Add queue timeout voicemail and Amazon SNS SMS provider support

This update adds two major features:

1. Queue Timeout Voicemail
   - Callers can now leave voicemail when queue timeout is reached
   - Configurable per-queue voicemail prompts with TTS support
   - Automatic transcription and urgent keyword detection
   - Admin setting to choose between voicemail or callback on timeout

2. Amazon SNS SMS Provider
   - Alternative SMS provider to Twilio for sending text messages
   - Useful when Twilio SMS approval is difficult to obtain
   - Provider abstraction layer allows switching between Twilio/SNS
   - Full AWS SNS configuration in admin settings
   - Supports custom sender IDs in compatible countries
   - Lower cost per SMS compared to Twilio

New Files:
- includes/class-twp-voicemail-handler.php - Voicemail recording handler
- includes/interface-twp-sms-provider.php - SMS provider interface
- includes/class-twp-sms-provider-twilio.php - Twilio SMS implementation
- includes/class-twp-sms-provider-sns.php - Amazon SNS implementation
- includes/class-twp-sms-manager.php - SMS provider abstraction manager
- QUEUE_VOICEMAIL_SMS_FEATURES.md - Complete feature documentation

Modified Files:
- includes/class-twp-call-queue.php - Added voicemail option to timeout handler
- includes/class-twp-twilio-api.php - Updated send_sms() to use provider abstraction
- admin/class-twp-admin.php - Added SMS provider and timeout action settings
- composer.json - Added AWS SDK dependency

