 * 
	 * Returns blank when page number is 1, since page 1 is assumed when no pagination number present in URL. 
	 * 
	 * This is the string that gets appended to the URL and typically looks like `page123`,
	 * but can be changed by modifying the `$config->pageNumUrlPrefix` setting, or specifying
	 * language-specific page number settings in the LanguageSupportPageNames module. 
	 * 
	 * #pw-group-URL-segments
	 * 
	 * @param int $pageNum Optionally specify page number to use (default=0, which means use current page number)
	 * @return string
	 * @since 3.0.106
	 * 
	 */
	public function pageNumStr($pageNum = 0) {
		$pageNumStr = '';
		$pageNum = (int) $pageNum;
		if($pageNum < 1) $pageNum = $this->pageNum();
		if($pageNum > 1) $pageNumStr = $this->wire()->config->pageNumUrlPrefix . $pageNum;
		return $pageNumStr;
	}

	/**
	 * Set the current page number. 
	 *
	 * - This is typically used only by the core. 
	 * - Note that the first page should be 1 (not 0).
	 * 
	 * #pw-group-URL-segments
	 *
	 * @param int $num
	 *
	 */
	public function setPageNum($num) {
		$this->pageNum = (int) $num;	
	}

	/**	
	 * Retrieve the get, post, cookie or whitelist vars using a direct reference, i.e. $input->cookie
	 *
	 * Can also be used with URL segments, i.e. $input->urlSegment1, $input->urlSegment2, $input->urlSegment3, etc. 
	 * And can also be used for $input->pageNum.
	 *
	 * @param string $key
	 * @return string|int|null
	 *
	 */
	public function __get($key) {

		if($key == 'pageNum') return $this->pageNum; 
		if($key == 'urlSegments') return $this->urlSegments; 
		if($key == 'urlSegmentsStr' || $key == 'urlSegmentStr') return $this->urlSegmentStr();
		if($key == 'url') return $this->url();
		if($key == 'httpUrl' || $key == 'httpURL') return $this->httpUrl();
		if($key == 'fragment') return $this->fragment();
		if($key == 'queryString') return $this->queryString();
		if($key == 'scheme') return $this->scheme();

		if(strpos($key, 'urlSegment') === 0) {
			if($key === 'urlSegmentFirst') {
				$num = 1;
			} else if($key === 'urlSegmentLast') {
				$num = -1;
			} else if(strlen($key) > 10) {
				$num = (int) substr($key, 10);
			} else {
				$num = 1;
			}
			return $this->urlSegment($num);
		}

		$value = null;
		$gpc = array('get', 'post', 'cookie', 'whitelist'); 

		if(in_array($key, $gpc)) {
			$value = $this->$key(); 

		} else {
			// Like PHP's $_REQUEST where accessing $input->var considers get/post/cookie/whitelist
			// what it actually considers depends on what's set in the $config->wireInputOrder variable
			$order = (string) $this->wire()->config->wireInputOrder; 
			if(!$order) return null;
			$types = explode(' ', $order); 
			foreach($types as $t) {
				if(!in_array($t, $gpc)) continue; 	
				$value = $this->$t($key); 
				if(!is_null($value)) break;
			}
		}
		return $value; 
	}

	public function __isset($key) {
		return $this->__get($key) !== null;
	}

	/**
	 * Get the URL that initiated the current request, including URL segments and page numbers
	 * 
	 * - This should be the same as `$page->url` except that it includes URL segments and page numbers, when present.
	 * 
	 * - Note that this does not include query string unless requested (see arguments). 
	 * 
	 * - WARNING: if query string requested, it can contain undefined/unsanitized user input. If you use it for output
	 *   make sure that you entity encode first (by running through `$sanitizer->entities()` for instance).
	 * 
	 * ~~~~~~
	 * $url = $input->url(); 
	 * $url = $sanitizer->entities($url); // entity encode for output
	 * echo "You accessed this page at: $url";
	 * ~~~~~~
	 * 
	 * #pw-group-URLs
	 * 
	 * @param array|bool $options Specify `withQueryString` (bool) option, or in 3.0.167+ you can also use an options array: 
	 *  - `withQueryString` (bool): Include the query string as well? (if present, default=false)
	 *  - `page` (Page): Page object to use, if different from $page (default=$page)
	 *  - `pageNum` (int): Override current pagination number with this one, 1 to exclude pageNum, 0 for no override (default=0). 3.0.169+
	 * @return string
	 * @see WireInput::httpUrl(), Page::url()
	 * 
	 */
	public function url($options = array()) {
		
		$defaults = array(
			'withQueryString' => is_bool($options) ? $options : false,
			'page' => $this->wire()->page, 
			'pageNum' => 0, 
		);

