<?php

if (! defined('BASEPATH')) exit('No direct script access allowed');

use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\SMTP;
use PHPMailer\PHPMailer\Exception;

/**
 * Library to manage the sending of the email
 */
class MailLib
{
	const ENABLE_DEBUG = 'enable_debug';

	private $_sended; // Sended email counter

	// Properties for storing the configuration
	private $email_number_to_sent;
	private $email_number_per_time_range;
	private $email_time_range;
	private $email_from_system;

	private $_ci; // Codeigniter instance
	private $_mail; // PHPMailer instance

	/**
	 * Class constructor
	 */
	public function __construct()
	{
		// Set the counter to 0
		$this->_sended = 0;

		// Get CI instance
		$this->_ci =& get_instance();

		// The second parameter is used to avoiding name collisions in the config array
		$this->_ci->config->load('mail', true);

		try
		{
			// PHPMailer configuration
			$this->_mail = new PHPMailer(true);
			$this->_mail->isSMTP();								// Send using SMTP
			$this->_mail->Host = $this->_getEmailCfgItem('smtp_host');			// Set the SMTP server to send through
			$this->_mail->Port = $this->_getEmailCfgItem('smtp_port');			// TCP port to connect to; use 587 if you have set `SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS`
			$this->_mail->SMTPAuth = $this->_getEmailCfgItem('smtp_auth');			// Enable SMTP authentication
			$this->_mail->Username = $this->_getEmailCfgItem('smtp_user');			// SMTP username
			$this->_mail->Password = $this->_getEmailCfgItem('smtp_pass');			// SMTP password
			$this->_mail->SMTPSecure = $this->_getEmailCfgItem('smtp_encryption');		// Enable implicit TLS encryption
			$this->_mail->Timeout = $this->_getEmailCfgItem('smtp_timeout');		// set the timeout (seconds)
			$this->_mail->SMTPKeepAlive = $this->_getEmailCfgItem('smtp_keepalive');	// Persistent SMTP connection
			$this->_mail->Priority = $this->_getEmailCfgItem('priority');			// 1 = High, 3 = Normal, 5 = low. When null, the header is not set at all.
			$this->_mail->WordWrap = $this->_getEmailCfgItem('wordwrap');
			$this->_mail->isHTML($this->_getEmailCfgItem('is_html'));			// html or text
			$this->_mail->SMTPDebug = $this->_getEmailCfgItem('enable_debug');
			$this->_mail->CharSet = 'UTF-8';

			// Set the configuration properties with the standard configuration values
			$this->email_number_to_sent = $this->_getEmailCfgItem('email_number_to_sent');
			$this->email_number_per_time_range = $this->_getEmailCfgItem('email_number_per_time_range');
			$this->email_time_range = $this->_getEmailCfgItem('email_time_range');
			$this->email_from_system = $this->_getEmailCfgItem('email_from_system');
			$this->alias_from_system = $this->_getEmailCfgItem('alias_from_system');
		}
		catch(Exception $e)
		{
			error_log($e->errorMessage());
		}
	}

	/**
	 * Sends a single email
	 */
	public function send($from, $to, $subject, $message, $alias = '', $cc = null, $bcc = null, $altMessage = '', $bulk = false, $autogenerated = false, $embeddedImages = array())
	{
		$result = false;

		try
		{
			// If it is configured then log mail info into the CI error logs
			if ($this->_getEmailCfgItem(self::ENABLE_DEBUG) === true)
			{
				$this->_ci->load->library('LogLib'); // Loads logging library

				// Log them all!
				$this->_ci->loglib->logError('From: '.$from);
				$this->_ci->loglib->logError('To: '.$to);
				$this->_ci->loglib->logError('Subject: '.$subject);
				$this->_ci->loglib->logError('Message: '.$message);
				$this->_ci->loglib->logError('Alias: '.$alias);
				$this->_ci->loglib->logError('CC: '.$cc);
				$this->_ci->loglib->logError('BCC: '.$bcc);
				$this->_ci->loglib->logError('Alternative message: '.$altMessage);
			}