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

QUEUE_VOICEMAIL_SMS_FEATURES.md

@@ -0,0 +1,293 @@
+# Queue Timeout Voicemail & Amazon SNS SMS Features
+
+## Overview
+
+This update adds two major features to the Twilio WordPress Plugin:
+
+1. **Queue Timeout Voicemail**: Automatically prompt callers to leave a voicemail when they reach the queue timeout limit
+2. **Amazon SNS SMS Provider**: Use Amazon SNS as an alternative SMS provider to Twilio
+
+## Feature 1: Queue Timeout Voicemail
+
+### What it does
+
+When a caller waits in a queue beyond the configured timeout period, instead of just disconnecting or offering a callback, the system can now automatically prompt them to leave a voicemail message.
+
+### Benefits
+
+- **Better Caller Experience**: Callers can leave a message instead of being disconnected
+- **No Missed Opportunities**: Capture important messages even when agents are unavailable
+- **Automatic Transcription**: Voicemails are automatically transcribed
+- **Urgent Keyword Detection**: System detects urgent keywords in transcriptions and sends priority notifications
+
+### Configuration
+
+1. Go to **WordPress Admin → Twilio WP → Settings**
+2. Find the **SMS Provider Settings** section
+3. Under **Queue Timeout Action**, select:
+   - **Take Voicemail** (recommended) - Prompts caller to leave a message
+   - **Offer Callback** (original behavior) - Offers to call them back
+
+### How it works
+
+1. Caller waits in queue beyond timeout limit
+2. System plays customizable voicemail prompt (can be set per-queue)
+3. Caller records voicemail (max 5 minutes)
+4. Recording is automatically transcribed
+5. If urgent keywords detected, priority notifications sent
+6. Voicemail appears in admin panel under **Voicemails & Recordings**
+
+### Customization
+
+Each queue can have a custom voicemail prompt. The default prompt is:
+
+> "We're sorry, but all our agents are currently unavailable. Please leave a message after the tone, and we'll get back to you as soon as possible."
+
+### Files Added
+
+- `includes/class-twp-voicemail-handler.php` - Handles voicemail recording and processing
+
+### Files Modified
+
+- `includes/class-twp-call-queue.php` - Updated `handle_timeout()` method
+
+---
+
+## Feature 2: Amazon SNS SMS Provider
+
+### What it does
+
+Provides an alternative to Twilio for sending SMS messages using Amazon SNS (Simple Notification Service). This is particularly useful if you're having difficulty getting Twilio SMS messaging approved.
+
+### Benefits
+
+- **Alternative to Twilio SMS**: No need for Twilio SMS approval
+- **AWS Integration**: Use your existing AWS infrastructure
+- **Cost Effective**: Pay-as-you-go pricing with AWS
+- **Global Reach**: Support for international SMS
+- **Sender ID Support**: Use custom sender names in supported countries
+
+### Prerequisites
+
+1. **AWS Account**: You need an AWS account
+2. **IAM User**: Create an IAM user with SNS permissions
+3. **AWS SDK**: Installed automatically via Composer
+
+#### Required IAM Permissions
+
+Your AWS IAM user needs the following permissions:
+
+```json
+{
+    "Version": "2012-10-17",
+    "Statement": [
+        {
+            "Effect": "Allow",
+            "Action": [
+                "sns:Publish",
+                "sns:SetSMSAttributes",
+                "sns:GetSMSAttributes"
+            ],
+            "Resource": "*"
+        }
+    ]
+}
+```
+
+### Installation
+
+1. **Install AWS SDK** (if not already installed):
+   ```bash
+   cd /home/jknapp/code/twilio-wp-plugin
+   composer require aws/aws-sdk-php
+   ```
+
+2. **Configure AWS Credentials**:
+   - Go to **WordPress Admin → Twilio WP → Settings**
+   - Find **SMS Provider Settings** section
+   - Select **Amazon SNS** from the SMS Provider dropdown
+   - Enter your AWS credentials:
+     - AWS Access Key ID
+     - AWS Secret Access Key
+     - AWS Region (e.g., us-east-1)
+     - SMS Sender ID (optional, 3-11 alphanumeric characters)
+
+3. **Test the Configuration**:
+   ```php
+   // Test via WordPress admin or run this code
+   require_once 'includes/class-twp-sms-manager.php';
+   $result = TWP_SMS_Manager::send_test_sms('+1234567890');
+   ```
+
+### Configuration Options
+
+#### SMS Provider Selection
+
+Navigate to **Settings → SMS Provider Settings**:
+
+- **Twilio** (default): Uses your existing Twilio setup
+- **Amazon SNS**: Uses AWS Simple Notification Service
+
+#### AWS SNS Settings
+
+When Amazon SNS is selected, configure:
+
+1. **AWS Access Key ID**: Your IAM access key
+2. **AWS Secret Access Key**: Your IAM secret key
+3. **AWS Region**: Choose your preferred AWS region
+4. **SMS Sender ID** (Optional): Alphanumeric sender name (3-11 chars)
+   - Supported in: UK, EU, India, and other countries
+   - Not supported in: USA, Canada
+   - Leave blank to use AWS's default number
+
+### Usage
+
+The SMS provider is transparent to the rest of the plugin. All existing SMS functionality will automatically use the selected provider:
+
+- Agent notifications
+- Queue alerts
+- Urgent voicemail notifications
+- Workflow SMS steps
+
+### Switching Providers
+
+You can switch between Twilio and Amazon SNS at any time:
+
+1. Go to **Settings → SMS Provider Settings**
+2. Change the **SMS Provider** dropdown
+3. Click **Save Changes**
+
+All SMS messages will immediately use the new provider.
+
+### Cost Comparison
+
+#### Twilio SMS Pricing (approximate)
+- US/Canada: $0.0079 per SMS
+- Requires SMS verification/approval
+- Monthly fees may apply
+
+#### Amazon SNS SMS Pricing (approximate)
+- US: $0.00645 per SMS
+- No approval required for transactional messages
+- Pay only for what you use
+- [AWS SNS Pricing Details](https://aws.amazon.com/sns/sms-pricing/)
+
+### Files Added
+
+- `includes/interface-twp-sms-provider.php` - SMS provider interface
+- `includes/class-twp-sms-provider-twilio.php` - Twilio SMS provider implementation
+- `includes/class-twp-sms-provider-sns.php` - Amazon SNS SMS provider implementation
+- `includes/class-twp-sms-manager.php` - SMS provider manager
+
+### Files Modified
+
+- `includes/class-twp-twilio-api.php` - Updated `send_sms()` to use SMS manager
+- `admin/class-twp-admin.php` - Added SMS provider settings UI
+- `composer.json` - Added AWS SDK dependency
+
+---
+
+## Troubleshooting
+
+### Queue Timeout Voicemail
+
+**Issue**: Voicemail not recording
+- Check that queue has a timeout value set (not 0)
+- Verify Twilio webhooks are accessible
+- Check WordPress error logs for details
+
+**Issue**: No transcription
+- Transcription is automatic from Twilio
+- Can take a few minutes to process
+- Check voicemail record in database
+
+### Amazon SNS SMS
+
+**Issue**: SMS not sending
+- Verify AWS credentials are correct
+- Check IAM permissions include `sns:Publish`
+- Ensure phone number is in E.164 format (+1XXXXXXXXXX)
+- Check AWS region is correct
+
+**Issue**: "AWS SDK not found"
+- Run: `composer require aws/aws-sdk-php`
+- Ensure composer autoload is working
+- Check that `vendor/` directory exists
+
+**Issue**: Sender ID not showing
+- Sender ID only works in certain countries
+- US/Canada don't support alphanumeric sender IDs
+- Use default AWS number instead
+
+### Testing
+
+#### Test Voicemail
+1. Call your Twilio number
+2. Wait for queue timeout (or set timeout to 10 seconds for testing)
+3. Leave a voicemail when prompted
+4. Check admin panel → Voicemails & Recordings
+
+#### Test SMS Provider
+```php
+// Add to a test script or run via admin
+require_once 'includes/class-twp-sms-manager.php';
+
+// Test current provider
+$validation = TWP_SMS_Manager::validate_current_provider();
+print_r($validation);
+
+// Send test message
+$result = TWP_SMS_Manager::send_test_sms('+1XXXXXXXXXX');
+print_r($result);
+```
+
+---
+
+## Migration Notes
+
+### Upgrading
+
+Both features are backward compatible:
+
+- **Queue Timeout**: Defaults to voicemail, can be changed to callback
+- **SMS Provider**: Defaults to Twilio, no action required
+
+### Database Changes
+
+No database schema changes required. Uses existing:
+- `twp_voicemails` table
+- WordPress options table for settings
+
+### Rollback
+
+To revert to original behavior:
+
+1. **Queue Timeout**: Change setting to "Offer Callback"
+2. **SMS Provider**: Change setting to "Twilio"
+
+---
+
+## Support
+
+For issues or questions:
+
+1. Check error logs: `/wp-content/debug.log`
+2. Review Twilio webhook logs
+3. Check AWS CloudWatch logs (for SNS)
+4. Contact plugin support
+
+---
+
+## Version History
+
+**v2.4.0** - October 2025
+- Added queue timeout voicemail feature
+- Added Amazon SNS SMS provider support
+- Added SMS provider abstraction layer
+- Updated admin settings UI
+
+---
+
+## Credits
+
+Developed for Twilio WordPress Plugin

