<?php
/**
 * Part of the Joomla Framework Application Package
 *
 * @copyright  Copyright (C) 2005 - 2021 Open Source Matters, Inc. All rights reserved.
 * @license    GNU General Public License version 2 or later; see LICENSE
 */

namespace Joomla\Application;

use Joomla\Application\Exception\UnableToWriteBody;
use Joomla\Input\Input;
use Joomla\Registry\Registry;
use Joomla\Uri\Uri;
use Laminas\Diactoros\Response;
use Laminas\Diactoros\Stream;
use Psr\Http\Message\ResponseInterface;

/**
 * Base class for a Joomla! Web application.
 *
 * @since  1.0
 *
 * @property-read  Input  $input  The application input object
 */
abstract class AbstractWebApplication extends AbstractApplication implements WebApplicationInterface
{
	/**
	 * The application input object.
	 *
	 * @var    Input
	 * @since  1.0
	 */
	protected $input;

	/**
	 * Character encoding string.
	 *
	 * @var    string
	 * @since  1.0
	 */
	public $charSet = 'utf-8';

	/**
	 * Response mime type.
	 *
	 * @var    string
	 * @since  1.0
	 */
	public $mimeType = 'text/html';

	/**
	 * HTTP protocol version.
	 *
	 * @var    string
	 * @since  1.9.0
	 */
	public $httpVersion = '1.1';

	/**
	 * The body modified date for response headers.
	 *
	 * @var    \DateTime
	 * @since  1.0
	 */
	public $modifiedDate;

	/**
	 * The application client object.
	 *
	 * @var    Web\WebClient
	 * @since  1.0
	 */
	public $client;

	/**
	 * The application response object.
	 *
	 * @var    ResponseInterface
	 * @since  1.0
	 */
	protected $response;

	/**
	 * Is caching enabled?
	 *
	 * @var    boolean
	 * @since  2.0.0
	 */
	private $cacheable = false;

