Replaced the report generators with a separated module for each report, to work with the diversity of the report formats without messing-up one another.

src/accounting/report/reports/__init__.py

@@ -0,0 +1,25 @@
+# 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 reports.
+
+"""
+from .balance_sheet import BalanceSheet
+from .income_expenses import IncomeExpenses
+from .income_statement import IncomeStatement
+from .journal import Journal
+from .ledger import Ledger
+from .trial_balance import TrialBalance

src/accounting/report/reports/balance_sheet.py

@@ -0,0 +1,505 @@
+# 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 balance sheet.
+
+"""
+import csv
+from decimal import Decimal
+from io import StringIO
+
+import sqlalchemy as sa
+from flask import url_for, render_template, Response
+
+from accounting import db
+from accounting.locale import gettext
+from accounting.models import Currency, BaseAccount, Account, Transaction, \
+    JournalEntry
+from accounting.report.option_link import OptionLink
+from accounting.report.page_params import PageParams
+from accounting.report.period import Period
+from accounting.report.period_choosers import BalanceSheetPeriodChooser
+from accounting.report.report_chooser import ReportChooser
+from accounting.report.report_type import ReportType
+
+
+class BalanceSheetAccount:
+    """An account in the balance sheet."""
+
+    def __init__(self, account: Account, amount: Decimal, url: str):
+        """Constructs an account in the balance sheet.
+
+        :param account: The account.
+        :param amount: The amount.
+        :param url: The URL to the ledger of the account.
+        """
+        self.account: Account = account
+        """The account."""
+        self.amount: Decimal = amount
+        """The amount of the account."""
+        self.url: str = url
+        """The URL to the ledger of the account."""
+
+
+class BalanceSheetSubsection:
+    """A subsection in the balance sheet."""
+
+    def __init__(self, title: BaseAccount):
+        """Constructs a subsection in the balance sheet.
+
+        :param title: The title account.
+        """
+        self.title: BaseAccount = title
+        """The title account."""
+        self.accounts: list[BalanceSheetAccount] = []
+        """The accounts in the subsection."""
+
+    @property
+    def total(self) -> Decimal:
+        """Returns the total of the subsection.
+
+        :return: The total of the subsection.
+        """
+        return sum([x.amount for x in self.accounts])
+
+
+class BalanceSheetSection:
+    """A section in the balance sheet."""
+
+    def __init__(self, title: BaseAccount):
+        """Constructs a section in the balance sheet.
+
+        :param title: The title account.
+        """
+        self.title: BaseAccount = title
+        """The title account."""
+        self.subsections: list[BalanceSheetSubsection] = []
+        """The subsections in the section."""
+
+    @property
+    def total(self) -> Decimal:
+        """Returns the total of the section.
+
+        :return: The total of the section.
+        """
+        return sum([x.total for x in self.subsections])
+
+
+class AccountCollector:
+    """The balance sheet account collector."""
+
+    def __init__(self, currency: Currency, period: Period):
+        """Constructs the balance sheet account collector.
+
+        :param currency: The currency.
+        :param period: The period.
+        """
+        self.__currency: Currency = currency
+        """The currency."""
+        self.__period: Period = period
+        """The period."""
+        self.accounts: list[BalanceSheetAccount] = self.__query_balances()
+        """The balance sheet accounts."""
+
+    def __query_balances(self) -> list[BalanceSheetAccount]:
+        """Queries and returns the balances.
+
+        :return: The balances.
+        """
+        sub_conditions: list[sa.BinaryExpression] \
+            = [Account.base_code.startswith(x) for x in {"1", "2", "3"}]
+        conditions: list[sa.BinaryExpression] \
+            = [JournalEntry.currency_code == self.__currency.code,
+               sa.or_(*sub_conditions)]
+        if self.__period.end is not None:
+            conditions.append(Transaction.date <= self.__period.end)
+        balance_func: sa.Function = sa.func.sum(sa.case(
+            (JournalEntry.is_debit, JournalEntry.amount),
+            else_=-JournalEntry.amount)).label("balance")
+        select_balance: sa.Select \
+            = sa.select(Account.id, Account.base_code, Account.no,
+                        balance_func)\
+            .join(Transaction).join(Account)\
+            .filter(*conditions)\
+            .group_by(Account.id, Account.base_code, Account.no)\
+            .order_by(Account.base_code, Account.no)
+        account_balances: list[sa.Row] \
+            = db.session.execute(select_balance).all()
+        self.__all_accounts: list[Account] = Account.query\
+            .filter(sa.or_(Account.id.in_({x.id for x in account_balances}),
+                           Account.base_code == "3351",
+                           Account.base_code == "3353")).all()
+        account_by_id: dict[int, Account] \
+            = {x.id: x for x in self.__all_accounts}
+
+        def get_url(account: Account) -> str:
+            """Returns the ledger URL of an account.
