<?php
/**
 * Twilio API integration class using official Twilio PHP SDK
 */
class TWP_Twilio_API {
    
    private $client;
    private $phone_number;
    
    /**
     * Constructor
     */
    public function __construct() {
        $this->init_sdk_client();
        // Try to get the SMS notification number first, or get the first available Twilio number
        $this->phone_number = get_option('twp_sms_notification_number');
        
        // If no SMS number configured, try to get the first phone number from the account
        if (empty($this->phone_number)) {
            $this->phone_number = $this->get_default_phone_number();
        }
    }
    
    /**
     * Get the default phone number from the account
     */
    private function get_default_phone_number() {
        try {
            // Get the first phone number from the account
            $numbers = $this->client->incomingPhoneNumbers->read([], 1);
            if (!empty($numbers)) {
                return $numbers[0]->phoneNumber;
            }
        } catch (\Exception $e) {
            error_log('TWP: Unable to get default phone number: ' . $e->getMessage());
        }
        return null;
    }
    
    /**
     * Initialize Twilio SDK client
     */
    private function init_sdk_client() {
        // Check if autoloader exists
        $autoloader_path = TWP_PLUGIN_DIR . 'vendor/autoload.php';
        if (!file_exists($autoloader_path)) {
            error_log('TWP Plugin: Autoloader not found at: ' . $autoloader_path);
            throw new Exception('Twilio SDK not found. Please run: ./install-twilio-sdk.sh');
        }
        
        // Load the autoloader
        require_once $autoloader_path;
        
        // Give more detailed error information
        if (!class_exists('Twilio\Rest\Client')) {
            $sdk_path = TWP_PLUGIN_DIR . 'vendor/twilio/sdk';
            $client_file = $sdk_path . '/Rest/Client.php';
            
            error_log('TWP Plugin: Twilio SDK classes not found.');
            error_log('TWP Plugin: Looking for SDK at: ' . $sdk_path);
            error_log('TWP Plugin: Client.php exists: ' . (file_exists($client_file) ? 'YES' : 'NO'));
            error_log('TWP Plugin: SDK directory contents: ' . print_r(scandir($sdk_path), true));
            
            throw new Exception('Twilio SDK classes not available. Please reinstall with: ./install-twilio-sdk.sh');
        }
        
        $account_sid = get_option('twp_twilio_account_sid');
        $auth_token = get_option('twp_twilio_auth_token');
        
        if (empty($account_sid) || empty($auth_token)) {
            throw new Exception('Twilio credentials not configured. Please check your WordPress admin settings.');
        }
        
        try {
            $this->client = new \Twilio\Rest\Client($account_sid, $auth_token);
            error_log('TWP Plugin: Twilio SDK initialized successfully');
        } catch (Exception $e) {
            error_log('TWP Plugin: Failed to initialize Twilio client: ' . $e->getMessage());
            throw new Exception('Failed to initialize Twilio SDK: ' . $e->getMessage());
        }
    }
    
    /**
     * Make a phone call
     */
    public function make_call($to_number, $twiml_url, $status_callback = null, $from_number = null) {
        try {
            $params = [
                'url' => $twiml_url,
                'from' => $from_number ?: $this->phone_number,
                'to' => $to_number
            ];
            
            if ($status_callback) {
                $params['statusCallback'] = $status_callback;
                $params['statusCallbackEvent'] = ['initiated', 'ringing', 'answered', 'completed'];
                $params['statusCallbackMethod'] = 'POST';
                $params['timeout'] = 20; // Ring for 20 seconds before giving up
                $params['machineDetection'] = 'Enable'; // Detect if voicemail answers
                $params['machineDetectionTimeout'] = 30; // Wait 30 seconds to detect machine
            }
            