		$options = is_array($options) ? array_merge($defaults, $options) : $defaults;
		
		/** @var Page $page */
		$page = $options['page'];
		$config = $this->wire()->config;
		$sanitizer = $this->wire()->sanitizer;
		$url = '';
		
		if($page && $page->id) {
			// pull URL from page
			$url = $page->url();
			$segmentStr = $this->urlSegmentStr();
			$pageNum = $options['pageNum'] > 0 ? (int) $options['pageNum'] : $this->pageNum();
			if(strlen($segmentStr) || $pageNum > 1) {
				if($segmentStr) $url = rtrim($url, '/') . '/' . $segmentStr;
				if($pageNum > 1) $url = rtrim($url, '/') . '/' . $this->pageNumStr($pageNum); 
				if(isset($_SERVER['REQUEST_URI'])) {
					$info = parse_url($_SERVER['REQUEST_URI']);
					if(!empty($info['path']) && substr($info['path'], -1) == '/') $url .= '/'; // trailing slash
				}
				if($pageNum > 1) {
					if($page->template->slashPageNum == 1) {
						if(substr($url, -1) != '/') $url .= '/';
					} else if($page->template->slashPageNum == -1) {
						if(substr($url, -1) == '/') $url = rtrim($url, '/');
					}
				} else if(strlen($segmentStr)) {
					if($page->template->slashUrlSegments == 1) {
						if(substr($url, -1) != '/') $url .= '/';
					} else if($page->template->slashUrlSegments == -1) {
						if(substr($url, -1) == '/') $url = rtrim($url, '/');
					}
				}
			}
			
		} else if(isset($_SERVER['REQUEST_URI'])) {
			// page not yet available, attempt to pull URL from request uri
			$info = parse_url($_SERVER['REQUEST_URI']);
			$parts = explode('/', $info['path']);
			$charset = $config ? $config->pageNameCharset : '';
			foreach($parts as $i => $part) {
				if($i > 0) $url .= "/";
				$url .= ($charset === 'UTF8' ? $sanitizer->pageNameUTF8($part) : $sanitizer->pageName($part, false));
			}
			if(!empty($info['path']) && substr($info['path'], -1) == '/') {
				$url = rtrim($url, '/') . '/'; // trailing slash
			}
		}
		
		if($options['withQueryString']) {
			$queryString = $this->queryString();
			if(strlen($queryString)) {
				$url .= "?$queryString";
			}
		}
		
		return $url;
	}

	/**
	 * Get the http URL that initiated the current request, including scheme, URL segments and page numbers
	 * 
	 * - This should be the same as `$page->httpUrl` except that it includes URL segments and page numbers, when present.
	 *
	 * - Note that this does not include query string unless requested (see arguments).
	 *
	 * - WARNING: if query string requested, it can contain undefined/unsanitized user input. If you use it for output
	 *   make sure that you entity encode first (by running through `$sanitizer->entities()` for instance).
	 * 
	 * ~~~~~~
	 * $url = $input->httpUrl();
	 * $url = $sanitizer->entities($url); // entity encode for output
	 * echo "You accessed this page at: $url";
	 * ~~~~~~
	 * 
	 * #pw-group-URLs
	 * 
	 * @param array|bool $options Specify `withQueryString` (bool) option, or in 3.0.167+ you can also use an options array:
	 *  - `withQueryString` (bool): Include the query string as well? (if present, default=false)
	 *  - `page` (Page): Page object to use, if different from $page (default=$page)
	 * @return string
	 * @see WireInput::url(), Page::httpUrl()
	 * 
	 */
	public function httpUrl($options = array()) {
		return $this->httpHostUrl() . $this->url($options);
	}

	/**
	 * Same as httpUrl() method but always uses https scheme, rather than current request scheme
	 * 
	 * See httpUrl() method for argument and usage details.
	 * 
	 * #pw-group-URLs
	 * 
	 * @param array|bool $options Specify `withQueryString` (bool) option, or in 3.0.167+ you can also use an options array:
	 *  - `withQueryString` (bool): Include the query string as well? (if present, default=false)
	 *  - `page` (Page): Page object to use, if different from $page (default=$page)
	 * @return string
	 * @see WireInput::httpUrl()
	 * 
	 */
	public function httpsUrl($options = array()) {
		return $this->httpHostUrl(true) . $this->url($options);
	}

