ECOM-890: Update invoice data model.

ECOM-891: Allow tracking of invoice transactions.

Authors: Awais Qureshi and Aamir Khan

common/djangoapps/student/tests/tests.py

@@ -299,8 +299,14 @@ class DashboardTest(ModuleStoreTestCase):
             recipient_name='Testw_1', recipient_email='test2@test.com', internal_reference="A",
             course_id=self.course.id, is_valid=False
         )
+        invoice_item = shoppingcart.models.CourseRegistrationCodeInvoiceItem.objects.create(
+            invoice=sale_invoice_1,
+            qty=1,
+            unit_price=1234.32,
+            course_id=self.course.id
+        )
         course_reg_code = shoppingcart.models.CourseRegistrationCode(
-            code="abcde", course_id=self.course.id, created_by=self.user, invoice=sale_invoice_1, mode_slug='honor'
+            code="abcde", course_id=self.course.id, created_by=self.user, invoice=sale_invoice_1, invoice_item=invoice_item, mode_slug='honor'
         )
         course_reg_code.save()
 

common/djangoapps/student/views.py

@@ -465,8 +465,8 @@ def is_course_blocked(request, redeemed_registration_codes, course_key):
         # registration codes may be generated via Bulk Purchase Scenario
         # we have to check only for the invoice generated registration codes
         # that their invoice is valid or not
-        if redeemed_registration.invoice:
-            if not getattr(redeemed_registration.invoice, 'is_valid'):
+        if redeemed_registration.invoice_item:
+            if not getattr(redeemed_registration.invoice_item.invoice, 'is_valid'):
                 blocked = True
                 # disabling email notifications for unpaid registration courses
                 Optout.objects.get_or_create(user=request.user, course_id=course_key)

lms/djangoapps/instructor/views/api.py

@@ -27,6 +27,7 @@ import string  # pylint: disable=deprecated-module
 import random
 import unicodecsv
 import urllib
+import decimal
 from student import auth
 from student.roles import CourseSalesAdminRole
 from util.file import store_uploaded_file, course_and_time_based_filename_generator, FileValidationException, UniversalNewlineIterator
@@ -49,7 +50,14 @@ from django_comment_common.models import (
 )
 from edxmako.shortcuts import render_to_response, render_to_string
 from courseware.models import StudentModule
-from shoppingcart.models import Coupon, CourseRegistrationCode, RegistrationCodeRedemption, Invoice, CourseMode
+from shoppingcart.models import (
+    Coupon,
+    CourseRegistrationCode,
+    RegistrationCodeRedemption,
+    Invoice,
+    CourseMode,
+    CourseRegistrationCodeInvoiceItem,
+)
 from student.models import CourseEnrollment, unique_id_for_user, anonymous_id_for_user
 import instructor_task.api
 from instructor_task.api_helper import AlreadyRunningError
@@ -885,9 +893,13 @@ def sale_validation(request, course_id):
 
     course_id = SlashSeparatedCourseKey.from_deprecated_string(course_id)
     try:
-        obj_invoice = Invoice.objects.select_related('is_valid').get(id=invoice_number, course_id=course_id)
-    except Invoice.DoesNotExist:
-        return HttpResponseNotFound(_("Invoice number '{0}' does not exist.").format(invoice_number))
+        obj_invoice = CourseRegistrationCodeInvoiceItem.objects.select_related('invoice').get(
+            invoice_id=invoice_number,
+            course_id=course_id
+        )
+        obj_invoice = obj_invoice.invoice
+    except CourseRegistrationCodeInvoiceItem.DoesNotExist:  # Check for old type invoices
+        return HttpResponseNotFound(_("Invoice number '{0}' does not exist.".format(invoice_number)))
 
     if event_type == "invalidate":
         return invalidate_invoice(obj_invoice)
@@ -1053,7 +1065,7 @@ def get_coupon_codes(request, course_id):  # pylint: disable=unused-argument
     return instructor_analytics.csvs.create_csv_response('Coupons.csv', header, data_rows)
 
 
-def save_registration_code(user, course_id, mode_slug, invoice=None, order=None):
+def save_registration_code(user, course_id, mode_slug, invoice=None, order=None, invoice_item=None):
     """
     recursive function that generate a new code every time and saves in the Course Registration Table
     if validation check passes
@@ -1064,6 +1076,7 @@ def save_registration_code(user, course_id, mode_slug, invoice=None, order=None)
         mode_slug (str): The Course Mode Slug associated with any enrollment made by these codes.
         invoice (Invoice): (Optional) The associated invoice for this code.
         order (Order): (Optional) The associated order for this code.
+        invoice_item (CourseRegistrationCodeInvoiceItem) : (Optional) The associated CourseRegistrationCodeInvoiceItem
 