            $call = $this->client->calls->create(
                $to_number,
                $from_number ?: $this->phone_number,
                $params
            );
            
            return [
                'success' => true,
                'data' => [
                    'sid' => $call->sid,
                    'status' => $call->status,
                    'from' => $call->from,
                    'to' => $call->to,
                    'direction' => $call->direction,
                    'price' => $call->price,
                    'priceUnit' => $call->priceUnit
                ]
            ];
        } catch (\Twilio\Exceptions\TwilioException $e) {
            return [
                'success' => false,
                'error' => $e->getMessage(),
                'code' => $e->getCode()
            ];
        }
    }
    
    /**
     * Forward a call
     */
    public function forward_call($call_sid, $to_number) {
        try {
            $twiml = new \Twilio\TwiML\VoiceResponse();
            $twiml->dial($to_number);
            
            $call = $this->client->calls($call_sid)->update([
                'twiml' => $twiml->asXML()
            ]);
            
            return [
                'success' => true,
                'data' => [
                    'sid' => $call->sid,
                    'status' => $call->status
                ]
            ];
        } catch (\Twilio\Exceptions\TwilioException $e) {
            return [
                'success' => false,
                'error' => $e->getMessage(),
                'code' => $e->getCode()
            ];
        }
    }
    
    /**
     * Update an active call
     */
    public function update_call($call_sid, $params) {
        try {
            $call = $this->client->calls($call_sid)->update($params);
            
            return [
                'success' => true,
                'data' => [
                    'sid' => $call->sid,
                    'status' => $call->status,
                    'from' => $call->from,
                    'to' => $call->to
                ]
            ];
        } catch (\Twilio\Exceptions\TwilioException $e) {
            return [
                'success' => false,
                'error' => $e->getMessage(),
                'code' => $e->getCode()
            ];
        }
    }
    
    /**
     * Get call details
     */
    public function get_call($call_sid) {
        try {
            $call = $this->client->calls($call_sid)->fetch();
            
            return [
                'success' => true,
                'data' => [
                    'sid' => $call->sid,
                    'status' => $call->status,
                    'from' => $call->from,
                    'to' => $call->to,
                    'direction' => $call->direction,
                    'duration' => $call->duration,
                    'price' => $call->price,
                    'priceUnit' => $call->priceUnit
                ]
            ];
        } catch (\Twilio\Exceptions\TwilioException $e) {
            return [
                'success' => false,
                'error' => $e->getMessage(),
                'code' => $e->getCode()
            ];
        }
    }
    
    /**
     * Create TwiML for queue
     */
    public function create_queue_twiml($queue_name, $wait_url = null, $wait_message = null) {
        try {
            $response = new \Twilio\TwiML\VoiceResponse();
            
            if ($wait_message) {
                $response->say($wait_message, ['voice' => 'alice']);
            }
            
            $enqueue = $response->enqueue($queue_name);
            
            if ($wait_url) {
                $enqueue->waitUrl($wait_url);
            }
            
            return $response->asXML();
        } catch (Exception $e) {
            error_log('TWP Plugin: Failed to create queue TwiML: ' . $e->getMessage());
            throw $e;
        }
    }
    
    /**
     * Create TwiML for IVR menu
     */
    public function create_ivr_twiml($message, $options = array()) {
        try {
            $response = new \Twilio\TwiML\VoiceResponse();
            
            $gather = $response->gather([
                'numDigits' => 1,
                'timeout' => 10,
                'action' => isset($options['action_url']) ? $options['action_url'] : null
            ]);
            
            $gather->say($message, ['voice' => 'alice']);
            
            if (!empty($options['no_input_message'])) {
                $response->say($options['no_input_message'], ['voice' => 'alice']);
            }
            
            return $response->asXML();
        } catch (Exception $e) {
            error_log('TWP Plugin: Failed to create IVR TwiML: ' . $e->getMessage());
            throw $e;
        }
    }
    
    /**
     * Send SMS
     */
    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()
            ];
        }
    }
    
    /**
     * Get available phone numbers
     */
    public function get_phone_numbers() {
        try {
            $numbers = $this->client->incomingPhoneNumbers->read([], 50);
            