	/**
	 * A map of integer HTTP response codes to the full HTTP Status for the headers.
	 *
	 * @var    array
	 * @since  1.6.0
	 * @link   https://www.iana.org/assignments/http-status-codes/http-status-codes.xhtml
	 */
	private $responseMap = [
		100 => 'HTTP/{version} 100 Continue',
		101 => 'HTTP/{version} 101 Switching Protocols',
		102 => 'HTTP/{version} 102 Processing',
		200 => 'HTTP/{version} 200 OK',
		201 => 'HTTP/{version} 201 Created',
		202 => 'HTTP/{version} 202 Accepted',
		203 => 'HTTP/{version} 203 Non-Authoritative Information',
		204 => 'HTTP/{version} 204 No Content',
		205 => 'HTTP/{version} 205 Reset Content',
		206 => 'HTTP/{version} 206 Partial Content',
		207 => 'HTTP/{version} 207 Multi-Status',
		208 => 'HTTP/{version} 208 Already Reported',
		226 => 'HTTP/{version} 226 IM Used',
		300 => 'HTTP/{version} 300 Multiple Choices',
		301 => 'HTTP/{version} 301 Moved Permanently',
		302 => 'HTTP/{version} 302 Found',
		303 => 'HTTP/{version} 303 See other',
		304 => 'HTTP/{version} 304 Not Modified',
		305 => 'HTTP/{version} 305 Use Proxy',
		306 => 'HTTP/{version} 306 (Unused)',
		307 => 'HTTP/{version} 307 Temporary Redirect',
		308 => 'HTTP/{version} 308 Permanent Redirect',
		400 => 'HTTP/{version} 400 Bad Request',
		401 => 'HTTP/{version} 401 Unauthorized',
		402 => 'HTTP/{version} 402 Payment Required',
		403 => 'HTTP/{version} 403 Forbidden',
		404 => 'HTTP/{version} 404 Not Found',
		405 => 'HTTP/{version} 405 Method Not Allowed',
		406 => 'HTTP/{version} 406 Not Acceptable',
		407 => 'HTTP/{version} 407 Proxy Authentication Required',
		408 => 'HTTP/{version} 408 Request Timeout',
		409 => 'HTTP/{version} 409 Conflict',
		410 => 'HTTP/{version} 410 Gone',
		411 => 'HTTP/{version} 411 Length Required',
		412 => 'HTTP/{version} 412 Precondition Failed',
		413 => 'HTTP/{version} 413 Payload Too Large',
		414 => 'HTTP/{version} 414 URI Too Long',
		415 => 'HTTP/{version} 415 Unsupported Media Type',
		416 => 'HTTP/{version} 416 Range Not Satisfiable',
		417 => 'HTTP/{version} 417 Expectation Failed',
		418 => 'HTTP/{version} 418 I\'m a teapot',
		421 => 'HTTP/{version} 421 Misdirected Request',
		422 => 'HTTP/{version} 422 Unprocessable Entity',
		423 => 'HTTP/{version} 423 Locked',
		424 => 'HTTP/{version} 424 Failed Dependency',
		426 => 'HTTP/{version} 426 Upgrade Required',
		428 => 'HTTP/{version} 428 Precondition Required',
		429 => 'HTTP/{version} 429 Too Many Requests',
		431 => 'HTTP/{version} 431 Request Header Fields Too Large',
		451 => 'HTTP/{version} 451 Unavailable For Legal Reasons',
		500 => 'HTTP/{version} 500 Internal Server Error',
		501 => 'HTTP/{version} 501 Not Implemented',
		502 => 'HTTP/{version} 502 Bad Gateway',
		503 => 'HTTP/{version} 503 Service Unavailable',
		504 => 'HTTP/{version} 504 Gateway Timeout',
		505 => 'HTTP/{version} 505 HTTP Version Not Supported',
		506 => 'HTTP/{version} 506 Variant Also Negotiates',
		507 => 'HTTP/{version} 507 Insufficient Storage',
		508 => 'HTTP/{version} 508 Loop Detected',
		510 => 'HTTP/{version} 510 Not Extended',
		511 => 'HTTP/{version} 511 Network Authentication Required',
	];

	/**
	 * Class constructor.
	 *
	 * @param   Input              $input     An optional argument to provide dependency injection for the application's
	 *                                        input object.  If the argument is an Input object that object will become
	 *                                        the application's input object, otherwise a default input object is
	 *                                        created.
	 * @param   Registry           $config    An optional argument to provide dependency injection for the application's
	 *                                        config object.  If the argument is a Registry object that object will
	 *                                        become the application's config object, otherwise a default config object
	 *                                        is created.
	 * @param   Web\WebClient      $client    An optional argument to provide dependency injection for the application's
	 *                                        client object.  If the argument is a Web\WebClient object that object will
	 *                                        become the application's client object, otherwise a default client object
	 *                                        is created.
	 * @param   ResponseInterface  $response  An optional argument to provide dependency injection for the application's
	 *                                        response object.  If the argument is a ResponseInterface object that object
	 *                                        will become the application's response object, otherwise a default response
	 *                                        object is created.
	 *
	 * @since   1.0
	 */
	public function __construct(Input $input = null, Registry $config = null, Web\WebClient $client = null, ResponseInterface $response = null)
	{
		$this->input  = $input ?: new Input;
		$this->client = $client ?: new Web\WebClient;

		// Setup the response object.
		if (!$response)
		{
			$response = new Response;
		}

		$this->setResponse($response);

		// Call the constructor as late as possible (it runs `initialise`).
		parent::__construct($config);