     Returns:
         The newly created CourseRegistrationCode.
@@ -1074,7 +1087,9 @@ def save_registration_code(user, course_id, mode_slug, invoice=None, order=None)
     # check if the generated code is in the Coupon Table
     matching_coupons = Coupon.objects.filter(code=code, is_active=True)
     if matching_coupons:
-        return save_registration_code(user, course_id, invoice, order)
+        return save_registration_code(
+            user, course_id, mode_slug, invoice=invoice, order=order, invoice_item=invoice_item
+        )
 
     course_registration = CourseRegistrationCode(
         code=code,
@@ -1082,13 +1097,16 @@ def save_registration_code(user, course_id, mode_slug, invoice=None, order=None)
         created_by=user,
         invoice=invoice,
         order=order,
-        mode_slug=mode_slug
+        mode_slug=mode_slug,
+        invoice_item=invoice_item
     )
     try:
         course_registration.save()
         return course_registration
     except IntegrityError:
-        return save_registration_code(user, course_id, invoice, order)
+        return save_registration_code(
+            user, course_id, mode_slug, invoice=invoice, order=order, invoice_item=invoice_item
+        )
 
 
 def registration_codes_csv(file_name, codes_list, csv_type=None):
@@ -1130,11 +1148,13 @@ def get_registration_codes(request, course_id):  # pylint: disable=unused-argume
     course_id = SlashSeparatedCourseKey.from_deprecated_string(course_id)
 
     #filter all the  course registration codes
-    registration_codes = CourseRegistrationCode.objects.filter(course_id=course_id).order_by('invoice__company_name')
+    registration_codes = CourseRegistrationCode.objects.filter(
+        course_id=course_id
+    ).order_by('invoice_item__invoice__company_name')
 
     company_name = request.POST['download_company_name']
     if company_name:
-        registration_codes = registration_codes.filter(invoice__company_name=company_name)
+        registration_codes = registration_codes.filter(invoice_item__invoice__company_name=company_name)
 
     csv_type = 'download'
     return registration_codes_csv("Registration_Codes.csv", registration_codes, csv_type)
@@ -1160,7 +1180,21 @@ def generate_registration_codes(request, course_id):
     company_name = request.POST['company_name']
     company_contact_name = request.POST['company_contact_name']
     company_contact_email = request.POST['company_contact_email']
-    sale_price = request.POST['sale_price']
+    unit_price = request.POST['unit_price']
+
+    try:
+        unit_price = (
+            decimal.Decimal(unit_price)
+        ).quantize(
+            decimal.Decimal('.01'),
+            rounding=decimal.ROUND_DOWN
+        )
+    except decimal.InvalidOperation:
+        return HttpResponse(
+            status=400,
+            content=_(u"Could not parse amount as a decimal")
+        )
+
     recipient_name = request.POST['recipient_name']
     recipient_email = request.POST['recipient_email']
     address_line_1 = request.POST['address_line_1']
@@ -1177,6 +1211,7 @@ def generate_registration_codes(request, course_id):
         recipient_list.append(request.user.email)
         invoice_copy = True
 
+    sale_price = unit_price * course_code_number
     UserPreference.set_preference(request.user, INVOICE_KEY, invoice_copy)
     sale_invoice = Invoice.objects.create(
         total_amount=sale_price,
@@ -1197,6 +1232,13 @@ def generate_registration_codes(request, course_id):
         customer_reference_number=customer_reference_number
     )
 
+    invoice_item = CourseRegistrationCodeInvoiceItem.objects.create(
+        invoice=sale_invoice,
+        qty=course_code_number,
+        unit_price=unit_price,
+        course_id=course_id
+    )
+
     course = get_course_by_id(course_id, depth=0)
     paid_modes = CourseMode.paid_modes_for_course(course_id)
 
@@ -1217,7 +1259,7 @@ def generate_registration_codes(request, course_id):
     registration_codes = []
     for __ in range(course_code_number):  # pylint: disable=redefined-outer-name
         generated_registration_code = save_registration_code(
-            request.user, course_id, course_mode.slug, sale_invoice, order=None
+            request.user, course_id, course_mode.slug, invoice=sale_invoice, order=None, invoice_item=invoice_item
         )
         registration_codes.append(generated_registration_code)
 