            $numbers_data = [];
            foreach ($numbers as $number) {
                $numbers_data[] = [
                    'sid' => $number->sid ?: '',
                    'phone_number' => $number->phoneNumber ?: '',
                    'friendly_name' => $number->friendlyName ?: $number->phoneNumber ?: 'Unknown',
                    'voice_url' => $number->voiceUrl ?: '',
                    'sms_url' => $number->smsUrl ?: '',
                    'status_callback_url' => $number->statusCallback ?: '',
                    'capabilities' => [
                        'voice' => $number->capabilities ? (bool)$number->capabilities->getVoice() : false,
                        'sms' => $number->capabilities ? (bool)$number->capabilities->getSms() : false,
                        'mms' => $number->capabilities ? (bool)$number->capabilities->getMms() : false
                    ]
                ];
            }
            
            return [
                'success' => true,
                'data' => [
                    'incoming_phone_numbers' => $numbers_data
                ]
            ];
        } catch (\Twilio\Exceptions\TwilioException $e) {
            return [
                'success' => false,
                'error' => $e->getMessage(),
                'code' => $e->getCode()
            ];
        }
    }
    
    /**
     * Search for available phone numbers
     */
    public function search_available_numbers($country_code = 'US', $area_code = null, $contains = null, $limit = 20) {
        try {
            $params = ['limit' => $limit];
            
            if ($area_code) {
                $params['areaCode'] = $area_code;
            }
            
            if ($contains) {
                $params['contains'] = $contains;
            }
            
            $numbers = $this->client->availablePhoneNumbers($country_code)
                ->local
                ->read($params, $limit);
            
            $numbers_data = [];
            foreach ($numbers as $number) {
                $numbers_data[] = [
                    'phone_number' => $number->phoneNumber ?: '',
                    'friendly_name' => $number->friendlyName ?: $number->phoneNumber ?: 'Available Number',
                    'locality' => $number->locality ?: '',
                    'region' => $number->region ?: '',
                    'postal_code' => $number->postalCode ?: '',
                    'capabilities' => [
                        'voice' => $number->capabilities ? (bool)$number->capabilities->getVoice() : false,
                        'sms' => $number->capabilities ? (bool)$number->capabilities->getSms() : false,
                        'mms' => $number->capabilities ? (bool)$number->capabilities->getMms() : false
                    ]
                ];
            }
            
            return [
                'success' => true,
                'data' => [
                    'available_phone_numbers' => $numbers_data
                ]
            ];
        } catch (\Twilio\Exceptions\TwilioException $e) {
            return [
                'success' => false,
                'error' => $e->getMessage(),
                'code' => $e->getCode()
            ];
        }
    }
    
    /**
     * Purchase a phone number
     */
    public function purchase_phone_number($phone_number, $voice_url = null, $sms_url = null) {
        try {
            $params = ['phoneNumber' => $phone_number];
            
            if ($voice_url) {
                $params['voiceUrl'] = $voice_url;
                $params['voiceMethod'] = 'POST';
            }
            
            if ($sms_url) {
                $params['smsUrl'] = $sms_url;
                $params['smsMethod'] = 'POST';
            }
            
            // Add status callback for real-time call state tracking
            $status_callback_url = home_url('/wp-json/twilio-webhook/v1/status');
            $params['statusCallback'] = $status_callback_url;
            $params['statusCallbackMethod'] = 'POST';
            
            $number = $this->client->incomingPhoneNumbers->create($params);
            
            return [
                'success' => true,
                'data' => [
                    'sid' => $number->sid,
                    'phone_number' => $number->phoneNumber,
                    'friendly_name' => $number->friendlyName,
                    'voice_url' => $number->voiceUrl,
                    'sms_url' => $number->smsUrl
                ]
            ];
        } catch (\Twilio\Exceptions\TwilioException $e) {
            return [
                'success' => false,
                'error' => $e->getMessage(),
                'code' => $e->getCode()
            ];
        }
    }
    