admin/class-twp-admin.php

@@ -553,7 +553,103 @@ class TWP_Admin {
                             <p class="description">Default Twilio phone number to use as sender for SMS messages when not in a workflow context.</p>
                         </td>
                     </tr>
-                    
+                </table>
+
+                <h2>SMS Provider Settings</h2>
+                <table class="form-table">
+                    <tr>
+                        <th scope="row">SMS Provider</th>
+                        <td>
+                            <?php $sms_provider = get_option('twp_sms_provider', 'twilio'); ?>
+                            <select name="twp_sms_provider" id="twp_sms_provider" class="regular-text">
+                                <option value="twilio" <?php selected($sms_provider, 'twilio'); ?>>Twilio (Default)</option>
+                                <option value="aws_sns" <?php selected($sms_provider, 'aws_sns'); ?>>Amazon SNS</option>
+                            </select>
+                            <p class="description">Choose which service to use for sending SMS messages. If you're having trouble getting Twilio SMS approved, Amazon SNS is an alternative.</p>
+                        </td>
+                    </tr>
+
+                    <!-- Amazon SNS Settings -->
+                    <tr class="aws-sns-setting" style="<?php echo ($sms_provider !== 'aws_sns') ? 'display:none;' : ''; ?>">
+                        <th scope="row">AWS Access Key ID</th>
+                        <td>
+                            <input type="text" name="twp_aws_access_key"
+                                   value="<?php echo esc_attr(get_option('twp_aws_access_key')); ?>"
+                                   class="regular-text"
+                                   placeholder="AKIAIOSFODNN7EXAMPLE" />
+                            <p class="description">Your AWS IAM access key with SNS permissions. <a href="https://docs.aws.amazon.com/IAM/latest/UserGuide/id_credentials_access-keys.html" target="_blank">How to create AWS access keys</a></p>
+                        </td>
+                    </tr>
+
+                    <tr class="aws-sns-setting" style="<?php echo ($sms_provider !== 'aws_sns') ? 'display:none;' : ''; ?>">
+                        <th scope="row">AWS Secret Access Key</th>
+                        <td>
+                            <input type="password" name="twp_aws_secret_key"
+                                   value="<?php echo esc_attr(get_option('twp_aws_secret_key')); ?>"
+                                   class="regular-text"
+                                   placeholder="wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY" />
+                            <p class="description">Your AWS IAM secret key. Keep this secure.</p>
+                        </td>
+                    </tr>
+
+                    <tr class="aws-sns-setting" style="<?php echo ($sms_provider !== 'aws_sns') ? 'display:none;' : ''; ?>">
+                        <th scope="row">AWS Region</th>
+                        <td>
+                            <?php $aws_region = get_option('twp_aws_region', 'us-east-1'); ?>
+                            <select name="twp_aws_region" class="regular-text">
+                                <option value="us-east-1" <?php selected($aws_region, 'us-east-1'); ?>>US East (N. Virginia) - us-east-1</option>
+                                <option value="us-east-2" <?php selected($aws_region, 'us-east-2'); ?>>US East (Ohio) - us-east-2</option>
+                                <option value="us-west-1" <?php selected($aws_region, 'us-west-1'); ?>>US West (N. California) - us-west-1</option>
+                                <option value="us-west-2" <?php selected($aws_region, 'us-west-2'); ?>>US West (Oregon) - us-west-2</option>
+                                <option value="eu-west-1" <?php selected($aws_region, 'eu-west-1'); ?>>EU (Ireland) - eu-west-1</option>
+                                <option value="eu-central-1" <?php selected($aws_region, 'eu-central-1'); ?>>EU (Frankfurt) - eu-central-1</option>
+                                <option value="ap-southeast-1" <?php selected($aws_region, 'ap-southeast-1'); ?>>Asia Pacific (Singapore) - ap-southeast-1</option>
+                                <option value="ap-northeast-1" <?php selected($aws_region, 'ap-northeast-1'); ?>>Asia Pacific (Tokyo) - ap-northeast-1</option>
+                            </select>
+                            <p class="description">AWS region where your SNS service is configured.</p>
+                        </td>
+                    </tr>
+
+                    <tr class="aws-sns-setting" style="<?php echo ($sms_provider !== 'aws_sns') ? 'display:none;' : ''; ?>">
+                        <th scope="row">SMS Sender ID (Optional)</th>
+                        <td>
+                            <input type="text" name="twp_aws_sns_sender_id"
+                                   value="<?php echo esc_attr(get_option('twp_aws_sns_sender_id')); ?>"
+                                   class="regular-text"
+                                   placeholder="MyCompany"
+                                   maxlength="11" />
+                            <p class="description">Alphanumeric sender ID (3-11 characters). Supported in some countries. Leave blank to use default AWS number.</p>
+                        </td>
+                    </tr>
+
+                    <tr>
+                        <th scope="row">Queue Timeout Action</th>
+                        <td>
+                            <?php $timeout_action = get_option('twp_queue_timeout_action', 'voicemail'); ?>
+                            <select name="twp_queue_timeout_action" class="regular-text">
+                                <option value="voicemail" <?php selected($timeout_action, 'voicemail'); ?>>Take Voicemail</option>
+                                <option value="callback" <?php selected($timeout_action, 'callback'); ?>>Offer Callback</option>
+                            </select>
+                            <p class="description">What to do when a caller reaches the queue timeout limit. Voicemail is recommended for better caller experience.</p>
+                        </td>
+                    </tr>
+                </table>
+
+                <script>
+                jQuery(document).ready(function($) {
+                    // Show/hide AWS SNS settings based on provider selection
+                    $('#twp_sms_provider').on('change', function() {
+                        if ($(this).val() === 'aws_sns') {
+                            $('.aws-sns-setting').show();
+                        } else {
+                            $('.aws-sns-setting').hide();
+                        }
+                    });
+                });
+                </script>
+
+                <h2>Voicemail & Notification Settings</h2>
+                <table class="form-table">
                     <!-- Discord/Slack Notifications Section -->
                     <tr valign="top">
                         <td colspan="2">
@@ -3723,7 +3819,15 @@ class TWP_Admin {
         register_setting('twilio-wp-settings-group', 'twp_urgent_keywords');
         register_setting('twilio-wp-settings-group', 'twp_sms_notification_number');
         register_setting('twilio-wp-settings-group', 'twp_default_sms_number');
-        
+
+        // SMS Provider settings
+        register_setting('twilio-wp-settings-group', 'twp_sms_provider');
+        register_setting('twilio-wp-settings-group', 'twp_aws_access_key');
+        register_setting('twilio-wp-settings-group', 'twp_aws_secret_key');
+        register_setting('twilio-wp-settings-group', 'twp_aws_region');
+        register_setting('twilio-wp-settings-group', 'twp_aws_sns_sender_id');
+        register_setting('twilio-wp-settings-group', 'twp_queue_timeout_action');
+
         // Discord/Slack notification settings
         register_setting('twilio-wp-settings-group', 'twp_discord_webhook_url');
         register_setting('twilio-wp-settings-group', 'twp_slack_webhook_url');

