<?php

/**
 * This file is part of the CodeIgniter 4 framework.
 *
 * (c) CodeIgniter Foundation <admin@codeigniter.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace CodeIgniter\Email;

use CodeIgniter\Events\Events;
use Config\Mimes;
use ErrorException;

/**
 * CodeIgniter Email Class
 *
 * Permits email to be sent using Mail, Sendmail, or SMTP.
 */
class Email
{
	/**
	 * Properties from the last successful send.
	 *
	 * @var array|null
	 */
	public $archive;

	/**
	 * Properties to be added to the next archive.
	 *
	 * @var array
	 */
	protected $tmpArchive = [];

	/**
	 * @var string
	 */
	public $fromEmail;

	/**
	 * @var string
	 */
	public $fromName;

	/**
	 * Used as the User-Agent and X-Mailer headers' value.
	 *
	 * @var string
	 */
	public $userAgent = 'CodeIgniter';

	/**
	 * Path to the Sendmail binary.
	 *
	 * @var string
	 */
	public $mailPath = '/usr/sbin/sendmail';

	/**
	 * Which method to use for sending e-mails.
	 *
	 * @var string 'mail', 'sendmail' or 'smtp'
	 */
	public $protocol = 'mail';

	/**
	 * STMP Server host
	 *
	 * @var string
	 */
	public $SMTPHost = '';

	/**
	 * SMTP Username
	 *
	 * @var string
	 */
	public $SMTPUser = '';

	/**
	 * SMTP Password
	 *
	 * @var string
	 */
	public $SMTPPass = '';

	/**
	 * SMTP Server port
	 *
	 * @var integer
	 */
	public $SMTPPort = 25;

	/**
	 * SMTP connection timeout in seconds
	 *
	 * @var integer
	 */
	public $SMTPTimeout = 5;

	/**
	 * SMTP persistent connection
	 *
	 * @var boolean
	 */
	public $SMTPKeepAlive = false;

	/**
	 * SMTP Encryption
	 *
	 * @var string Empty, 'tls' or 'ssl'
	 */
	public $SMTPCrypto = '';

	/**
	 * Whether to apply word-wrapping to the message body.
	 *
	 * @var boolean
	 */
	public $wordWrap = true;

	/**
	 * Number of characters to wrap at.
	 *
	 * @see Email::$wordWrap
	 * @var integer
	 */
	public $wrapChars = 76;

	/**
	 * Message format.
	 *
	 * @var string 'text' or 'html'
	 */
	public $mailType = 'text';

	/**
	 * Character set (default: utf-8)
	 *
	 * @var string
	 */
	public $charset = 'utf-8';

	/**
	 * Alternative message (for HTML messages only)
	 *
	 * @var string
	 */
	public $altMessage = '';

	/**
	 * Whether to validate e-mail addresses.
	 *
	 * @var boolean
	 */
	public $validate = true;

	/**
	 * X-Priority header value.
	 *
	 * @var integer 1-5
	 */
	public $priority = 3;

	/**
	 * Newline character sequence.
	 * Use "\r\n" to comply with RFC 822.
	 *
	 * @link http://www.ietf.org/rfc/rfc822.txt
	 * @var  string "\r\n" or "\n"
	 */
	public $newline = "\n";

	/**
	 * CRLF character sequence
	 *
	 * RFC 2045 specifies that for 'quoted-printable' encoding,
	 * "\r\n" must be used. However, it appears that some servers
	 * (even on the receiving end) don't handle it properly and
	 * switching to "\n", while improper, is the only solution
	 * that seems to work for all environments.
	 *
	 * @link http://www.ietf.org/rfc/rfc822.txt
	 * @var  string
	 */
	public $CRLF = "\n";

	/**
	 * Whether to use Delivery Status Notification.
	 *
	 * @var boolean
	 */
	public $DSN = false;

	/**
	 * Whether to send multipart alternatives.
	 * Yahoo! doesn't seem to like these.
	 *
	 * @var boolean
	 */
	public $sendMultipart = true;

	/**
	 * Whether to send messages to BCC recipients in batches.
	 *
	 * @var boolean
	 */
	public $BCCBatchMode = false;

	/**
	 * BCC Batch max number size.
	 *
	 * @see Email::$BCCBatchMode
	 * @var integer|string
	 */
	public $BCCBatchSize = 200;

	/**
	 * Subject header
	 *
	 * @var string
	 */
	protected $subject = '';

	/**
	 * Message body
	 *
	 * @var string
	 */
	protected $body = '';

	/**
	 * Final message body to be sent.
	 *
	 * @var string
	 */
	protected $finalBody = '';

	/**
	 * Final headers to send
	 *
	 * @var string
	 */
	protected $headerStr = '';

	/**
	 * SMTP Connection socket placeholder
	 *
	 * @var resource|null
	 */
	protected $SMTPConnect;

	/**
	 * Mail encoding
	 *
	 * @var string '8bit' or '7bit'
	 */
	protected $encoding = '8bit';

	/**
	 * Whether to perform SMTP authentication
	 *
	 * @var boolean
	 */
	protected $SMTPAuth = false;

	/**
	 * Whether to send a Reply-To header
	 *
	 * @var boolean
	 */
	protected $replyToFlag = false;

	/**
	 * Debug messages
	 *
	 * @see Email::printDebugger()
	 * @var array
	 */
	protected $debugMessage = [];

	/**
	 * Recipients
	 *
	 * @var array|string
	 */
	protected $recipients = [];

	/**
	 * CC Recipients
	 *
	 * @var array
	 */
	protected $CCArray = [];

	/**
	 * BCC Recipients
	 *
	 * @var array
	 */
	protected $BCCArray = [];

	/**
	 * Message headers
	 *
	 * @var array
	 */
	protected $headers = [];

	/**
	 * Attachment data
	 *
	 * @var array
	 */
	protected $attachments = [];

	/**
	 * Valid $protocol values
	 *
	 * @see Email::$protocol
	 * @var array
	 */
	protected $protocols = [
		'mail',
		'sendmail',
		'smtp',
	];

	/**
	 * Base charsets
	 *
	 * Character sets valid for 7-bit encoding,
	 * excluding language suffix.
	 *
	 * @var array
	 */
	protected $baseCharsets = [
		'us-ascii',
		'iso-2022-',
	];

	/**
	 * Bit depths
	 *
	 * Valid mail encodings
	 *
	 * @see Email::$encoding
	 * @var array
	 */
	protected $bitDepths = [
		'7bit',
		'8bit',
	];

	/**
	 * $priority translations
	 *
	 * Actual values to send with the X-Priority header
	 *
	 * @var array
	 */
	protected $priorities = [
		1 => '1 (Highest)',
		2 => '2 (High)',
		3 => '3 (Normal)',
		4 => '4 (Low)',
		5 => '5 (Lowest)',
	];

	/**
	 * mbstring.func_overload flag
	 *
	 * @var boolean
	 */
	protected static $func_overload;

	/**
	 * Constructor - Sets Email Preferences
	 *
	 * The constructor can be passed an array of config values
	 *
	 * @param array|null $config
	 */
	public function __construct($config = null)
	{
		$this->initialize($config);
		isset(static::$func_overload) || static::$func_overload = (extension_loaded('mbstring') && ini_get('mbstring.func_overload'));
	}