+
+            :param account: The account.
+            :return: The ledger URL of the account.
+            """
+            if self.__period.is_default:
+                return url_for("accounting.report.ledger-default",
+                               currency=self.__currency, account=account)
+            return url_for("accounting.report.ledger",
+                           currency=self.__currency, account=account,
+                           period=self.__period)
+
+        self.accounts: list[BalanceSheetAccount] \
+            = [BalanceSheetAccount(account=account_by_id[x.id],
+                                   amount=x.balance,
+                                   url=get_url(account_by_id[x.id]))
+               for x in account_balances]
+        self.__add_accumulated()
+        self.__add_current_period()
+        self.accounts.sort(key=lambda x: (x.account.base_code, x.account.no))
+        for balance in self.accounts:
+            if not balance.account.base_code.startswith("1"):
+                balance.amount = -balance.amount
+        return self.accounts
+
+    def __add_accumulated(self) -> None:
+        """Adds the accumulated profit or loss to the balances.
+
+        :return: None.
+        """
+        code: str = "3351-001"
+        amount: Decimal | None = self.__query_accumulated()
+        url: str = url_for("accounting.report.income-statement",
+                           currency=self.__currency,
+                           period=self.__period.before)
+        self.__add_owner_s_equity(code, amount, url)
+
+    def __query_accumulated(self) -> Decimal | None:
+        """Queries and returns the accumulated profit or loss.
+
+        :return: The accumulated profit or loss.
+        """
+        if self.__period.start is None:
+            return None
+        conditions: list[sa.BinaryExpression] \
+            = [JournalEntry.currency_code == self.__currency.code,
+               Transaction.date < self.__period.start]
+        conditions.extend([sa.not_(Account.base_code.startswith(x))
+                           for x in {"1", "2"}])
+        balance_func: sa.Function = sa.func.sum(sa.case(
+            (JournalEntry.is_debit, JournalEntry.amount),
+            else_=-JournalEntry.amount)).label("balance")
+        select_balance: sa.Select = sa.select(balance_func)\
+            .join(Transaction).join(Account).filter(*conditions)
+        return db.session.scalar(select_balance)
+
+    def __add_current_period(self) -> None:
+        """Adds the accumulated profit or loss to the balances.
+
+        :return: None.
+        """
+        code: str = "3353-001"
+        amount: Decimal | None = self.__query_currency_period()
+        url: str = url_for("accounting.report.income-statement",
+                           currency=self.__currency, period=self.__period)
+        self.__add_owner_s_equity(code, amount, url)
+
+    def __query_currency_period(self) -> Decimal | None:
+        """Queries and returns the net income or loss for current period.
+
+        :return: The net income or loss for current period.
+        """
+        conditions: list[sa.BinaryExpression] \
+            = [JournalEntry.currency_code == self.__currency.code]
+        if self.__period.start is not None:
+            conditions.append(Transaction.date >= self.__period.start)
+        if self.__period.end is not None:
+            conditions.append(Transaction.date <= self.__period.end)
+        conditions.extend([sa.not_(Account.base_code.startswith(x))
+                           for x in {"1", "2"}])
+        balance_func: sa.Function = sa.func.sum(sa.case(
+            (JournalEntry.is_debit, JournalEntry.amount),
+            else_=-JournalEntry.amount)).label("balance")
+        select_balance: sa.Select = sa.select(balance_func)\
+            .join(Transaction).join(Account).filter(*conditions)
+        return db.session.scalar(select_balance)
+
+    def __add_owner_s_equity(self, code: str, amount: Decimal | None,
+                             url: str) -> None:
+        """Adds an owner's equity balance.
+
+        :param code: The code of the account to add.
+        :param amount: The amount.
+        :return: None.
+        """
+        # There is an existing balance.
+        account_balance_by_code: dict[str, BalanceSheetAccount] \
+            = {x.account.code: x for x in self.accounts}
+        if code in account_balance_by_code:
+            balance: BalanceSheetAccount = account_balance_by_code[code]
+            balance.url = url
+            if amount is not None:
+                balance.amount = balance.amount + amount
+            return
+        # Add a new balance
+        if amount is None:
+            return
+        account_by_code: dict[str, Account] \
+            = {x.code: x for x in self.__all_accounts}
+        self.accounts.append(BalanceSheetAccount(account=account_by_code[code],
+                                                 amount=amount,
+                                                 url=url))
+
+
+class CSVHalfRow:
+    """A half row in the CSV balance sheet."""
