"""
Notification service for creating and managing user notifications.

This service handles the creation, delivery, and management of notifications
for various events including submission approvals/rejections.
"""

from django.utils import timezone
from django.contrib.contenttypes.models import ContentType
from django.template.loader import render_to_string
from django.conf import settings
from django.db import models
from typing import Optional, Dict, Any, List
from datetime import datetime, timedelta
import logging

from apps.accounts.models import User, UserNotification, NotificationPreference
from django_forwardemail.services import EmailService

logger = logging.getLogger(__name__)


class NotificationService:
    """Service for creating and managing user notifications."""

    @staticmethod
    def create_notification(
        user: User,
        notification_type: str,
        title: str,
        message: str,
        related_object: Optional[Any] = None,
        priority: str = UserNotification.Priority.NORMAL,
        extra_data: Optional[Dict[str, Any]] = None,
        expires_at: Optional[datetime] = None,
    ) -> UserNotification:
        """
        Create a new notification for a user.

        Args:
            user: The user to notify
            notification_type: Type of notification (from UserNotification.NotificationType)
            title: Notification title
            message: Notification message
            related_object: Optional related object (submission, review, etc.)
            priority: Notification priority
            extra_data: Additional data to store with notification
            expires_at: When the notification expires

        Returns:
            UserNotification: The created notification
        """
        # Get content type and object ID if related object provided
        content_type = None
        object_id = None
        if related_object:
            content_type = ContentType.objects.get_for_model(related_object)
            object_id = related_object.pk

        # Create the notification
        notification = UserNotification.objects.create(
            user=user,
            notification_type=notification_type,
            title=title,
            message=message,
            content_type=content_type,
            object_id=object_id,
            priority=priority,
            extra_data=extra_data or {},
            expires_at=expires_at,
        )

        # Send notification through appropriate channels
        NotificationService._send_notification(notification)

        return notification

    @staticmethod
    def create_submission_approved_notification(
        user: User,
        submission_object: Any,
        submission_type: str,
        additional_message: str = "",
    ) -> UserNotification:
        """
        Create a notification for submission approval.

        Args:
            user: User who submitted the content
            submission_object: The approved submission object
            submission_type: Type of submission (e.g., "park photo", "ride review")
            additional_message: Additional message from moderator

        Returns:
            UserNotification: The created notification
        """
        title = f"Your {submission_type} has been approved!"
        message = f"Great news! Your {submission_type} submission has been approved and is now live on ThrillWiki."

        if additional_message:
            message += f"\n\nModerator note: {additional_message}"

        extra_data = {
            "submission_type": submission_type,
            "moderator_message": additional_message,
            "approved_at": timezone.now().isoformat(),
        }

        return NotificationService.create_notification(
            user=user,
            notification_type=UserNotification.NotificationType.SUBMISSION_APPROVED,
            title=title,
            message=message,
            related_object=submission_object,
            priority=UserNotification.Priority.NORMAL,
            extra_data=extra_data,
        )

    @staticmethod
    def create_submission_rejected_notification(
        user: User,
        submission_object: Any,
        submission_type: str,
        rejection_reason: str,
        additional_message: str = "",
    ) -> UserNotification:
        """
        Create a notification for submission rejection.

        Args:
            user: User who submitted the content
            submission_object: The rejected submission object
            submission_type: Type of submission (e.g., "park photo", "ride review")
            rejection_reason: Reason for rejection
            additional_message: Additional message from moderator

        Returns:
            UserNotification: The created notification
        """
        title = f"Your {submission_type} needs attention"
        message = f"Your {submission_type} submission has been reviewed and needs some changes before it can be approved."
        message += f"\n\nReason: {rejection_reason}"

        if additional_message:
            message += f"\n\nModerator note: {additional_message}"

        message += "\n\nYou can edit and resubmit your content from your profile page."

        extra_data = {
            "submission_type": submission_type,
            "rejection_reason": rejection_reason,
            "moderator_message": additional_message,
            "rejected_at": timezone.now().isoformat(),
        }

        return NotificationService.create_notification(
            user=user,
            notification_type=UserNotification.NotificationType.SUBMISSION_REJECTED,
            title=title,
            message=message,
            related_object=submission_object,
            priority=UserNotification.Priority.HIGH,
            extra_data=extra_data,
        )

    @staticmethod
    def create_submission_pending_notification(
        user: User, submission_object: Any, submission_type: str
    ) -> UserNotification:
        """
        Create a notification for submission pending review.