	/**
	 * Initialize preferences
	 *
	 * @param array|\Config\Email $config
	 *
	 * @return Email
	 */
	public function initialize($config)
	{
		$this->clear();

		if ($config instanceof \Config\Email)
		{
			$config = get_object_vars($config);
		}

		foreach (get_class_vars(get_class($this)) as $key => $value)
		{
			if (property_exists($this, $key) && isset($config[$key]))
			{
				$method = 'set' . ucfirst($key);

				if (method_exists($this, $method))
				{
					$this->$method($config[$key]);
				}
				else
				{
					$this->$key = $config[$key];
				}
			}
		}

		$this->charset  = strtoupper($this->charset);
		$this->SMTPAuth = isset($this->SMTPUser[0], $this->SMTPPass[0]);

		return $this;
	}

	/**
	 * Initialize the Email Data
	 *
	 * @param boolean $clearAttachments
	 *
	 * @return Email
	 */
	public function clear($clearAttachments = false)
	{
		$this->subject      = '';
		$this->body         = '';
		$this->finalBody    = '';
		$this->headerStr    = '';
		$this->replyToFlag  = false;
		$this->recipients   = [];
		$this->CCArray      = [];
		$this->BCCArray     = [];
		$this->headers      = [];
		$this->debugMessage = [];

		$this->setHeader('Date', $this->setDate());

		if ($clearAttachments !== false)
		{
			$this->attachments = [];
		}

		return $this;
	}

	/**
	 * Set FROM
	 *
	 * @param string      $from
	 * @param string      $name
	 * @param string|null $returnPath Return-Path
	 *
	 * @return Email
	 */
	public function setFrom($from, $name = '', $returnPath = null)
	{
		if (preg_match('/\<(.*)\>/', $from, $match))
		{
			$from = $match[1];
		}

		if ($this->validate)
		{
			$this->validateEmail($this->stringToArray($from));

			if ($returnPath)
			{
				$this->validateEmail($this->stringToArray($returnPath));
			}
		}

		// Store the plain text values
		$this->tmpArchive['fromEmail'] = $from;
		$this->tmpArchive['fromName']  = $name;

		// prepare the display name
		if ($name !== '')
		{
			// only use Q encoding if there are characters that would require it
			if (! preg_match('/[\200-\377]/', $name))
			{
				// add slashes for non-printing characters, slashes, and double quotes, and surround it in double quotes
				$name = '"' . addcslashes($name, "\0..\37\177'\"\\") . '"';
			}
			else
			{
				$name = $this->prepQEncoding($name);
			}
		}

		$this->setHeader('From', $name . ' <' . $from . '>');
		isset($returnPath) || $returnPath = $from;
		$this->setHeader('Return-Path', '<' . $returnPath . '>');
		$this->tmpArchive['returnPath'] = $returnPath;

		return $this;
	}

	/**
	 * Set Reply-to
	 *
	 * @param string $replyto
	 * @param string $name
	 *
	 * @return Email
	 */
	public function setReplyTo($replyto, $name = '')
	{
		if (preg_match('/\<(.*)\>/', $replyto, $match))
		{
			$replyto = $match[1];
		}

		if ($this->validate)
		{
			$this->validateEmail($this->stringToArray($replyto));
		}

		if ($name !== '')
		{
			$this->tmpArchive['replyName'] = $name;

			// only use Q encoding if there are characters that would require it
			if (! preg_match('/[\200-\377]/', $name))
			{
				// add slashes for non-printing characters, slashes, and double quotes, and surround it in double quotes
				$name = '"' . addcslashes($name, "\0..\37\177'\"\\") . '"';
			}
			else
			{
				$name = $this->prepQEncoding($name);
			}
		}

		$this->setHeader('Reply-To', $name . ' <' . $replyto . '>');
		$this->replyToFlag           = true;
		$this->tmpArchive['replyTo'] = $replyto;

		return $this;
	}

	/**
	 * Set Recipients
	 *
	 * @param string|array $to
	 *
	 * @return Email
	 */
	public function setTo($to)
	{
		$to = $this->stringToArray($to);
		$to = $this->cleanEmail($to);

		if ($this->validate)
		{
			$this->validateEmail($to);
		}

		if ($this->getProtocol() !== 'mail')
		{
			$this->setHeader('To', implode(', ', $to));
		}

		$this->recipients = $to;

		return $this;
	}

	/**
	 * Set CC
	 *
	 * @param string $cc
	 *
	 * @return Email
	 */
	public function setCC($cc)
	{
		$cc = $this->cleanEmail($this->stringToArray($cc));

		if ($this->validate)
		{
			$this->validateEmail($cc);
		}

		$this->setHeader('Cc', implode(', ', $cc));

		if ($this->getProtocol() === 'smtp')
		{
			$this->CCArray = $cc;
		}

		$this->tmpArchive['CCArray'] = $cc;

		return $this;
	}

	/**
	 * Set BCC
	 *
	 * @param string $bcc
	 * @param string $limit
	 *
	 * @return Email
	 */
	public function setBCC($bcc, $limit = '')
	{
		if ($limit !== '' && is_numeric($limit))
		{
			$this->BCCBatchMode = true;
			$this->BCCBatchSize = $limit;
		}

		$bcc = $this->cleanEmail($this->stringToArray($bcc));

		if ($this->validate)
		{
			$this->validateEmail($bcc);
		}

		if ($this->getProtocol() === 'smtp' || ($this->BCCBatchMode && count($bcc) > $this->BCCBatchSize))
		{
			$this->BCCArray = $bcc;
		}
		else
		{
			$this->setHeader('Bcc', implode(', ', $bcc));
			$this->tmpArchive['BCCArray'] = $bcc;
		}

		return $this;
	}

	/**
	 * Set Email Subject
	 *
	 * @param string $subject
	 *
	 * @return Email
	 */
	public function setSubject($subject)
	{
		$this->tmpArchive['subject'] = $subject;

		$subject = $this->prepQEncoding($subject);
		$this->setHeader('Subject', $subject);

		return $this;
	}

	/**
	 * Set Body
	 *
	 * @param string $body
	 *
	 * @return Email
	 */
	public function setMessage($body)
	{
		$this->body = rtrim(str_replace("\r", '', $body));

		return $this;
	}

	/**
	 * Assign file attachments
	 *
	 * @param string      $file        Can be local path, URL or buffered content
	 * @param string      $disposition 'attachment'
	 * @param string|null $newname
	 * @param string      $mime
	 *
	 * @return Email|boolean
	 */
	public function attach($file, $disposition = '', $newname = null, $mime = '')
	{
		if ($mime === '')
		{
			if (strpos($file, '://') === false && ! is_file($file))
			{
				$this->setErrorMessage(lang('Email.attachmentMissing', [$file]));

				return false;
			}

			if (! $fp = @fopen($file, 'rb'))
			{
				$this->setErrorMessage(lang('Email.attachmentUnreadable', [$file]));

				return false;
			}

			$fileContent = stream_get_contents($fp);

			$mime = $this->mimeTypes(pathinfo($file, PATHINFO_EXTENSION));

			fclose($fp);
		}
		else
		{
			$fileContent = & $file; // buffered file
		}

		// declare names on their own, to make phpcbf happy
		$namesAttached = [
			$file,
			$newname,
		];