		// Set the system URIs.
		$this->loadSystemUris();
	}

	/**
	 * Magic method to access properties of the application.
	 *
	 * @param   string  $name  The name of the property.
	 *
	 * @return  mixed   A value if the property name is valid, null otherwise.
	 *
	 * @since       2.0.0
	 * @deprecated  3.0  This is a B/C proxy for deprecated read accesses
	 */
	public function __get($name)
	{
		switch ($name)
		{
			case 'input':
				trigger_deprecation(
					'joomla/application',
					'2.0.0',
					'Accessing the input property of %s is deprecated, use the %s::getInput() method instead.',
					self::class,
					self::class
				);

				return $this->getInput();

			default:
				$trace = debug_backtrace();
				trigger_error(
					sprintf(
						'Undefined property via __get(): %1$s in %2$s on line %3$s',
						$name,
						$trace[0]['file'],
						$trace[0]['line']
					),
					E_USER_NOTICE
				);
		}
	}

	/**
	 * Execute the application.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 */
	public function execute()
	{
		try
		{
			$this->dispatchEvent(ApplicationEvents::BEFORE_EXECUTE);

			// Perform application routines.
			$this->doExecute();

			$this->dispatchEvent(ApplicationEvents::AFTER_EXECUTE);

			// If gzip compression is enabled in configuration and the server is compliant, compress the output.
			if ($this->get('gzip') && !ini_get('zlib.output_compression') && (ini_get('output_handler') != 'ob_gzhandler'))
			{
				$this->compress();
			}
		}
		catch (\Throwable $throwable)
		{
			$this->dispatchEvent(ApplicationEvents::ERROR, new Event\ApplicationErrorEvent($throwable, $this));
		}

		$this->dispatchEvent(ApplicationEvents::BEFORE_RESPOND);

		// Send the application response.
		$this->respond();

		$this->dispatchEvent(ApplicationEvents::AFTER_RESPOND);
	}

	/**
	 * Checks the accept encoding of the browser and compresses the data before sending it to the client if possible.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 */
	protected function compress()
	{
		// Supported compression encodings.
		$supported = [
			'x-gzip'  => 'gz',
			'gzip'    => 'gz',
			'deflate' => 'deflate',
		];

		// Get the supported encoding.
		$encodings = array_intersect($this->client->encodings, array_keys($supported));

		// If no supported encoding is detected do nothing and return.
		if (empty($encodings))
		{
			return;
		}

		// Verify that headers have not yet been sent, and that our connection is still alive.
		if ($this->checkHeadersSent() || !$this->checkConnectionAlive())
		{
			return;
		}

		// Iterate through the encodings and attempt to compress the data using any found supported encodings.
		foreach ($encodings as $encoding)
		{
			if (($supported[$encoding] == 'gz') || ($supported[$encoding] == 'deflate'))
			{
				// Verify that the server supports gzip compression before we attempt to gzip encode the data.
				// @codeCoverageIgnoreStart
				if (!\extension_loaded('zlib') || ini_get('zlib.output_compression'))
				{
					continue;
				}

				// @codeCoverageIgnoreEnd

				// Attempt to gzip encode the data with an optimal level 4.
				$data   = $this->getBody();
				$gzdata = gzencode($data, 4, ($supported[$encoding] == 'gz') ? FORCE_GZIP : FORCE_DEFLATE);

				// If there was a problem encoding the data just try the next encoding scheme.
				// @codeCoverageIgnoreStart
				if ($gzdata === false)
				{
					continue;
				}

				// @codeCoverageIgnoreEnd

				// Set the encoding headers.
				$this->setHeader('Content-Encoding', $encoding);
				$this->setHeader('Vary', 'Accept-Encoding');
				$this->setHeader('X-Content-Encoded-By', 'Joomla');

				// Replace the output with the encoded data.
				$this->setBody($gzdata);

				// Compression complete, let's break out of the loop.
				break;
			}
		}
	}

	/**
	 * Method to send the application response to the client.  All headers will be sent prior to the main application output data.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 */
	protected function respond()
	{
		// Send the content-type header.
		if (!$this->getResponse()->hasHeader('Content-Type'))
		{
			$this->setHeader('Content-Type', $this->mimeType . '; charset=' . $this->charSet);
		}