+
+    def __init__(self, title: str | None, amount: Decimal | None):
+        """The constructs a half row in the CSV balance sheet.
+
+        :param title: The title.
+        :param amount: The amount.
+        """
+        self.title: str | None = title
+        """The title."""
+        self.amount: Decimal | None = amount
+        """The amount."""
+
+
+class CSVRow:
+    """A row in the CSV balance sheet."""
+
+    def __init__(self):
+        """Constructs a row in the CSV balance sheet."""
+        self.asset_title: str | None = None
+        """The title of the asset."""
+        self.asset_amount: Decimal | None = None
+        """The amount of the asset."""
+        self.liability_title: str | None = None
+        """The title of the liability."""
+        self.liability_amount: Decimal | None = None
+        """The amount of the liability."""
+
+    @property
+    def values(self) -> list[str | Decimal | None]:
+        """Returns the values of the row.
+
+        :return: The values of the row.
+        """
+        return [self.asset_title, self.asset_amount,
+                self.liability_title, self.liability_amount]
+
+
+class BalanceSheetPageParams(PageParams):
+    """The HTML parameters of the balance sheet."""
+
+    def __init__(self, currency: Currency,
+                 period: Period,
+                 has_data: bool,
+                 assets: BalanceSheetSection,
+                 liabilities: BalanceSheetSection,
+                 owner_s_equity: BalanceSheetSection):
+        """Constructs the HTML parameters of the balance sheet.
+
+        :param currency: The currency.
+        :param period: The period.
+        :param has_data: True if there is any data, or False otherwise.
+        :param assets: The assets.
+        :param liabilities: The liabilities.
+        :param owner_s_equity: The owner's equity.
+        """
+        self.currency: Currency = currency
+        """The currency."""
+        self.period: Period = period
+        """The period."""
+        self.__has_data: bool = has_data
+        """True if there is any data, or False otherwise."""
+        self.assets: BalanceSheetSection = assets
+        """The assets."""
+        self.liabilities: BalanceSheetSection = liabilities
+        """The liabilities."""
+        self.owner_s_equity: BalanceSheetSection = owner_s_equity
+        """The owner's equity."""
+        self.period_chooser: BalanceSheetPeriodChooser \
+            = BalanceSheetPeriodChooser(currency)
+        """The period chooser."""
+
+    @property
+    def has_data(self) -> bool:
+        """Returns whether there is any data on the page.
+
+        :return: True if there is any data, or False otherwise.
+        """
+        return self.__has_data
+
+    @property
+    def report_chooser(self) -> ReportChooser:
+        """Returns the report chooser.
+
+        :return: The report chooser.
+        """
+        return ReportChooser(ReportType.BALANCE_SHEET,
+                             currency=self.currency,
+                             period=self.period)
+
+    @property
+    def currency_options(self) -> list[OptionLink]:
+        """Returns the currency options.
+
+        :return: The currency options.
+        """
+        def get_url(currency: Currency):
+            if self.period.is_default:
+                return url_for("accounting.report.balance-sheet-default",
+                               currency=currency)
+            return url_for("accounting.report.balance-sheet",
+                           currency=currency, period=self.period)
+
+        in_use: set[str] = set(db.session.scalars(
+            sa.select(JournalEntry.currency_code)
+            .group_by(JournalEntry.currency_code)).all())
+        return [OptionLink(str(x), get_url(x), x.code == self.currency.code)
+                for x in Currency.query.filter(Currency.code.in_(in_use))
+                .order_by(Currency.code).all()]
+
+
+class BalanceSheet:
+    """The balance sheet."""
+
+    def __init__(self, currency: Currency, period: Period):
+        """Constructs a balance sheet.
+
+        :param currency: The currency.
+        :param period: The period.
+        """
+        self.__currency: Currency = currency
+        """The currency."""
+        self.__period: Period = period
+        """The period."""
+        self.__has_data: bool
+        """True if there is any data, or False otherwise."""
+        self.__assets: BalanceSheetSection
+        """The assets."""
+        self.__liabilities: BalanceSheetSection
+        """The liabilities."""
+        self.__owner_s_equity: BalanceSheetSection
+        """The owner's equity."""
+        self.__set_data()
+
+    def __set_data(self) -> None:
+        """Queries and sets assets, the liabilities, and the owner's equity
+        sections in the balance sheet.
+
+        :return: None.
