<?php
/**
 * @link http://www.yiiframework.com/
 * @copyright Copyright (c) 2008 Yii Software LLC
 * @license http://www.yiiframework.com/license/
 */

namespace yii\mail;

use Yii;
use yii\base\Component;
use yii\base\InvalidConfigException;
use yii\base\ViewContextInterface;
use yii\web\View;
use yii\base\MailEvent;

/**
 * BaseMailer serves as a base class that implements the basic functions required by [[MailerInterface]].
 *
 * Concrete child classes should may focus on implementing the [[sendMessage()]] method.
 *
 * @see BaseMessage
 *
 * @property View $view View instance. Note that the type of this property differs in getter and setter. See
 * [[getView()]] and [[setView()]] for details.
 *
 * @author Paul Klimov <klimov.paul@gmail.com>
 * @since 2.0
 */
abstract class BaseMailer extends Component implements MailerInterface, ViewContextInterface
{
    /**
     * @event \yii\base\MailEvent an event raised right before send.
     * You may set [[\yii\base\MailEvent::isValid]] to be false to cancel the send.
     */
    const EVENT_BEFORE_SEND = 'beforeSend';
    /**
     * @event \yii\base\MailEvent an event raised right after send.
     */
    const EVENT_AFTER_SEND = 'afterSend';
    /**
     * @var string directory containing view files for this email messages.
     * This can be specified as an absolute path or path alias.
     */
    public $viewPath = '@app/mail';
    /**
     * @var string|boolean HTML layout view name. This is the layout used to render HTML mail body.
     * The property can take the following values:
     *
     * - a relative view name: a view file relative to [[viewPath]], e.g., 'layouts/html'.
     * - a path alias: an absolute view file path specified as a path alias, e.g., '@app/mail/html'.
     * - a boolean false: the layout is disabled.
     */
    public $htmlLayout = 'layouts/html';
    /**
     * @var string|boolean text layout view name. This is the layout used to render TEXT mail body.
     * Please refer to [[htmlLayout]] for possible values that this property can take.
     */
    public $textLayout = 'layouts/text';
    /**
     * @var array the configuration that should be applied to any newly created
     * email message instance by [[createMessage()]] or [[compose()]]. Any valid property defined
     * by [[MessageInterface]] can be configured, such as `from`, `to`, `subject`, `textBody`, `htmlBody`, etc.
     *
     * For example:
     *
     * ~~~
     * [
     *     'charset' => 'UTF-8',
     *     'from' => 'noreply@mydomain.com',
     *     'bcc' => 'developer@mydomain.com',
     * ]
     * ~~~
     */
    public $messageConfig = [];
    /**
     * @var string the default class name of the new message instances created by [[createMessage()]]
     */
    public $messageClass = 'yii\mail\BaseMessage';
    /**
     * @var boolean whether to save email messages as files under [[fileTransportPath]] instead of sending them
     * to the actual recipients. This is usually used during development for debugging purpose.
     * @see fileTransportPath
     */
    public $useFileTransport = false;
    /**
     * @var string the directory where the email messages are saved when [[useFileTransport]] is true.
     */
    public $fileTransportPath = '@runtime/mail';
    /**
     * @var callable a PHP callback that will be called by [[send()]] when [[useFileTransport]] is true.
     * The callback should return a file name which will be used to save the email message.
     * If not set, the file name will be generated based on the current timestamp.
     *
     * The signature of the callback is:
     *
     * ~~~
     * function ($mailer, $message)
     * ~~~
     */
    public $fileTransportCallback;

    /**
     * @var \yii\base\View|array view instance or its array configuration.
     */
    private $_view = [];

    /**
     * @param array|View $view view instance or its array configuration that will be used to
     * render message bodies.
     * @throws InvalidConfigException on invalid argument.
     */
    public function setView($view)
    {
        if (!is_array($view) && !is_object($view)) {
            throw new InvalidConfigException('"' . get_class($this) . '::view" should be either object or configuration array, "' . gettype($view) . '" given.');
        }
        $this->_view = $view;
    }

    /**
     * @return View view instance.
     */
    public function getView()
    {
        if (!is_object($this->_view)) {
            $this->_view = $this->createView($this->_view);
        }

        return $this->_view;
    }

    /**
     * Creates view instance from given configuration.
     * @param array $config view configuration.
     * @return View view instance.
     */
    protected function createView(array $config)
    {
        if (!array_key_exists('class', $config)) {
            $config['class'] = View::className();
        }

        return Yii::createObject($config);
    }

    /**
     * Creates a new message instance and optionally composes its body content via view rendering.
     *
     * @param string|array $view the view to be used for rendering the message body. This can be:
     *
     * - a string, which represents the view name or path alias for rendering the HTML body of the email.
     *   In this case, the text body will be generated by applying `strip_tags()` to the HTML body.
     * - an array with 'html' and/or 'text' elements. The 'html' element refers to the view name or path alias
     *   for rendering the HTML body, while 'text' element is for rendering the text body. For example,
     *   `['html' => 'contact-html', 'text' => 'contact-text']`.
     * - null, meaning the message instance will be returned without body content.
     *
     * The view to be rendered can be specified in one of the following formats:
     *
     * - path alias (e.g. "@app/mail/contact");
     * - a relative view name (e.g. "contact"): the actual view file will be resolved by [[findViewFile()]]
     *
     * @param array $params the parameters (name-value pairs) that will be extracted and made available in the view file.
     * @return MessageInterface message instance.
     */
    public function compose($view = null, array $params = [])
    {
        $message = $this->createMessage();
        if ($view !== null) {
            $params['message'] = $message;
            if (is_array($view)) {
                if (isset($view['html'])) {
                    $html = $this->render($view['html'], $params, $this->htmlLayout);
                }
                if (isset($view['text'])) {
                    $text = $this->render($view['text'], $params, $this->textLayout);
                }
            } else {
                $html = $this->render($view, $params, $this->htmlLayout);
            }
            if (isset($html)) {
                $message->setHtmlBody($html);
            }
            if (isset($text)) {
                $message->setTextBody($text);
            } elseif (isset($html)) {
                $message->setTextBody(strip_tags($html));
            }
        }