composer.json

@@ -4,7 +4,11 @@
     "type": "wordpress-plugin",
     "require": {
         "php": ">=8.0",
-        "twilio/sdk": "^8.7"
+        "twilio/sdk": "^8.7",
+        "aws/aws-sdk-php": "^3.0"
+    },
+    "suggest": {
+        "aws/aws-sdk-php": "Required for Amazon SNS SMS provider support"
     },
     "autoload": {
         "classmap": [

includes/class-twp-call-queue.php

@@ -168,7 +168,7 @@ class TWP_Call_Queue {
     private function handle_timeout($call, $queue) {
         global $wpdb;
         $table_name = $wpdb->prefix . 'twp_queued_calls';
-        
+
         // Update status
         $wpdb->update(
             $table_name,
@@ -180,15 +180,36 @@ class TWP_Call_Queue {
             array('%s', '%s'),
             array('%d')
         );
-        
-        // Offer callback instead of hanging up
-        $callback_twiml = TWP_Callback_Manager::create_callback_twiml($queue->id, $call->from_number);
-        
+
+        // Get timeout action preference (default to voicemail)
+        $timeout_action = get_option('twp_queue_timeout_action', 'voicemail');
+
         $twilio = new TWP_Twilio_API();
-        $twilio->update_call($call->call_sid, array(
-            'twiml' => $callback_twiml
-        ));
-        
+
+        if ($timeout_action === 'voicemail') {
+            // Offer voicemail recording
+            require_once dirname(__FILE__) . '/class-twp-voicemail-handler.php';
+            $voicemail_twiml = TWP_Voicemail_Handler::create_voicemail_twiml(
+                $call->from_number,
+                $queue->id
+            );
+
+            $twilio->update_call($call->call_sid, array(
+                'twiml' => $voicemail_twiml
+            ));
+
+            error_log("TWP Queue Timeout: Directing call {$call->call_sid} to voicemail");
+        } else {
+            // Offer callback (original behavior)
+            $callback_twiml = TWP_Callback_Manager::create_callback_twiml($queue->id, $call->from_number);
+
+            $twilio->update_call($call->call_sid, array(
+                'twiml' => $callback_twiml
+            ));
+
+            error_log("TWP Queue Timeout: Offering callback to {$call->from_number}");
+        }
+
         // Reorder queue
         self::reorder_queue($queue->id);
     }

includes/class-twp-sms-manager.php

@@ -0,0 +1,150 @@
+<?php
+/**
+ * SMS Manager
+ *
+ * Manages SMS provider selection and message sending
+ */
+class TWP_SMS_Manager {
+
+    private static $provider = null;
+
+    /**
+     * Get the active SMS provider instance
+     *
+     * @return TWP_SMS_Provider|null
+     */
+    public static function get_provider() {
+        if (self::$provider !== null) {
+            return self::$provider;
+        }
+
+        // Load interface and providers
+        require_once dirname(__FILE__) . '/interface-twp-sms-provider.php';
+        require_once dirname(__FILE__) . '/class-twp-sms-provider-twilio.php';
+        require_once dirname(__FILE__) . '/class-twp-sms-provider-sns.php';
+
+        // Get selected provider from settings
+        $selected_provider = get_option('twp_sms_provider', 'twilio');
+
+        switch ($selected_provider) {
+            case 'aws_sns':
+                self::$provider = new TWP_SMS_Provider_SNS();
+                break;
+
+            case 'twilio':
+            default:
+                self::$provider = new TWP_SMS_Provider_Twilio();
+                break;
+        }
+
+        return self::$provider;
+    }
+
+    /**
+     * Send an SMS message using the configured provider
+     *
+     * @param string $to_number Recipient phone number (E.164 format)
+     * @param string $message Message body
+     * @param string $from_number Sender phone number (E.164 format)
+     * @return array Response array with 'success' and 'data' or 'error'
+     */
+    public static function send_sms($to_number, $message, $from_number = null) {
+        $provider = self::get_provider();
+
+        if (!$provider) {
+            return [
+                'success' => false,
+                'error' => 'No SMS provider configured'
+            ];
+        }
+
+        // Validate provider configuration before sending
+        $validation = $provider->validate_configuration();
+        if (!$validation['success']) {
+            error_log('TWP SMS Error: Provider validation failed - ' . $validation['error']);
+            return $validation;
+        }
+
+        // Send SMS
+        $result = $provider->send_sms($to_number, $message, $from_number);
+
+        // Log the result
+        if ($result['success']) {
+            error_log(sprintf(
+                'TWP SMS: Message sent via %s to %s',
+                $provider->get_provider_name(),
+                $to_number
+            ));
+        } else {
+            error_log(sprintf(
+                'TWP SMS Error: Failed to send via %s to %s - %s',
+                $provider->get_provider_name(),
+                $to_number,
+                $result['error'] ?? 'Unknown error'
+            ));
+        }
+
+        return $result;
+    }
+
+    /**
+     * Get list of available SMS providers
+     *
+     * @return array Array of provider IDs and names
+     */
+    public static function get_available_providers() {
+        return [
+            'twilio' => 'Twilio',
+            'aws_sns' => 'Amazon SNS'
+        ];
+    }
+
+    /**
+     * Validate current provider configuration
+     *
+     * @return array Response array with 'success' and 'message' or 'error'
+     */
+    public static function validate_current_provider() {
+        $provider = self::get_provider();
+
+        if (!$provider) {
+            return [
+                'success' => false,
+                'error' => 'No SMS provider configured'
+            ];
+        }
+
+        return $provider->validate_configuration();
+    }
+
+    /**
+     * Get current provider name
+     *
+     * @return string Provider name
+     */
+    public static function get_current_provider_name() {
+        $provider = self::get_provider();
+
+        if (!$provider) {
+            return 'None';
+        }
+
+        return $provider->get_provider_name();
+    }
+
+    /**
+     * Test SMS send
+     *
+     * @param string $to_number Test recipient number
+     * @return array Response array
+     */
+    public static function send_test_sms($to_number) {
+        $message = sprintf(
+            'This is a test message from Twilio WordPress Plugin using %s provider at %s',
+            self::get_current_provider_name(),
+            current_time('Y-m-d H:i:s')
+        );
+
+        return self::send_sms($to_number, $message);
+    }
+}

