import random
import string
from django.db.models.signals import post_save, pre_delete, post_delete, m2m_changed
from django.db.transaction import DatabaseError
from django.dispatch import receiver
from django.conf import settings
from django.apps import apps
from django.utils import timezone
from django.db.models import Q

from .models import Club, FailedApiCall, CustomUser, Log, DataAccess, ModelLog, BaseModel
import requests

from channels.layers import get_channel_layer
from asgiref.sync import async_to_sync

# Synchronization

@receiver([post_save, post_delete])
def synchronization_notifications(sender, instance, **kwargs):
    """
    Signal handler that sends notifications through WebSocket channels when model instances are saved or deleted.
    The function creates a WebSocket group name for each affected user and sends a sync update message
    to all clients connected to that group.
    """

    if sender in [FailedApiCall, Log, ModelLog]:
        return

    channel_layer = get_channel_layer()

    user_ids = set()
    if isinstance(instance, CustomUser):
        user_ids.add(instance.id)
    elif isinstance(instance, DataAccess):
        for shared_user in instance.shared_with.all():
            user_ids.add(shared_user.id)
    elif isinstance(instance, BaseModel):
        owner = instance.get_owner()
        if owner is not None:
            user_ids.add(owner.id)

    if isinstance(instance, BaseModel):
        parent_model, data_access_reference_id = instance.get_parent_reference()
        data_access_query = Q(model_id=instance.id)
        if data_access_reference_id is not None:
            data_access_query |= Q(model_id=data_access_reference_id)
        data_access_list = DataAccess.objects.filter(data_access_query)
        for data_access in data_access_list:
            user_ids.add(data_access.owner.id)
            for shared_user in data_access.shared_with.all():
                user_ids.add(shared_user.id)

    for user_id in user_ids:
        group_name = f"sync_{user_id}"
        print(f">>> send to group {group_name}")

        # Send to all clients in the sync group
        async_to_sync(channel_layer.group_send)(
            group_name, {"type": "sync.update", "message": "hello"}
        )

@receiver(m2m_changed, sender=DataAccess.shared_with.through)
def handle_shared_with_changes(sender, instance, action, pk_set, **kwargs):
    if action == "post_add":
        for user_id in pk_set:
            user = CustomUser.objects.get(id=user_id)
            instance.create_access_log(user, 'GRANT_ACCESS')
    elif action == "post_remove":
        for user_id in pk_set:
            user = CustomUser.objects.get(id=user_id)
            instance.create_access_log(user, 'REVOKE_ACCESS')

@receiver(pre_delete, sender=DataAccess)
def store_users_before_delete(sender, instance, **kwargs):
    # Store the users in a temporary attribute that we can access after deletion
    instance._users_to_revoke = list(instance.shared_with.all())

@receiver(post_delete, sender=DataAccess)
def revoke_access_after_delete(sender, instance, **kwargs):
    # Create revoke logs for all previously stored users
    if hasattr(instance, '_users_to_revoke'):
        for user in instance._users_to_revoke:
            instance.create_access_log(user, 'REVOKE_ACCESS')

# Others

def generate_unique_code():
    characters = string.ascii_letters + string.digits
    while True:
        code = ''.join(random.sample(characters, 3))
        if not Club.objects.filter(broadcast_code=code).exists():
            return code

@receiver(post_save, sender=Club)
def assign_unique_code(sender, instance, created, **kwargs):
    if created and not instance.broadcast_code:
        instance.broadcast_code = generate_unique_code()
        instance.save()

DISCORD_FAILED_CALLS_WEBHOOK_URL = 'https://discord.com/api/webhooks/1248191778134163486/sSoTL6cULCElWr2YFwyllsg7IXxHcCx_YMDJA_cUHtVUU4WOfN-5M7drCJuwNBBfAk9a'
DISCORD_LOGS_WEBHOOK_URL = 'https://discord.com/api/webhooks/1257987637449588736/TtOUwzYgSlQH2d3Ps7SfIKRcFALQVa3hfkC-j9K4_UAcWtsfiw4v8NUPbnX2_ZPOYzuv'

@receiver(post_save, sender=FailedApiCall)
def notify_discord_on_create(sender, instance, created, **kwargs):
    notify_object_creation_on_discord(created, instance, DISCORD_FAILED_CALLS_WEBHOOK_URL)

@receiver(post_save, sender=Log)
def notify_log_creation_on_discord(sender, instance, created, **kwargs):
    notify_object_creation_on_discord(created, instance, DISCORD_LOGS_WEBHOOK_URL)

# WARNING: using this method requires the instance to have a discord_string method
def notify_object_creation_on_discord(created, instance, webhook_url):
    if created:
        default_db_engine = settings.DATABASES['default']['ENGINE']
        if default_db_engine != 'django.db.backends.sqlite3':
            if hasattr(instance, 'discord_string'):
                message = f'New {instance.__class__.__name__} created: {instance.discord_string()}'
            else:
                message = "no message. Please configure 'discord_string' on your instance"
            send_discord_message(webhook_url, message)

def send_discord_message(webhook_url, content):
    data = {
        "content": content
    }
    response = requests.post(webhook_url, json=data)
    if response.status_code != 204:
        raise ValueError(
            f'Error sending message to Discord webhook: {response.status_code}, {response.text}'
        )