def list(self, request, *args, **kwargs):
serializer = TrendTimeInputSerializer(data=request.query_params)
serializer.is_valid(raise_exception=True)
self.filters = serializer.validated_data
results, links = [], {}
# Get first and last bank transaction to prevent infinite pager. If
# one is missing, it just mean that there is no data at all.
first, last = self.get_queryset_dates_delimiters()
if first and last:
base_date = self.filters['date']
granularity = self.filters['granularity']
# Requested date is out of range?
first_range = get_date_ranges(first, granularity)[0]
last_range = get_date_ranges(last, granularity)[1]
if first_range <= base_date <= last_range:
date_start, date_end = get_date_ranges(
base_date,
granularity,
)
balance = self.get_queryset_balance(date_start)['sum'] or 0
balance += self.bankaccount.balance_initial
items_qs = self.get_queryset_items(date_start, date_end)
items = {item['date']: item for item in items_qs}
# Start and end iterator at first/last bank transaction,
# not the range calculated.
iterator = DateIterator(
first if first > date_start else date_start,
last if last < date_end else date_end,
)
instances = []
for date_step in iterator:
delta = percentage = count = 0
# If no new bank transaction, same as previous.
if date_step in items:
delta = items[date_step]['sum']
percentage = (delta * 100 / balance) if balance else 0
balance += items[date_step]['sum']
count = items[date_step]['count']
instances.append({
'date': date_step,
'count': count,
'delta': delta,
'balance': balance,
'percentage': percentage,
})
results = TrendTimeOuputSerializer(instances, many=True).data
paginator = DatePaginator(first_range, last_range, granularity)
links = paginator.get_links(base_date, request)
return Response({
'results': results,
'previous': links.get('previous'),
'next': links.get('next'),
})
