<?php
/**
 * Email Service
 * Handles email notifications via Mailgun
 */

class EmailService {
    private $config;
    private $enabled;

    public function __construct() {
        $appConfig = require __DIR__ . '/config.php';
        $this->config = $appConfig['email'];
        $this->enabled = $this->config['enabled'] ?? false;

        // Load email templates
        require_once __DIR__ . '/EmailTemplates.php';
    }

    /**
     * Send email via Mailgun API or SMTP
     */
    public function send($to, $subject, $text, $html = null) {
        if (!$this->enabled) {
            error_log('Email not sent (service disabled): ' . $subject);
            return ['success' => true, 'message' => 'Email disabled'];
        }

        $service = $this->config['service'] ?? 'mailgun';

        if ($service === 'smtp') {
            return $this->sendViaSMTP($to, $subject, $text, $html);
        } else {
            return $this->sendViaMailgunAPI($to, $subject, $text, $html);
        }
    }

    /**
     * Send templated email
     */
    public function sendTemplate($to, $templateName, $data) {
        $html = EmailTemplates::getTemplate($templateName, $data);

        // Extract subject from HTML title
        preg_match('/<h1[^>]*>(.*?)<\/h1>/', $html, $matches);
        $subject = $matches[1] ?? 'L\'Oréal OMG Assistant Notification';

        // Create plain text version from data
        $text = strip_tags($subject) . "\n\n" . json_encode($data, JSON_PRETTY_PRINT);

        return $this->send($to, $subject, $text, $html);
    }

    /**
     * Send email via Mailgun API
     */
    private function sendViaMailgunAPI($to, $subject, $text) {
        try {
            $url = 'https://api.mailgun.net/v3/' . $this->config['domain'] . '/messages';

            $postData = [
                'from' => $this->config['from'],
                'to' => $to,
                'subject' => $subject,
                'text' => $text
            ];

            $ch = curl_init($url);
            curl_setopt_array($ch, [
                CURLOPT_POST => true,
                CURLOPT_POSTFIELDS => $postData,
                CURLOPT_RETURNTRANSFER => true,
                CURLOPT_USERPWD => 'api:' . $this->config['mailgun_api_key'],
                CURLOPT_HTTPAUTH => CURLAUTH_BASIC,
                CURLOPT_TIMEOUT => 10
            ]);

            $response = curl_exec($ch);
            $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
            $curlError = curl_error($ch);
            curl_close($ch);

            if ($curlError) {
                error_log('Email send failed: ' . $curlError);
                return [
                    'success' => false,
                    'error' => 'Email delivery failed',
                    'details' => $curlError
                ];
            }

            if ($httpCode !== 200) {
                error_log('Email send failed (HTTP ' . $httpCode . '): ' . $response);
                return [
                    'success' => false,
                    'error' => 'Email service error',
                    'details' => 'HTTP ' . $httpCode,
                    'httpCode' => $httpCode
                ];
            }

            error_log('Email sent successfully to ' . $to);

            return [
                'success' => true,
                'httpCode' => $httpCode
            ];

        } catch (Exception $e) {
            error_log('Email exception: ' . $e->getMessage());

            return [
                'success' => false,
                'error' => 'Email exception',
                'details' => $e->getMessage()
            ];
        }
    }

    /**
     * Send email via SMTP
     */
    private function sendViaSMTP($to, $subject, $text, $html = null) {
        try {
            error_log('===== EMAIL SEND START =====');
            error_log('To: ' . $to);
            error_log('Subject: ' . $subject);
            error_log('Service: SMTP');

            $from = $this->config['from'];
            $host = $this->config['smtp_host'];
            $port = $this->config['smtp_port'];
            $username = $this->config['smtp_username'];
            $password = $this->config['smtp_password'];

            error_log('SMTP Host: ' . $host . ':' . $port);
            error_log('SMTP User: ' . $username);
            error_log('From: ' . $from);

            // Build email message with multipart if HTML provided
            $boundary = md5(time());

            $headers = "From: {$from}\r\n";
            $headers .= "Reply-To: {$from}\r\n";
            $headers .= "X-Mailer: PHP/" . phpversion() . "\r\n";
            $headers .= "MIME-Version: 1.0\r\n";

            if ($html) {
                $headers .= "Content-Type: multipart/alternative; boundary=\"{$boundary}\"\r\n";
            } else {
                $headers .= "Content-Type: text/plain; charset=UTF-8\r\n";
            }

