from enum import Enum
from typing import Optional

import structlog
from notifications.signals import notify
from sendgrid import Mail, SendGridAPIClient
from storages.utils import setting

from vbv_lernwelt.core.models import User
from vbv_lernwelt.notify.models import Notification, NotificationType

logger = structlog.get_logger(__name__)


class EmailTemplate(Enum):
    """Enum for the different Sendgrid email templates."""

    # VBV - Erinnerung Präsenzkurse
    ATTENDANCE_COURSE_REMINDER = {
        "de": "d-9af079f98f524d85ac6e4166de3480da",
        "it": "d-ab78ddca8a7a46b8afe50aaba3efee81",
        "fr": "d-f88d9912e5484e55a879571463e4a166",
    }

    # VBV - Geleitete Fallarbeit abgegeben
    CASEWORK_SUBMITTED = {"de": "d-599f0b35ddcd4fac99314cdf8f5446a2"}

    # VBV - Geleitete Fallarbeit bewertet
    CASEWORK_EVALUATED = {"de": "d-8c57fa13116b47be8eec95dfaf2aa030"}

    # VBV - Neues Feedback für Circle
    NEW_FEEDBACK = {"de": "d-40fb94d5149949e7b8e7ddfcf0fcfdde"}


class EmailService:
    """Email service class implemented using the Sendgrid API"""

    _sendgrid_client = SendGridAPIClient(setting("SENDGRID_API_KEY"))

    @classmethod
    def send_email(
        cls,
        recipient: User,
        template: EmailTemplate,
        template_data: dict,
    ) -> None:
        message = Mail(
            from_email="noreply@my.vbv-afa.ch",
            to_emails=recipient.email,
        )
        message.template_id = template.value.get(
            recipient.language, template.value["de"]
        )
        message.dynamic_template_data = template_data
        cls._sendgrid_client.send(message)


class NotificationService:
    @classmethod
    def send_user_interaction_notification(
        cls,
        recipient: User,
        verb: str,
        sender: User,
        course: str,
        target_url: str,
        email_template: EmailTemplate,
        template_data: dict = {},
    ) -> None:
        cls._send_notification(
            recipient=recipient,
            verb=verb,
            sender=sender,
            course=course,
            target_url=target_url,
            notification_type=NotificationType.USER_INTERACTION,
            email_template=email_template,
            template_data=template_data,
        )

    @classmethod
    def send_progress_notification(
        cls,
        recipient: User,
        verb: str,
        course: str,
        target_url: str,
        email_template: EmailTemplate,
        template_data: dict = {},
    ) -> None:
        cls._send_notification(
            recipient=recipient,
            verb=verb,
            course=course,
            target_url=target_url,
            notification_type=NotificationType.PROGRESS,
            email_template=email_template,
            template_data=template_data,
        )

    @classmethod
    def send_information_notification(
        cls,
        recipient: User,
        verb: str,
        target_url: str,
        email_template: EmailTemplate,
        template_data: dict = {},
    ) -> None:
        cls._send_notification(
            recipient=recipient,
            verb=verb,
            target_url=target_url,
            notification_type=NotificationType.INFORMATION,
            email_template=email_template,
            template_data=template_data,
        )

    @classmethod
    def _send_notification(
        cls,
        recipient: User,
        verb: str,
        notification_type: NotificationType,
        email_template: EmailTemplate,
        template_data: dict,
        sender: User | None = None,
        course: str | None = None,
        target_url: str | None = None,
    ) -> None:
        actor_avatar_url: Optional[str] = None
        if not sender:
            sender = User.objects.get(email="admin")
        else:
            actor_avatar_url = sender.avatar_url
        log = logger.bind(
            recipient=recipient.get_full_name(),
            sender=sender.get_full_name(),
            verb=verb,
            notification_type=notification_type,
            course=course,
            target_url=target_url,
            template_data=template_data,
        )
        if NotificationService._is_duplicate_notification(
            recipient=recipient,
            verb=verb,
            notification_type=notification_type,
            target_url=target_url,
            template_name=email_template.name,
            template_data=template_data,
        ):
            log.warn("A duplicate notification was omitted from being sent")
            return

        emailed = False
        if cls._should_send_email(notification_type, recipient):
            emailed = cls._send_email(
                recipient=recipient,
                template=email_template,
                template_data={
                    "target_url": f"https://my.vbv-afa.ch{target_url}",
                    **template_data,
                },
            )

        try:
            response = notify.send(
                sender=sender,
                recipient=recipient,
                verb=verb,
                emailed=emailed,
                # The metadata is saved in the 'data' member of the AbstractNotification model
                email_template=email_template.name,
                template_data=template_data,
            )
            sent_notification: Notification = response[0][1][0]  # 🫨
            sent_notification.target_url = target_url
            sent_notification.notification_type = notification_type
            sent_notification.course = course
            sent_notification.actor_avatar_url = actor_avatar_url
            sent_notification.save()
        except Exception as e:
            log.error("Failed to send notification", exception=str(e))
        else:
            log.info("Notification sent successfully")

    @staticmethod
    def _should_send_email(
        notification_type: NotificationType, recipient: User
    ) -> bool:
        return str(notification_type) in recipient.additional_json_data.get(
            "email_notification_types", []
        )

    @staticmethod
    def _send_email(
        recipient: User,
        template: EmailTemplate,
        template_data: dict | None,
    ) -> bool:
        log = logger.bind(
            recipient=recipient.username,
            template=template.name,
            template_data=template_data,
        )
        try:
            EmailService.send_email(
                recipient=recipient,
                template=template,
                template_data=template_data,
            )
            log.info("Email sent successfully")
            return True
        except Exception as e:
            log.error(
                "Failed to send Email", exception=str(e), exc_info=True, stack_info=True
            )
            return False

    @staticmethod
    def _is_duplicate_notification(
        recipient: User,
        verb: str,
        notification_type: NotificationType,
        template_name: str,
        template_data: dict,
        target_url: str | None,
    ) -> bool:
        """Check if a notification with the same parameters has already been sent to the recipient.
        This is to prevent duplicate notifications from being sent and to protect against potential programming errors.
        """
        return Notification.objects.filter(
            recipient=recipient,
            verb=verb,
            notification_type=notification_type,
            target_url=target_url,
            data={
                "email_template": template_name,
                "template_data": template_data,
            },
        ).exists()