		// If the response is set to uncachable, we need to set some appropriate headers so browsers don't cache the response.
		if (!$this->allowCache())
		{
			// Expires in the past.
			$this->setHeader('Expires', 'Wed, 17 Aug 2005 00:00:00 GMT', true);

			// Always modified.
			$this->setHeader('Last-Modified', gmdate('D, d M Y H:i:s') . ' GMT', true);
			$this->setHeader('Cache-Control', 'no-store, no-cache, must-revalidate, post-check=0, pre-check=0', false);

			// HTTP 1.0
			$this->setHeader('Pragma', 'no-cache');
		}
		else
		{
			// Expires.
			if (!$this->getResponse()->hasHeader('Expires'))
			{
				$this->setHeader('Expires', gmdate('D, d M Y H:i:s', time() + 900) . ' GMT');
			}

			// Last modified.
			if (!$this->getResponse()->hasHeader('Last-Modified') && $this->modifiedDate instanceof \DateTime)
			{
				$this->modifiedDate->setTimezone(new \DateTimeZone('UTC'));
				$this->setHeader('Last-Modified', $this->modifiedDate->format('D, d M Y H:i:s') . ' GMT');
			}
		}

		// Make sure there is a status header already otherwise generate it from the response
		if (!$this->getResponse()->hasHeader('Status'))
		{
			$this->setHeader('Status', (string) $this->getResponse()->getStatusCode());
		}

		$this->sendHeaders();

		echo $this->getBody();
	}

	/**
	 * Method to get the application input object.
	 *
	 * @return  Input
	 *
	 * @since   2.0.0
	 */
	public function getInput(): Input
	{
		return $this->input;
	}

	/**
	 * Redirect to another URL.
	 *
	 * If the headers have not been sent the redirect will be accomplished using a "301 Moved Permanently" or "303 See Other" code in the header
	 * pointing to the new location. If the headers have already been sent this will be accomplished using a JavaScript statement.
	 *
	 * @param   string           $url     The URL to redirect to. Can only be http/https URL
	 * @param   integer|boolean  $status  The HTTP status code to be provided. 303 is assumed by default.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 * @throws  \InvalidArgumentException
	 */
	public function redirect($url, $status = 303)
	{
		// Check for relative internal links.
		if (preg_match('#^index\.php#', $url))
		{
			$url = $this->get('uri.base.full') . $url;
		}

		// Perform a basic sanity check to make sure we don't have any CRLF garbage.
		$url = preg_split("/[\r\n]/", $url);
		$url = $url[0];

		/*
		 * Here we need to check and see if the URL is relative or absolute.  Essentially, do we need to
		 * prepend the URL with our base URL for a proper redirect.  The rudimentary way we are looking
		 * at this is to simply check whether or not the URL string has a valid scheme or not.
		 */
		if (!preg_match('#^[a-z]+\://#i', $url))
		{
			// Get a Uri instance for the requested URI.
			$uri = new Uri($this->get('uri.request'));

			// Get a base URL to prepend from the requested URI.
			$prefix = $uri->toString(['scheme', 'user', 'pass', 'host', 'port']);

			// We just need the prefix since we have a path relative to the root.
			if ($url[0] == '/')
			{
				$url = $prefix . $url;
			}
			else
			{
				// It's relative to where we are now, so lets add that.
				$parts = explode('/', $uri->toString(['path']));
				array_pop($parts);
				$path = implode('/', $parts) . '/';
				$url  = $prefix . $path . $url;
			}
		}