		$this->attachments[] = [
			'name'        => $namesAttached,
			'disposition' => empty($disposition) ? 'attachment' : $disposition,
			// Can also be 'inline'  Not sure if it matters
			'type'        => $mime,
			'content'     => chunk_split(base64_encode($fileContent)),
			'multipart'   => 'mixed',
		];

		return $this;
	}

	/**
	 * Set and return attachment Content-ID
	 *
	 * Useful for attached inline pictures
	 *
	 * @param string $filename
	 *
	 * @return string|boolean
	 */
	public function setAttachmentCID($filename)
	{
		for ($i = 0, $c = count($this->attachments); $i < $c; $i ++)
		{
			if ($this->attachments[$i]['name'][0] === $filename)
			{
				$this->attachments[$i]['multipart'] = 'related';

				$this->attachments[$i]['cid'] = uniqid(basename($this->attachments[$i]['name'][0]) . '@', true);

				return $this->attachments[$i]['cid'];
			}
		}

		return false;
	}

	/**
	 * Add a Header Item
	 *
	 * @param string $header
	 * @param string $value
	 *
	 * @return Email
	 */
	public function setHeader($header, $value)
	{
		$this->headers[$header] = str_replace(["\n", "\r"], '', $value);

		return $this;
	}

	/**
	 * Convert a String to an Array
	 *
	 * @param string $email
	 *
	 * @return array
	 */
	protected function stringToArray($email)
	{
		if (! is_array($email))
		{
			return (strpos($email, ',') !== false) ? preg_split('/[\s,]/', $email, -1, PREG_SPLIT_NO_EMPTY) : (array) trim($email);
		}

		return $email;
	}

	/**
	 * Set Multipart Value
	 *
	 * @param string $str
	 *
	 * @return Email
	 */
	public function setAltMessage($str)
	{
		$this->altMessage = (string) $str;

		return $this;
	}

	/**
	 * Set Mailtype
	 *
	 * @param string $type
	 *
	 * @return Email
	 */
	public function setMailType($type = 'text')
	{
		$this->mailType = ($type === 'html') ? 'html' : 'text';

		return $this;
	}

	/**
	 * Set Wordwrap
	 *
	 * @param boolean $wordWrap
	 *
	 * @return Email
	 */
	public function setWordWrap($wordWrap = true)
	{
		$this->wordWrap = (bool) $wordWrap;

		return $this;
	}

	/**
	 * Set Protocol
	 *
	 * @param string $protocol
	 *
	 * @return Email
	 */
	public function setProtocol($protocol = 'mail')
	{
		$this->protocol = in_array($protocol, $this->protocols, true) ? strtolower($protocol) : 'mail';

		return $this;
	}

	/**
	 * Set Priority
	 *
	 * @param integer $n
	 *
	 * @return Email
	 */
	public function setPriority($n = 3)
	{
		$this->priority = preg_match('/^[1-5]$/', (string) $n) ? (int) $n : 3;

		return $this;
	}

	/**
	 * Set Newline Character
	 *
	 * @param string $newline
	 *
	 * @return Email
	 */
	public function setNewline($newline = "\n")
	{
		$this->newline = in_array($newline, ["\n", "\r\n", "\r"], true) ? $newline : "\n";

		return $this;
	}

	/**
	 * Set CRLF
	 *
	 * @param string $CRLF
	 *
	 * @return Email
	 */
	public function setCRLF($CRLF = "\n")
	{
		$this->CRLF = ($CRLF !== "\n" && $CRLF !== "\r\n" && $CRLF !== "\r") ? "\n" : $CRLF;

		return $this;
	}

	/**
	 * Get the Message ID
	 *
	 * @return string
	 */
	protected function getMessageID()
	{
		$from = str_replace(['>', '<'], '', $this->headers['Return-Path']);

		return '<' . uniqid('', true) . strstr($from, '@') . '>';
	}

	/**
	 * Get Mail Protocol
	 *
	 * @return string
	 */
	protected function getProtocol()
	{
		$this->protocol = strtolower($this->protocol);

		in_array($this->protocol, $this->protocols, true) || $this->protocol = 'mail'; // @phpstan-ignore-line

		return $this->protocol;
	}

	/**
	 * Get Mail Encoding
	 *
	 * @return string
	 */
	protected function getEncoding()
	{
		in_array($this->encoding, $this->bitDepths, true) || $this->encoding = '8bit'; // @phpstan-ignore-line

		foreach ($this->baseCharsets as $charset)
		{
			if (strpos($this->charset, $charset) === 0)
			{
				$this->encoding = '7bit';

				break;
			}
		}

		return $this->encoding;
	}

	/**
	 * Get content type (text/html/attachment)
	 *
	 * @return string
	 */
	protected function getContentType()
	{
		if ($this->mailType === 'html')
		{
			return empty($this->attachments) ? 'html' : 'html-attach';
		}

		if ($this->mailType === 'text' && ! empty($this->attachments))
		{
			return 'plain-attach';
		}

		return 'plain';
	}

	/**
	 * Set RFC 822 Date
	 *
	 * @return string
	 */
	protected function setDate()
	{
		$timezone = date('Z');
		$operator = ($timezone[0] === '-') ? '-' : '+';
		$timezone = abs($timezone);
		$timezone = floor($timezone / 3600) * 100 + ($timezone % 3600) / 60;

		return sprintf('%s %s%04d', date('D, j M Y H:i:s'), $operator, $timezone);
	}

	/**
	 * Mime message
	 *
	 * @return string
	 */
	protected function getMimeMessage()
	{
		return 'This is a multi-part message in MIME format.' . $this->newline . 'Your email application may not support this format.';
	}

	/**
	 * Validate Email Address
	 *
	 * @param string|array $email
	 *
	 * @return boolean
	 */
	public function validateEmail($email)
	{
		if (! is_array($email))
		{
			$this->setErrorMessage(lang('Email.mustBeArray'));

			return false;
		}

		foreach ($email as $val)
		{
			if (! $this->isValidEmail($val))
			{
				$this->setErrorMessage(lang('Email.invalidAddress', [$val]));

				return false;
			}
		}

		return true;
	}

	/**
	 * Email Validation
	 *
	 * @param string $email
	 *
	 * @return boolean
	 */
	public function isValidEmail($email)
	{
		if (function_exists('idn_to_ascii') && defined('INTL_IDNA_VARIANT_UTS46') && $atpos = strpos($email, '@'))
		{
			$email = static::substr($email, 0, ++$atpos)
				. idn_to_ascii(static::substr($email, $atpos), 0, INTL_IDNA_VARIANT_UTS46);
		}

		return (bool) filter_var($email, FILTER_VALIDATE_EMAIL);
	}

	/**
	 * Clean Extended Email Address: Joe Smith <joe@smith.com>
	 *
	 * @param string|array $email
	 *
	 * @return array|string
	 */
	public function cleanEmail($email)
	{
		if (! is_array($email))
		{
			return preg_match('/\<(.*)\>/', $email, $match) ? $match[1] : $email;
		}