+        """
+        balances: list[BalanceSheetAccount] = AccountCollector(
+            self.__currency, self.__period).accounts
+
+        titles: list[BaseAccount] = BaseAccount.query\
+            .filter(BaseAccount.code.in_({"1", "2", "3"})).all()
+        subtitles: list[BaseAccount] = BaseAccount.query\
+            .filter(BaseAccount.code.in_({x.account.base_code[:2]
+                                          for x in balances})).all()
+
+        sections: dict[str, BalanceSheetSection] \
+            = {x.code: BalanceSheetSection(x) for x in titles}
+        subsections: dict[str, BalanceSheetSubsection] \
+            = {x.code: BalanceSheetSubsection(x) for x in subtitles}
+        for subsection in subsections.values():
+            sections[subsection.title.code[0]].subsections.append(subsection)
+        for balance in balances:
+            subsections[balance.account.base_code[:2]].accounts.append(balance)
+
+        self.__has_data = len(balances) > 0
+        self.__assets = sections["1"]
+        self.__liabilities = sections["2"]
+        self.__owner_s_equity = sections["3"]
+
+    def csv(self) -> Response:
+        """Returns the report as CSV for download.
+
+        :return: The response of the report for download.
+        """
+        filename: str = "balance-sheet-{currency}-{period}.csv"\
+            .format(currency=self.__currency.code, period=self.__period.spec)
+        rows: list[CSVRow] = self.__get_csv_rows()
+        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 __get_csv_rows(self) -> list[CSVRow]:
+        """Composes and returns the CSV rows.
+
+        :return: The CSV rows.
+        """
+        asset_rows: list[CSVHalfRow] = self.__section_csv_rows(self.__assets)
+        liability_rows: list[CSVHalfRow] = []
+        liability_rows.extend(self.__section_csv_rows(self.__liabilities))
+        liability_rows.append(CSVHalfRow(gettext("Total"),
+                                         self.__liabilities.total))
+        liability_rows.append(CSVHalfRow(None, None))
+        liability_rows.extend(self.__section_csv_rows(self.__owner_s_equity))
+        liability_rows.append(CSVHalfRow(gettext("Total"),
+                                         self.__owner_s_equity.total))
+        rows: list[CSVRow] = [CSVRow() for _ in
+                              range(max(len(asset_rows), len(liability_rows)))]
+        for i in range(len(rows)):
+            if i < len(asset_rows):
+                rows[i].asset_title = asset_rows[i].title
+                rows[i].asset_amount = asset_rows[i].amount
+            if i < len(liability_rows) and liability_rows[i].title is not None:
+                rows[i].liability_title = liability_rows[i].title
+                rows[i].liability_amount = liability_rows[i].amount
+        total: CSVRow = CSVRow()
+        total.asset_title = gettext("Total")
+        total.asset_amount = self.__assets.total
+        total.liability_title = gettext("Total")
+        total.liability_amount \
+            = self.__liabilities.total + self.__owner_s_equity.total
+        rows.append(total)
+        return rows
+
+    @staticmethod
+    def __section_csv_rows(section: BalanceSheetSection) -> list[CSVHalfRow]:
+        """Gathers the CSV rows for a section.
+
+        :param section: The section.
+        :return: The CSV rows for the section.
+        """
+        rows: list[CSVHalfRow] \
+            = [CSVHalfRow(section.title.title.title(), None)]
+        for subsection in section.subsections:
+            rows.append(CSVHalfRow(f" {subsection.title.title.title()}", None))
+            for account in subsection.accounts:
+                rows.append(CSVHalfRow(f"  {str(account.account).title()}",
+                                       account.amount))
+        return rows
+
+    def html(self) -> str:
+        """Composes and returns the report as HTML.
+
+        :return: The report as HTML.
+        """
+        params: BalanceSheetPageParams = BalanceSheetPageParams(
+            currency=self.__currency,
+            period=self.__period,
+            has_data=self.__has_data,
+            assets=self.__assets,
+            liabilities=self.__liabilities,
+            owner_s_equity=self.__owner_s_equity)
+        return render_template("accounting/report/balance-sheet.html",
+                               report=params)

src/accounting/report/reports/income_expenses.py

@@ -0,0 +1,466 @@
+# 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 income and expenses log.
