import collections

import datetime

from django.db.models import Count, Max, Sum

@report_view("Paid invoices by date", form_type=forms.ProductAndCategoryForm)

def paid_invoices_by_date(request, form):

    ''' Shows the number of paid invoices containing given products or

    categories per day. '''

    products = form.cleaned_data["product"]

    categories = form.cleaned_data["category"]

    invoices = commerce.Invoice.objects.filter(

        Q(lineitem__product__in=products) | Q(lineitem__product__category__in=categories),

        status=commerce.Invoice.STATUS_PAID,

    )

    payments = commerce.PaymentBase.objects.all()

    payments = payments.filter(

        invoice__in=invoices,

    )

    payments = payments.order_by("invoice")

    invoice_max_time = payments.values("invoice").annotate(max_time=Max("time"))

    by_date = collections.defaultdict(int)

    for line in invoice_max_time:

        time = line["max_time"]

        date = datetime.datetime(

            year=time.year, month=time.month, day=time.day

        )

        by_date[date] += 1

    data = [(date, count) for date, count in sorted(by_date.items())]

    data = [(date.strftime("%Y-%m-%d"), count) for date, count in data]

    return ListReport(

        "Paid Invoices By Date",

        ["date", "count"],

        data,

    )

    url(

        r"^paid_invoices_by_date/?$",

        rv.paid_invoices_by_date,

        name="paid_invoices_by_date"

    ),