		// If the headers have already been sent we need to send the redirect statement via JavaScript.
		if ($this->checkHeadersSent())
		{
			echo '<script>document.location.href=' . json_encode($url) . ";</script>\n";
		}
		// We have to use a JavaScript redirect here because MSIE doesn't play nice with UTF-8 URLs.
		elseif (($this->client->engine == Web\WebClient::TRIDENT) && !static::isAscii($url))
		{
			$html = '<html><head>';
			$html .= '<meta http-equiv="content-type" content="text/html; charset=' . $this->charSet . '" />';
			$html .= '<script>document.location.href=' . json_encode($url) . ';</script>';
			$html .= '</head><body></body></html>';

			echo $html;
		}
		else
		{
			// Check if we have a boolean for the status variable for compatability with v1 of the framework
			// @deprecated 3.0
			if (\is_bool($status))
			{
				trigger_deprecation(
					'joomla/application',
					'2.0.0',
					'Passing a boolean value for the $status argument in %s() is deprecated, an integer should be passed instead.',
					__METHOD__
				);

				$status = $status ? 301 : 303;
			}

			if (!\is_int($status) && !$this->isRedirectState($status))
			{
				throw new \InvalidArgumentException('You have not supplied a valid HTTP status code');
			}

			// All other cases use the more efficient HTTP header for redirection.
			$this->setHeader('Status', (string) $status, true);
			$this->setHeader('Location', $url, true);
		}

		$this->dispatchEvent(ApplicationEvents::BEFORE_RESPOND);

		// Set appropriate headers
		$this->respond();

		$this->dispatchEvent(ApplicationEvents::AFTER_RESPOND);

		// Close the application after the redirect.
		$this->close();
	}

	/**
	 * Set/get cachable state for the response.
	 *
	 * If $allow is set, sets the cachable state of the response.  Always returns the current state.
	 *
	 * @param   boolean  $allow  True to allow browser caching.
	 *
	 * @return  boolean
	 *
	 * @since   1.0
	 */
	public function allowCache($allow = null)
	{
		if ($allow !== null)
		{
			$this->cacheable = (bool) $allow;
		}

		return $this->cacheable;
	}

	/**
	 * Method to set a response header.
	 *
	 * If the replace flag is set then all headers with the given name will be replaced by the new one.
	 * The headers are stored in an internal array to be sent when the site is sent to the browser.
	 *
	 * @param   string   $name     The name of the header to set.
	 * @param   string   $value    The value of the header to set.
	 * @param   boolean  $replace  True to replace any headers with the same name.
	 *
	 * @return  $this
	 *
	 * @since   1.0
	 */
	public function setHeader($name, $value, $replace = false)
	{
		// Sanitize the input values.
		$name     = (string) $name;
		$value    = (string) $value;
		$response = $this->getResponse();

		// If the replace flag is set, unset all known headers with the given name.
		if ($replace && $response->hasHeader($name))
		{
			$response = $response->withoutHeader($name);
		}

		// Add the header to the internal array.
		$this->setResponse($response->withAddedHeader($name, $value));

		return $this;
	}

	/**
	 * Method to get the array of response headers to be sent when the response is sent to the client.
	 *
	 * @return  array
	 *
	 * @since   1.0
	 */
	public function getHeaders()
	{
		$return = [];

		foreach ($this->getResponse()->getHeaders() as $name => $values)
		{
			foreach ($values as $value)
			{
				$return[] = ['name' => $name, 'value' => $value];
			}
		}

		return $return;
	}

	/**
	 * Method to clear any set response headers.
	 *
	 * @return  $this
	 *
	 * @since   1.0
	 */
	public function clearHeaders()
	{
		$response = $this->getResponse();

		foreach ($response->getHeaders() as $name => $values)
		{
			$response = $response->withoutHeader($name);
		}

		$this->setResponse($response);

		return $this;
	}

	/**
	 * Send the response headers.
	 *
	 * @return  $this
	 *
	 * @since   1.0
	 */
	public function sendHeaders()
	{
		if (!$this->checkHeadersSent())
		{
			foreach ($this->getHeaders() as $header)
			{
				if (strtolower($header['name']) == 'status')
				{
					// 'status' headers indicate an HTTP status, and need to be handled slightly differently
					$status = $this->getHttpStatusValue($header['value']);