		$cleanEmail = [];

		foreach ($email as $addy)
		{
			$cleanEmail[] = preg_match('/\<(.*)\>/', $addy, $match) ? $match[1] : $addy;
		}

		return $cleanEmail;
	}

	/**
	 * Build alternative plain text message
	 *
	 * Provides the raw message for use in plain-text headers of
	 * HTML-formatted emails.
	 * If the user hasn't specified his own alternative message
	 * it creates one by stripping the HTML
	 *
	 * @return string
	 */
	protected function getAltMessage()
	{
		if (! empty($this->altMessage))
		{
			return ($this->wordWrap) ? $this->wordWrap($this->altMessage, 76) : $this->altMessage;
		}

		$body = preg_match('/\<body.*?\>(.*)\<\/body\>/si', $this->body, $match) ? $match[1] : $this->body;
		$body = str_replace("\t", '', preg_replace('#<!--(.*)--\>#', '', trim(strip_tags($body))));

		for ($i = 20; $i >= 3; $i --)
		{
			$body = str_replace(str_repeat("\n", $i), "\n\n", $body);
		}

		// Reduce multiple spaces
		$body = preg_replace('| +|', ' ', $body);

		return ($this->wordWrap) ? $this->wordWrap($body, 76) : $body;
	}

	/**
	 * Word Wrap
	 *
	 * @param string       $str
	 * @param integer|null $charlim Line-length limit
	 *
	 * @return string
	 */
	public function wordWrap($str, $charlim = null)
	{
		// Set the character limit, if not already present
		if (empty($charlim))
		{
			$charlim = empty($this->wrapChars) ? 76 : $this->wrapChars;
		}

		// Standardize newlines
		if (strpos($str, "\r") !== false)
		{
			$str = str_replace(["\r\n", "\r"], "\n", $str);
		}

		// Reduce multiple spaces at end of line
		$str = preg_replace('| +\n|', "\n", $str);

		// If the current word is surrounded by {unwrap} tags we'll
		// strip the entire chunk and replace it with a marker.
		$unwrap = [];

		if (preg_match_all('|\{unwrap\}(.+?)\{/unwrap\}|s', $str, $matches))
		{
			for ($i = 0, $c = count($matches[0]); $i < $c; $i ++)
			{
				$unwrap[] = $matches[1][$i];
				$str      = str_replace($matches[0][$i], '{{unwrapped' . $i . '}}', $str);
			}
		}

		// Use PHP's native function to do the initial wordwrap.
		// We set the cut flag to FALSE so that any individual words that are
		// too long get left alone. In the next step we'll deal with them.
		$str = wordwrap($str, $charlim, "\n", false);

		// Split the string into individual lines of text and cycle through them
		$output = '';

		foreach (explode("\n", $str) as $line)
		{
			// Is the line within the allowed character count?
			// If so we'll join it to the output and continue
			if (static::strlen($line) <= $charlim)
			{
				$output .= $line . $this->newline;

				continue;
			}

			$temp = '';

			do
			{
				// If the over-length word is a URL we won't wrap it
				if (preg_match('!\[url.+\]|://|www\.!', $line))
				{
					break;
				}

				// Trim the word down
				$temp .= static::substr($line, 0, $charlim - 1);
				$line = static::substr($line, $charlim - 1);
			}
			while (static::strlen($line) > $charlim);

			// If $temp contains data it means we had to split up an over-length
			// word into smaller chunks so we'll add it back to our current line
			if ($temp !== '')
			{
				$output .= $temp . $this->newline;
			}

			$output .= $line . $this->newline;
		}

		// Put our markers back
		if ($unwrap)
		{
			foreach ($unwrap as $key => $val)
			{
				$output = str_replace('{{unwrapped' . $key . '}}', $val, $output);
			}
		}

		return $output;
	}

	/**
	 * Build final headers
	 */
	protected function buildHeaders()
	{
		$this->setHeader('User-Agent', $this->userAgent);
		$this->setHeader('X-Sender', $this->cleanEmail($this->headers['From']));
		$this->setHeader('X-Mailer', $this->userAgent);
		$this->setHeader('X-Priority', $this->priorities[$this->priority]);
		$this->setHeader('Message-ID', $this->getMessageID());
		$this->setHeader('Mime-Version', '1.0');
	}

	/**
	 * Write Headers as a string
	 */
	protected function writeHeaders()
	{
		if ($this->protocol === 'mail')
		{
			if (isset($this->headers['Subject']))
			{
				$this->subject = $this->headers['Subject'];
				unset($this->headers['Subject']);
			}
		}

		reset($this->headers);
		$this->headerStr = '';

		foreach ($this->headers as $key => $val)
		{
			$val = trim($val);

			if ($val !== '')
			{
				$this->headerStr .= $key . ': ' . $val . $this->newline;
			}
		}

		if ($this->getProtocol() === 'mail')
		{
			$this->headerStr = rtrim($this->headerStr);
		}
	}

	/**
	 * Build Final Body and attachments
	 */
	protected function buildMessage()
	{
		if ($this->wordWrap === true && $this->mailType !== 'html')
		{
			$this->body = $this->wordWrap($this->body);
		}

		$this->writeHeaders();
		$hdr  = ($this->getProtocol() === 'mail') ? $this->newline : '';
		$body = '';

		switch ($this->getContentType())
		{
			case 'plain':
				$hdr .= 'Content-Type: text/plain; charset='
					. $this->charset
					. $this->newline
					. 'Content-Transfer-Encoding: '
					. $this->getEncoding();

				if ($this->getProtocol() === 'mail')
				{
					$this->headerStr .= $hdr;
					$this->finalBody = $this->body;
				}
				else
				{
					$this->finalBody = $hdr . $this->newline . $this->newline . $this->body;
				}

				return;

			case 'html':
				if ($this->sendMultipart === false)
				{
					$hdr .= 'Content-Type: text/html; charset='
						. $this->charset . $this->newline
						. 'Content-Transfer-Encoding: quoted-printable';
				}
				else
				{
					$boundary = uniqid('B_ALT_', true);

					$hdr  .= 'Content-Type: multipart/alternative; boundary="' . $boundary . '"';
					$body .= $this->getMimeMessage() . $this->newline . $this->newline
						. '--' . $boundary . $this->newline
						. 'Content-Type: text/plain; charset=' . $this->charset . $this->newline
						. 'Content-Transfer-Encoding: ' . $this->getEncoding() . $this->newline . $this->newline
						. $this->getAltMessage() . $this->newline . $this->newline
						. '--' . $boundary . $this->newline
						. 'Content-Type: text/html; charset=' . $this->charset . $this->newline
						. 'Content-Transfer-Encoding: quoted-printable' . $this->newline . $this->newline;
				}

				$this->finalBody = $body . $this->prepQuotedPrintable($this->body) . $this->newline . $this->newline;

				if ($this->getProtocol() === 'mail')
				{
					  $this->headerStr .= $hdr;
				}
				else
				{
					$this->finalBody = $hdr . $this->newline . $this->newline . $this->finalBody;
				}

				if ($this->sendMultipart !== false)
				{
					$this->finalBody .= '--' . $boundary . '--'; // @phpstan-ignore-line
				}

				return;

			case 'plain-attach':
				$boundary = uniqid('B_ATC_', true);
				$hdr .= 'Content-Type: multipart/mixed; boundary="' . $boundary . '"';

				if ($this->getProtocol() === 'mail')
				{
					$this->headerStr .= $hdr;
				}

				$body .= $this->getMimeMessage() . $this->newline
					. $this->newline
					. '--' . $boundary . $this->newline
					. 'Content-Type: text/plain; charset=' . $this->charset . $this->newline
					. 'Content-Transfer-Encoding: ' . $this->getEncoding() . $this->newline
					. $this->newline
					. $this->body . $this->newline . $this->newline;