@@ -1309,13 +1351,17 @@ def active_registration_codes(request, course_id):  # pylint: disable=unused-arg
     course_id = SlashSeparatedCourseKey.from_deprecated_string(course_id)
 
     # find all the registration codes in this course
-    registration_codes_list = CourseRegistrationCode.objects.filter(course_id=course_id).order_by('invoice__company_name')
+    registration_codes_list = CourseRegistrationCode.objects.filter(
+        course_id=course_id
+    ).order_by('invoice_item__invoice__company_name')
 
     company_name = request.POST['active_company_name']
     if company_name:
-        registration_codes_list = registration_codes_list.filter(invoice__company_name=company_name)
+        registration_codes_list = registration_codes_list.filter(invoice_item__invoice__company_name=company_name)
     # find the redeemed registration codes if any exist in the db
-    code_redemption_set = RegistrationCodeRedemption.objects.select_related('registration_code').filter(registration_code__course_id=course_id)
+    code_redemption_set = RegistrationCodeRedemption.objects.select_related(
+        'registration_code', 'registration_code__invoice_item__invoice'
+    ).filter(registration_code__course_id=course_id)
     if code_redemption_set.exists():
         redeemed_registration_codes = [code.registration_code.code for code in code_redemption_set]
         # exclude the redeemed registration codes from the registration codes list and you will get
@@ -1346,11 +1392,11 @@ def spent_registration_codes(request, course_id):  # pylint: disable=unused-argu
         # you will get a list of all the spent(Redeemed) Registration Codes
         spent_codes_list = CourseRegistrationCode.objects.filter(
             course_id=course_id, code__in=redeemed_registration_codes
-        ).order_by('invoice__company_name')
+        ).order_by('invoice_item__invoice__company_name').select_related('invoice_item__invoice')
 
         company_name = request.POST['spent_company_name']
         if company_name:
-            spent_codes_list = spent_codes_list.filter(invoice__company_name=company_name)  # pylint: disable=maybe-no-member
+            spent_codes_list = spent_codes_list.filter(invoice_item__invoice__company_name=company_name)  # pylint: disable=maybe-no-member
 
     csv_type = 'spent'
     return registration_codes_csv("Spent_Registration_Codes.csv", spent_codes_list, csv_type)

lms/djangoapps/instructor_analytics/basic.py

@@ -6,7 +6,7 @@ Serve miscellaneous course and student data
 import json
 from shoppingcart.models import (
     PaidCourseRegistration, CouponRedemption, Invoice, CourseRegCodeItem,
-    OrderTypes, RegistrationCodeRedemption, CourseRegistrationCode
+    OrderTypes, RegistrationCodeRedemption, CourseRegistrationCode, CourseRegistrationCodeInvoiceItem
 )
 from django.db.models import Q
 from django.conf import settings
@@ -110,22 +110,25 @@ def sale_record_features(course_id, features):
         {'company_name': 'group_C', 'total_codes': '3', total_amount:'total_amount3 in decimal'.}
     ]
     """
-    sales = Invoice.objects.filter(course_id=course_id)
+    sales = CourseRegistrationCodeInvoiceItem.objects.select_related('invoice').filter(course_id=course_id)
 
     def sale_records_info(sale, features):
-        """ convert sales records to dictionary """
+        """
+        Convert sales records to dictionary
 
+        """
+        invoice = sale.invoice
         sale_features = [x for x in SALE_FEATURES if x in features]
         course_reg_features = [x for x in COURSE_REGISTRATION_FEATURES if x in features]
 
         # Extracting sale information
-        sale_dict = dict((feature, getattr(sale, feature))
+        sale_dict = dict((feature, getattr(invoice, feature))
                          for feature in sale_features)
 
         total_used_codes = RegistrationCodeRedemption.objects.filter(
             registration_code__in=sale.courseregistrationcode_set.all()
         ).count()
-        sale_dict.update({"invoice_number": getattr(sale, 'id')})
+        sale_dict.update({"invoice_number": getattr(invoice, 'id')})
         sale_dict.update({"total_codes": sale.courseregistrationcode_set.all().count()})
         sale_dict.update({'total_used_codes': total_used_codes})
 