    /**
     * Release a phone number
     */
    public function release_phone_number($phone_number_sid) {
        try {
            $this->client->incomingPhoneNumbers($phone_number_sid)->delete();
            
            return [
                'success' => true,
                'data' => [
                    'message' => 'Phone number released successfully'
                ]
            ];
        } catch (\Twilio\Exceptions\TwilioException $e) {
            return [
                'success' => false,
                'error' => $e->getMessage(),
                'code' => $e->getCode()
            ];
        }
    }
    
    /**
     * Configure phone number webhook
     */
    public function configure_phone_number($phone_sid, $voice_url, $sms_url = null) {
        try {
            $params = [
                'voiceUrl' => $voice_url,
                'voiceMethod' => 'POST'
            ];
            
            if ($sms_url) {
                $params['smsUrl'] = $sms_url;
                $params['smsMethod'] = 'POST';
            }
            
            // Add status callback for real-time call state tracking
            $status_callback_url = home_url('/wp-json/twilio-webhook/v1/status');
            $params['statusCallback'] = $status_callback_url;
            $params['statusCallbackMethod'] = 'POST';
            
            $number = $this->client->incomingPhoneNumbers($phone_sid)->update($params);
            
            return [
                'success' => true,
                'data' => [
                    'sid' => $number->sid,
                    'phone_number' => $number->phoneNumber,
                    'voice_url' => $number->voiceUrl,
                    'sms_url' => $number->smsUrl
                ]
            ];
        } catch (\Twilio\Exceptions\TwilioException $e) {
            return [
                'success' => false,
                'error' => $e->getMessage(),
                'code' => $e->getCode()
            ];
        }
    }
    
    /**
     * Create TwiML helper - returns SDK VoiceResponse
     */
    public function create_twiml() {
        return new \Twilio\TwiML\VoiceResponse();
    }
    
    /**
     * Get the Twilio client instance
     */
    public function get_client() {
        return $this->client;
    }
    
    /**
     * Get SMS from number with proper priority
     */
    public static function get_sms_from_number($workflow_id = null) {
        // Priority 1: If we have a workflow_id, get the workflow's phone number
        if ($workflow_id) {
            $workflow = TWP_Workflow::get_workflow($workflow_id);
            if ($workflow && !empty($workflow->phone_number)) {
                return $workflow->phone_number;
            }
        }
        
        // Priority 2: Use default SMS number setting
        $default_sms_number = get_option('twp_default_sms_number');
        if (!empty($default_sms_number)) {
            return $default_sms_number;
        }
        
        // Priority 3: Fall back to first available Twilio number
        $twilio = new self();
        $phone_numbers = $twilio->get_phone_numbers();
        if ($phone_numbers['success'] && !empty($phone_numbers['data']['incoming_phone_numbers'])) {
            return $phone_numbers['data']['incoming_phone_numbers'][0]['phone_number'];
        }
        
        return null;
    }
    
    /**
     * Validate webhook signature
     */
    public function validate_webhook_signature($url, $params, $signature) {
        $validator = new \Twilio\Security\RequestValidator(get_option('twp_twilio_auth_token'));
        return $validator->validate($signature, $url, $params);
    }
    
    /**
     * Get call information from Twilio
     */
    public function get_call_info($call_sid) {
        try {
            $call = $this->client->calls($call_sid)->fetch();
            
            return [
                'sid' => $call->sid,
                'status' => $call->status,
                'from' => $call->from,
                'to' => $call->to,
                'duration' => $call->duration,
                'start_time' => $call->startTime ? $call->startTime->format('Y-m-d H:i:s') : null,
                'end_time' => $call->endTime ? $call->endTime->format('Y-m-d H:i:s') : null,
                'direction' => $call->direction,
                'price' => $call->price,
                'priceUnit' => $call->priceUnit
            ];
        } catch (\Twilio\Exceptions\TwilioException $e) {
            error_log('TWP: Error fetching call info for ' . $call_sid . ': ' . $e->getMessage());
            return null;
        }
    }
    
