tec: Provide a Minz_Mailer class (#2476)

* Add Minz_View::_path method (replace change_view)

The `_path` method is more powerful since it allows to choose the file
extension. It is also Minz_Request-agnostic, which is useful to reuse
the Minz_View class in other places.

`change_view` is now deprecated and a warning is logged if we use it.

* Provide a Minz_Mailer to send emails

It uses PHPMailer under the hood and only supports PHP >= 5.5

3 files changed, 133 insertions, 9 deletions

diff --git a/lib/Minz/ActionController.php b/lib/Minz/ActionController.php
index 232a4ef9b..123b9054c 100644
--- a/lib/Minz/ActionController.php
+++ b/lib/Minz/ActionController.php
@@ -14,7 +14,9 @@ class Minz_ActionController {
 	 * Constructeur
 	 */
 	public function __construct () {
-		$this->view = new Minz_View ();
+		$this->view = new Minz_View();
+		$view_path = Minz_Request::controllerName() . '/' . Minz_Request::actionName() . '.phtml';
+		$this->view->_path($view_path);
 		$this->view->attributeParams ();
 	}
 
diff --git a/lib/Minz/Mailer.php b/lib/Minz/Mailer.php
new file mode 100644
index 000000000..0e88f71d9
--- /dev/null
+++ b/lib/Minz/Mailer.php
@@ -0,0 +1,117 @@
+<?php
+
+use PHPMailer\PHPMailer\PHPMailer;
+use PHPMailer\PHPMailer\Exception;
+
+require LIB_PATH . '/PHPMailer/PHPMailer.php';
+require LIB_PATH . '/PHPMailer/Exception.php';
+require LIB_PATH . '/PHPMailer/SMTP.php';
+
+/**
+ * Allow to send emails.
+ *
+ * The Minz_Mailer class must be inherited by classes under app/Mailers.
+ * They work similarly to the ActionControllers in the way they have a view to
+ * which you can pass params (eg. $this->view->foo = 'bar').
+ *
+ * The view file is not determined automatically, so you have to select one
+ * with, for instance:
+ *
+ * ```
+ * $this->view->_path('user_mailer/email_need_validation.txt')
+ * ```
+ *
+ * Minz_Mailer uses the PHPMailer library under the hood. The latter requires
+ * PHP >= 5.5 to work. If you instantiate a Minz_Mailer with PHP < 5.5, a
+ * warning will be logged.
+ *
+ * The email is sent by calling the `mail` method.
+ */
+class Minz_Mailer {
+	/**
+	 * The view attached to the mailer.
+	 * You should set its file with `$this->view->_path($path)`
+	 *
+	 * @var Minz_View
+	 */
+	protected $view;
+
+	/**
+	 * Constructor.
+	 *
+	 * If PHP version is < 5.5, a warning is logged.
+	 */
+	public function __construct () {
+		if (version_compare(PHP_VERSION, '5.5') < 0) {
+			Minz_Log::warning('Minz_Mailer cannot be used with a version of PHP < 5.5.');
+		}
+
+		$this->view = new Minz_View();
+		$this->view->_layout(false);
+		$this->view->attributeParams();
+
+		$conf = Minz_Configuration::get('system');
+		$this->mailer = $conf->mailer;
+		$this->smtp_config = $conf->smtp;
+
+		// According to https://github.com/PHPMailer/PHPMailer/wiki/SMTP-Debugging#debug-levels
+		// we should not use debug level above 2 unless if we have big trouble
+		// to connect.
+		if ($conf->environment === 'development') {
+			$this->debug_level = 2;
+		} else {
+			$this->debug_level = 0;
+		}
+	}
+
+	/**
+	 * Send an email.
+	 *
+	 * @param string $to The recipient of the email
+	 * @param string $subject The subject of the email
+	 *
+	 * @return bool true on success, false if a SMTP error happens
+	 */
+	public function mail($to, $subject) {
+		ob_start();
+		$this->view->render();
+		$body = ob_get_contents();
+		ob_end_clean();
+
+		$mail = new PHPMailer(true);
+		try {
+			// Server settings
+			$mail->SMTPDebug = $this->debug_level;
+			$mail->Debugoutput = 'error_log';
+
+			if ($this->mailer === 'smtp') {
+				$mail->isSMTP();
+				$mail->Hostname = $this->smtp_config['hostname'];
+				$mail->Host = $this->smtp_config['host'];
+				$mail->SMTPAuth = $this->smtp_config['auth'];
+				$mail->Username = $this->smtp_config['username'];
+				$mail->Password = $this->smtp_config['password'];
+				$mail->SMTPSecure = $this->smtp_config['secure'];
+				$mail->Port = $this->smtp_config['port'];
+			} else {
+				$mail->isMail();
+			}
+
+			// Recipients
+			$mail->setFrom($this->smtp_config['from']);
+			$mail->addAddress($to);
+
+			// Content
+			$mail->isHTML(false);
+			$mail->CharSet = 'utf-8';
+			$mail->Subject = $subject;
+			$mail->Body = $body;
+
+			$mail->send();
+			return true;
+		} catch (Exception $e) {
+			Minz_Log::error('Minz_Mailer cannot send a message: ' . $mail->ErrorInfo);
+			return false;
+		}
+	}
+}
diff --git a/lib/Minz/View.php b/lib/Minz/View.php
index 6f044c98e..5b6676690 100644
--- a/lib/Minz/View.php
+++ b/lib/Minz/View.php
@@ -26,22 +26,27 @@ class Minz_View {
 	 * Constructeur
 	 * Détermine si on utilise un layout ou non
 	 */
-	public function __construct () {
-		$this->change_view(Minz_Request::controllerName(),
-		                   Minz_Request::actionName());
-
+	public function __construct() {
 		$this->_layout(self::LAYOUT_DEFAULT);
 		$conf = Minz_Configuration::get('system');
 		self::$title = $conf->title;
 	}
 
 	/**
-	 * Change le fichier de vue en fonction d'un controller / action
+	 * [deprecated] Change the view file based on controller and action.
 	 */
 	public function change_view($controller_name, $action_name) {
-		$this->view_filename = self::VIEWS_PATH_NAME . '/'
-		                     . $controller_name . '/'
-		                     . $action_name . '.phtml';
+		Minz_Log::warning('Minz_View::change_view is deprecated, it will be removed in a future version. Please use Minz_View::_path instead.');
+		$this->_path($controller_name. '/' . $action_name . '.phtml');
+	}
+
+	/**
+	 * Change the view file based on a pathname relative to VIEWS_PATH_NAME.
+	 *
+	 * @param string $path the new path
+	 */
+	public function _path($path) {
+		$this->view_filename = self::VIEWS_PATH_NAME . '/' . $path;
 	}
 
 	/**