+
+"""
+import csv
+from datetime import date
+from decimal import Decimal
+from io import StringIO
+
+import sqlalchemy as sa
+from flask import url_for, render_template, Response
+
+from accounting import db
+from accounting.locale import gettext
+from accounting.models import Currency, Account, Transaction, JournalEntry
+from accounting.report.option_link import OptionLink
+from accounting.report.page_params import PageParams
+from accounting.report.period import Period
+from accounting.report.period_choosers import IncomeExpensesPeriodChooser
+from accounting.report.report_chooser import ReportChooser
+from accounting.report.report_type import ReportType
+from accounting.utils.pagination import Pagination
+
+
+class Entry:
+    """An entry in the income and expenses log."""
+
+    def __init__(self, entry: JournalEntry | None = None):
+        """Constructs the entry in the income and expenses log.
+
+        :param entry: The journal entry.
+        """
+        self.entry: JournalEntry | None = None
+        """The journal entry."""
+        self.transaction: Transaction | None = None
+        """The transaction."""
+        self.is_brought_forward: bool = False
+        """Whether this is the brought-forward entry."""
+        self.is_total: bool = False
+        """Whether this is the total entry."""
+        self.date: date | None = None
+        """The date."""
+        self.account: Account | None = None
+        """The account."""
+        self.summary: str | None = None
+        """The summary."""
+        self.income: Decimal | None = None
+        """The income amount."""
+        self.expense: Decimal | None = None
+        """The expense amount."""
+        self.balance: Decimal | None = None
+        """The balance."""
+        self.note: str | None = None
+        """The note."""
+        if entry is not None:
+            self.entry = entry
+            self.summary = entry.summary
+            self.income = None if entry.is_debit else entry.amount
+            self.expense = entry.amount if entry.is_debit else None
+
+
+class EntryCollector:
+    """The income and expenses log entry collector."""
+
+    def __init__(self, currency: Currency, account: Account, period: Period):
+        """Constructs the income and expenses log entry collector.
+
+        :param currency: The currency.
+        :param account: The account.
+        :param period: The period.
+        """
+        self.__currency: Currency = currency
+        """The currency."""
+        self.__account: Account = account
+        """The account."""
+        self.__period: Period = period
+        """The period"""
+        self.brought_forward: Entry | None
+        """The brought-forward entry."""
+        self.entries: list[Entry]
+        """The log entries."""
+        self.total: Entry
+        """The total entry."""
+        self.brought_forward = self.__get_brought_forward_entry()
+        self.entries = self.__query_entries()
+        self.total = self.__get_total_entry()
+        self.__populate_balance()
+
+    def __get_brought_forward_entry(self) -> Entry | None:
+        """Queries, composes and returns the brought-forward entry.
+
+        :return: The brought-forward entry, or None if the period starts from
+            the beginning.
+        """
+        if self.__period.start is None:
+            return None
+        balance_func: sa.Function = sa.func.sum(sa.case(
+            (JournalEntry.is_debit, JournalEntry.amount),
+            else_=-JournalEntry.amount))
+        select: sa.Select = sa.Select(balance_func).join(Transaction)\
+            .filter(JournalEntry.currency_code == self.__currency.code,
+                    JournalEntry.account_id == self.__account.id,
+                    Transaction.date < self.__period.start)
+        balance: int | None = db.session.scalar(select)
+        if balance is None:
+            return None
+        entry: Entry = Entry()
+        entry.is_brought_forward = True
+        entry.date = self.__period.start
+        entry.account = Account.find_by_code("3351-001")
+        entry.summary = gettext("Brought forward")
+        if balance > 0:
+            entry.income = balance
+        elif balance < 0:
+            entry.expense = -balance
+        entry.balance = balance
+        return entry
+
+    def __query_entries(self) -> list[Entry]:
+        """Queries and returns the log entries.
+
+        :return: The log entries.
+        """
+        conditions: list[sa.BinaryExpression] \
+            = [JournalEntry.currency_code == self.__currency.code,
+               JournalEntry.account_id == self.__account.id]
+        if self.__period.start is not None:
+            conditions.append(Transaction.date >= self.__period.start)
+        if self.__period.end is not None:
+            conditions.append(Transaction.date <= self.__period.end)
+        txn_with_account: sa.Select = sa.Select(Transaction.id).\
+            join(JournalEntry).filter(*conditions)
+
+        return [Entry(x)
+                for x in JournalEntry.query.join(Transaction)
+                .filter(JournalEntry.transaction_id.in_(txn_with_account),
+                        JournalEntry.currency_code == self.__currency.code,
+                        JournalEntry.account_id != self.__account.id)
+                .order_by(Transaction.date,
+                          JournalEntry.is_debit,
+                          JournalEntry.no)]
+
+    def __get_total_entry(self) -> Entry:
+        """Composes the total entry.
+
+        :return: None.
