Moved the "accounting.report.reports.utils" module to "accounting.report.utils". It does not make sense to have a wierd and long module name just to make the import pretty.

src/accounting/report/utils/csv_export.py

@@ -0,0 +1,108 @@
+# The Mia! Accounting Flask Project.
+# Author: imacat@mail.imacat.idv.tw (imacat), 2023/3/7
+
+#  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 utilities to export the report as CSV for download.
+
+"""
+import csv
+from abc import ABC, abstractmethod
+from datetime import timedelta, date
+from decimal import Decimal
+from io import StringIO
+
+from flask import Response
+
+from accounting.report.period import Period
+
+
+class BaseCSVRow(ABC):
+    """The base CSV row."""
+
+    @property
+    @abstractmethod
+    def values(self) -> list[str | Decimal | None]:
+        """Returns the values of the row.
+
+        :return: The values of the row.
+        """
+
+
+def csv_download(filename: str, rows: list[BaseCSVRow]) -> Response:
+    """Exports the data rows as a CSV file for download.
+
+    :param filename: The download file name.
+    :param rows: The data rows.
+    :return: The response for download the CSV file.
+    """
+    with StringIO() as fp:
+        writer = csv.writer(fp)
+        writer.writerows([x.values for x in rows])
+        fp.seek(0)
+        response: Response = Response(fp.read(), mimetype="text/csv")
+        response.headers["Content-Disposition"] \
+            = f"attachment; filename={filename}"
+        return response
+
+
+def period_spec(period: Period) -> str:
+    """Constructs the period specification to be used in the filename.
+
+    :param period: The period.
+    :return: The period specification to be used in the filename.
+    """
+    start: str | None = __get_start_str(period.start)
+    end: str | None = __get_end_str(period.end)
+    if period.start is None and period.end is None:
+        return "all-time"
+    if start == end:
+        return start
+    if period.start is None:
+        return f"until-{end}"
+    if period.end is None:
+        return f"since-{start}"
+    return f"{start}-{end}"
+
+
+def __get_start_str(start: date | None) -> str | None:
+    """Returns the string representation of the start date.
+
+    :param start: The start date.
+    :return: The string representation of the start date, or None if the start
+        date is None.
+    """
+    if start is None:
+        return None
+    if start.month == 1 and start.day == 1:
+        return str(start.year)
+    if start.day == 1:
+        return start.strftime("%Y%m")
+    return start.strftime("%Y%m%d")
+
+
+def __get_end_str(end: date | None) -> str | None:
+    """Returns the string representation of the end date.
+
+    :param end: The end date.
+    :return: The string representation of the end date, or None if the end
+        date is None.
+    """
+    if end is None:
+        return None
+    if end.month == 12 and end.day == 31:
+        return str(end.year)
+    if (end + timedelta(days=1)).day == 1:
+        return end.strftime("%Y%m")
+    return end.strftime("%Y%m%d")