					$this->header($status, true, (int) $header['value']);
				}
				else
				{
					$this->header($header['name'] . ': ' . $header['value']);
				}
			}
		}

		return $this;
	}

	/**
	 * Set body content.  If body content already defined, this will replace it.
	 *
	 * @param   string  $content  The content to set as the response body.
	 *
	 * @return  $this
	 *
	 * @since   1.0
	 */
	public function setBody($content)
	{
		$stream = new Stream('php://memory', 'rw');
		$stream->write((string) $content);
		$this->setResponse($this->getResponse()->withBody($stream));

		return $this;
	}

	/**
	 * Prepend content to the body content
	 *
	 * @param   string  $content  The content to prepend to the response body.
	 *
	 * @return  $this
	 *
	 * @since   1.0
	 */
	public function prependBody($content)
	{
		$currentBody = $this->getResponse()->getBody();

		if (!$currentBody->isReadable())
		{
			throw new UnableToWriteBody;
		}

		$stream = new Stream('php://memory', 'rw');
		$stream->write((string) $content . (string) $currentBody);
		$this->setResponse($this->getResponse()->withBody($stream));

		return $this;
	}

	/**
	 * Append content to the body content
	 *
	 * @param   string  $content  The content to append to the response body.
	 *
	 * @return  $this
	 *
	 * @since   1.0
	 */
	public function appendBody($content)
	{
		$currentStream = $this->getResponse()->getBody();

		if ($currentStream->isWritable())
		{
			$currentStream->write((string) $content);
			$this->setResponse($this->getResponse()->withBody($currentStream));
		}
		elseif ($currentStream->isReadable())
		{
			$stream = new Stream('php://memory', 'rw');
			$stream->write((string) $currentStream . (string) $content);
			$this->setResponse($this->getResponse()->withBody($stream));
		}
		else
		{
			throw new UnableToWriteBody;
		}

		return $this;
	}

	/**
	 * Return the body content
	 *
	 * @return  string  The response body as a string.
	 *
	 * @since   1.0
	 */
	public function getBody()
	{
		return (string) $this->getResponse()->getBody();
	}

	/**
	 * Get the PSR-7 Response Object.
	 *
	 * @return  ResponseInterface
	 *
	 * @since   2.0.0
	 */
	public function getResponse(): ResponseInterface
	{
		return $this->response;
	}

	/**
	 * Check if a given value can be successfully mapped to a valid http status value
	 *
	 * @param   string|int  $value  The given status as int or string
	 *
	 * @return  string
	 *
	 * @since   1.8.0
	 */
	protected function getHttpStatusValue($value)
	{
		$code = (int) $value;

		if (array_key_exists($code, $this->responseMap))
		{
			$value = $this->responseMap[$code];
		}
		else
		{
			$value = 'HTTP/{version} ' . $code;
		}

		return str_replace('{version}', $this->httpVersion, $value);
	}

	/**
	 * Check if the value is a valid HTTP status code
	 *
	 * @param   integer  $code  The potential status code
	 *
	 * @return  boolean
	 *
	 * @since   1.8.1
	 */
	public function isValidHttpStatus($code)
	{
		return array_key_exists($code, $this->responseMap);
	}

	/**
	 * Method to check the current client connection status to ensure that it is alive.  We are
	 * wrapping this to isolate the connection_status() function from our code base for testing reasons.
	 *
	 * @return  boolean  True if the connection is valid and normal.
	 *
	 * @codeCoverageIgnore
	 * @see     connection_status()
	 * @since   1.0
	 */
	protected function checkConnectionAlive()
	{
		return connection_status() === CONNECTION_NORMAL;
	}