+        """
+        entry: Entry = Entry()
+        entry.is_total = True
+        entry.summary = gettext("Total")
+        entry.income = sum([x.income for x in self.entries
+                            if x.income is not None])
+        entry.expense = sum([x.expense for x in self.entries
+                             if x.expense is not None])
+        entry.balance = entry.income - entry.expense
+        if self.brought_forward is not None:
+            entry.balance = self.brought_forward.balance + entry.balance
+        return entry
+
+    def __populate_balance(self) -> None:
+        """Populates the balance of the entries.
+
+        :return: None.
+        """
+        balance: Decimal = 0 if self.brought_forward is None \
+            else self.brought_forward.balance
+        for entry in self.entries:
+            if entry.income is not None:
+                balance = balance + entry.income
+            if entry.expense is not None:
+                balance = balance - entry.expense
+            entry.balance = balance
+
+
+class CSVRow:
+    """A row in the CSV income and expenses log."""
+
+    def __init__(self, txn_date: date | str | None,
+                 account: str | None,
+                 summary: str | None,
+                 income: str | Decimal | None,
+                 expense: str | Decimal | None,
+                 balance: str | Decimal | None,
+                 note: str | None):
+        """Constructs a row in the CSV income and expenses log.
+
+        :param txn_date: The transaction date.
+        :param account: The account.
+        :param summary: The summary.
+        :param income: The income.
+        :param expense: The expense.
+        :param balance: The balance.
+        :param note: The note.
+        """
+        self.date: date | str | None = txn_date
+        """The date."""
+        self.account: str | None = account
+        """The account."""
+        self.summary: str | None = summary
+        """The summary."""
+        self.income: str | Decimal | None = income
+        """The income."""
+        self.expense: str | Decimal | None = expense
+        """The expense."""
+        self.balance: str | Decimal | None = balance
+        """The balance."""
+        self.note: str | None = note
+        """The note."""
+
+    @property
+    def values(self) -> list[str | Decimal | None]:
+        """Returns the values of the row.
+
+        :return: The values of the row.
+        """
+        return [self.date, self.account, self.summary,
+                self.income, self.expense, self.balance, self.note]
+
+
+class IncomeExpensesPageParams(PageParams):
+    """The HTML parameters of the income and expenses log."""
+
+    def __init__(self, currency: Currency,
+                 account: Account,
+                 period: Period,
+                 has_data: bool,
+                 pagination: Pagination[Entry],
+                 brought_forward: Entry | None,
+                 entries: list[Entry],
+                 total: Entry | None):
+        """Constructs the HTML parameters of the income and expenses log.
+
+        :param currency: The currency.
+        :param account: The account.
+        :param period: The period.
+        :param has_data: True if there is any data, or False otherwise.
+        :param brought_forward: The brought-forward entry.
+        :param entries: The log entries.
+        :param total: The total entry.
+        """
+        self.currency: Currency = currency
+        """The currency."""
+        self.account: Account = account
+        """The account."""
+        self.period: Period = period
+        """The period."""
+        self.__has_data: bool = has_data
+        """True if there is any data, or False otherwise."""
+        self.pagination: Pagination[Entry] = pagination
+        """The pagination."""
+        self.brought_forward: Entry | None = brought_forward
+        """The brought-forward entry."""
+        self.entries: list[Entry] = entries
+        """The entries."""
+        self.total: Entry | None = total
+        """The total entry."""
+        self.period_chooser: IncomeExpensesPeriodChooser \
+            = IncomeExpensesPeriodChooser(currency, account)
+        """The period chooser."""
+
+    @property
+    def has_data(self) -> bool:
+        """Returns whether there is any data on the page.
+
+        :return: True if there is any data, or False otherwise.
+        """
+        return self.__has_data
+
+    @property
+    def report_chooser(self) -> ReportChooser:
+        """Returns the report chooser.
+
+        :return: The report chooser.
+        """
+        return ReportChooser(ReportType.INCOME_EXPENSES,
+                             currency=self.currency,
+                             account=self.account,
+                             period=self.period)
+
+    @property
+    def currency_options(self) -> list[OptionLink]:
+        """Returns the currency options.
+
+        :return: The currency options.
+        """
+        def get_url(currency: Currency):
+            if self.period.is_default:
+                return url_for("accounting.report.income-expenses-default",
+                               currency=currency, account=self.account)
+            return url_for("accounting.report.income-expenses",
+                           currency=currency, account=self.account,
+                           period=self.period)
+
+        in_use: set[str] = set(db.session.scalars(
+            sa.select(JournalEntry.currency_code)
+            .group_by(JournalEntry.currency_code)).all())
+        return [OptionLink(str(x), get_url(x), x.code == self.currency.code)
+                for x in Currency.query.filter(Currency.code.in_(in_use))
+                .order_by(Currency.code).all()]
+
+    @property
+    def account_options(self) -> list[OptionLink]:
+        """Returns the account options.
