<?php
/**
 * Tom's Java Jive - Twilio SMS Service
 * 
 * Handles all SMS notifications using Twilio API
 */

class TwilioSMS {
    private string $accountSid;
    private string $authToken;
    private string $fromNumber;
    
    public function __construct() {
        // Load from settings or config
        $this->accountSid = getSetting('twilio_account_sid', 'YOUR_TWILIO_ACCOUNT_SID');
        $this->authToken = getSetting('twilio_auth_token', 'YOUR_TWILIO_AUTH_TOKEN');
        $this->fromNumber = getSetting('twilio_phone_number', '+1234567890');
    }
    
    /**
     * Send SMS via Twilio API
     */
    public function send(string $to, string $message): array {
        // Ensure phone number is in E.164 format
        $to = $this->formatPhoneNumber($to);
        
        if (!$to) {
            return ['success' => false, 'error' => 'Invalid phone number'];
        }
        
        $url = "https://api.twilio.com/2010-04-01/Accounts/{$this->accountSid}/Messages.json";
        
        $data = [
            'To' => $to,
            'From' => $this->fromNumber,
            'Body' => $message
        ];
        
        $ch = curl_init($url);
        curl_setopt_array($ch, [
            CURLOPT_POST => true,
            CURLOPT_POSTFIELDS => http_build_query($data),
            CURLOPT_USERPWD => "{$this->accountSid}:{$this->authToken}",
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_TIMEOUT => 30
        ]);
        
        $response = curl_exec($ch);
        $httpCode = curl_getinfo($ch, CURLINFO_HTTP_CODE);
        $error = curl_error($ch);
        curl_close($ch);
        
        if ($error) {
            return ['success' => false, 'error' => $error];
        }
        
        $result = json_decode($response, true);
        
        if ($httpCode >= 200 && $httpCode < 300) {
            return [
                'success' => true,
                'sid' => $result['sid'] ?? null,
                'status' => $result['status'] ?? 'queued'
            ];
        }
        
        return [
            'success' => false,
            'error' => $result['message'] ?? 'Failed to send SMS',
            'code' => $result['code'] ?? $httpCode
        ];
    }
    
    /**
     * Format phone number to E.164 format
     */
    private function formatPhoneNumber(string $phone): ?string {
        // Remove all non-numeric characters except +
        $phone = preg_replace('/[^0-9+]/', '', $phone);
        
        // If already in E.164 format
        if (preg_match('/^\+[1-9]\d{1,14}$/', $phone)) {
            return $phone;
        }
        
        // US number without country code
        if (preg_match('/^1?\d{10}$/', $phone)) {
            $phone = preg_replace('/^1?/', '', $phone);
            return '+1' . $phone;
        }
        
        return null;
    }
    
    /**
     * Send order confirmation SMS
     */
    public function sendOrderConfirmation(array $order, string $phone): array {
        $message = "Tom's Java Jive: Your order #{$order['order_number']} has been confirmed! " .
                   "Total: " . formatCurrency($order['total']) . ". " .
                   "Thank you for your purchase!";
        
        return $this->send($phone, $message);
    }
    
    /**
     * Send shipping notification SMS
     */
    public function sendShippingNotification(array $order, string $phone): array {
        $message = "Tom's Java Jive: Your order #{$order['order_number']} has shipped! " .
                   "Tracking: {$order['tracking_number']}. " .
                   "Track at: " . ($order['tracking_url'] ?? SITE_URL);
        
        return $this->send($phone, $message);
    }
    
    /**
     * Send delivery notification SMS
     */
    public function sendDeliveryNotification(array $order, string $phone): array {
        $message = "Tom's Java Jive: Great news! Your order #{$order['order_number']} " .
                   "has been delivered. Enjoy your coffee!";
        
        return $this->send($phone, $message);
    }
    
    /**
     * Send password reset SMS
     */
    public function sendPasswordResetCode(string $phone, string $code): array {
        $message = "Tom's Java Jive: Your password reset code is {$code}. " .
                   "This code expires in 15 minutes. Don't share it with anyone.";
        
        return $this->send($phone, $message);
    }
    
    /**
     * Send OTP verification SMS
     */
    public function sendVerificationCode(string $phone, string $code): array {
        $message = "Tom's Java Jive: Your verification code is {$code}. " .
                   "Valid for 10 minutes.";
        
        return $this->send($phone, $message);
    }
    
    /**
     * Send promotional SMS (with opt-out info)
     */
    public function sendPromotion(string $phone, string $promoMessage): array {
        $message = "Tom's Java Jive: {$promoMessage} " .
                   "Reply STOP to unsubscribe.";
        
        return $this->send($phone, $message);
    }
    
    /**
     * Send order ready for pickup SMS
     */
    public function sendReadyForPickup(array $order, string $phone): array {
        $message = "Tom's Java Jive: Your order #{$order['order_number']} is ready for pickup! " .
                   "Show this message at the counter.";
        
        return $this->send($phone, $message);
    }
    
    /**
     * Send low wallet balance alert
     */
    public function sendLowBalanceAlert(string $phone, float $balance): array {
        $message = "Tom's Java Jive: Your wallet balance is " . formatCurrency($balance) . ". " .
                   "Top up now to continue enjoying fast checkout!";
        
        return $this->send($phone, $message);
    }
    
    /**
     * Send loyalty tier upgrade notification
     */
    public function sendTierUpgrade(string $phone, string $tierName): array {
        $message = "Tom's Java Jive: Congratulations! You've reached {$tierName} status! " .
                   "Enjoy your new benefits and rewards. Thank you for being a loyal customer!";
        
        return $this->send($phone, $message);
    }
}

// Helper function for easy access
function sendSMS(): TwilioSMS {
    static $instance = null;
    if ($instance === null) {
        $instance = new TwilioSMS();
    }
    return $instance;
}