Implement invoice model and admin API

gnuviechadmin/invoices/models.py

@@ -0,0 +1,56 @@
+import magic
+from django.conf import settings
+from django.core.exceptions import ValidationError
+from django.core.validators import FileExtensionValidator
+from django.db import models
+from django.utils.translation import ugettext_lazy as _
+
+CURRENCIES = [(1, "EUR")]
+
+
+def customer_invoice_path(instance, filename):
+    return "invoices/{0}/{1}.pdf".format(
+        instance.customer.username, instance.invoice_number
+    )
+
+
+def validate_pdf(value):
+    valid_mime_types = ["application/pdf"]
+    file_mime_type = magic.from_buffer(value.read(1024), mime=True)
+    if file_mime_type not in valid_mime_types:
+        raise ValidationError("Unsupported file type.")
+
+
+class Invoice(models.Model):
+    customer = models.ForeignKey(
+        settings.AUTH_USER_MODEL, verbose_name=_("customer"), on_delete=models.CASCADE
+    )
+    invoice = models.FileField(
+        upload_to=customer_invoice_path,
+        validators=[validate_pdf, FileExtensionValidator(allowed_extensions=["pdf"])],
+    )
+    invoice_number = models.SlugField(
+        verbose_name=_("invoice number"), max_length=10, unique=True
+    )
+    invoice_date = models.DateField(verbose_name=_("invoice date"))
+    invoice_value = models.DecimalField(
+        verbose_name=_("amount"), decimal_places=2, max_digits=10
+    )
+    invoice_currency = models.PositiveSmallIntegerField(
+        verbose_name=_("currency"), choices=CURRENCIES
+    )
+    due_date = models.DateField(verbose_name=_("due date"))
+    payment_date = models.DateField(
+        verbose_name=_("payment date"), blank=True, null=True
+    )
+    payment_variant = models.TextField(
+        verbose_name=_("payment variant"), blank=True, null=True
+    )
+
+    class Meta:
+        verbose_name = _("invoice")
+        verbose_name_plural = _("invoices")
+        ordering = ["-invoice_date", "customer"]
+
+    def __str__(self):
+        return _("Invoice {0}").format(self.invoice_number)