+
+        :return: The account options.
+        """
+        def get_url(account: Account):
+            if self.period.is_default:
+                return url_for("accounting.report.income-expenses-default",
+                               currency=self.currency, account=account)
+            return url_for("accounting.report.income-expenses",
+                           currency=self.currency, account=account,
+                           period=self.period)
+
+        in_use: sa.Select = sa.Select(JournalEntry.account_id)\
+            .join(Account)\
+            .filter(JournalEntry.currency_code == self.currency.code,
+                    sa.or_(Account.base_code.startswith("11"),
+                           Account.base_code.startswith("12"),
+                           Account.base_code.startswith("21"),
+                           Account.base_code.startswith("22")))\
+            .group_by(JournalEntry.account_id)
+        return [OptionLink(str(x), get_url(x), x.id == self.account.id)
+                for x in Account.query.filter(Account.id.in_(in_use))
+                .order_by(Account.base_code, Account.no).all()]
+
+
+def _populate_entries(entries: list[Entry]) -> None:
+    """Populates the income and expenses entries with relative data.
+
+    :param entries: The income and expenses entries.
+    :return: None.
+    """
+    transactions: dict[int, Transaction] \
+        = {x.id: x for x in Transaction.query.filter(
+           Transaction.id.in_({x.entry.transaction_id for x in entries
+                               if x.entry is not None}))}
+    accounts: dict[int, Account] \
+        = {x.id: x for x in Account.query.filter(
+           Account.id.in_({x.entry.account_id for x in entries
+                           if x.entry is not None}))}
+    for entry in entries:
+        if entry.entry is not None:
+            entry.transaction = transactions[entry.entry.transaction_id]
+            entry.date = entry.transaction.date
+            entry.note = entry.transaction.note
+            entry.account = accounts[entry.entry.account_id]
+
+
+class IncomeExpenses:
+    """The income and expenses log."""
+
+    def __init__(self, currency: Currency, account: Account, period: Period):
+        """Constructs an income and expenses log.
+
+        :param currency: The currency.
+        :param account: The account.
+        :param period: The period.
+        """
+        self.__currency: Currency = currency
+        """The currency."""
+        self.__account: Account = account
+        """The account."""
+        self.__period: Period = period
+        """The period."""
+        collector: EntryCollector = EntryCollector(
+            self.__currency, self.__account, self.__period)
+        self.__brought_forward: Entry | None = collector.brought_forward
+        """The brought-forward entry."""
+        self.__entries: list[Entry] = collector.entries
+        """The log entries."""
+        self.__total: Entry = collector.total
+        """The total entry."""
+
+    def csv(self) -> Response:
+        """Returns the report as CSV for download.
+
+        :return: The response of the report for download.
+        """
+        filename: str = "income-expenses-{currency}-{account}-{period}.csv"\
+            .format(currency=self.__currency.code, account=self.__account.code,
+                    period=self.__period.spec)
+        rows: list[CSVRow] = self.__get_csv_rows()
+        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 __get_csv_rows(self) -> list[CSVRow]:
+        """Composes and returns the CSV rows.
+
+        :return: The CSV rows.
+        """
+        _populate_entries(self.__entries)
+        rows: list[CSVRow] = [CSVRow(gettext("Date"), gettext("Account"),
+                                     gettext("Summary"), gettext("Income"),
+                                     gettext("Expense"), gettext("Balance"),
+                                     gettext("Note"))]
+        if self.__brought_forward is not None:
+            rows.append(CSVRow(self.__brought_forward.date,
+                               str(self.__brought_forward.account).title(),
+                               self.__brought_forward.summary,
+                               self.__brought_forward.income,
+                               self.__brought_forward.expense,
+                               self.__brought_forward.balance,
+                               None))
+        rows.extend([CSVRow(x.date, str(x.account).title(), x.summary,
+                            x.income, x.expense, x.balance, x.note)
+                     for x in self.__entries])
+        rows.append(CSVRow(gettext("Total"), None, None,
+                           self.__total.income, self.__total.expense,
+                           self.__total.balance, None))
+        return rows
+
+    def html(self) -> str:
+        """Composes and returns the report as HTML.
+
+        :return: The report as HTML.