	/**
	 * Method to check to see if headers have already been sent.
	 *
	 * @return  boolean  True if the headers have already been sent.
	 *
	 * @codeCoverageIgnore
	 * @see     headers_sent()
	 * @since   1.0
	 */
	protected function checkHeadersSent()
	{
		return headers_sent();
	}

	/**
	 * Method to detect the requested URI from server environment variables.
	 *
	 * @return  string  The requested URI
	 *
	 * @since   1.0
	 */
	protected function detectRequestUri()
	{
		// First we need to detect the URI scheme.
		$scheme = $this->isSslConnection() ? 'https://' : 'http://';

		/*
		 * There are some differences in the way that Apache and IIS populate server environment variables.  To
		 * properly detect the requested URI we need to adjust our algorithm based on whether or not we are getting
		 * information from Apache or IIS.
		 */

		$phpSelf    = $this->input->server->getString('PHP_SELF', '');
		$requestUri = $this->input->server->getString('REQUEST_URI', '');

		// If PHP_SELF and REQUEST_URI are both populated then we will assume "Apache Mode".
		if (!empty($phpSelf) && !empty($requestUri))
		{
			// The URI is built from the HTTP_HOST and REQUEST_URI environment variables in an Apache environment.
			$uri = $scheme . $this->input->server->getString('HTTP_HOST') . $requestUri;
		}
		else
		{
			// If not in "Apache Mode" we will assume that we are in an IIS environment and proceed.
			// IIS uses the SCRIPT_NAME variable instead of a REQUEST_URI variable... thanks, MS
			$uri       = $scheme . $this->input->server->getString('HTTP_HOST') . $this->input->server->getString('SCRIPT_NAME');
			$queryHost = $this->input->server->getString('QUERY_STRING', '');

			// If the QUERY_STRING variable exists append it to the URI string.
			if (!empty($queryHost))
			{
				$uri .= '?' . $queryHost;
			}
		}

		return trim($uri);
	}

	/**
	 * Method to send a header to the client.
	 *
	 * @param   string   $string   The header string.
	 * @param   boolean  $replace  The optional replace parameter indicates whether the header should replace a previous similar header, or add
	 *                             a second header of the same type.
	 * @param   integer  $code     Forces the HTTP response code to the specified value. Note that this parameter only has an effect if the string
	 *                             is not empty.
	 *
	 * @return  void
	 *
	 * @codeCoverageIgnore
	 * @see     header()
	 * @since   1.0
	 */
	protected function header($string, $replace = true, $code = null)
	{
		if ($code === null)
		{
			$code = 0;
		}

		header(str_replace(\chr(0), '', $string), $replace, $code);
	}

	/**
	 * Set the PSR-7 Response Object.
	 *
	 * @param   ResponseInterface  $response  The response object
	 *
	 * @return  void
	 *
	 * @since   2.0.0
	 */
	public function setResponse(ResponseInterface $response): void
	{
		$this->response = $response;
	}

	/**
	 * Checks if a state is a redirect state
	 *
	 * @param   integer  $state  The HTTP status code.
	 *
	 * @return  boolean
	 *
	 * @since   1.8.0
	 */
	protected function isRedirectState($state)
	{
		$state = (int) $state;

		return $state > 299 && $state < 400 && array_key_exists($state, $this->responseMap);
	}

	/**
	 * Determine if we are using a secure (SSL) connection.
	 *
	 * @return  boolean  True if using SSL, false if not.
	 *
	 * @since   1.0
	 */
	public function isSslConnection()
	{
		$serverSSLVar = $this->input->server->getString('HTTPS', '');

		if (!empty($serverSSLVar) && strtolower($serverSSLVar) !== 'off')
		{
			return true;
		}

		$serverForwarderProtoVar = $this->input->server->getString('HTTP_X_FORWARDED_PROTO', '');

		return !empty($serverForwarderProtoVar) && strtolower($serverForwarderProtoVar) === 'https';
	}

