PartonTransactionEvent: Fix decimal amount problem.

* Creates an extension to check if event amount contains a maximum of 2
  decimals.
* Reorganizing some codes from `PatronTransaction` resource to be more
  readable/usable.
* Closes rero#2602.

Co-Authored-by: Renaud Michotte <[email protected]>

rero_ils/modules/loans/listener.py

@@ -22,7 +22,8 @@
 
 from ..items.api import Item
 from ..loans.logs.api import LoanOperationLog
-from ..patron_transactions.api import PatronTransaction
+from ..patron_transactions.utils import \
+    create_patron_transaction_from_overdue_loan
 
 
 def enrich_loan_data(sender, json=None, record=None, index=None,
@@ -58,8 +59,6 @@ def listener_loan_state_changed(
 
     # Create fees for checkin or extend operations
     if trigger in ['checkin', 'extend']:
-        PatronTransaction.create_patron_transaction_from_overdue_loan(
-            initial_loan
-        )
+        create_patron_transaction_from_overdue_loan(initial_loan)
 
     LoanOperationLog.create(loan)

rero_ils/modules/notifications/api.py

@@ -32,6 +32,8 @@
 from ..minters import id_minter
 from ..patron_transactions.api import PatronTransaction, \
     PatronTransactionsSearch
+from ..patron_transactions.utils import \
+    create_patron_transaction_from_notification
 from ..providers import Provider
 
 # notification provider
@@ -102,7 +104,7 @@ def create(cls, data, id_=None, delete_pid=False, dbcommit=False,
         data.setdefault('status', NotificationStatus.CREATED)
         record = super().create(data, id_, delete_pid, dbcommit, reindex,
                                 **kwargs)
-        PatronTransaction.create_patron_transaction_from_notification(
+        create_patron_transaction_from_notification(
             notification=record, dbcommit=dbcommit, reindex=reindex,
             delete_pid=delete_pid
         )

rero_ils/modules/patron_transaction_events/api.py

@@ -23,8 +23,9 @@
 
 from flask_babelex import gettext as _
 
+from .extentions import DecimalAmountExtension
 from .models import PatronTransactionEventIdentifier, \
-    PatronTransactionEventMetadata
+    PatronTransactionEventMetadata, PatronTransactionEventType
 from ..api import IlsRecord, IlsRecordsIndexer, IlsRecordsSearch
 from ..fetchers import id_fetcher
 from ..minters import id_minter
@@ -76,15 +77,16 @@ class PatronTransactionEvent(IlsRecord):
         }
     }
 
+    _extensions = [
+        DecimalAmountExtension('amount')
+    ]
+
     @classmethod
     def create(cls, data, id_=None, delete_pid=False,
                dbcommit=False, reindex=False, update_parent=True, **kwargs):
         """Create patron transaction event record."""
         if 'creation_date' not in data:
             data['creation_date'] = datetime.now(timezone.utc).isoformat()
-        if 'amount' in data:
-            # ensure multiple of 0.01
-            data['amount'] = round(data['amount'], 2)
         record = super().create(
             data, id_, delete_pid, dbcommit, reindex, **kwargs)
         if update_parent:
@@ -149,18 +151,20 @@ def update_parent_patron_transaction(self):
         #   digits, we can multiply amounts by 100, cast result as integer,
         #   do operation with these values, and (at the end) divide the result
         #   by 100.
-        patron_transaction = self.patron_transaction()
-        total_amount = int(patron_transaction.get('total_amount') * 100)
-        if self.event_type == 'fee':
-            total_amount += int(self.amount * 100)
-        elif self.event_type in ('payment', 'cancel'):
-            total_amount -= int(self.amount * 100)
-        patron_transaction['total_amount'] = total_amount / 100
+        pttr = self.patron_transaction
+        total_amount = int(pttr.get('total_amount') * 100)
+        amount = int(self.amount * 100)
+        if self.event_type == PatronTransactionEventType.FEE:
+            total_amount += amount
+        elif self.event_type in [PatronTransactionEventType.PAYMENT,
+                                 PatronTransactionEventType.CANCEL]:
+            total_amount -= amount
+        pttr['total_amount'] = total_amount / 100
         if total_amount == 0:
-            patron_transaction['status'] = 'closed'
-        patron_transaction.update(
-            patron_transaction, dbcommit=True, reindex=True)
+            pttr['status'] = 'closed'
+        pttr.update(pttr, dbcommit=True, reindex=True)
 