    /**
     * Toggle status callback for a specific phone number
     */
    public function toggle_number_status_callback($phone_sid, $enable = true) {
        try {
            $params = [];
            
            if ($enable) {
                $params['statusCallback'] = home_url('/wp-json/twilio-webhook/v1/status');
                $params['statusCallbackMethod'] = 'POST';
            } else {
                // Clear the status callback
                $params['statusCallback'] = '';
            }
            
            $number = $this->client->incomingPhoneNumbers($phone_sid)->update($params);
            
            return [
                'success' => true,
                'data' => [
                    'sid' => $number->sid,
                    'phone_number' => $number->phoneNumber,
                    'status_callback' => $number->statusCallback,
                    'enabled' => !empty($number->statusCallback)
                ]
            ];
        } catch (\Twilio\Exceptions\TwilioException $e) {
            return [
                'success' => false,
                'error' => $e->getMessage()
            ];
        }
    }
    
    /**
     * Update all existing phone numbers to include status callbacks
     */
    public function enable_status_callbacks_for_all_numbers() {
        try {
            $numbers = $this->get_phone_numbers();
            if (!$numbers['success']) {
                return [
                    'success' => false,
                    'error' => 'Failed to retrieve phone numbers: ' . $numbers['error']
                ];
            }
            
            $status_callback_url = home_url('/wp-json/twilio-webhook/v1/status');
            $updated_count = 0;
            $errors = [];
            
            foreach ($numbers['data']['incoming_phone_numbers'] as $number) {
                try {
                    $this->client->incomingPhoneNumbers($number['sid'])->update([
                        'statusCallback' => $status_callback_url,
                        'statusCallbackMethod' => 'POST'
                    ]);
                    $updated_count++;
                    error_log('TWP: Added status callback to phone number: ' . $number['phone_number']);
                } catch (\Twilio\Exceptions\TwilioException $e) {
                    $errors[] = 'Failed to update ' . $number['phone_number'] . ': ' . $e->getMessage();
                    error_log('TWP: Error updating phone number ' . $number['phone_number'] . ': ' . $e->getMessage());
                }
            }
            
            return [
                'success' => true,
                'data' => [
                    'updated_count' => $updated_count,
                    'total_numbers' => count($numbers['data']['incoming_phone_numbers']),
                    'errors' => $errors
                ]
            ];
        } catch (\Twilio\Exceptions\TwilioException $e) {
            return [
                'success' => false,
                'error' => $e->getMessage()
            ];
        }
    }
    
    /**
     * Generate capability token for Browser Phone
     */
    public function generate_capability_token($client_name = null) {
        $account_sid = get_option('twp_twilio_account_sid');
        $auth_token = get_option('twp_twilio_auth_token');
        $twiml_app_sid = get_option('twp_twiml_app_sid');
        
        if (empty($account_sid) || empty($auth_token)) {
            return [
                'success' => false,
                'error' => 'Twilio credentials not configured'
            ];
        }
        
        if (empty($twiml_app_sid)) {
            return [
                'success' => false,
                'error' => 'TwiML App SID not configured. Please set up a TwiML App in your Twilio Console.'
            ];
        }
        
        try {
            // Create client name if not provided
            if (!$client_name) {
                $current_user = wp_get_current_user();
                // Twilio requires alphanumeric characters only - remove all non-alphanumeric
                $clean_name = preg_replace('/[^a-zA-Z0-9]/', '', $current_user->display_name);
                if (empty($clean_name)) {
                    $clean_name = 'user';
                }
                $client_name = 'agent' . $current_user->ID . $clean_name;
            }
            
            $capability = new \Twilio\Jwt\ClientToken($account_sid, $auth_token);
            $capability->allowClientOutgoing($twiml_app_sid);
            $capability->allowClientIncoming($client_name);
            
            $token = $capability->generateToken(3600); // Valid for 1 hour
            
            return [
                'success' => true,
                'data' => [
                    'token' => $token,
                    'client_name' => $client_name,
                    'expires_in' => 3600
                ]
            ];
        } catch (\Exception $e) {
            return [
                'success' => false,
                'error' => 'Failed to generate capability token: ' . $e->getMessage()
            ];
        }
    }
}