##
## decorators / functions to make the task calls easier
##
from django.utils.dateparse import parse_duration
from django.db import models
from django.utils import timezone
from django.apps import apps
import re

# Regular expression pattern with named groups for "1w2d5h30m10s500ms1000us" without spaces
pattern = re.compile(
	r'(\+|-)?'
	r'(?:(?P<weeks>\d+)w)?'
	r'(?:(?P<days>\d+)d)?'
	r'(?:(?P<hours>\d+)h)?'
	r'(?:(?P<minutes>\d+)m)?'
	r'(?:(?P<seconds>\d+)s)?'
	r'(?:(?P<milliseconds>\d+)ms)?'
	r'(?:(?P<microseconds>\d+)us)?'
)

def task( *args, **kwargs ):
	from .models import Task

	jitter = kwargs.pop('jitter', "")
	match = pattern.match( jitter )
	if jitter and match:
		kwargs['jitter_length'] = timezone.timedelta( **{
			k: int(v)
			for k, v in match.groupdict().items()
			if v is not None
		} )
		kwargs['jitter_pivot'] = {
			"-":  "S",
			None: "M",
			"+":  "E",
		}[match.group(1)]

	for f in Task._meta.fields:
		if not isinstance(f, models.DurationField): continue
		if f not in kwargs: continue
		if not kwargs[f]: continue

		kwargs[f] = parse_duration( kwargs[f] )

	return Task( *args, **kwargs ).register



def run_on_model_change( *models ):
	models = [
		apps.get_model(m) if isinstance(m, str) else m
		for m in models
	]
	def decorator( f ):
		f.watching_models = models
		return f
	return decorator

from .extender import Extender
def extension( *args, **kwargs ):
	assert Extender.capturing_instance, "Cannot only extend a model during inital import and after apps are ready!"
	return Extender.capturing_instance( *args, **kwargs )













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