+    @property
     def patron_transaction(self):
         """Return the parent patron transaction of the event."""
         from ..patron_transactions.api import PatronTransaction

rero_ils/modules/patron_transaction_events/extentions.py

@@ -0,0 +1,67 @@
+# -*- coding: utf-8 -*-
+#
+# RERO ILS
+# Copyright (C) 2022 RERO
+# Copyright (C) 2022 UCLouvain
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, version 3 of the License.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program. If not, see <http://www.gnu.org/licenses/>.
+
+"""PatronTransactionEvent record extensions."""
+
+from invenio_records.extensions import RecordExtension
+from jsonschema import ValidationError
+
+
+class DecimalAmountExtension(RecordExtension):
+    """Check and transform a decimal amount into integer representation."""
+
+    def __init__(self, field_name, decimals=2):
+        """Extension initialization.
+
+        :param field_name: the field name where found the amount to analyze.
+        :param decimals: the number of decimal accepted.
+        """
+        self.amount_field = field_name
+        self.multiplier = pow(10, decimals)
+
+    def _check_amount(self, record):
+        """Check if the record has the correct decimal number.
+
+        :param record: the record to validate.
+        :raise ValidationError if the amount doesn't respect the decimal amount
+        """
+        # Check `self.amount_field` exists into the record. If not, we can
+        # return without record modification.
+        if self.amount_field not in record:
+            return
+
+        # Check that the amount field has the correct decimals. If not, a
+        # `ValidationError` error will be raised.
+        # NOTE:
+        #   an amount of "123,450" is true despite if we configure only 2
+        #   decimals. In same way "123,4" is also a valid value.
+        # DEV NOTE :
+        #   rounding the number, keeping one decimal will prevent the floating
+        #   numbers problem
+        #   >>> 2.2 * 100              --> 220.00000000000003
+        #   >>> round(2.2 * 100, 1)    --> 220.0
+        #   >>> round(2.234 * 100, 1)  --> 223.4
+        #   >>> round(2.2345 * 100, 1) --> 223.5
+        quotient = round(record[self.amount_field] * self.multiplier, 1)
+        if (quotient % 1) != 0:
+            decimal = 1 / self.multiplier
+            msg = f'`{self.amount_field}` must be multiple of {decimal}'
+            raise ValidationError(msg)
+
+    pre_commit = _check_amount
+    pre_create = _check_amount

rero_ils/modules/patron_transaction_events/jsonschemas/patron_transaction_events/patron_transaction_event-v0.0.1.json

@@ -42,9 +42,9 @@
     },
     "amount": {
       "title": "Amount",
+      "description": "The fee amount as cents",
       "type": "number",
-      "exclusiveMinimum": 0,
-      "multipleOf": 0.01
+      "exclusiveMinimum": 0
     },
     "steps": {
       "title": "Steps",
@@ -60,8 +60,7 @@
           },
           "amount": {
             "type": "number",
-            "exclusiveMinimum": 0,
-            "multipleOf": 0.01
+            "exclusiveMinimum": 0
           }
         },
         "required": [

rero_ils/modules/patron_transaction_events/models.py

@@ -40,3 +40,12 @@ class PatronTransactionEventMetadata(db.Model, RecordMetadataBase):
     """PatronTransactionEvent record metadata."""
 
     __tablename__ = 'patron_transaction_event_metadata'
+
+
+class PatronTransactionEventType:
+    """Type of PatronTransactionEvent."""
+
+    FEE = 'fee'
+    PAYMENT = 'payment'
+    DISPUTE = 'dispute'
+    CANCEL = 'cancel'