				$this->appendAttachments($body, $boundary);
				break;

			case 'html-attach':
				$altBoundary  = uniqid('B_ALT_', true);
				$lastBoundary = null;

				if ($this->attachmentsHaveMultipart('mixed'))
				{
					$atcBoundary = uniqid('B_ATC_', true);
					$hdr .= 'Content-Type: multipart/mixed; boundary="' . $atcBoundary . '"';
					$lastBoundary = $atcBoundary;
				}

				if ($this->attachmentsHaveMultipart('related'))
				{
					$relBoundary = uniqid('B_REL_', true);

					$relBoundaryHeader = 'Content-Type: multipart/related; boundary="' . $relBoundary . '"';

					if (isset($lastBoundary))
					{
						$body .= '--' . $lastBoundary . $this->newline . $relBoundaryHeader;
					}
					else
					{
						$hdr .= $relBoundaryHeader;
					}

					$lastBoundary = $relBoundary;
				}

				if ($this->getProtocol() === 'mail')
				{
					$this->headerStr .= $hdr;
				}

				static::strlen($body) && $body .= $this->newline . $this->newline;

				$body .= $this->getMimeMessage() . $this->newline . $this->newline
					. '--' . $lastBoundary . $this->newline
					. 'Content-Type: multipart/alternative; boundary="' . $altBoundary . '"' . $this->newline . $this->newline
					. '--' . $altBoundary . $this->newline
					. 'Content-Type: text/plain; charset=' . $this->charset . $this->newline
					. 'Content-Transfer-Encoding: ' . $this->getEncoding() . $this->newline . $this->newline
					. $this->getAltMessage() . $this->newline . $this->newline
					. '--' . $altBoundary . $this->newline
					. 'Content-Type: text/html; charset=' . $this->charset . $this->newline
					. 'Content-Transfer-Encoding: quoted-printable' . $this->newline . $this->newline
					. $this->prepQuotedPrintable($this->body) . $this->newline . $this->newline
					. '--' . $altBoundary . '--' . $this->newline . $this->newline;

				if (! empty($relBoundary))
				{
					$body .= $this->newline . $this->newline;
					$this->appendAttachments($body, $relBoundary, 'related');
				}

				// multipart/mixed attachments
				if (! empty($atcBoundary))
				{
					$body .= $this->newline . $this->newline;
					$this->appendAttachments($body, $atcBoundary, 'mixed');
				}

				break;
		}

		$this->finalBody = ($this->getProtocol() === 'mail') ? $body : $hdr . $this->newline . $this->newline . $body;
	}

	/**
	 * @return boolean
	 */
	protected function attachmentsHaveMultipart($type)
	{
		foreach ($this->attachments as &$attachment)
		{
			if ($attachment['multipart'] === $type)
			{
				return true;
			}
		}

		return false;
	}

	/**
	 * Prepares attachment string
	 *
	 * @param string      $body      Message body to append to
	 * @param string      $boundary  Multipart boundary
	 * @param string|null $multipart When provided, only attachments of this type will be processed
	 *
	 * @return void
	 */
	protected function appendAttachments(&$body, $boundary, $multipart = null)
	{
		for ($i = 0, $c = count($this->attachments); $i < $c; $i++)
		{
			if (isset($multipart) && $this->attachments[$i]['multipart'] !== $multipart)
			{
				continue;
			}

			$name = isset($this->attachments[$i]['name'][1]) ? $this->attachments[$i]['name'][1] : basename($this->attachments[$i]['name'][0]);

			$body .= '--' . $boundary . $this->newline
				. 'Content-Type: ' . $this->attachments[$i]['type'] . '; name="' . $name . '"' . $this->newline
				. 'Content-Disposition: ' . $this->attachments[$i]['disposition'] . ';' . $this->newline
				. 'Content-Transfer-Encoding: base64' . $this->newline
				. (empty($this->attachments[$i]['cid']) ? '' : 'Content-ID: <' . $this->attachments[$i]['cid'] . '>' . $this->newline)
				. $this->newline
				. $this->attachments[$i]['content'] . $this->newline;
		}

		// $name won't be set if no attachments were appended,
		// and therefore a boundary wouldn't be necessary
		empty($name) || $body .= '--' . $boundary . '--';
	}

	/**
	 * Prep Quoted Printable
	 *
	 * Prepares string for Quoted-Printable Content-Transfer-Encoding
	 * Refer to RFC 2045 http://www.ietf.org/rfc/rfc2045.txt
	 *
	 * @param string $str
	 *
	 * @return string
	 */
	protected function prepQuotedPrintable($str)
	{
		// ASCII code numbers for "safe" characters that can always be
		// used literally, without encoding, as described in RFC 2049.
		// http://www.ietf.org/rfc/rfc2049.txt
		static $asciiSafeChars = [
			// ' (  )   +   ,   -   .   /   :   =   ?
			39,
			40,
			41,
			43,
			44,
			45,
			46,
			47,
			58,
			61,
			63,
			// numbers
			48,
			49,
			50,
			51,
			52,
			53,
			54,
			55,
			56,
			57,
			// upper-case letters
			65,
			66,
			67,
			68,
			69,
			70,
			71,
			72,
			73,
			74,
			75,
			76,
			77,
			78,
			79,
			80,
			81,
			82,
			83,
			84,
			85,
			86,
			87,
			88,
			89,
			90,
			// lower-case letters
			97,
			98,
			99,
			100,
			101,
			102,
			103,
			104,
			105,
			106,
			107,
			108,
			109,
			110,
			111,
			112,
			113,
			114,
			115,
			116,
			117,
			118,
			119,
			120,
			121,
			122,
		];

		// We are intentionally wrapping so mail servers will encode characters
		// properly and MUAs will behave, so {unwrap} must go!
		$str = str_replace(['{unwrap}', '{/unwrap}'], '', $str);

		// RFC 2045 specifies CRLF as "\r\n".
		// However, many developers choose to override that and violate
		// the RFC rules due to (apparently) a bug in MS Exchange,
		// which only works with "\n".
		if ($this->CRLF === "\r\n")
		{
			return quoted_printable_encode($str);
		}

		// Reduce multiple spaces & remove nulls
		$str = preg_replace(['| +|', '/\x00+/'], [' ', ''], $str);

		// Standardize newlines
		if (strpos($str, "\r") !== false)
		{
			$str = str_replace(["\r\n", "\r"], "\n", $str);
		}

		$escape = '=';
		$output = '';

		foreach (explode("\n", $str) as $line)
		{
			$length = static::strlen($line);
			$temp   = '';

			// Loop through each character in the line to add soft-wrap
			// characters at the end of a line " =\r\n" and add the newly
			// processed line(s) to the output (see comment on $crlf class property)
			for ($i = 0; $i < $length; $i ++)
			{
				// Grab the next character
				$char  = $line[$i];
				$ascii = ord($char);