	/**
	 * Get current scheme and URL for hostname without any path or query string
	 * 
	 * For example: `https://www.domain.com`
	 * 
	 * #pw-group-URLs
	 * 
	 * @param string|bool|null Optionally specify this argument to force a particular scheme (rather than using current):
	 *  - boolean true or string "https" to force “https”
	 *  - boolean false or string "http" to force “http”
	 *  - string with some other scheme you want to use
	 *  - blank string or "//" for no scheme, i.e. URL begins with "//" which refers to current scheme. 
	 *  - omit argument or null to use current request scheme (default behavior). 
	 * @param string $httpHost HTTP host to use or leave blank for current host
	 * @return string
	 * 
	 */
	public function httpHostUrl($scheme = null, $httpHost = '') {
		if(empty($httpHost)) {
			$httpHost = $this->wire()->config->httpHost;
		}
		if($scheme === true) {
			$scheme = 'https://';
		} else if($scheme === false) {
			$scheme = 'http' . '://';
		} else if(is_string($scheme)) {
			if(strlen($scheme)) {
				if(strpos($scheme, '//') === false) $scheme = "$scheme://";
			} else {
				$scheme = '//';
			}
		} else {
			$scheme = $this->scheme() . '://';
		}
		return $scheme . $httpHost;
	}

	/**
	 * Generate canonical URL for current page and request
	 * 
	 * Canonical URL includes full scheme, hostname, path and optionally: 
	 * URL segments, page numbers and query string.
	 * 
	 * #pw-group-URLs
	 * 
	 * @param array $options
	 *  - `scheme` (string|bool): Scheme "https", "http", or omit to auto-detect (default='').
	 *  - `host` (string): Hostname or omit to use current http host (default='').
	 *  - `page` (Page): Page to use for URL or omit for current Page (default=$page).
	 *  - `urlSegments` (array|string|bool): True to include current URL segments, false to disable, 
	 *     or specify array or string of URL segments to use (default=true).
	 *  - `notSegments` (array|string): Full URL segments or patterns (wildcard or regex) to exclude 
	 *     from canonical URL (default=[])
	 *  - `pageNum` (bool|int): True to include current page/pagination number, false to disable, 
	 *     or specify pagination number (int) to use (default=true).
	 *  - `queryString` (bool|string|array): True to use current whitelist query string, false to disable,
	 *     or specify array of query string vars, or actual query string as string (default=true).
	 *  - `language` (bool|Language): True for current language, false to force default or no language,
	 *     or specify Language object to use that language. (default=true) 
	 * @return string
	 * @since 3.0.155
	 * 
	 */
	public function canonicalUrl(array $options = array()) {
		
		$defaults = array(
			'page' => $this->wire()->page,
			'scheme' => '', 
			'host' => '',
			'urlSegments' => true, 
			'notSegments' => array(), 
			'pageNum' => true, 
			'queryString' => true, 
			'language' => true, 
		);
		
		$options = array_merge($defaults, $options);
		$page = $options['page']; /** @var Page $page */
		$pageUrl = $page->url();
		$template = $page->template;
		$requestUrl = isset($_SERVER['REQUEST_URI']) ? $_SERVER['REQUEST_URI'] : '';
		$languages = $this->wire()->languages;
		$language = $options['language']; /** @var Language|int|string|bool */
		
		if(is_string($options['notSegments'])) {
			$options['notSegments'] = array($options['notSegments']);
		}

		if($language !== true && $languages) {
			if($language === false) {
				$language = $languages->getDefault();
			} else if(!$language instanceof Language) {
				$language = $languages->get($language);
			}
			if($language instanceof Language) {
				$pageUrl = $page->localUrl($language);
			}
		}
		
		// Scheme
		if($options['scheme'] === '') {
			// auto-detect according to template setting and/or current request
			if($template->https > 0) {
				$scheme = 'https';
			} else if($template->https < 0) {
				$scheme = 'http';
			} else {
				$scheme = $this->scheme();
			}
		} else if($options['scheme'] === true || $options['scheme'] === 'https') {
			// force https
			$scheme = 'https';
		} else if($options['scheme'] === false || $options['scheme'] === 'http') {
			// force http
			$scheme = 'http';
		} else if($options['scheme'] && is_string($options['scheme'])) {
			// some other scheme
			$scheme = strtolower($options['scheme']);
		} else {
			// use current scheme
			$scheme = $this->scheme();
		}
	
		// URL Segments String
		if(is_bool($options['urlSegments'])) {
			$urlSegments = $options['urlSegments'] ? $this->urlSegments() : array();
		} else if(is_array($options['urlSegments'])) {
			$urlSegments = $options['urlSegments'];
		} else if(is_string($options['urlSegments'])) {
			$urlSegments = explode('/', trim($options['urlSegments'], '/')); 
		} else {
			$urlSegments = $this->urlSegments();
		}
	
		// remove excluded segments
		if(count($urlSegments) && !empty($options['notSegments'])) {
			foreach($options['notSegments'] as $pattern) {
				foreach($urlSegments as $key => $segment) {
					if($this->patternMatchesValue($pattern, $segment)) unset($urlSegments[$key]); 
				}
			}
		}
		