@@ -261,11 +264,11 @@ def course_registration_features(features, registration_codes, csv_type):
 
         course_registration_dict = dict((feature, getattr(registration_code, feature)) for feature in registration_features)
         course_registration_dict['company_name'] = None
-        if registration_code.invoice:
-            course_registration_dict['company_name'] = getattr(registration_code.invoice, 'company_name')
+        if registration_code.invoice_item:
+            course_registration_dict['company_name'] = getattr(registration_code.invoice_item.invoice, 'company_name')
         course_registration_dict['redeemed_by'] = None
-        if registration_code.invoice:
-            sale_invoice = Invoice.objects.get(id=registration_code.invoice_id)
+        if registration_code.invoice_item:
+            sale_invoice = registration_code.invoice_item.invoice
             course_registration_dict['invoice_id'] = sale_invoice.id
             course_registration_dict['purchaser'] = sale_invoice.recipient_name
             course_registration_dict['customer_reference_number'] = sale_invoice.customer_reference_number

lms/djangoapps/instructor_analytics/tests/test_basic.py

@@ -11,7 +11,7 @@ from student.tests.factories import UserFactory, CourseModeFactory
 from opaque_keys.edx.locations import SlashSeparatedCourseKey
 from shoppingcart.models import (
     CourseRegistrationCode, RegistrationCodeRedemption, Order,
-    Invoice, Coupon, CourseRegCodeItem, CouponRedemption
+    Invoice, Coupon, CourseRegCodeItem, CouponRedemption, CourseRegistrationCodeInvoiceItem
 )
 from course_modes.models import CourseMode
 from instructor_analytics.basic import (
@@ -147,10 +147,16 @@ class TestCourseSaleRecordsAnalyticsBasic(ModuleStoreTestCase):
             company_contact_email='test@company.com', recipient_name='Testw_1', recipient_email='test2@test.com',
             customer_reference_number='2Fwe23S', internal_reference="ABC", course_id=self.course.id
         )
+        invoice_item = CourseRegistrationCodeInvoiceItem.objects.create(
+            invoice=sale_invoice,
+            qty=1,
+            unit_price=1234.32,
+            course_id=self.course.id
+        )
         for i in range(5):
             course_code = CourseRegistrationCode(
                 code="test_code{}".format(i), course_id=self.course.id.to_deprecated_string(),
-                created_by=self.instructor, invoice=sale_invoice, mode_slug='honor'
+                created_by=self.instructor, invoice=sale_invoice, invoice_item=invoice_item, mode_slug='honor'
             )
             course_code.save()
 
@@ -272,7 +278,7 @@ class TestCourseRegistrationCodeAnalyticsBasic(ModuleStoreTestCase):
                       kwargs={'course_id': self.course.id.to_deprecated_string()})
 
         data = {
-            'total_registration_codes': 12, 'company_name': 'Test Group', 'sale_price': 122.45,
+            'total_registration_codes': 12, 'company_name': 'Test Group', 'unit_price': 122.45,
             'company_contact_name': 'TestName', 'company_contact_email': 'test@company.com', 'recipient_name': 'Test123',
             'recipient_email': 'test@123.com', 'address_line_1': 'Portland Street', 'address_line_2': '',
             'address_line_3': '', 'city': '', 'state': '', 'zip': '', 'country': '',
@@ -306,11 +312,17 @@ class TestCourseRegistrationCodeAnalyticsBasic(ModuleStoreTestCase):
             )
             self.assertIn(
                 course_registration['company_name'],
-                [getattr(registration_code.invoice, 'company_name') for registration_code in registration_codes]
+                [
+                    getattr(registration_code.invoice_item.invoice, 'company_name')
+                    for registration_code in registration_codes
+                ]
             )
             self.assertIn(
                 course_registration['invoice_id'],
-                [registration_code.invoice_id for registration_code in registration_codes]
+                [
+                    registration_code.invoice_item.invoice_id
+                    for registration_code in registration_codes
+                ]
             )
 
     def test_coupon_codes_features(self):

lms/djangoapps/shoppingcart/admin.py

-"""
-Allows django admin site to add PaidCourseRegistrationAnnotations
-"""
+"""Django admin interface for the shopping cart models. """
 from ratelimitbackend import admin
 from shoppingcart.models import (
-    PaidCourseRegistrationAnnotation, Coupon, DonationConfiguration
+    PaidCourseRegistrationAnnotation,
+    Coupon,
+    DonationConfiguration,
+    Invoice,
+    CourseRegistrationCodeInvoiceItem,
+    InvoiceTransaction
 )
 
 
@@ -49,6 +52,128 @@ class SoftDeleteCouponAdmin(admin.ModelAdmin):
 
     really_delete_selected.short_description = "Delete s selected entries"
 