				// Convert spaces and tabs but only if it's the end of the line
				if ($ascii === 32 || $ascii === 9)
				{
					if ($i === ($length - 1))
					{
						$char = $escape . sprintf('%02s', dechex($ascii));
					}
				}
				// DO NOT move this below the $ascii_safe_chars line!
				//
				// = (equals) signs are allowed by RFC2049, but must be encoded
				// as they are the encoding delimiter!
				elseif ($ascii === 61)
				{
					$char = $escape . strtoupper(sprintf('%02s', dechex($ascii)));  // =3D
				}
				elseif (! in_array($ascii, $asciiSafeChars, true))
				{
					$char = $escape . strtoupper(sprintf('%02s', dechex($ascii)));
				}

				// If we're at the character limit, add the line to the output,
				// reset our temp variable, and keep on chuggin'
				if ((static::strlen($temp) + static::strlen($char)) >= 76)
				{
					$output .= $temp . $escape . $this->CRLF;
					$temp = '';
				}

				// Add the character to our temporary line
				$temp .= $char;
			}

			// Add our completed line to the output
			$output .= $temp . $this->CRLF;
		}

		// get rid of extra CRLF tacked onto the end
		return static::substr($output, 0, static::strlen($this->CRLF) * -1);
	}

	/**
	 * Prep Q Encoding
	 *
	 * Performs "Q Encoding" on a string for use in email headers.
	 * It's related but not identical to quoted-printable, so it has its
	 * own method.
	 *
	 * @param string $str
	 *
	 * @return string
	 */
	protected function prepQEncoding($str)
	{
		$str = str_replace(["\r", "\n"], '', $str);

		if ($this->charset === 'UTF-8')
		{
			// Note: We used to have mb_encode_mimeheader() as the first choice
			//       here, but it turned out to be buggy and unreliable. DO NOT
			//       re-add it! -- Narf
			if (extension_loaded('iconv'))
			{
				$output = @iconv_mime_encode('', $str, [
					'scheme'           => 'Q',
					'line-length'      => 76,
					'input-charset'    => $this->charset,
					'output-charset'   => $this->charset,
					'line-break-chars' => $this->CRLF,
				]);

				// There are reports that iconv_mime_encode() might fail and return FALSE
				if ($output !== false)
				{
					// iconv_mime_encode() will always put a header field name.
					// We've passed it an empty one, but it still prepends our
					// encoded string with ': ', so we need to strip it.
					return static::substr($output, 2);
				}

				$chars = iconv_strlen($str, 'UTF-8');
			}
			elseif (extension_loaded('mbstring'))
			{
				$chars = mb_strlen($str, 'UTF-8');
			}
		}

		// We might already have this set for UTF-8
		isset($chars) || $chars = static::strlen($str);

		$output = '=?' . $this->charset . '?Q?';

		for ($i = 0, $length = static::strlen($output); $i < $chars; $i ++) // @phpstan-ignore-line
		{
			$chr = ($this->charset === 'UTF-8' && extension_loaded('iconv')) ? '=' . implode('=', str_split(strtoupper(bin2hex(iconv_substr($str, $i, 1, $this->charset))), 2)) : '=' . strtoupper(bin2hex($str[$i]));

			// RFC 2045 sets a limit of 76 characters per line.
			// We'll append ?= to the end of each line though.
			if ($length + ($l = static::strlen($chr)) > 74)
			{
				$output .= '?=' . $this->CRLF // EOL
					. ' =?' . $this->charset . '?Q?' . $chr; // New line

				$length = 6 + static::strlen($this->charset) + $l; // Reset the length for the new line
			}
			else
			{
				$output .= $chr;
				$length += $l;
			}
		}

		// End the header
		return $output . '?=';
	}

	/**
	 * Send Email
	 *
	 * @param boolean $autoClear
	 *
	 * @return boolean
	 */
	public function send($autoClear = true)
	{
		if (! isset($this->headers['From']) && ! empty($this->fromEmail))
		{
			$this->setFrom($this->fromEmail, $this->fromName);
		}

		if (! isset($this->headers['From']))
		{
			$this->setErrorMessage(lang('Email.noFrom'));

			return false;
		}

		if ($this->replyToFlag === false)
		{
			$this->setReplyTo($this->headers['From']);
		}

		if (empty($this->recipients) && ! isset($this->headers['To']) && empty($this->BCCArray) && ! isset($this->headers['Bcc']) && ! isset($this->headers['Cc']))
		{
			$this->setErrorMessage(lang('Email.noRecipients'));

			return false;
		}

		$this->buildHeaders();

		if ($this->BCCBatchMode && count($this->BCCArray) > $this->BCCBatchSize)
		{
			$this->batchBCCSend();

			if ($autoClear)
			{
				$this->clear();
			}

			return true;
		}

		$this->buildMessage();
		$result = $this->spoolEmail();

		if ($result)
		{
			$this->setArchiveValues();

			if ($autoClear)
			{
				$this->clear();
			}

			Events::trigger('email', $this->archive);
		}

		return $result;
	}

	/**
	 * Batch Bcc Send. Sends groups of BCCs in batches
	 */
	public function batchBCCSend()
	{
		$float = $this->BCCBatchSize - 1;
		$set   = '';
		$chunk = [];

		for ($i = 0, $c = count($this->BCCArray); $i < $c; $i++)
		{
			if (isset($this->BCCArray[$i]))
			{
				$set .= ', ' . $this->BCCArray[$i];
			}

			if ($i === $float)
			{
				$chunk[] = static::substr($set, 1);
				$float += $this->BCCBatchSize;
				$set = '';
			}

			if ($i === $c - 1)
			{
				$chunk[] = static::substr($set, 1);
			}
		}

		for ($i = 0, $c = count($chunk); $i < $c; $i ++)
		{
			unset($this->headers['Bcc']);
			$bcc = $this->cleanEmail($this->stringToArray($chunk[$i]));

			if ($this->protocol !== 'smtp')
			{
				$this->setHeader('Bcc', implode(', ', $bcc));
			}
			else
			{
				$this->BCCArray = $bcc;
			}

			$this->buildMessage();
			$this->spoolEmail();
		}

		// Update the archive
		$this->setArchiveValues();
		Events::trigger('email', $this->archive);
	}

	/**
	 * Unwrap special elements
	 */
	protected function unwrapSpecials()
	{
		$this->finalBody = preg_replace_callback(
			'/\{unwrap\}(.*?)\{\/unwrap\}/si',
			[$this, 'removeNLCallback'],
			$this->finalBody
		);
	}