		// Page/Pagination number
		if($options['pageNum'] === true) {
			$pageNumStr = $this->pageNum() > 1 ? $this->pageNumStr() : '';
		} else if(is_int($options['pageNum']) && $options['pageNum'] > 1) {
			$pageNumStr = $this->pageNumStr($options['pageNum']);
		} else {
			$pageNumStr = '';
		}
		
		// Query string
		if($options['queryString'] === true) {
			// use query string vars from $input->whitelist()
			$queryString = $this->whitelist()->queryString();
		} else if(is_array($options['queryString'])) {
			// use given array to create query string
			$queryString = http_build_query($options['queryString']);
		} else if(is_string($options['queryString'])) {
			// use given string as query string
			$queryString = $options['queryString'];
		} else {
			$queryString = '';
		}

		// Start building final URL
		$url = $pageUrl;

		// add in URL segments if applicable
		if(count($urlSegments)) {
			$urlSegmentStr = implode('/', $urlSegments);
			$slashUrlSegments = (int) $template->slashUrlSegments;
			$url = rtrim($url, '/') . '/' . $urlSegmentStr; 
			if($slashUrlSegments > 0 || $pageNumStr) {
				// add trailing slash to URL segments
				$url .= '/';
			} else if($slashUrlSegments === 0) {
				// use current request as model for whether slash should be used
				$testUrl = rtrim($pageUrl, '/') . "/$urlSegmentStr/";
				if(strpos($requestUrl, $testUrl) !== false) $url .= '/';	
			} else if($slashUrlSegments < 0) {
				// no trailing slash
			}
		}
	
		// add in page/pagination number if applicable
		if($pageNumStr) {
			$url = rtrim($url, '/') . '/' . $pageNumStr; 
			$slashPageNum = (int) $template->slashPageNum;
			if($slashPageNum > 0) {
				// add trailing slash to page number
				$url .= '/';
			} else if($slashPageNum === 0) {
				// use current request as model for whether slash should be used
				$testUrl = rtrim($url, '/') . "/$pageNumStr/";
				if(strpos($requestUrl, $testUrl) !== false) $url .= '/';	
			} else if($slashPageNum < 0) {
				// no trailing slash
			}
		}
		
		if($url === '/') {
			// homepage-only URL and trailing slash specifically disabled. Note that Google
			// considers slash implied in domain-only URL, so this apparently doesn’t matter.
			if(((int) $template->slashUrls) < 1) $url = '';
		}
	
		// add in query string if applicable
		if(strlen($queryString)) {
			$url .= '?' . ltrim($queryString, '?'); 
		}
	
		// bundle in scheme and host and return canonical URL
		$url = $this->httpHostUrl($scheme, $options['host']) . $url;
		
		if($page->of()) $url = $this->wire()->sanitizer->entities($url);
		
		return $url;
	}
	
	/**
	 * Anchor/fragment for current request (i.e. #fragment)
	 * 
	 * Note that this is not sanitized. Fragments generally can't be seen
	 * by the server, so this function may be useless.
	 * 
	 * #pw-internal
	 *
	 * @return string
	 * @deprecated
	 *
	 */
	public function fragment() {
		if(strpos($_SERVER['REQUEST_URI'], '#') === false) return '';
		$info = parse_url($_SERVER['REQUEST_URI']);
		return empty($info['fragment']) ? '' : $info['fragment']; 
	}

	/**
	 * Return the unsanitized query string that was part of this request, or blank if none
	 * 
	 * Note that the returned query string is not sanitized, so if you use it in any output
	 * be sure to run it through `$sanitizer->entities()` first. An optional assoc array
	 * param can be used to add new GET params or override existing ones.
	 * 
	 * #pw-group-URLs
	 * 
	 * @param array $overrides Optional assoc array for overriding or adding GET params
	 * @return string Returns the unsanitized query string
	 * @see WireInput::queryStringClean()
	 * 
	 */
	public function queryString($overrides = array()) {
		return $this->get()->queryString($overrides);
	}