+
+class CourseRegistrationCodeInvoiceItemInline(admin.StackedInline):
+    """Admin for course registration code invoice items.
+
+    Displayed inline within the invoice admin UI.
+    """
+    model = CourseRegistrationCodeInvoiceItem
+    extra = 0
+    can_delete = False
+    readonly_fields = (
+        'qty',
+        'unit_price',
+        'currency',
+        'course_id',
+    )
+
+    def has_add_permission(self, request):
+        return False
+
+
+class InvoiceTransactionInline(admin.StackedInline):
+    """Admin for invoice transactions.
+
+    Displayed inline within the invoice admin UI.
+    """
+    model = InvoiceTransaction
+    extra = 0
+    readonly_fields = (
+        'created',
+        'modified',
+        'created_by',
+        'last_modified_by'
+    )
+
+
+class InvoiceAdmin(admin.ModelAdmin):
+    """Admin for invoices.
+
+    This is intended for the internal finance team
+    to be able to view and update invoice information,
+    including payments and refunds.
+
+    """
+    date_hierarchy = 'created'
+    can_delete = False
+    readonly_fields = ('created', 'modified')
+    search_fields = (
+        'internal_reference',
+        'customer_reference_number',
+        'company_name',
+    )
+    fieldsets = (
+        (
+            None, {
+                'fields': (
+                    'internal_reference',
+                    'customer_reference_number',
+                    'created',
+                    'modified',
+                )
+            }
+        ),
+        (
+            'Billing Information', {
+                'fields': (
+                    'company_name',
+                    'company_contact_name',
+                    'company_contact_email',
+                    'recipient_name',
+                    'recipient_email',
+                    'address_line_1',
+                    'address_line_2',
+                    'address_line_3',
+                    'city',
+                    'state',
+                    'zip',
+                    'country'
+                )
+            }
+        )
+    )
+    readonly_fields = (
+        'internal_reference',
+        'customer_reference_number',
+        'created',
+        'modified',
+        'company_name',
+        'company_contact_name',
+        'company_contact_email',
+        'recipient_name',
+        'recipient_email',
+        'address_line_1',
+        'address_line_2',
+        'address_line_3',
+        'city',
+        'state',
+        'zip',
+        'country'
+    )
+    inlines = [
+        CourseRegistrationCodeInvoiceItemInline,
+        InvoiceTransactionInline
+    ]
+
+    def save_formset(self, request, form, formset, change):
+        """Save the user who created and modified invoice transactions. """
+        instances = formset.save(commit=False)
+        for instance in instances:
+            if isinstance(instance, InvoiceTransaction):
+                if not hasattr(instance, 'created_by'):
+                    instance.created_by = request.user
+                instance.last_modified_by = request.user
+                instance.save()
+
+    def has_add_permission(self, request):
+        return False
+
+    def has_delete_permission(self, request, obj=None):
+        return False
+
+
 admin.site.register(PaidCourseRegistrationAnnotation)
 admin.site.register(Coupon, SoftDeleteCouponAdmin)
 admin.site.register(DonationConfiguration)
+admin.site.register(Invoice, InvoiceAdmin)

lms/djangoapps/shoppingcart/models.py

@@ -18,7 +18,7 @@ from django.conf import settings
 from django.core.exceptions import ObjectDoesNotExist
 from django.core.mail import send_mail
 from django.contrib.auth.models import User
-from django.utils.translation import ugettext as _
+from django.utils.translation import ugettext as _, ugettext_lazy
 from django.db import transaction
 from django.db.models import Sum
 from django.core.urlresolvers import reverse
@@ -773,11 +773,11 @@ class OrderItem(TimeStampedModel):
         self.save()
 