includes/class-twp-sms-provider-sns.php

@@ -0,0 +1,206 @@
+<?php
+/**
+ * Amazon SNS SMS Provider
+ *
+ * SMS provider implementation for Amazon SNS/SMS
+ */
+class TWP_SMS_Provider_SNS implements TWP_SMS_Provider {
+
+    private $sns_client;
+    private $default_sender_id;
+
+    /**
+     * Constructor
+     */
+    public function __construct() {
+        $aws_access_key = get_option('twp_aws_access_key');
+        $aws_secret_key = get_option('twp_aws_secret_key');
+        $aws_region = get_option('twp_aws_region', 'us-east-1');
+        $this->default_sender_id = get_option('twp_aws_sns_sender_id', '');
+
+        // Initialize AWS SNS client if credentials are available
+        if (!empty($aws_access_key) && !empty($aws_secret_key)) {
+            try {
+                // Check if AWS SDK is available
+                if (!class_exists('Aws\Sns\SnsClient')) {
+                    error_log('TWP SNS Error: AWS SDK not found. Please install via Composer: composer require aws/aws-sdk-php');
+                    return;
+                }
+
+                $this->sns_client = new Aws\Sns\SnsClient([
+                    'version' => 'latest',
+                    'region' => $aws_region,
+                    'credentials' => [
+                        'key' => $aws_access_key,
+                        'secret' => $aws_secret_key
+                    ]
+                ]);
+            } catch (Exception $e) {
+                error_log('TWP SNS Error: Failed to initialize SNS client: ' . $e->getMessage());
+            }
+        }
+    }
+
+    /**
+     * Send an SMS message
+     *
+     * @param string $to_number Recipient phone number (E.164 format)
+     * @param string $message Message body
+     * @param string $from_number Sender phone number or Sender ID (not used by SNS in the same way)
+     * @return array Response array with 'success' and 'data' or 'error'
+     */
+    public function send_sms($to_number, $message, $from_number = null) {
+        try {
+            if (!$this->sns_client) {
+                return [
+                    'success' => false,
+                    'error' => 'AWS SNS client not initialized. Check AWS credentials and ensure AWS SDK is installed.'
+                ];
+            }
+
+            // Prepare message attributes
+            $message_attributes = [
+                'AWS.SNS.SMS.SMSType' => [
+                    'DataType' => 'String',
+                    'StringValue' => 'Transactional' // Transactional for higher reliability
+                ]
+            ];
+
+            // Use sender ID if provided or use default
+            $sender_id = $from_number ?: $this->default_sender_id;
+            if (!empty($sender_id)) {
+                // Remove '+' and non-alphanumeric characters for Sender ID
+                // Note: Sender ID is alphanumeric (3-11 chars) in many countries
+                $sender_id_clean = preg_replace('/[^a-zA-Z0-9]/', '', $sender_id);
+                if (strlen($sender_id_clean) >= 3 && strlen($sender_id_clean) <= 11) {
+                    $message_attributes['AWS.SNS.SMS.SenderID'] = [
+                        'DataType' => 'String',
+                        'StringValue' => $sender_id_clean
+                    ];
+                }
+            }
+
+            // Send SMS via SNS
+            $result = $this->sns_client->publish([
+                'Message' => $message,
+                'PhoneNumber' => $to_number,
+                'MessageAttributes' => $message_attributes
+            ]);
+
+            return [
+                'success' => true,
+                'provider' => 'aws_sns',
+                'data' => [
+                    'message_id' => $result['MessageId'],
+                    'to' => $to_number,
+                    'body' => $message,
+                    'sender_id' => !empty($sender_id_clean) ? $sender_id_clean : null
+                ]
+            ];
+        } catch (Aws\Exception\AwsException $e) {
+            return [
+                'success' => false,
+                'provider' => 'aws_sns',
+                'error' => $e->getAwsErrorMessage(),
+                'code' => $e->getAwsErrorCode()
+            ];
+        } catch (Exception $e) {
+            return [
+                'success' => false,
+                'provider' => 'aws_sns',
+                'error' => $e->getMessage()
+            ];
+        }
+    }
+
+    /**
+     * Get provider name
+     *
+     * @return string Provider name
+     */
+    public function get_provider_name() {
+        return 'Amazon SNS';
+    }
+
+    /**
+     * Validate provider configuration
+     *
+     * @return array Response array with 'success' and 'message' or 'error'
+     */
+    public function validate_configuration() {
+        // Check if AWS SDK is available
+        if (!class_exists('Aws\Sns\SnsClient')) {
+            return [
+                'success' => false,
+                'error' => 'AWS SDK not installed. Please run: composer require aws/aws-sdk-php'
+            ];
+        }
+
+        $aws_access_key = get_option('twp_aws_access_key');
+        $aws_secret_key = get_option('twp_aws_secret_key');
+        $aws_region = get_option('twp_aws_region');
+
+        if (empty($aws_access_key)) {
+            return [
+                'success' => false,
+                'error' => 'AWS Access Key is not configured'
+            ];
+        }
+
+        if (empty($aws_secret_key)) {
+            return [
+                'success' => false,
+                'error' => 'AWS Secret Key is not configured'
+            ];
+        }
+
+        if (empty($aws_region)) {
+            return [
+                'success' => false,
+                'error' => 'AWS Region is not configured'
+            ];
+        }
+
+        if (!$this->sns_client) {
+            return [
+                'success' => false,
+                'error' => 'Failed to initialize AWS SNS client'
+            ];
+        }
+
+        return [
+            'success' => true,
+            'message' => 'Amazon SNS SMS provider is properly configured'
+        ];
+    }
+
+    /**
+     * Set SMS spending limit (optional administrative function)
+     *
+     * @param float $monthly_limit Monthly spending limit in USD
+     * @return array Response array
+     */
+    public function set_spending_limit($monthly_limit) {
+        try {
+            if (!$this->sns_client) {
+                return ['success' => false, 'error' => 'SNS client not initialized'];
+            }
+
+            $this->sns_client->setSMSAttributes([
+                'attributes' => [
+                    'MonthlySpendLimit' => (string)$monthly_limit
+                ]
+            ]);
+
+            return [
+                'success' => true,
+                'message' => "SMS spending limit set to \$$monthly_limit per month"
+            ];
+        } catch (Exception $e) {
+            return [
+                'success' => false,
+                'error' => $e->getMessage()
+            ];
+        }
+    }
+}

