<?php
/**
 * File: EmailHelper.php
 * Version: 2.10
 * Path: /app/Utilities/EmailHelper.php
 * Purpose: Low-level utility for PHPMailer configuration, rendering, and transport of outbound email.
 * Project: Wizdom Networks Website
 */

namespace WizdomNetworks\WizeWeb\Utilities;

use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;
use WizdomNetworks\WizeWeb\Services\TokenService;
use WizdomNetworks\WizeWeb\Services\UnsubscribeTokenService;

class EmailHelper
{
    /**
     * Configures PHPMailer with environment settings.
     *
     * @param PHPMailer $mail
     * @return void
     */
    public static function configureMailer(PHPMailer $mail): void
    {
        $mail->isSMTP();
        $mail->Host = $_ENV['SMTP_HOST'] ?? 'localhost';
        $mail->Port = $_ENV['SMTP_PORT'] ?? 25;

        $mail->SMTPAuth = filter_var($_ENV['SMTP_AUTH'] ?? false, FILTER_VALIDATE_BOOLEAN);
        $mail->Username = $_ENV['SMTP_USER'] ?? '';
        $mail->Password = $_ENV['SMTP_PASS'] ?? '';

        $mail->SMTPAutoTLS = filter_var($_ENV['SMTP_AUTO_TLS'] ?? true, FILTER_VALIDATE_BOOLEAN);

        $encryption = strtolower(trim($_ENV['SMTP_ENCRYPTION'] ?? ''));
        if ($encryption === 'ssl') {
            $mail->SMTPSecure = PHPMailer::ENCRYPTION_SMTPS;
        } elseif ($encryption === 'tls') {
            $mail->SMTPSecure = PHPMailer::ENCRYPTION_STARTTLS;
        } else {
            $mail->SMTPSecure = '';
        }

        $fromEmail = $_ENV['SMTP_FROM_EMAIL'] ?? 'no-reply@localhost';
        $fromName  = $_ENV['SMTP_FROM_NAME'] ?? 'Wizdom Mailer';
        $mail->setFrom($fromEmail, $fromName);

        $mail->SMTPOptions = [
            'ssl' => [
                'verify_peer'       => false,
                'verify_peer_name'  => false,
                'allow_self_signed' => true
            ]
        ];
    }

    /**
     * Parses a comma-separated list of emails and returns an array of valid addresses.
     *
     * @param string $rawList
     * @return array
     */
    private static function parseRecipients(string $rawList): array
    {
        $emails = explode(',', $rawList);
        $validEmails = [];

        foreach ($emails as $email) {
            $email = trim($email);
            if (filter_var($email, FILTER_VALIDATE_EMAIL)) {
                $validEmails[] = $email;
            }
        }

        return $validEmails;
    }

    /**
     * Sends a basic HTML email.
     *
     * @param string $to
     * @param string $subject
     * @param string $body
     * @return bool
     */
    public static function send(string $to, string $subject, string $body): bool
    {
        try {
            $mail = new PHPMailer(true);
            self::configureMailer($mail);
            $mail->addAddress($to);
            $mail->Subject = $subject;
            $mail->Body = $body;
            $mail->isHTML(true);

            $mail->send();
            Logger::info("Email sent successfully to $to with subject: $subject");
            return true;
        } catch (\Throwable $e) {
            Logger::error("Email send failed to $to: " . $e->getMessage());
            return false;
        }
    }

    /**
     * Sends a system-level alert email to admins using an HTML template.
     *
     * @param string $context
     * @param string $errorMessage
     * @param array|string $data
     * @return void
     */
    public static function alertAdmins(string $context, string $errorMessage, $data = []): void
    {
        $recipients = self::parseRecipients($_ENV['ADMIN_EMAILS'] ?? '');
        if (empty($recipients)) {
            Logger::error("EmailHelper: No valid ADMIN_EMAILS configured.");
            return;
        }

        $htmlBody = self::renderTemplate('system_alert', [
            'context' => $context,
            'errorMessage' => $errorMessage,
            'data' => $data
        ]);

        foreach ($recipients as $email) {
            self::send($email, "[System Alert] Error in {$context}", $htmlBody);
        }
    }

    /**
     * Renders an email template with dynamic variables.
     *
     * @param string $templateName
     * @param array $vars
     * @return string
     */
    public static function renderTemplate(string $templateName, array $vars = []): string
    {
        try {
            $templatePath = __DIR__ . '/../../resources/views/emails/' . $templateName . '.php';
            if (!file_exists($templatePath)) {
                throw new \Exception("Template not found: $templateName");
            }

            extract($vars);
            ob_start();
            include $templatePath;
            return ob_get_clean();
        } catch (\Throwable $e) {
            Logger::error("Failed to render email template: $templateName - " . $e->getMessage());
            ErrorHandler::exception($e);
            return '';
        }
    }
    /**
     * Generate a secure unsubscribe link for a subscriber email.
     *
     * @param string $email
     * @return string
     */
    public static function buildUnsubscribeLink(string $email): string
    {
        $ts = time();
        $tokenService = new TokenService();
        $unsubscribeTokenService = new UnsubscribeTokenService($tokenService);

        $sig = $unsubscribeTokenService->generate($email, $ts);

        return $_ENV['APP_URL'] . "/unsubscribe?email=" . urlencode($email) . "&ts=$ts&sig=$sig";
    }
}