			// If from is not specified then use the standard one
			if (is_null($from) || $from == '')
			{
				$from = $this->email_from_system;
				// If alias is not specified then use the standard one
				if (is_null($alias) || $alias == '')
				{
					$alias = $this->alias_from_system;
				}
			}
			if (defined('MAIL_FROM') && MAIL_FROM != '')
			{
				$from = MAIL_FROM;
				if (is_null($alias) || $alias == '')
				{
					$alias = $this->alias_from_system;
				}
			}

			$this->_mail->setFrom($from, $alias);

			// Check if the email address of the debug recipient is a valid one
			$recipient = $to;
			$recipientCC = $cc;
			$recipientBCC = $bcc;

			// If we the an email for debugging has been set
			if (defined('MAIL_DEBUG') && MAIL_DEBUG != '')
			{
				// if is it valid use it!!!
				$recipient = MAIL_DEBUG;
				if ($recipientCC != '') $recipientCC = MAIL_DEBUG;
				if ($recipientBCC != '') $recipientBCC = MAIL_DEBUG;
			}

			// Recipients
			$this->_mail->addAddress($recipient);
			if (!is_null($recipientCC)) $this->_mail->addCC($recipientCC);
			if (!is_null($recipientBCC)) $this->_mail->addBCC($recipientBCC);

			// Subject & body & alternative body
			$this->_mail->Subject = $subject;
			$this->_mail->Body = $message;
			if (!isEmptyString($altMessage)) $this->_mail->AltBody = $altMessage;

			// Custom headers
			if ($bulk) $this->_mail->addCustomHeader('Precedence', 'bulk');
			if ($autogenerated) $this->_mail->addCustomHeader('Auto-Submitted', 'auto-generated');

			// Embedded images
			foreach ($embeddedImages as $embeddedImage)
			{
				if (!$this->_mail->addEmbeddedImage($embeddedImage['file_name'], $embeddedImage['cid'])) return false;
			}

			$result = $this->_mail->send();

			// If the email was succesfully sended then increment the counter and checks if it has to _wait until the sending of the next
			if ($result != false)
			{
				$this->_sended++;
				$this->_wait();
			}

			// Clear the properties for the next message
			$this->_mail->clearAddresses();
			$this->_mail->clearAllRecipients();
			$this->_mail->clearAttachments();
		}
		catch (Exception $e)
		{
			error_log($e->errorMessage());
		}

		return $result;
	}

	/**
	 * Overrides configuration parameters
	 * If the given parameters are not null or empty strings then they are used to override
	 * the following properties of this object:
	 * - email_number_to_sent
	 * - email_number_per_time_range
	 * - email_time_range
	 * - email_from_system
	 */
	public function overrideConfigs($numberToSent, $numberPerTimeRange, $emailTimeRange, $emailFromSystem)
	{
		if (is_numeric($numberToSent)) $this->email_number_to_sent = $numberToSent;

		if (is_numeric($numberPerTimeRange)) $this->email_number_per_time_range = $numberPerTimeRange;

		if (is_numeric($emailTimeRange)) $this->email_time_range = $emailTimeRange;

		if (!isEmptyString($emailFromSystem) && filter_var($emailFromSystem, FILTER_VALIDATE_EMAIL))
		{
			$this->email_from_system = $emailFromSystem;
		}
	}

	/**
	 * Returns value of property email_number_to_sent
	 */
	public function getEmailNumberToSent()
	{
		return $this->email_number_to_sent;
	}

	/**
	 * Validates an email address
	 */
	public function validateEmailAddress($emailAddress)
	{
		$valid = false;

		if (!isEmptyString($emailAddress))
		{
			$valid = filter_var($emailAddress, FILTER_VALIDATE_EMAIL);
		}

		return $valid;
	}

	/**
	 * Checks if it has to _wait until the sending of the next
	 */
	private function _wait()
	{
		if ($this->_sended == $this->email_number_per_time_range)
		{
			$this->_sended = 0;
			sleep($this->email_time_range); // Wait!!!
		}
	}

	/**
	 * Gets an item from the email configuration array
	 */
	private function _getEmailCfgItem($itemName)
	{
		return $this->_ci->config->item($itemName, EMAIL_CONFIG_INDEX);
	}
}