 
-class Invoice(models.Model):
+class Invoice(TimeStampedModel):
     """
-         This table capture all the information needed to support "invoicing"
-         which is when a user wants to purchase Registration Codes,
-         but will not do so via a Credit Card transaction.
+    This table capture all the information needed to support "invoicing"
+    which is when a user wants to purchase Registration Codes,
+    but will not do so via a Credit Card transaction.
     """
     company_name = models.CharField(max_length=255, db_index=True)
     company_contact_name = models.CharField(max_length=255)
@@ -785,16 +785,39 @@ class Invoice(models.Model):
     recipient_name = models.CharField(max_length=255)
     recipient_email = models.CharField(max_length=255)
     address_line_1 = models.CharField(max_length=255)
-    address_line_2 = models.CharField(max_length=255, null=True)
-    address_line_3 = models.CharField(max_length=255, null=True)
+    address_line_2 = models.CharField(max_length=255, null=True, blank=True)
+    address_line_3 = models.CharField(max_length=255, null=True, blank=True)
     city = models.CharField(max_length=255, null=True)
     state = models.CharField(max_length=255, null=True)
     zip = models.CharField(max_length=15, null=True)
     country = models.CharField(max_length=64, null=True)
-    course_id = CourseKeyField(max_length=255, db_index=True)
+
+    # This field has been deprecated.
+    # The total amount can now be calculated as the sum
+    # of each invoice item associated with the invoice.
+    # For backwards compatibility, this field is maintained
+    # and written to during invoice creation.
     total_amount = models.FloatField()
-    internal_reference = models.CharField(max_length=255, null=True)
-    customer_reference_number = models.CharField(max_length=63, null=True)
+
+    # This field has been deprecated in order to support
+    # invoices for items that are not course-related.
+    # Although this field is still maintained for backwards
+    # compatibility, you should use CourseRegistrationCodeInvoiceItem
+    # to look up the course ID for purchased redeem codes.
+    course_id = CourseKeyField(max_length=255, db_index=True)
+
+    internal_reference = models.CharField(
+        max_length=255,
+        null=True,
+        blank=True,
+        help_text=ugettext_lazy("Internal reference code for this invoice.")
+    )
+    customer_reference_number = models.CharField(
+        max_length=63,
+        null=True,
+        blank=True,
+        help_text=ugettext_lazy("Customer's reference code for this invoice.")
+    )
     is_valid = models.BooleanField(default=True)
 
     def generate_pdf_invoice(self, course, course_price, quantity, sale_price):
@@ -824,6 +847,125 @@ class Invoice(models.Model):
 
         return pdf_buffer
 
+    def __unicode__(self):
+        label = (
+            unicode(self.internal_reference)
+            if self.internal_reference
+            else u"No label"
+        )
+
+        created = (
+            self.created.strftime("%Y-%m-%d")  # pylint: disable=no-member
+            if self.created
+            else u"No date"
+        )
+
+        return u"{label} ({date_created})".format(
+            label=label, date_created=created
+        )
+
+
+INVOICE_TRANSACTION_STATUSES = (
+    # A payment/refund is in process, but money has not yet been transferred
+    ('started', 'started'),
+
+    # A payment/refund has completed successfully
+    # This should be set ONLY once money has been successfully exchanged.
+    ('completed', 'completed'),
+
+    # A payment/refund was promised, but was cancelled before
+    # money had been transferred.  An example would be
+    # cancelling a refund check before the recipient has
+    # a chance to deposit it.
+    ('cancelled', 'cancelled')
+)
+
+
+class InvoiceTransaction(TimeStampedModel):
+    """Record payment and refund information for invoices.
+
+    There are two expected use cases:
+
+    1) We send an invoice to someone, and they send us a check.
+       We then manually create an invoice transaction to represent
+       the payment.
+
+    2) We send an invoice to someone, and they pay us.  Later, we
+       need to issue a refund for the payment.  We manually
+       create a transaction with a negative amount to represent
+       the refund.
+
+    """
+    invoice = models.ForeignKey(Invoice)
+    amount = models.DecimalField(
+        default=0.0, decimal_places=2, max_digits=30,
+        help_text=ugettext_lazy(
+            "The amount of the transaction.  Use positive amounts for payments"
+            " and negative amounts for refunds."
+        )
+    )
+    currency = models.CharField(
+        default="usd",
+        max_length=8,
+        help_text=ugettext_lazy("Lower-case ISO currency codes")
+    )
+    comments = models.TextField(
+        null=True,
+        blank=True,
+        help_text=ugettext_lazy("Optional: provide additional information for this transaction")
+    )
+    status = models.CharField(
+        max_length=32,
+        default='started',
+        choices=INVOICE_TRANSACTION_STATUSES,
+        help_text=ugettext_lazy(
+            "The status of the payment or refund. "
+            "'started' means that payment is expected, but money has not yet been transferred. "
+            "'completed' means that the payment or refund was received. "
+            "'cancelled' means that payment or refund was expected, but was cancelled before money was transferred. "
+        )
+    )
+    created_by = models.ForeignKey(User)
+    last_modified_by = models.ForeignKey(User, related_name='last_modified_by_user')
+
+
+class InvoiceItem(TimeStampedModel):
+    """
+    This is the basic interface for invoice items.
+
+    Each invoice item represents a "line" in the invoice.
+    For example, in an invoice for course registration codes,
+    there might be an invoice item representing 10 registration
+    codes for the DemoX course.
+
+    """
+    objects = InheritanceManager()
+    invoice = models.ForeignKey(Invoice, db_index=True)
+    qty = models.IntegerField(
+        default=1,
+        help_text=ugettext_lazy("The number of items sold.")
+    )
+    unit_price = models.DecimalField(
+        default=0.0,
+        decimal_places=2,
+        max_digits=30,
+        help_text=ugettext_lazy("The price per item sold, including discounts.")
+    )
+    currency = models.CharField(
+        default="usd",
+        max_length=8,
+        help_text=ugettext_lazy("Lower-case ISO currency codes")
+    )
+
+
+class CourseRegistrationCodeInvoiceItem(InvoiceItem):
+    """
+    This is an invoice item that represents a payment for
+    a course registration.
+
+    """
+    course_id = CourseKeyField(max_length=128, db_index=True)
+
 