	/**
	 * Return a cleaned query string that was part of this request, or blank if none
	 * 
	 * Note: it is recommended that you always specify $options with this method as the defaults 
	 * may or may not be consistent with your needs. 
	 * 
	 * #pw-group-URLs
	 * 
	 * @param array $options
	 *  - `values` (array): Optional associative array of [name=value] to use in query string rather than current GET vars. (default=[])
	 *  - `overrides` (array): Array of values to override or add to current request values. (default=[])
	 *  - `validNames` (array): Only include query string variables with these names, and omit any others. (default=[])
	 *  - `maxItems` (int): Maximum number of variables/items to include in the query string or 0 for no max. (default=20)
	 *  - `maxLength` (int): Max overall length of returned query string or 0 for no max. (default=1024)
	 *  - `maxNameLength` (int): Max length of any “name” in the “name=value” portion of a query string or 0 for no max. (default=50)
	 *  - `maxValueLength` (int): Max length of any “value” in the “name=value” portion of a query string or 0 for no max. (default=255)
	 *  - `maxArrayDepth` (int): Maximum depth for arrays, or 0 to disallow arrays. (default=0)
	 *  - `maxArrayItems` (int): Maximum number of items allowed in arrays or 0 for no max. (default=20)
	 *  - `associative` (bool): Allow associative arrays? (default=false)
	 *  - `sanitizeName` (string): Sanitize query string variable names with this sanitizer method or blank to ignore. (default='fieldName')
	 *  - `sanitizeValue` (string): Sanitize query string variable values with this sanitizer method or blank to ignore. (default='line')
	 *  - `sanitizeRemove` (bool): Remove any variables from query string that are changed as the result of sanitization? (default=true)
	 *  - `entityEncode` (bool): Should returned query string be entity encoded for HTML output? (default=true)
	 *  - `encType` (int): Use PHP_QUERY_RFC3986 for spaces encoded to '%20' or PHP_QUERY_RFC1738 for spaces as '+'. (default=PHP_QUERY_RFC3986)
	 *  - `separator` (string): Character(s) that separate each “name=value” in query string. (default='&')
	 * @return string
	 * @since 3.0.167
	 * 
	 */
	public function queryStringClean(array $options = array()) {
		
		$defaults = array(
			'values' => array(),
			'overrides' => array(),
			'validNames' => array(), 
			'maxItems' => 20, 
			'maxLength' => 1024, // max overall length
			'maxNameLength' => 50,
			'maxValueLength' => 255,
			'allowArrays' => false, 
			'maxArrayDepth' => 0, 
			'maxArrayItems' => 20,
			'sanitizeName' => 'fieldName',
			'sanitizeValue' => 'line',
			'sanitizeRemove' => true, 
			'entityEncode' => true, 
			'encType' => PHP_QUERY_RFC3986, // Spaces are '%20', for '+' use PHP_QUERY_RFC1738
			'separator' => '&',
		);
		
		$options = array_merge($defaults, $options);
		$values = empty($options['values']) ? $this->get()->getArray() : $options['values'];
		$sanitizer = $this->wire()->sanitizer;
		$separator = $options['separator'];
		$maxArrayDepth = $options['maxArrayDepth'];
		
		if(count($options['overrides'])) {
			$values = array_merge($values, $options['overrides']); 
		}
	
		// only allow specific names/keys from the array
		if(!empty($options['validNames'])) {
			$a = array();
			foreach($values as $name => $value) {
				if(in_array($name, $options['validNames'], true)) $a[$name] = $value;
			}
			$values = $a;
		}
	
		// limit to a max quantity of items
		if($options['maxItems'] && count($values) > $options['maxItems']) {
			$values = array_slice($values, 0, $options['maxItems']);
		}
	
		// sanitize or remove arrays
		foreach($values as $name => $value) {
			if(!is_array($value)) continue;
			if($options['allowArrays']) {
				$a = $sanitizer->arrayVal($value, array(
					'maxItems' => $options['maxArrayItems'],
					'maxDepth' => $maxArrayDepth, 
					'sanitizer' => $options['sanitizeValue'], 
					'keySanitizer' => $options['sanitizeName'],
				));
				if($options['sanitizeRemove'] && $a != $value) {
					unset($values[$name]);
				} else {
					$values[$name] = $a;
				}
			} else {
				unset($values[$name]); 
			}
		}

		// sanitize names
		if($options['sanitizeName'] || $options['maxNameLength']) {
			$method = $options['sanitizeName'];
			$max = $options['maxNameLength'];
			$a = array();
			foreach($values as $name => $value) {
				$newName = $method ? $sanitizer->$method($name) : $name;
				if($max && strlen($newName) > $max) {
					$newName = substr($newName, 0, $max);
				}
				if($newName === $name) {
					$a[$name] = $value;
				} else if(!$options['sanitizeRemove']) {
					$a[$newName] = $value;
				}
			}
			$values = $a;
		}
	
		// sanitize values
		if($options['sanitizeValue'] || $options['maxValueLength']) {
			$method = $options['sanitizeValue'];
			$max = $options['maxValueLength'];
			$a = array();
			foreach($values as $name => $value) {
				if(is_array($value) && $options['allowArrays']) {
					// arrays already handled earlier
					$a[$name] = $value;
					continue;
				} 
				$newValue = $method ? $sanitizer->$method($value) : $value;
				if($max && strlen($newValue) > $max) {
					$newValue = substr($newValue, 0, $max);
				}
				if($newValue === $value) {
					$a[$name] = $value;
				} else if(!$options['sanitizeRemove']) {
					$a[$name] = $newValue;
				}
			}
			$values = $a;
		}
		
		if(!count($values)) return '';
	