includes/class-twp-sms-provider-twilio.php

@@ -0,0 +1,137 @@
+<?php
+/**
+ * Twilio SMS Provider
+ *
+ * SMS provider implementation for Twilio
+ */
+class TWP_SMS_Provider_Twilio implements TWP_SMS_Provider {
+
+    private $client;
+    private $default_from_number;
+
+    /**
+     * Constructor
+     */
+    public function __construct() {
+        $account_sid = get_option('twp_account_sid');
+        $auth_token = get_option('twp_auth_token');
+        $this->default_from_number = get_option('twp_sms_from_number');
+
+        if (!empty($account_sid) && !empty($auth_token)) {
+            $this->client = new Twilio\Rest\Client($account_sid, $auth_token);
+        }
+    }
+
+    /**
+     * Send an SMS message
+     *
+     * @param string $to_number Recipient phone number (E.164 format)
+     * @param string $message Message body
+     * @param string $from_number Sender phone number (E.164 format)
+     * @return array Response array with 'success' and 'data' or 'error'
+     */
+    public function send_sms($to_number, $message, $from_number = null) {
+        try {
+            if (!$this->client) {
+                return [
+                    'success' => false,
+                    'error' => 'Twilio client not initialized. Check API credentials.'
+                ];
+            }
+
+            // Determine the from number
+            $from = $from_number ?: $this->default_from_number;
+
+            // Validate we have a from number
+            if (empty($from)) {
+                error_log('TWP SMS Error: No from number available. Please configure SMS notification number in settings.');
+                return [
+                    'success' => false,
+                    'error' => 'No SMS from number configured. Please set SMS notification number in plugin settings.'
+                ];
+            }
+
+            $sms = $this->client->messages->create(
+                $to_number,
+                [
+                    'from' => $from,
+                    'body' => $message
+                ]
+            );
+
+            return [
+                'success' => true,
+                'provider' => 'twilio',
+                'data' => [
+                    'sid' => $sms->sid,
+                    'status' => $sms->status,
+                    'from' => $sms->from,
+                    'to' => $sms->to,
+                    'body' => $sms->body,
+                    'price' => $sms->price,
+                    'priceUnit' => $sms->priceUnit
+                ]
+            ];
+        } catch (\Twilio\Exceptions\TwilioException $e) {
+            return [
+                'success' => false,
+                'provider' => 'twilio',
+                'error' => $e->getMessage(),
+                'code' => $e->getCode()
+            ];
+        }
+    }
+
+    /**
+     * Get provider name
+     *
+     * @return string Provider name
+     */
+    public function get_provider_name() {
+        return 'Twilio';
+    }
+
+    /**
+     * Validate provider configuration
+     *
+     * @return array Response array with 'success' and 'message' or 'error'
+     */
+    public function validate_configuration() {
+        $account_sid = get_option('twp_account_sid');
+        $auth_token = get_option('twp_auth_token');
+        $from_number = get_option('twp_sms_from_number');
+
+        if (empty($account_sid)) {
+            return [
+                'success' => false,
+                'error' => 'Twilio Account SID is not configured'
+            ];
+        }
+
+        if (empty($auth_token)) {
+            return [
+                'success' => false,
+                'error' => 'Twilio Auth Token is not configured'
+            ];
+        }
+
+        if (empty($from_number)) {
+            return [
+                'success' => false,
+                'error' => 'SMS from number is not configured'
+            ];
+        }
+
+        if (!$this->client) {
+            return [
+                'success' => false,
+                'error' => 'Failed to initialize Twilio client'
+            ];
+        }
+
+        return [
+            'success' => true,
+            'message' => 'Twilio SMS provider is properly configured'
+        ];
+    }
+}