 class CourseRegistrationCode(models.Model):
     """
@@ -835,9 +977,14 @@ class CourseRegistrationCode(models.Model):
     created_by = models.ForeignKey(User, related_name='created_by_user')
     created_at = models.DateTimeField(default=datetime.now(pytz.utc))
     order = models.ForeignKey(Order, db_index=True, null=True, related_name="purchase_order")
-    invoice = models.ForeignKey(Invoice, null=True)
     mode_slug = models.CharField(max_length=100, null=True)
 
+    # For backwards compatibility, we maintain the FK to "invoice"
+    # In the future, we will remove this in favor of the FK
+    # to "invoice_item" (which can be used to look up the invoice).
+    invoice = models.ForeignKey(Invoice, null=True)
+    invoice_item = models.ForeignKey(CourseRegistrationCodeInvoiceItem, null=True)
+
 
 class RegistrationCodeRedemption(models.Model):
     """
@@ -1227,7 +1374,7 @@ class CourseRegCodeItem(OrderItem):
         # is in another PR (for another feature)
         from instructor.views.api import save_registration_code
         for i in range(total_registration_codes):  # pylint: disable=unused-variable
-            save_registration_code(self.user, self.course_id, self.mode, invoice=None, order=self.order)
+            save_registration_code(self.user, self.course_id, self.mode, order=self.order)
 
         log.info("Enrolled {0} in paid course {1}, paid ${2}"
                  .format(self.user.email, self.course_id, self.line_cost))  # pylint: disable=no-member

lms/djangoapps/shoppingcart/tests/test_views.py

@@ -1518,7 +1518,7 @@ class RegistrationCodeRedemptionCourseEnrollment(ModuleStoreTestCase):
 
         data = {
             'total_registration_codes': 12, 'company_name': 'Test Group', 'company_contact_name': 'Test@company.com',
-            'company_contact_email': 'Test@company.com', 'sale_price': 122.45, 'recipient_name': 'Test123',
+            'company_contact_email': 'Test@company.com', 'unit_price': 122.45, 'recipient_name': 'Test123',
             'recipient_email': 'test@123.com', 'address_line_1': 'Portland Street',
             'address_line_2': '', 'address_line_3': '', 'city': '', 'state': '', 'zip': '', 'country': '',
             'customer_reference_number': '123A23F', 'internal_reference': '', 'invoice': ''

lms/static/sass/course/instructor/_instructor_2.scss

@@ -1664,7 +1664,7 @@ input[name="subject"] {
           height: auto;
         }
       }
-      li#generate-registration-modal-field-country ~  li#generate-registration-modal-field-total-price,
+      li#generate-registration-modal-field-country ~  li#generate-registration-modal-field-unit-price,
       li#generate-registration-modal-field-country ~  li#generate-registration-modal-field-internal-reference {
         @include margin-left(0px !important);
         @include margin-right(15px !important);

lms/templates/instructor/instructor_dashboard_2/e-commerce.html

@@ -296,7 +296,7 @@
       var total_registration_codes = $('input[name="total_registration_codes"]').val();
       var recipient_name = $('input[name="recipient_name"]').val();
       var recipient_email = $('input[name="recipient_email"]').val();
-      var sale_price = $('input[name="sale_price"]').val();
+      var unit_price = $('input[name="unit_price"]').val();
       var company_name = $('input[name="company_name"]').val();
       var company_contact_name = $('input[name="company_contact_name"]').val();
       var company_contact_email = $('input[name="company_contact_email"]').val();
@@ -305,91 +305,91 @@
 