		// prevent double encoding if an encoded & was provided in $options
		if(strtolower($separator) === '&amp;' && $options['entityEncode']) {
			$separator = '&';
		}

		// build the query string
		$queryString = http_build_query($values, '', $separator, $options['encType']);
		
		// %5Bfoobar%5D => [foobar]
		// if(strpos($queryString, '%5D=')) {
		//	$queryString = preg_replace('/%5B([-_.a-zA-Z0-9]+)%5D=/', '[$1]=', $queryString);
		// }
	
		// entity encode if requested
		if($options['entityEncode']) {
			$queryString = $sanitizer->entities($queryString);
			$separator = $sanitizer->entities($separator);
		}
	
		// if query string exceeds max allowed length then truncate it
		if($options['maxLength'] && strlen($queryString) > $options['maxLength']) { 
			while(strlen($queryString) > $options['maxLength'] && strpos($queryString, $separator)) {
				$a = explode($separator, $queryString);
				array_pop($a);
				$queryString = implode($separator, $a);
			}
			if(strlen($queryString) > $options['maxLength']) $queryString = '';
		}
		
		return $queryString;
	}

	/**
	 * Return the current access scheme/protocol 
	 *
	 * Note that this is only useful for http/https, as we don't detect other schemes.
	 * 
	 * #pw-group-URLs
	 *
	 * @return string Return value is either "https" or "http"
	 *
	 */
	public function scheme() {
		return $this->wire()->config->https ? 'https' : 'http'; 
	}

	/**
	 * Return the current request method (i.e. GET, POST, etc.) or blank if not known
	 * 
	 * Possible return values are:
	 * - GET
	 * - POST
	 * - HEAD
	 * - PUT
	 * - DELETE
	 * - OPTIONS
	 * - or blank if not known
	 * 
	 * @param string $method Optionally enter the request method to return bool if current method matches
	 * @return string|bool
	 * @since 3.0.39
	 * 
	 */
	public function requestMethod($method = '') {
		if(isset($_SERVER['REQUEST_METHOD'])) {
			$m = strtoupper($_SERVER['REQUEST_METHOD']);
			$requestMethod = isset($this->requestMethods[$m]) ? $this->requestMethods[$m] : '';
		} else {
			$requestMethod = '';
		}
		if($method) return strtoupper($method) === $requestMethod;
		return $requestMethod; 
	}

	/**
	 * Is the current request of the specified type?
	 * 
	 * This is a more readable/shorter alias of `$input->requestMethod('type')` for syntax convenience.
	 * Internally, it determines the request type without accessing any input data, so it is efficient.
	 * 
	 * ~~~~~
	 * // The following are equivalent:
	 * $isPost = $input->is('post');
	 * $isPost = $input->requestMethod('post');
	 * ~~~~~
	 * 
	 * @param string $method Specify one of: post, get, head, put, delete, options, patch (not case sensitive)
	 * @return bool
	 * @since 3.0.145
	 * 
	 */
	public function is($method) {
		return empty($method) ? false : $this->requestMethod($method);
	}
	
	/**
	 * Provides the implementation for get/post/cookie method validation and fallback features
	 *
	 * @param WireInputData $input 
	 * @param string $key Name of variable to pull from $input
	 * @param array|string|callable|mixed|null $valid String containing name of Sanitizer method, or array of allowed values.
	 * @param string|array|int|mixed $fallback Return this value rather than null if input value is not present or not valid.
	 * @return array|int|mixed|null|WireInputData|string
	 * @throws WireException if given unknown Sanitizer method or some other invalid arguments.
	 *
	 */
	protected function getValidInputValue(WireInputData $input, $key, $valid, $fallback) {

		if(!strlen($key)) return $input; // return all
		
		if(strpos($key, '[]')) {
			$key = trim($key, '[]');
			$forceArray = true;
		} else {
			$forceArray = false;
		}

		$value = $input->__get($key);
		$cleanValue = null;

		if($value === null && $fallback !== null) {
			// no value present, use fallback
			$cleanValue = $fallback;
			
		} else if($value === null && $valid === null && $fallback === null) {
			// everything null
			// $cleanValue = null;
			
		} else if($valid === null) {
			// no sanitization/validation requested
			$cleanValue = $value === null ? $fallback : $value;