	/**
	 * Strip line-breaks via callback
	 *
	 * @param string $matches
	 *
	 * @return string
	 */
	protected function removeNLCallback($matches)
	{
		if (strpos($matches[1], "\r") !== false || strpos($matches[1], "\n") !== false)
		{
			$matches[1] = str_replace(["\r\n", "\r", "\n"], '', $matches[1]);
		}

		return $matches[1];
	}

	/**
	 * Spool mail to the mail server
	 *
	 * @return boolean
	 */
	protected function spoolEmail()
	{
		$this->unwrapSpecials();
		$protocol = $this->getProtocol();
		$method   = 'sendWith' . ucfirst($protocol);

		try
		{
			$success = $this->$method();
		}
		catch (ErrorException $e)
		{
			$success = false;
			log_message('error', 'Email: ' . $method . ' throwed ' . $e->getMessage());
		}

		if (! $success)
		{
			$this->setErrorMessage(lang('Email.sendFailure' . ($protocol === 'mail' ? 'PHPMail' : ucfirst($protocol))));

			return false;
		}

		$this->setErrorMessage(lang('Email.sent', [$protocol]));

		return true;
	}

	/**
	 * Validate email for shell
	 *
	 * Applies stricter, shell-safe validation to email addresses.
	 * Introduced to prevent RCE via sendmail's -f option.
	 *
	 * @see     https://github.com/codeigniter4/CodeIgniter/issues/4963
	 * @see     https://gist.github.com/Zenexer/40d02da5e07f151adeaeeaa11af9ab36
	 * @license https://creativecommons.org/publicdomain/zero/1.0/    CC0 1.0, Public Domain
	 *
	 * Credits for the base concept go to Paul Buonopane <paul@namepros.com>
	 *
	 * @param string $email
	 *
	 * @return boolean
	 */
	protected function validateEmailForShell(&$email)
	{
		if (function_exists('idn_to_ascii') && $atpos = strpos($email, '@'))
		{
			$email = static::substr($email, 0, ++$atpos)
				. idn_to_ascii(static::substr($email, $atpos), 0, INTL_IDNA_VARIANT_UTS46);
		}

		return (filter_var($email, FILTER_VALIDATE_EMAIL) === $email && preg_match('#\A[a-z0-9._+-]+@[a-z0-9.-]{1,253}\z#i', $email));
	}

	/**
	 * Send using mail()
	 *
	 * @return boolean
	 */
	protected function sendWithMail()
	{
		$recipients = is_array($this->recipients) ? implode(', ', $this->recipients) : $this->recipients;

		// _validate_email_for_shell() below accepts by reference,
		// so this needs to be assigned to a variable
		$from = $this->cleanEmail($this->headers['Return-Path']);

		if (! $this->validateEmailForShell($from))
		{
			return mail($recipients, $this->subject, $this->finalBody, $this->headerStr);
		}

		// most documentation of sendmail using the "-f" flag lacks a space after it, however
		// we've encountered servers that seem to require it to be in place.
		return mail($recipients, $this->subject, $this->finalBody, $this->headerStr, '-f ' . $from);
	}

	/**
	 * Send using Sendmail
	 *
	 * @return boolean
	 */
	protected function sendWithSendmail()
	{
		// _validate_email_for_shell() below accepts by reference,
		// so this needs to be assigned to a variable
		$from = $this->cleanEmail($this->headers['From']);

		if ($this->validateEmailForShell($from))
		{
			$from = '-f ' . $from;
		}
		else
		{
			$from = '';
		}

		// is popen() enabled?
		if (! function_usable('popen') || false === ($fp = @popen($this->mailPath . ' -oi ' . $from . ' -t', 'w')))
		{
			// server probably has popen disabled, so nothing we can do to get a verbose error.
			return false;
		}

		fputs($fp, $this->headerStr);
		fputs($fp, $this->finalBody);
		$status = pclose($fp);

		if ($status !== 0)
		{
			$this->setErrorMessage(lang('Email.exitStatus', [$status]));
			$this->setErrorMessage(lang('Email.noSocket'));

			return false;
		}

		return true;
	}

	/**
	 * Send using SMTP
	 *
	 * @return boolean
	 */
	protected function sendWithSmtp()
	{
		if ($this->SMTPHost === '')
		{
			$this->setErrorMessage(lang('Email.noHostname'));

			return false;
		}

		if (! $this->SMTPConnect() || ! $this->SMTPAuthenticate())
		{
			return false;
		}

		if (! $this->sendCommand('from', $this->cleanEmail($this->headers['From'])))
		{
			$this->SMTPEnd();

			return false;
		}

		foreach ($this->recipients as $val)
		{
			if (! $this->sendCommand('to', $val))
			{
				$this->SMTPEnd();

				return false;
			}
		}

		foreach ($this->CCArray as $val)
		{
			if ($val !== '' && ! $this->sendCommand('to', $val))
			{
				$this->SMTPEnd();

				return false;
			}
		}

		foreach ($this->BCCArray as $val)
		{
			if ($val !== '' && ! $this->sendCommand('to', $val))
			{
				$this->SMTPEnd();

				return false;
			}
		}

		if (! $this->sendCommand('data'))
		{
			$this->SMTPEnd();

			return false;
		}

		// perform dot transformation on any lines that begin with a dot
		$this->sendData($this->headerStr . preg_replace('/^\./m', '..$1', $this->finalBody));
		$this->sendData($this->newline . '.');
		$reply = $this->getSMTPData();
		$this->setErrorMessage($reply);
		$this->SMTPEnd();

		if (strpos($reply, '250') !== 0)
		{
			$this->setErrorMessage(lang('Email.SMTPError', [$reply]));

			return false;
		}

		return true;
	}

	/**
	 * SMTP End
	 *
	 * Shortcut to send RSET or QUIT depending on keep-alive
	 */
	protected function SMTPEnd()
	{
		$this->sendCommand($this->SMTPKeepAlive ? 'reset' : 'quit');
	}

	/**
	 * SMTP Connect
	 *
	 * @return string|boolean
	 */
	protected function SMTPConnect()
	{
		if (is_resource($this->SMTPConnect))
		{
			return true;
		}

		$ssl = '';

		if ($this->SMTPPort === 465)
		{
			$ssl = 'tls://';
		}
		elseif ($this->SMTPCrypto === 'ssl')
		{
			$ssl = 'ssl://';
		}

		$this->SMTPConnect = fsockopen(
			$ssl . $this->SMTPHost,
			$this->SMTPPort,
			$errno,
			$errstr,
			$this->SMTPTimeout
		);

		if (! is_resource($this->SMTPConnect))
		{
			$this->setErrorMessage(lang('Email.SMTPError', [$errno . ' ' . $errstr]));

			return false;
		}

		stream_set_timeout($this->SMTPConnect, $this->SMTPTimeout);
		$this->setErrorMessage($this->getSMTPData());

		if ($this->SMTPCrypto === 'tls')
		{
			$this->sendCommand('hello');
			$this->sendCommand('starttls');
			$crypto = stream_socket_enable_crypto(
				$this->SMTPConnect,
				true,
				STREAM_CRYPTO_METHOD_TLSv1_0_CLIENT | STREAM_CRYPTO_METHOD_TLSv1_1_CLIENT | STREAM_CRYPTO_METHOD_TLSv1_2_CLIENT
			);

			if ($crypto !== true)
			{
				$this->setErrorMessage(lang('Email.SMTPError', [$this->getSMTPData()]));

				return false;
			}
		}

		return $this->sendCommand('hello');
	}

	/**
	 * Send SMTP command
	 *
	 * @param string $cmd
	 * @param string $data
	 *
	 * @return boolean
	 */
	protected function sendCommand($cmd, $data = '')
	{
		switch ($cmd)
		{
			case 'hello':
				if ($this->SMTPAuth || $this->getEncoding() === '8bit')
				{
					$this->sendData('EHLO ' . $this->getHostname());
				}
				else
				{
					$this->sendData('HELO ' . $this->getHostname());
				}