       if (company_name == '') {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the company name');
+        registration_code_error.text("${_('Please enter the company name')}");
         generate_registration_button.removeAttr('disabled');
         return false;
       }
       if (($.isNumeric(company_name))) {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the non-numeric value for company name');
+        registration_code_error.text("${_('Please enter the non-numeric value for company name')}");
         generate_registration_button.removeAttr('disabled');
         return false;
       }
       if (company_contact_name == '') {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the company contact name');
+        registration_code_error.text("${_('Please enter the company contact name')}");
         generate_registration_button.removeAttr('disabled');
         return false;
       }
       if (($.isNumeric(company_contact_name))) {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the non-numeric value for company contact name');
+        registration_code_error.text("${_('Please enter the non-numeric value for company contact name')}");
         generate_registration_button.removeAttr('disabled');
         return false;
       }
       if (company_contact_email == '') {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the company contact email');
+        registration_code_error.text("${_('Please enter the company contact email')}");
         generate_registration_button.removeAttr('disabled');
         return false;
       }
       if (!(validateEmail(company_contact_email))) {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the valid email address');
+        registration_code_error.text("${_('Please enter the valid email address')}");
         generate_registration_button.removeAttr('disabled');
         return false;
       }
       if (recipient_name == '') {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the recipient name');
+        registration_code_error.text("${_('Please enter the recipient name')}");
         generate_registration_button.removeAttr('disabled');
         return false;
       }
       if (($.isNumeric(recipient_name))) {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the non-numeric value for recipient name');
+        registration_code_error.text("${_('Please enter the non-numeric value for recipient name')}");
         generate_registration_button.removeAttr('disabled');
         return false;
       }
       if (recipient_email == '') {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the recipient email');
+        registration_code_error.text("${_('Please enter the recipient email')}");
         generate_registration_button.removeAttr('disabled');
         return false;
       }
       if (!(validateEmail(recipient_email))) {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the valid email address');
+        registration_code_error.text("${_('Please enter the valid email address')}");
         generate_registration_button.removeAttr('disabled');
         return false;
       }
       if (address_line == '') {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the billing address');
+        registration_code_error.text("${_('Please enter the billing address')}");
         generate_registration_button.removeAttr('disabled');
         return false;
       }
-      if (sale_price == '') {
+      if (unit_price == '') {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the sale price');
+        registration_code_error.text("${_('Please enter the unit price')}");
         generate_registration_button.removeAttr('disabled');
         return false
       }
-      if (!($.isNumeric(sale_price))) {
+      if (!($.isNumeric(unit_price))) {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the numeric value for sale price');
+        registration_code_error.text("${_('Please enter the numeric value for unit price')}");
         generate_registration_button.removeAttr('disabled');
         return false
       }
       if (total_registration_codes == '') {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the total registration codes');
+        registration_code_error.text("${_('Please enter the number of enrollment codes')}");
         generate_registration_button.removeAttr('disabled');
         return false
       }
       if (!($.isNumeric(total_registration_codes))) {
         registration_code_error.attr('style', 'display: block !important');
-        registration_code_error.text('Please enter the numeric value for total registration codes');
+        registration_code_error.text("${_('Please enter the numeric value for number of enrollment codes')}");
         generate_registration_button.removeAttr('disabled');
         return false;
       }
@@ -600,7 +600,7 @@
      $('input[name="country"]').val('');
      $('input[name="customer_reference_number"]').val('');
      $('input[name="recipient_name"]').val('');
-     $('input[name="sale_price"]').val('');
+     $('input[name="unit_price"]').val('');
      $('input[name="recipient_email"]').val('');
      $('input[name="company_contact_name"]').val('');
      $('input[name="company_contact_email"]').val('');

lms/templates/instructor/instructor_dashboard_2/generate_registarion_codes_modal.html

@@ -102,12 +102,12 @@
               </span>
             </li>
             <div class="clearfix"></div>
-            <li class="field required text" id="generate-registration-modal-field-total-price">
-              <label for="id_sale_price" class="required text">${_("Sale Price")}</label>
-              <input class="field required" id="id_sale_price" type="text" name="sale_price"
+            <li class="field required text" id="generate-registration-modal-field-unit-price">
+              <label for="id_unit_price" class="required text">${_("Unit Price")}</label>
+              <input class="field required" id="id_unit_price" type="text" name="unit_price"
                      aria-required="true" />
               <span class="tip-text">
-                ${_("The total price for all enrollments purchased")}
+                ${_("The price per enrollment purchased")}
               </span>
             </li>
             <li class="field required text" id="generate-registration-modal-field-total-codes">