		} else if(is_string($valid)) {
			// sanitizer "name" or multiple "name1,name2,name3" specified for $valid argument
			$cleanValue = $this->sanitizeValue($valid, $value, ($forceArray || is_array($fallback)));

		} else if(is_array($valid)) {
			// whitelist provided for $valid argument
			$cleanValue = $this->filterValue($value, $valid, ($forceArray || is_array($fallback))); 

		} else if(is_callable($valid)) {
			// callable function provided for sanitization and validation
			$cleanValue = call_user_func($valid, $value);

		} else if(is_int($valid)) {
			// single integer provided as only allowed value
			if(ctype_digit("$value")) {
				$value = (int) $value;
				if($valid === $value) $cleanValue = $valid;
			}
		}

		if(($cleanValue === null || ($forceArray && empty($cleanValue))) && $fallback !== null) {
			$cleanValue = $fallback;
		}
		if($forceArray && !is_array($cleanValue)) {
			$cleanValue = ($cleanValue === null ? array() : array($cleanValue));
		}

		return $cleanValue;
	}

	/**
	 * Filter value against given $valid whitelist
	 * 
	 * @param string|array $value
	 * @param array $valid Whitelist of valid values
	 * @param bool $getArray Filter to allow multiple values (array)?
	 * @return array|string|null
	 * @throws WireException If given a multidimensional array for $valid argument
	 * 
	 */
	protected function filterValue($value, array $valid, $getArray) {
		
		$cleanValue = $getArray ? array() : null;
		
		if($getArray) {
			if(!is_array($value)) {
				// array expected but input value is not an array, so convert it to one
				$value = ($value === null ? array() : array($value));
			}
		} else while(is_array($value)) {
			$value = reset($value);
		}
		
		foreach($valid as $validValue) {
			if(is_array($validValue)) {
				throw new WireException('Array of arrays not supported for valid value whitelist');
			}
			if($getArray) {
				// input value is an array, as is the fallback, so array is expected return value
				foreach($value as $dirtyValue) {
					if(is_array($dirtyValue)) continue;
					// multiple items allowed
					if("$validValue" === "$dirtyValue") $cleanValue[] = $validValue;
				}
			} else if("$value" === "$validValue") {
				$cleanValue = $validValue;
				break; // stop at one
			}
		}
		
		return $cleanValue;
	}

	/**
	 * Sanitize the given value with the given method(s)
	 * 
	 * @param string $method Sanitizer method name or CSV string of sanitizer method names
	 * @param string|array|null $value
	 * @param bool $getArray
	 * @return array|mixed|null
	 * @throws WireException If given unknown sanitizer method
	 * 
	 */
	protected function sanitizeValue($method, $value, $getArray) {
		
		$sanitizer = $this->wire()->sanitizer;
		$sanitizers = $sanitizer->getAll(true);
		$methods = array();
		
		foreach(explode(',', $method) as $name) {
			$name = trim($name);
			if(empty($name)) continue;
			if(!isset($sanitizers[$name])) throw new WireException("Unknown sanitizer '$method'"); 
			$methods[$name] = $sanitizers[$name]; // value is return type(s)
		}
	
		$lastReturnType = end($methods); 
		if(!$getArray) {
			if($lastReturnType === 'a') {
				$getArray = true; // array return value implied
			} else if(strpos($lastReturnType, 'a') !== false) {
				$getArray = 1; // array return value possible
			}
		}
		
		foreach($methods as $methodName => $returnType) {
			
			$methodName = trim($methodName);
			if(empty($methodName)) continue;
			
			if(is_array($value)) {
				// array value
				if(!count($value)) {
					// nothing to do with value
					$value = array();
				} else if($getArray && strpos($returnType, 'a') === false) {
					// sanitize array with sanitizer that does not do arrays, 1 item at a time
					$a = array();
					foreach($value as $v) {
						$cv = $sanitizer->sanitize($v, $methodName);
						if($cv !== null) $a[] = $cv;
					}
					$value = $a;
				} else if($getArray) {
					// sanitizer that can handle arrays
					$value = $sanitizer->sanitize($value, $methodName);
				} else {
					// sanitizer does not do arrays, reduce to 1st array item
					$value = reset($value);
					$value = $sanitizer->sanitize($value, $methodName);
				}
				
			} else {
				// non-array value
				$value = $sanitizer->sanitize($value, $methodName);
			}
		}
		
		if($getArray === true && !is_array($value)) {
			$value = array($value);
		}
		
		return $value; 
	}


	/**
	 * Emulate register globals OFF
	 *
	 * Should be called after session_start()
	 * 
	 * #pw-internal
	 *
	 * This function is from the PHP documentation at:
	 * http://www.php.net/manual/en/faq.misc.php#faq.misc.registerglobals
	 *
	 */
	protected function unregisterGLOBALS() {

		if(!ini_get('register_globals')) {
			return;
		}

		if(isset($_REQUEST['GLOBALS']) || isset($_FILES['GLOBALS'])) {
			unset($_GET['GLOBALS'], $_POST['GLOBALS'], $_COOKIE['GLOBALS'], $_FILES['GLOBALS']);
		}