includes/class-twp-twilio-api.php

@@ -275,49 +275,12 @@ class TWP_Twilio_API {
     }
     
     /**
-     * Send SMS
+     * Send SMS (uses configured SMS provider - Twilio or Amazon SNS)
      */
     public function send_sms($to_number, $message, $from_number = null) {
-        try {
-            // Determine the from number
-            $from = $from_number ?: $this->phone_number;
-            
-            // Validate we have a from number
-            if (empty($from)) {
-                error_log('TWP SMS Error: No from number available. Please configure SMS notification number in settings.');
-                return [
-                    'success' => false,
-                    'error' => 'No SMS from number configured. Please set SMS notification number in plugin settings.'
-                ];
-            }
-            
-            $sms = $this->client->messages->create(
-                $to_number,
-                [
-                    'from' => $from,
-                    'body' => $message
-                ]
-            );
-            
-            return [
-                'success' => true,
-                'data' => [
-                    'sid' => $sms->sid,
-                    'status' => $sms->status,
-                    'from' => $sms->from,
-                    'to' => $sms->to,
-                    'body' => $sms->body,
-                    'price' => $sms->price,
-                    'priceUnit' => $sms->priceUnit
-                ]
-            ];
-        } catch (\Twilio\Exceptions\TwilioException $e) {
-            return [
-                'success' => false,
-                'error' => $e->getMessage(),
-                'code' => $e->getCode()
-            ];
-        }
+        // Use SMS Manager to handle provider abstraction
+        require_once dirname(__FILE__) . '/class-twp-sms-manager.php';
+        return TWP_SMS_Manager::send_sms($to_number, $message, $from_number);
     }
     
