"""
Survey Delivery Service - Sends surveys to patients via SMS/Email

This service handles:
- Generating secure survey URLs
- Sending SMS with survey links
- Sending emails with survey links
- Tracking delivery status

Uses NotificationService for all delivery operations.
"""
from django.conf import settings
from django.utils import timezone
import logging

logger = logging.getLogger(__name__)


class SurveyDeliveryService:
    """Service for delivering surveys to patients"""
    
    @staticmethod
    def generate_survey_url(survey_instance) -> str:
        """
        Generate secure survey URL with access token.
        
        Args:
            survey_instance: SurveyInstance object
        
        Returns:
            Full survey URL
        """
        base_url = getattr(settings, 'SURVEY_BASE_URL', 'http://localhost:8000')
        survey_path = survey_instance.get_survey_url()
        return f"{base_url}{survey_path}"
    
    @staticmethod
    def generate_sms_message(recipient_name: str, survey_url: str, hospital_name: str = None, is_staff: bool = False) -> str:
        """
        Generate SMS message with survey link.
        
        Args:
            recipient_name: Recipient's first name (patient or staff)
            survey_url: Survey link
            hospital_name: Optional hospital name
            is_staff: Whether recipient is staff member
        
        Returns:
            SMS message text
        """
        message = f"Dear {recipient_name},\n\n"
        
        if hospital_name:
            message += f"Thank you for being part of {hospital_name}. "
        
        if is_staff:
            message += "We value your feedback! Please take a moment to complete our staff experience survey:\n\n"
        else:
            message += "We value your feedback! Please take a moment to complete our patient experience survey:\n\n"
        
        message += f"{survey_url}\n\n"
        message += "This survey will take approximately 2-3 minutes.\n"
        message += "Thank you for helping us improve our services!"
        
        return message
    
    @staticmethod
    def generate_email_message(recipient_name: str, survey_url: str, hospital_name: str = None, is_staff: bool = False) -> str:
        """
        Generate email message with survey link.
        
        Args:
            recipient_name: Recipient's first name (patient or staff)
            survey_url: Survey link
            hospital_name: Optional hospital name
            is_staff: Whether recipient is staff member
        
        Returns:
            Email message text
        """
        message = f"Dear {recipient_name},\n\n"
        
        if hospital_name:
            message += f"Thank you for being part of {hospital_name}.\n\n"
        else:
            message += "Thank you for being part of our hospital.\n\n"
        
        if is_staff:
            message += "We value your feedback and would appreciate it if you could take a moment to complete our staff experience survey.\n\n"
            message += "Your feedback helps us improve our services and create a better work environment.\n\n"
        else:
            message += "We value your feedback and would appreciate it if you could take a moment to complete our patient experience survey.\n\n"
            message += "Your feedback helps us improve our services and provide better care for all our patients.\n\n"
        
        message += f"Survey Link: {survey_url}\n\n"
        message += "This survey will take approximately 2-3 minutes to complete.\n\n"
        message += "If you have any questions or concerns, please don't hesitate to contact us.\n\n"
        message += "Thank you for helping us improve our services!\n\n"
        
        if is_staff:
            message += "Best regards,\n"
            message += "Hospital Administration Team"
        else:
            message += "Best regards,\n"
            message += "Patient Experience Team"
        
        return message
    
    @staticmethod
    def send_survey_sms(survey_instance) -> bool:
        """
        Send survey via SMS using NotificationService API.
        
        Args:
            survey_instance: SurveyInstance object
        
        Returns:
            True if sent successfully, False otherwise
        """
        if not survey_instance.recipient_phone:
            logger.warning(f"No phone number for survey {survey_instance.id}")
            return False
        
        try:
            # Generate survey URL and message
            survey_url = SurveyDeliveryService.generate_survey_url(survey_instance)
            recipient_name = survey_instance.get_recipient_name().split()[0]  # First name only
            is_staff = survey_instance.staff is not None
            hospital_name = survey_instance.hospital.name
            message = SurveyDeliveryService.generate_sms_message(
                recipient_name, survey_url, hospital_name, is_staff
            )
            
            # Use NotificationService for delivery (supports API backend)
            from apps.notifications.services import NotificationService
            
            # Build metadata
            metadata = {
                'survey_id': str(survey_instance.id),
                'hospital_id': str(survey_instance.hospital.id),
                'is_staff_survey': is_staff
            }
            
            if survey_instance.patient:
                metadata['patient_id'] = str(survey_instance.patient.id)
            if survey_instance.staff:
                metadata['staff_id'] = str(survey_instance.staff.id)
            
            notification_log = NotificationService.send_sms_via_api(
                message=message,
                phone=survey_instance.recipient_phone,
                related_object=survey_instance,
                metadata=metadata
            )
            