				$resp = 250;
				break;

			case 'starttls':
				$this->sendData('STARTTLS');
				$resp = 220;
				break;

			case 'from':
				$this->sendData('MAIL FROM:<' . $data . '>');
				$resp = 250;
				break;

			case 'to':
				if ($this->DSN)
				{
					$this->sendData('RCPT TO:<' . $data . '> NOTIFY=SUCCESS,DELAY,FAILURE ORCPT=rfc822;' . $data);
				}
				else
				{
					$this->sendData('RCPT TO:<' . $data . '>');
				}
				$resp = 250;
				break;

			case 'data':
				$this->sendData('DATA');
				$resp = 354;
				break;

			case 'reset':
				$this->sendData('RSET');
				$resp = 250;
				break;

			case 'quit':
				$this->sendData('QUIT');
				$resp = 221;
				break;
		}

		$reply = $this->getSMTPData();

		$this->debugMessage[] = '<pre>' . $cmd . ': ' . $reply . '</pre>';

		if ((int) static::substr($reply, 0, 3) !== $resp) // @phpstan-ignore-line
		{
			$this->setErrorMessage(lang('Email.SMTPError', [$reply]));

			return false;
		}

		if ($cmd === 'quit')
		{
			fclose($this->SMTPConnect);
		}

		return true;
	}

	/**
	 * SMTP Authenticate
	 *
	 * @return boolean
	 */
	protected function SMTPAuthenticate()
	{
		if (! $this->SMTPAuth)
		{
			return true;
		}

		if ($this->SMTPUser === '' && $this->SMTPPass === '')
		{
			$this->setErrorMessage(lang('Email.noSMTPAuth'));

			return false;
		}

		$this->sendData('AUTH LOGIN');
		$reply = $this->getSMTPData();

		if (strpos($reply, '503') === 0)    // Already authenticated
		{
			return true;
		}

		if (strpos($reply, '334') !== 0)
		{
			$this->setErrorMessage(lang('Email.failedSMTPLogin', [$reply]));

			return false;
		}

		$this->sendData(base64_encode($this->SMTPUser));
		$reply = $this->getSMTPData();

		if (strpos($reply, '334') !== 0)
		{
			$this->setErrorMessage(lang('Email.SMTPAuthUsername', [$reply]));

			return false;
		}

		$this->sendData(base64_encode($this->SMTPPass));
		$reply = $this->getSMTPData();

		if (strpos($reply, '235') !== 0)
		{
			$this->setErrorMessage(lang('Email.SMTPAuthPassword', [$reply]));

			return false;
		}

		if ($this->SMTPKeepAlive)
		{
			$this->SMTPAuth = false;
		}

		return true;
	}

	/**
	 * Send SMTP data
	 *
	 * @param string $data
	 *
	 * @return boolean
	 */
	protected function sendData($data)
	{
		$data .= $this->newline;

		for ($written = $timestamp = 0, $length = static::strlen($data); $written < $length; $written += $result)
		{
			if (($result = fwrite($this->SMTPConnect, static::substr($data, $written))) === false)
			{
				break;
			}

			// See https://bugs.php.net/bug.php?id=39598 and http://php.net/manual/en/function.fwrite.php#96951
			if ($result === 0)
			{
				if ($timestamp === 0)
				{
					$timestamp = time();
				}
				elseif ($timestamp < (time() - $this->SMTPTimeout))
				{
					$result = false;

					break;
				}

				usleep(250000);

				continue;
			}

			$timestamp = 0;
		}

		if ($result === false) // @phpstan-ignore-line
		{
			$this->setErrorMessage(lang('Email.SMTPDataFailure', [$data]));

			return false;
		}

		return true;
	}

	/**
	 * Get SMTP data
	 *
	 * @return string
	 */
	protected function getSMTPData()
	{
		$data = '';

		while ($str = fgets($this->SMTPConnect, 512))
		{
			$data .= $str;

			if ($str[3] === ' ')
			{
				break;
			}
		}

		return $data;
	}

	/**
	 * Get Hostname
	 *
	 * There are only two legal types of hostname - either a fully
	 * qualified domain name (eg: "mail.example.com") or an IP literal
	 * (eg: "[1.2.3.4]").
	 *
	 * @link https://tools.ietf.org/html/rfc5321#section-2.3.5
	 * @link http://cbl.abuseat.org/namingproblems.html
	 *
	 * @return string
	 */
	protected function getHostname()
	{
		if (isset($_SERVER['SERVER_NAME']))
		{
			return $_SERVER['SERVER_NAME'];
		}

		return isset($_SERVER['SERVER_ADDR']) ? '[' . $_SERVER['SERVER_ADDR'] . ']' : '[127.0.0.1]';
	}

	/**
	 * Get Debug Message
	 *
	 * @param array $include List of raw data chunks to include in the output
	 *                       Valid options are: 'headers', 'subject', 'body'
	 *
	 * @return string
	 */
	public function printDebugger($include = ['headers', 'subject', 'body'])
	{
		$msg = implode('', $this->debugMessage);

		// Determine which parts of our raw data needs to be printed
		$rawData = '';

		is_array($include) || $include = [$include]; // @phpstan-ignore-line

		in_array('headers', $include, true) && $rawData = htmlspecialchars($this->headerStr) . "\n";
		in_array('subject', $include, true) && $rawData .= htmlspecialchars($this->subject) . "\n";
		in_array('body', $include, true) && $rawData    .= htmlspecialchars($this->finalBody);

		return $msg . ($rawData === '' ? '' : '<pre>' . $rawData . '</pre>');
	}

	/**
	 * Set Message
	 *
	 * @param string $msg
	 */
	protected function setErrorMessage($msg)
	{
		$this->debugMessage[] = $msg . '<br />';
	}

	/**
	 * Mime Types
	 *
	 * @param string $ext
	 *
	 * @return string
	 */
	protected function mimeTypes($ext = '')
	{
		$mime = Mimes::guessTypeFromExtension(strtolower($ext));

		return ! empty($mime) ? $mime : 'application/x-unknown-content-type';
	}

	/**
	 * Destructor
	 */
	public function __destruct()
	{
		is_resource($this->SMTPConnect) && $this->sendCommand('quit');
	}

	/**
	 * Byte-safe strlen()
	 *
	 * @param string $str
	 *
	 * @return integer
	 */
	protected static function strlen($str)
	{
		return (static::$func_overload) ? mb_strlen($str, '8bit') : strlen($str);
	}

	/**
	 * Byte-safe substr()
	 *
	 * @param string       $str
	 * @param integer      $start
	 * @param integer|null $length
	 *
	 * @return string
	 */
	protected static function substr($str, $start, $length = null)
	{
		if (static::$func_overload)
		{
			return mb_substr($str, $start, $length, '8bit');
		}

		return isset($length) ? substr($str, $start, $length) : substr($str, $start);
	}

	/**
	 * Determines the values that should be stored in $archive.
	 *
	 * @return array The updated archive values
	 */
	protected function setArchiveValues(): array
	{
		// Get property values and add anything prepped in tmpArchive
		$this->archive = array_merge(get_object_vars($this), $this->tmpArchive);
		unset($this->archive['archive']);

		// Clear tmpArchive for next run
		$this->tmpArchive = [];

		return $this->archive;
	}
}