		// Variables that shouldn't be unset
		$noUnset = array('GLOBALS', '_GET', '_POST', '_COOKIE', '_REQUEST', '_SERVER', '_ENV', '_FILES');

		$input = array_merge($_GET, $_POST, $_COOKIE, $_SERVER, $_ENV, $_FILES, isset($_SESSION) && is_array($_SESSION) ? $_SESSION : array());

		foreach ($input as $k => $v) {
			if(!in_array($k, $noUnset) && isset($GLOBALS[$k])) {
				unset($GLOBALS[$k]);
			}
		}
	}
	
	/**
	 * debugInfo PHP 5.6+ magic method
	 *
	 * This is used when you print_r() an object instance.
	 *
	 * @return array
	 *
	 */
	public function __debugInfo() {
		$info = parent::__debugInfo();
		$info['get'] = $this->getVars ? $this->getVars->getArray() : null;
		$info['post'] = $this->postVars ? $this->postVars->getArray() : null;
		$info['cookie'] = $this->cookieVars ? $this->cookieVars->getArray() : null;
		$info['whitelist'] = $this->whitelist ? $this->whitelist->getArray() : null;
		$info['urlSegments'] = $this->urlSegments;
		$info['pageNum'] = $this->pageNum;
		return $info;
	}

	/**
	 * Call unknown method
	 * 
	 * #pw-internal 
	 * 
	 * @param string $method
	 * @param array $arguments
	 * @return mixed|null
	 * @throws WireException
	 * 
	 */
	public function ___callUnknown($method, $arguments) {
		if(strpos($method, 'urlSegment') === 0) {
			// Allow for method calls: urlSegment1(), urlSegment2('sort-*'), urlSegmentLast(), etc. 
			list(,$num) = explode('urlSegment', $method, 2);
			if(ctype_digit($num)) $num = (int) $num;
			if($num === 'Last') $num = -1;
			if($num === 'First') $num = 1; 
			if(is_int($num)) {
				if(empty($arguments)) {
					return $this->urlSegment((int) $num); 
				} else {
					return $this->urlSegmentMatch($arguments[0], (int) $num);
				}
			} 
		}
		return parent::___callUnknown($method, $arguments);
	}

	/**
	 * Does given wildcard, pattern or string match given value? (or any of given values if array)
	 * 
	 * #pw-internal
	 *
	 * @param string $pattern
	 * @param string|array $value
	 * @param bool $partial Perform a partial match if not a wildcard or regex? (default=false)
	 * @return string Returns match on success or blank string if no match
	 * @since 3.0.155
	 *
	 */
	protected function patternMatchesValue($pattern, $value, $partial = false) {
		if(is_array($value)) {
			$result = '';
			foreach($value as $v) {
				$result = $this->patternMatchesValue($pattern, $v, $partial); 
				if($result !== '') break;
			}
			return $result;
		}
		$regex = in_array($pattern[0], $this->regexDelims) ? $pattern : $this->patternToRegex($pattern);
		if($regex) {
			if(preg_match($regex, $value, $matches)) {
				$result = isset($matches[1]) ? $matches[1] : $value;
			} else {
				$result = '';
			}
		} else if($partial) {
			$result = strpos($value, $pattern) !== false ? $value : '';
		} else {
			$result = $pattern === $value ? $value : '';
		}
		return $result;
	}

	/**
	 * Convert wildcard pattern to regex (if not already a regex) or blank string if not a pattern
	 *
	 * #pw-internal
	 *
	 * @param string $pattern
	 * @return string
	 * @since 3.0.155
	 *
	 */
	protected function patternToRegex($pattern) {
		if(!strlen($pattern)) {
			// nothing to do
			$regex = '';
		} else if(in_array($pattern[0], $this->regexDelims) && strrpos($pattern, $pattern[0])) {
			// already a regular expression
			$regex = $pattern;
		} else if(strpos($pattern, '*') !== false) {
			// wildcard, convert to regex
			$a = explode('*', $pattern);
			foreach($a as $k => $v) {
				$a[$k] = preg_quote($v);
			}
			$regex = '/^' . implode('.+', $a) . '$/';
			$regex = str_replace(
				array('\\(', '\\)', '\\[', '\\]'), 
				array('(', ')', '[', ']'), 
				$regex
			);
		} else {
			$regex = '';
		}
		return $regex;
	}

}