	/**
	 * Method to load the system URI strings for the application.
	 *
	 * @param   string  $requestUri  An optional request URI to use instead of detecting one from the server environment variables.
	 *
	 * @return  void
	 *
	 * @since   1.0
	 */
	protected function loadSystemUris($requestUri = null)
	{
		// Set the request URI.
		if (!empty($requestUri))
		{
			$this->set('uri.request', $requestUri);
		}
		else
		{
			$this->set('uri.request', $this->detectRequestUri());
		}

		// Check to see if an explicit base URI has been set.
		$siteUri = trim($this->get('site_uri'));

		if ($siteUri != '')
		{
			$uri  = new Uri($siteUri);
			$path = $uri->toString(['path']);
		}
		else
		{
			// No explicit base URI was set so we need to detect it. Start with the requested URI.
			$uri = new Uri($this->get('uri.request'));

			$requestUri = $this->input->server->getString('REQUEST_URI', '');

			// If we are working from a CGI SAPI with the 'cgi.fix_pathinfo' directive disabled we use PHP_SELF.
			if (strpos(PHP_SAPI, 'cgi') !== false && !ini_get('cgi.fix_pathinfo') && !empty($requestUri))
			{
				// We aren't expecting PATH_INFO within PHP_SELF so this should work.
				$path = \dirname($this->input->server->getString('PHP_SELF', ''));
			}
			else
			{
				// Pretty much everything else should be handled with SCRIPT_NAME.
				$path = \dirname($this->input->server->getString('SCRIPT_NAME', ''));
			}
		}

		// Get the host from the URI.
		$host = $uri->toString(['scheme', 'user', 'pass', 'host', 'port']);

		// Check if the path includes "index.php".
		if (strpos($path, 'index.php') !== false)
		{
			// Remove the index.php portion of the path.
			$path = substr_replace($path, '', strpos($path, 'index.php'), 9);
		}

		$path = rtrim($path, '/\\');

		// Set the base URI both as just a path and as the full URI.
		$this->set('uri.base.full', $host . $path . '/');
		$this->set('uri.base.host', $host);
		$this->set('uri.base.path', $path . '/');

		// Set the extended (non-base) part of the request URI as the route.
		if (stripos($this->get('uri.request'), $this->get('uri.base.full')) === 0)
		{
			$this->set('uri.route', substr_replace($this->get('uri.request'), '', 0, \strlen($this->get('uri.base.full'))));
		}

		// Get an explicitly set media URI is present.
		$mediaURI = trim($this->get('media_uri'));

		if ($mediaURI)
		{
			if (strpos($mediaURI, '://') !== false)
			{
				$this->set('uri.media.full', $mediaURI);
				$this->set('uri.media.path', $mediaURI);
			}
			else
			{
				// Normalise slashes.
				$mediaURI = trim($mediaURI, '/\\');
				$mediaURI = !empty($mediaURI) ? '/' . $mediaURI . '/' : '/';
				$this->set('uri.media.full', $this->get('uri.base.host') . $mediaURI);
				$this->set('uri.media.path', $mediaURI);
			}
		}
		else
		{
			// No explicit media URI was set, build it dynamically from the base uri.
			$this->set('uri.media.full', $this->get('uri.base.full') . 'media/');
			$this->set('uri.media.path', $this->get('uri.base.path') . 'media/');
		}
	}

	/**
	 * Tests whether a string contains only 7bit ASCII bytes.
	 *
	 * You might use this to conditionally check whether a string
	 * needs handling as UTF-8 or not, potentially offering performance
	 * benefits by using the native PHP equivalent if it's just ASCII e.g.;
	 *
	 * @param   string  $str  The string to test.
	 *
	 * @return  boolean  True if the string is all ASCII
	 *
	 * @since   1.4.0
	 */
	public static function isAscii($str)
	{
		// Search for any bytes which are outside the ASCII range...
		return preg_match('/(?:[^\x00-\x7F])/', $str) !== 1;
	}
}