        Args:
            user: User who submitted the content
            submission_object: The pending submission object
            submission_type: Type of submission (e.g., "park photo", "ride review")

        Returns:
            UserNotification: The created notification
        """
        title = f"Your {submission_type} is under review"
        message = f"Thanks for your {submission_type} submission! It's now under review by our moderation team."
        message += "\n\nWe'll notify you once it's been reviewed. This usually takes 1-2 business days."

        extra_data = {
            "submission_type": submission_type,
            "submitted_at": timezone.now().isoformat(),
        }

        return NotificationService.create_notification(
            user=user,
            notification_type=UserNotification.NotificationType.SUBMISSION_PENDING,
            title=title,
            message=message,
            related_object=submission_object,
            priority=UserNotification.Priority.LOW,
            extra_data=extra_data,
        )

    @staticmethod
    def _send_notification(notification: UserNotification) -> None:
        """
        Send notification through appropriate channels based on user preferences.

        Args:
            notification: The notification to send
        """
        user = notification.user

        # Get user's notification preferences
        try:
            preferences = user.notification_preference
        except NotificationPreference.DoesNotExist:
            # Create default preferences if they don't exist
            preferences = NotificationPreference.objects.create(user=user)

        # Send email notification if enabled
        if preferences.should_send_notification(
            notification.notification_type, "email"
        ):
            NotificationService._send_email_notification(notification)

        # Toast notifications are always created (the notification object itself)
        # The frontend will display them as toast notifications based on preferences

    @staticmethod
    def _send_email_notification(notification: UserNotification) -> None:
        """
        Send email notification to user using the custom ForwardEmail service.

        Args:
            notification: The notification to send via email
        """
        try:
            user = notification.user

            # Prepare email context
            context = {
                "user": user,
                "notification": notification,
                "site_name": "ThrillWiki",
                "site_url": getattr(settings, "SITE_URL", "https://thrillwiki.com"),
            }

            # Render email templates
            subject = f"ThrillWiki: {notification.title}"
            html_message = render_to_string("emails/notification.html", context)
            plain_message = render_to_string("emails/notification.txt", context)

            # Send email using custom ForwardEmail service
            EmailService.send_email(
                to=user.email,
                subject=subject,
                text=plain_message,
                html=html_message,
            )

            # Mark as sent
            notification.email_sent = True
            notification.email_sent_at = timezone.now()
            notification.save(update_fields=["email_sent", "email_sent_at"])

            logger.info(
                f"Email notification sent to {user.email} for notification {notification.id}"
            )

        except Exception as e:
            logger.error(
                f"Failed to send email notification {notification.id}: {str(e)}"
            )

    @staticmethod
    def get_user_notifications(
        user: User,
        unread_only: bool = False,
        notification_types: Optional[List[str]] = None,
        limit: Optional[int] = None,
    ) -> List[UserNotification]:
        """
        Get notifications for a user.

        Args:
            user: User to get notifications for
            unread_only: Only return unread notifications
            notification_types: Filter by notification types
            limit: Limit number of results

        Returns:
            List[UserNotification]: List of notifications
        """
        queryset = UserNotification.objects.filter(user=user)

        if unread_only:
            queryset = queryset.filter(is_read=False)

        if notification_types:
            queryset = queryset.filter(notification_type__in=notification_types)

        # Exclude expired notifications
        queryset = queryset.filter(
            models.Q(expires_at__isnull=True) | models.Q(expires_at__gt=timezone.now())
        )

        if limit:
            queryset = queryset[:limit]

        return list(queryset)

    @staticmethod
    def mark_notifications_read(
        user: User, notification_ids: Optional[List[int]] = None
    ) -> int:
        """
        Mark notifications as read for a user.

        Args:
            user: User whose notifications to mark as read
            notification_ids: Specific notification IDs to mark as read (if None, marks all)

        Returns:
            int: Number of notifications marked as read
        """
        queryset = UserNotification.objects.filter(user=user, is_read=False)

        if notification_ids:
            queryset = queryset.filter(id__in=notification_ids)

        return queryset.update(is_read=True, read_at=timezone.now())

    @staticmethod
    def cleanup_old_notifications(days: int = 90) -> int:
        """
        Clean up old read notifications.

        Args:
            days: Number of days to keep read notifications

        Returns:
            int: Number of notifications deleted
        """
        cutoff_date = timezone.now() - timedelta(days=days)

        old_notifications = UserNotification.objects.filter(
            is_read=True, read_at__lt=cutoff_date
        )

        count = old_notifications.count()
        old_notifications.delete()

        logger.info(f"Cleaned up {count} old notifications")
        return count