            // Create SMTP connection
            error_log('Connecting to SMTP server...');
            $socket = fsockopen($host, $port, $errno, $errstr, 10);

            if (!$socket) {
                error_log('SMTP connection failed: ' . $errstr . ' (errno: ' . $errno . ')');
                return [
                    'success' => false,
                    'error' => 'SMTP connection failed',
                    'details' => $errstr
                ];
            }

            error_log('SMTP connection established');

            // SMTP conversation
            $this->smtpCommand($socket, null, 220);  // Wait for greeting
            $this->smtpCommand($socket, "EHLO " . $host, 250);
            $this->smtpCommand($socket, "AUTH LOGIN", 334);
            $this->smtpCommand($socket, base64_encode($username), 334);
            $this->smtpCommand($socket, base64_encode($password), 235);
            $this->smtpCommand($socket, "MAIL FROM: <{$from}>", 250);
            $this->smtpCommand($socket, "RCPT TO: <{$to}>", 250);
            $this->smtpCommand($socket, "DATA", 354);

            // Send email data
            $message = "Subject: {$subject}\r\n";
            $message .= $headers;
            $message .= "\r\n";

            if ($html) {
                // Multipart message
                $message .= "--{$boundary}\r\n";
                $message .= "Content-Type: text/plain; charset=UTF-8\r\n\r\n";
                $message .= $text . "\r\n\r\n";
                $message .= "--{$boundary}\r\n";
                $message .= "Content-Type: text/html; charset=UTF-8\r\n\r\n";
                $message .= $html . "\r\n\r\n";
                $message .= "--{$boundary}--\r\n";
            } else {
                // Plain text only
                $message .= $text . "\r\n";
            }

            $message .= ".\r\n";

            error_log('Sending email data...');
            $this->smtpCommand($socket, $message, 250);

            error_log('Sending QUIT command...');
            $this->smtpCommand($socket, "QUIT", 221);

            fclose($socket);

            error_log('✅ Email sent successfully via SMTP to ' . $to);
            error_log('===== EMAIL SEND END (SUCCESS) =====');

            return [
                'success' => true,
                'method' => 'smtp'
            ];

        } catch (Exception $e) {
            error_log('❌ SMTP exception: ' . $e->getMessage());
            error_log('Stack trace: ' . $e->getTraceAsString());
            error_log('===== EMAIL SEND END (FAILED) =====');

            return [
                'success' => false,
                'error' => 'SMTP exception',
                'details' => $e->getMessage()
            ];
        }
    }

    /**
     * Send SMTP command and check response
     */
    private function smtpCommand($socket, $command, $expectedCode) {
        if ($command !== null) {
            fwrite($socket, $command . "\r\n");
        }

        $response = '';
        while ($line = fgets($socket, 515)) {
            $response .= $line;
            if (substr($line, 3, 1) === ' ') {
                break;
            }
        }

        $code = intval(substr($response, 0, 3));

        if ($code !== $expectedCode) {
            throw new Exception("SMTP Error: Expected {$expectedCode}, got {$code}. Response: {$response}");
        }

        return $response;
    }

    /**
     * Send process started notification
     */
    public function notifyStarted($userEmail, $data) {
        return $this->sendTemplate($userEmail, 'global_to_local_started', $data);
    }

    /**
     * Send process completed notification
     */
    public function notifyCompleted($userEmail, $data) {
        return $this->sendTemplate($userEmail, 'global_to_local_complete', $data);
    }

    /**
     * Send error notification
     */
    public function notifyError($userEmail, $data) {
        return $this->sendTemplate($userEmail, 'global_to_local_failed', $data);
    }

    /**
     * Send asset submission success notification
     */
    public function notifyAssetSubmissionSuccess($userEmail, $data) {
        return $this->sendTemplate($userEmail, 'asset_submission_success', $data);
    }

    /**
     * Send asset submission failed notification
     */
    public function notifyAssetSubmissionFailed($userEmail, $data) {
        return $this->sendTemplate($userEmail, 'asset_submission_failed', $data);
    }
}