            # Update survey instance based on notification status
            if notification_log and notification_log.status == 'sent':
                from apps.surveys.models import SurveyStatus
                survey_instance.status = SurveyStatus.SENT
                survey_instance.sent_at = notification_log.sent_at
                survey_instance.save(update_fields=['status', 'sent_at'])
                logger.info(f"Survey SMS sent successfully to {survey_instance.recipient_phone}")
                return True
            else:
                logger.warning(f"Survey SMS delivery failed for {survey_instance.id}")
                return False
            
        except Exception as e:
            logger.error(f"Error sending SMS for survey {survey_instance.id}: {str(e)}")
            return False
    
    @staticmethod
    def send_survey_email(survey_instance) -> bool:
        """
        Send survey via Email using NotificationService API.
        
        Args:
            survey_instance: SurveyInstance object
        
        Returns:
            True if sent successfully, False otherwise
        """
        if not survey_instance.recipient_email:
            logger.warning(f"No email address for survey {survey_instance.id}")
            return False
        
        try:
            # Generate survey URL and message
            survey_url = SurveyDeliveryService.generate_survey_url(survey_instance)
            recipient_name = survey_instance.get_recipient_name().split()[0]  # First name only
            is_staff = survey_instance.staff is not None
            hospital_name = survey_instance.hospital.name
            message = SurveyDeliveryService.generate_email_message(
                recipient_name, survey_url, hospital_name, is_staff
            )
            
            # Use NotificationService for delivery (supports API backend)
            from apps.notifications.services import NotificationService
            
            # Build metadata
            metadata = {
                'survey_id': str(survey_instance.id),
                'hospital_id': str(survey_instance.hospital.id),
                'is_staff_survey': is_staff
            }
            
            if survey_instance.patient:
                metadata['patient_id'] = str(survey_instance.patient.id)
            if survey_instance.staff:
                metadata['staff_id'] = str(survey_instance.staff.id)
            
            # Set email subject
            if is_staff:
                subject = f'Staff Experience Survey - {survey_instance.hospital.name}'
            else:
                subject = f'Patient Experience Survey - {survey_instance.hospital.name}'
            
            notification_log = NotificationService.send_email_via_api(
                message=message,
                email=survey_instance.recipient_email,
                subject=subject,
                html_message=None,  # Plain text for now
                related_object=survey_instance,
                metadata=metadata
            )
            
            # Update survey instance based on notification status
            if notification_log and notification_log.status == 'sent':
                from apps.surveys.models import SurveyStatus
                survey_instance.status = SurveyStatus.SENT
                survey_instance.sent_at = notification_log.sent_at
                survey_instance.save(update_fields=['status', 'sent_at'])
                logger.info(f"Survey email sent successfully to {survey_instance.recipient_email}")
                return True
            else:
                logger.warning(f"Survey email delivery failed for {survey_instance.id}")
                return False
            
        except Exception as e:
            logger.error(f"Error sending email for survey {survey_instance.id}: {str(e)}")
            return False
    
    @staticmethod
    def deliver_survey(survey_instance) -> bool:
        """
        Deliver survey based on configured delivery channel.
        
        Args:
            survey_instance: SurveyInstance object
        
        Returns:
            True if delivered successfully, False otherwise
        """
        # Normalize delivery channel to lowercase for comparison
        delivery_channel = (survey_instance.delivery_channel or '').lower()
        
        # Get recipient (patient or staff)
        recipient = survey_instance.get_recipient()
        
        # Ensure contact info is set
        if delivery_channel == 'sms':
            if recipient:
                survey_instance.recipient_phone = survey_instance.recipient_phone or recipient.phone
        elif delivery_channel == 'email':
            if recipient:
                survey_instance.recipient_email = survey_instance.recipient_email or getattr(recipient, 'email', None)
        
        # Save contact info
        survey_instance.save()
        
        # Send based on channel
        if delivery_channel == 'sms':
            return SurveyDeliveryService.send_survey_sms(survey_instance)
        elif delivery_channel == 'email':
            return SurveyDeliveryService.send_survey_email(survey_instance)
        elif delivery_channel == 'whatsapp':
            # TODO: Implement WhatsApp delivery
            logger.warning(f"WhatsApp delivery not yet implemented for survey {survey_instance.id}")
            return False
        else:
            logger.error(f"Unknown delivery channel: {survey_instance.delivery_channel}")
            return False