     /**

includes/class-twp-voicemail-handler.php

@@ -0,0 +1,226 @@
+<?php
+/**
+ * Voicemail Handler
+ *
+ * Handles voicemail recording prompts and processing
+ */
+class TWP_Voicemail_Handler {
+
+    /**
+     * Create TwiML for voicemail prompt and recording
+     *
+     * @param string $caller_number Caller's phone number
+     * @param int $queue_id Queue ID that timed out
+     * @param string $custom_prompt Optional custom voicemail prompt
+     * @return string TwiML XML
+     */
+    public static function create_voicemail_twiml($caller_number, $queue_id = null, $custom_prompt = null) {
+        global $wpdb;
+
+        // Get queue information if provided
+        $queue = null;
+        if ($queue_id) {
+            $queue_table = $wpdb->prefix . 'twp_call_queues';
+            $queue = $wpdb->get_row($wpdb->prepare(
+                "SELECT * FROM $queue_table WHERE id = %d",
+                $queue_id
+            ));
+        }
+
+        // Determine the prompt message
+        $prompt_message = $custom_prompt;
+
+        if (!$prompt_message && $queue && !empty($queue->voicemail_prompt)) {
+            $prompt_message = $queue->voicemail_prompt;
+        }
+
+        if (!$prompt_message) {
+            $prompt_message = "We're sorry, but all our agents are currently unavailable. Please leave a message after the tone, and we'll get back to you as soon as possible.";
+        }
+
+        // Generate TTS for the prompt
+        require_once dirname(__FILE__) . '/class-twp-tts-helper.php';
+        $tts_result = TWP_TTS_Helper::text_to_speech($prompt_message);
+
+        // Build TwiML response
+        $response = new \Twilio\TwiML\VoiceResponse();
+
+        if ($tts_result['success'] && !empty($tts_result['file_url'])) {
+            // Use generated TTS audio
+            $response->play($tts_result['file_url']);
+        } else {
+            // Fallback to Twilio's Say
+            $response->say($prompt_message, ['voice' => 'alice']);
+        }
+
+        // Record the voicemail
+        $record_params = [
+            'action' => home_url('/wp-json/twilio-webhook/v1/voicemail-complete'),
+            'recordingStatusCallback' => home_url('/wp-json/twilio-webhook/v1/voicemail-callback?' . http_build_query([
+                'from' => $caller_number,
+                'queue_id' => $queue_id,
+                'source' => 'queue_timeout'
+            ])),
+            'recordingStatusCallbackMethod' => 'POST',
+            'maxLength' => 300, // 5 minutes max
+            'playBeep' => true,
+            'finishOnKey' => '#',
+            'transcribe' => true,
+            'transcribeCallback' => home_url('/wp-json/twilio-webhook/v1/voicemail-transcription')
+        ];
+
+        $response->record($record_params);
+
+        // Thank you message after recording
+        $response->say('Thank you for your message. Goodbye.', ['voice' => 'alice']);
+
+        return $response;
+    }
+
+    /**
+     * Save voicemail to database
+     *
+     * @param array $voicemail_data Voicemail data
+     * @return int|false Voicemail ID or false on failure
+     */
+    public static function save_voicemail($voicemail_data) {
+        global $wpdb;
+        $table_name = $wpdb->prefix . 'twp_voicemails';
+
+        $insert_data = array(
+            'call_sid' => sanitize_text_field($voicemail_data['call_sid']),
+            'from_number' => sanitize_text_field($voicemail_data['from_number']),
+            'to_number' => !empty($voicemail_data['to_number']) ? sanitize_text_field($voicemail_data['to_number']) : '',
+            'recording_url' => esc_url_raw($voicemail_data['recording_url']),
+            'recording_duration' => intval($voicemail_data['recording_duration']),
+            'workflow_id' => !empty($voicemail_data['workflow_id']) ? intval($voicemail_data['workflow_id']) : null,
+            'queue_id' => !empty($voicemail_data['queue_id']) ? intval($voicemail_data['queue_id']) : null,
+            'source' => !empty($voicemail_data['source']) ? sanitize_text_field($voicemail_data['source']) : 'workflow',
+            'status' => 'new',
+            'received_at' => current_time('mysql')
+        );
+
+        $result = $wpdb->insert($table_name, $insert_data);
+
+        if ($result) {
+            $voicemail_id = $wpdb->insert_id;
+
+            // Log the voicemail
+            if (class_exists('TWP_Call_Logger')) {
+                TWP_Call_Logger::log_action(
+                    $voicemail_data['call_sid'],
+                    'Voicemail recorded from queue timeout (' . $voicemail_data['recording_duration'] . 's)'
+                );
+            }
+
+            return $voicemail_id;
+        }
+
+        return false;
+    }
+
+    /**
+     * Update voicemail transcription
+     *
+     * @param int $voicemail_id Voicemail ID
+     * @param string $transcription Transcription text
+     * @param string $transcription_status Transcription status
+     * @return bool Success
+     */
+    public static function update_transcription($voicemail_id, $transcription, $transcription_status = 'completed') {
+        global $wpdb;
+        $table_name = $wpdb->prefix . 'twp_voicemails';
+
+        $result = $wpdb->update(
+            $table_name,
+            array(
+                'transcription' => sanitize_textarea_field($transcription),
+                'transcription_status' => $transcription_status
+            ),
+            array('id' => $voicemail_id),
+            array('%s', '%s'),
+            array('%d')
+        );
+
+        // Check for urgent keywords in transcription
+        if ($result && !empty($transcription)) {
+            self::check_urgent_keywords($voicemail_id, $transcription);
+        }
+
+        return $result !== false;
+    }
+
+    /**
+     * Check transcription for urgent keywords
+     *
+     * @param int $voicemail_id Voicemail ID
+     * @param string $transcription Transcription text
+     */
+    private static function check_urgent_keywords($voicemail_id, $transcription) {
+        global $wpdb;
+
+        // Get urgent keywords from settings
+        $urgent_keywords = get_option('twp_urgent_voicemail_keywords', array('urgent', 'emergency', 'asap', 'critical'));
+        if (is_string($urgent_keywords)) {
+            $urgent_keywords = array_map('trim', explode(',', $urgent_keywords));
+        }
+
+        // Check if transcription contains any urgent keywords
+        $transcription_lower = strtolower($transcription);
+        $found_keyword = null;
+
+        foreach ($urgent_keywords as $keyword) {
+            if (stripos($transcription_lower, strtolower(trim($keyword))) !== false) {
+                $found_keyword = $keyword;
+                break;
+            }
+        }
+
+        if ($found_keyword) {
+            // Mark voicemail as urgent
+            $table_name = $wpdb->prefix . 'twp_voicemails';
+            $wpdb->update(
+                $table_name,
+                array('is_urgent' => 1),
+                array('id' => $voicemail_id),
+                array('%d'),
+                array('%d')
+            );
+
+            // Send urgent notification
+            $voicemail = $wpdb->get_row($wpdb->prepare(
+                "SELECT * FROM $table_name WHERE id = %d",
+                $voicemail_id
+            ));
+
+            if ($voicemail && class_exists('TWP_Notifications')) {
+                TWP_Notifications::send_call_notification('urgent_voicemail', array(
+                    'type' => 'urgent_voicemail',
+                    'from_number' => $voicemail->from_number,
+                    'keyword' => $found_keyword,
+                    'transcription' => $transcription,
+                    'voicemail_id' => $voicemail_id,
+                    'admin_url' => admin_url('admin.php?page=twilio-wp-voicemails&voicemail_id=' . $voicemail_id)
+                ));
+            }
+
+            error_log("TWP Voicemail: Urgent keyword '$found_keyword' detected in voicemail $voicemail_id");
+        }
+    }
+
+    /**
+     * Get voicemail by ID
+     *
+     * @param int $voicemail_id Voicemail ID
+     * @return object|null Voicemail object
+     */
+    public static function get_voicemail($voicemail_id) {
+        global $wpdb;
+        $table_name = $wpdb->prefix . 'twp_voicemails';
+
+        return $wpdb->get_row($wpdb->prepare(
+            "SELECT * FROM $table_name WHERE id = %d",
+            $voicemail_id
+        ));
+    }
+}

includes/interface-twp-sms-provider.php

@@ -0,0 +1,32 @@
+<?php
+/**
+ * SMS Provider Interface
+ *
+ * Interface for SMS providers (Twilio, Amazon SNS, etc.)
+ */
+interface TWP_SMS_Provider {
+
+    /**
+     * Send an SMS message
+     *
+     * @param string $to_number Recipient phone number (E.164 format)
+     * @param string $message Message body
+     * @param string $from_number Sender phone number (E.164 format)
+     * @return array Response array with 'success' and 'data' or 'error'
+     */
+    public function send_sms($to_number, $message, $from_number = null);
+
+    /**
+     * Get provider name
+     *
+     * @return string Provider name
+     */
+    public function get_provider_name();
+
+    /**
+     * Validate provider configuration
+     *
+     * @return array Response array with 'success' and 'message' or 'error'
+     */
+    public function validate_configuration();
+}