        return $message;
    }

    /**
     * Creates a new message instance.
     * The newly created instance will be initialized with the configuration specified by [[messageConfig]].
     * If the configuration does not specify a 'class', the [[messageClass]] will be used as the class
     * of the new message instance.
     * @return MessageInterface message instance.
     */
    protected function createMessage()
    {
        $config = $this->messageConfig;
        if (!array_key_exists('class', $config)) {
            $config['class'] = $this->messageClass;
        }

        return Yii::createObject($config);
    }

    /**
     * Sends the given email message.
     * This method will log a message about the email being sent.
     * If [[useFileTransport]] is true, it will save the email as a file under [[fileTransportPath]].
     * Otherwise, it will call [[sendMessage()]] to send the email to its recipient(s).
     * Child classes should implement [[sendMessage()]] with the actual email sending logic.
     * @param MessageInterface $message email message instance to be sent
     * @return boolean whether the message has been sent successfully
     */
    public function send($message)
    {
        if (!$this->beforeSend($message)) {
            return false;
        }

        $address = $message->getTo();
        if (is_array($address)) {
            $address = implode(', ', array_keys($address));
        }
        Yii::info('Sending email "' . $message->getSubject() . '" to "' . $address . '"', __METHOD__);

        if ($this->useFileTransport) {
            $isSuccessful = $this->saveMessage($message);
        } else {
            $isSuccessful = $this->sendMessage($message);
        }
        $this->afterSend($message, $isSuccessful);

        return $isSuccessful;
    }

    /**
     * Sends multiple messages at once.
     *
     * The default implementation simply calls [[send()]] multiple times.
     * Child classes may override this method to implement more efficient way of
     * sending multiple messages.
     *
     * @param array $messages list of email messages, which should be sent.
     * @return integer number of messages that are successfully sent.
     */
    public function sendMultiple(array $messages)
    {
        $successCount = 0;
        foreach ($messages as $message) {
            if ($this->send($message)) {
                $successCount++;
            }
        }

        return $successCount;
    }

    /**
     * Renders the specified view with optional parameters and layout.
     * The view will be rendered using the [[view]] component.
     * @param string $view the view name or the path alias of the view file.
     * @param array $params the parameters (name-value pairs) that will be extracted and made available in the view file.
     * @param string|boolean $layout layout view name or path alias. If false, no layout will be applied.
     * @return string the rendering result.
     */
    public function render($view, $params = [], $layout = false)
    {
        $output = $this->getView()->render($view, $params, $this);
        if ($layout !== false) {
            return $this->getView()->render($layout, ['content' => $output], $this);
        } else {
            return $output;
        }
    }

    /**
     * Sends the specified message.
     * This method should be implemented by child classes with the actual email sending logic.
     * @param MessageInterface $message the message to be sent
     * @return boolean whether the message is sent successfully
     */
    abstract protected function sendMessage($message);

    /**
     * Saves the message as a file under [[fileTransportPath]].
     * @param MessageInterface $message
     * @return boolean whether the message is saved successfully
     */
    protected function saveMessage($message)
    {
        $path = Yii::getAlias($this->fileTransportPath);
        if (!is_dir(($path))) {
            mkdir($path, 0777, true);
        }
        if ($this->fileTransportCallback !== null) {
            $file = $path . '/' . call_user_func($this->fileTransportCallback, $this, $message);
        } else {
            $file = $path . '/' . $this->generateMessageFileName();
        }
        file_put_contents($file, $message->toString());

        return true;
    }

    /**
     * @return string the file name for saving the message when [[useFileTransport]] is true.
     */
    public function generateMessageFileName()
    {
        $time = microtime(true);

        return date('Ymd-His-', $time) . sprintf('%04d', (int) (($time - (int) $time) * 10000)) . '-' . sprintf('%04d', mt_rand(0, 10000)) . '.eml';
    }

    /**
     * Finds the view file corresponding to the specified relative view name.
     * This method will return the view file by prefixing the view name with [[viewPath]].
     * @param string $view a relative view name. The name does NOT start with a slash.
     * @return string the view file path. Note that the file may not exist.
     */
    public function findViewFile($view)
    {
        return Yii::getAlias($this->viewPath) . DIRECTORY_SEPARATOR . $view;
    }

    /**
     * This method is invoked right before mail send.
     * You may override this method to do last-minute preparation for the message.
     * If you override this method, please make sure you call the parent implementation first.
     * @param MessageInterface $message
     * @return boolean whether to continue sending an email.
     */
    public function beforeSend($message)
    {
        $event = new MailEvent(['message' => $message]);
        $this->trigger(self::EVENT_BEFORE_SEND, $event);

        return $event->isValid;
    }

    /**
     * This method is invoked right after mail was send.
     * You may override this method to do some postprocessing or logging based on mail send status.
     * If you override this method, please make sure you call the parent implementation first.
     * @param MessageInterface $message
     * @param boolean $isSuccessful
     */
    public function afterSend($message, $isSuccessful)
    {
        $event = new MailEvent(['message' => $message, 'isSuccessful' => $isSuccessful]);
        $this->trigger(self::EVENT_AFTER_SEND, $event);
    }
}
