Added the currency management.

src/accounting/currency/forms.py

@@ -0,0 +1,93 @@
+# The Mia! Accounting Flask Project.
+# Author: imacat@mail.imacat.idv.tw (imacat), 2023/2/6
+
+#  Copyright (c) 2023 imacat.
+#
+#  Licensed under the Apache License, Version 2.0 (the "License");
+#  you may not use this file except in compliance with the License.
+#  You may obtain a copy of the License at
+#
+#      http://www.apache.org/licenses/LICENSE-2.0
+#
+#  Unless required by applicable law or agreed to in writing, software
+#  distributed under the License is distributed on an "AS IS" BASIS,
+#  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#  See the License for the specific language governing permissions and
+#  limitations under the License.
+"""The forms for the currency management.
+
+"""
+from __future__ import annotations
+
+import sqlalchemy as sa
+from flask_wtf import FlaskForm
+from wtforms import StringField, ValidationError
+from wtforms.validators import DataRequired, Regexp, NoneOf
+
+from accounting.database import db
+from accounting.locale import lazy_gettext
+from accounting.models import Currency
+from accounting.utils.strip_text import strip_text
+from accounting.utils.user import get_current_user_pk
+
+
+class CurrencyForm(FlaskForm):
+    """The form to create or edit a currency."""
+    CODE_BLOCKLIST: list[str] = ["create", "store", "exists-code"]
+    """The reserved codes that are not available."""
+
+    class CodeUnique:
+        """The validator to check if the code is unique."""
+        def __call__(self, form: CurrencyForm, field: StringField) -> None:
+            if field.data == "":
+                return
+            if form.obj_code is not None and form.obj_code == field.data:
+                return
+            if db.session.get(Currency, field.data) is not None:
+                raise ValidationError(lazy_gettext(
+                    "Code conflicts with another currency."))
+
+    code = StringField(
+        filters=[strip_text],
+        validators=[DataRequired(lazy_gettext("Please fill in the code.")),
+                    Regexp(r"^[A-Z]{3}$",
+                           message=lazy_gettext(
+                               "Code can only be composed of 3 upper-cased"
+                               " letters.")),
+                    NoneOf(CODE_BLOCKLIST, message=lazy_gettext(
+                        "This code is not available.")),
+                    CodeUnique()])
+    """The code.  It may not conflict with another currency."""
+    name = StringField(
+        filters=[strip_text],
+        validators=[DataRequired(lazy_gettext("Please fill in the name."))])
+    """The name."""
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.obj_code: str | None = None
+        """The current code of the currency, or None when adding a new
+        currency."""
+
+    def populate_obj(self, obj: Currency) -> None:
+        """Populates the form data into a currency object.
+
+        :param obj: The currency object.
+        :return: None.
+        """
+        is_new: bool = obj.code is None
+        obj.code = self.code.data
+        obj.name = self.name.data
+        if is_new:
+            current_user_pk: int = get_current_user_pk()
+            obj.created_by_id = current_user_pk
+            obj.updated_by_id = current_user_pk
+
+    def post_update(self, obj) -> None:
+        """The post-processing after the update.
+
+        :return: None
+        """
+        current_user_pk: int = get_current_user_pk()
+        obj.updated_by_id = current_user_pk
+        obj.updated_at = sa.func.now()