+        """
+        all_entries: list[Entry] = []
+        if self.__brought_forward is not None:
+            all_entries.append(self.__brought_forward)
+        all_entries.extend(self.__entries)
+        all_entries.append(self.__total)
+        pagination: Pagination[Entry] = Pagination[Entry](all_entries)
+        page_entries: list[Entry] = pagination.list
+        has_data: bool = len(page_entries) > 0
+        _populate_entries(page_entries)
+        brought_forward: Entry | None = None
+        if page_entries[0].is_brought_forward:
+            brought_forward = page_entries[0]
+            page_entries = page_entries[1:]
+        total: Entry | None = None
+        if page_entries[-1].is_total:
+            total = page_entries[-1]
+            page_entries = page_entries[:-1]
+        params: IncomeExpensesPageParams = IncomeExpensesPageParams(
+            currency=self.__currency,
+            account=self.__account,
+            period=self.__period,
+            has_data=has_data,
+            pagination=pagination,
+            brought_forward=brought_forward,
+            entries=page_entries,
+            total=total)
+        return render_template("accounting/report/income-expenses.html",
+                               report=params)

src/accounting/report/reports/income_statement.py

@@ -0,0 +1,356 @@
+# 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 income statement.
+
+"""
+import csv
+from decimal import Decimal
+from io import StringIO
+
+import sqlalchemy as sa
+from flask import url_for, render_template, Response
+
+from accounting import db
+from accounting.locale import gettext
+from accounting.models import Currency, BaseAccount, Account, Transaction, \
+    JournalEntry
+from accounting.report.option_link import OptionLink
+from accounting.report.page_params import PageParams
+from accounting.report.period import Period
+from accounting.report.period_choosers import IncomeStatementPeriodChooser
+from accounting.report.report_chooser import ReportChooser
+from accounting.report.report_type import ReportType
+
+
+class IncomeStatementAccount:
+    """An account in the income statement."""
+
+    def __init__(self, account: Account, amount: Decimal, url: str):
+        """Constructs an account in the income statement.
+
+        :param account: The account.
+        :param amount: The amount.
+        :param url: The URL to the ledger of the account.
+        """
+        self.account: Account = account
+        """The account."""
+        self.amount: Decimal = amount
+        """The amount of the account."""
+        self.url: str = url
+        """The URL to the ledger of the account."""
+
+
+class IncomeStatementAccumulatedTotal:
+    """An accumulated total in the income statement."""
+
+    def __init__(self, title: str):
+        """Constructs an accumulated total in the income statement.
+
+        :param title: The title.
+        """
+        self.title: str = title
+        """The account."""
+        self.amount: Decimal = Decimal("0")
+        """The amount of the account."""
+
+
+class IncomeStatementSubsection:
+    """A subsection in the income statement."""
+
+    def __init__(self, title: BaseAccount):
+        """Constructs a subsection in the income statement.
+
+        :param title: The title account.
+        """
+        self.title: BaseAccount = title
+        """The title account."""
+        self.accounts: list[IncomeStatementAccount] = []
+        """The accounts in the subsection."""
+
+    @property
+    def total(self) -> Decimal:
+        """Returns the total of the subsection.
+
+        :return: The total of the subsection.
+        """
+        return sum([x.amount for x in self.accounts])
+
+
+class IncomeStatementSection:
+    """A section in the income statement."""
+
+    def __init__(self, title: BaseAccount, accumulated_title: str):
+        """Constructs a section in the income statement.
+
+        :param title: The title account.
+        :param accumulated_title: The title for the accumulated total.
+        """
+        self.title: BaseAccount = title
+        """The title account."""
+        self.subsections: list[IncomeStatementSubsection] = []
+        """The subsections in the section."""
+        self.accumulated: IncomeStatementAccumulatedTotal \
+            = IncomeStatementAccumulatedTotal(accumulated_title)
+
+    @property
+    def total(self) -> Decimal:
+        """Returns the total of the section.
+
+        :return: The total of the section.
+        """
+        return sum([x.total for x in self.subsections])
+
+
+class CSVRow:
+    """A row in the CSV income statement."""
+
+    def __init__(self, text: str | None, amount: str | Decimal | None):
+        """Constructs a row in the CSV income statement.
+
+        :param text: The text.
+        :param amount: The amount.
+        """
+        self.text: str | None = text
+        """The text."""
+        self.amount: str | Decimal | None = amount
+        """The amount."""
+
+    @property
+    def values(self) -> list[str | Decimal | None]:
+        """Returns the values of the row.
+
+        :return: The values of the row.
+        """
+        return [self.text, self.amount]
+
+
+class IncomeStatementPageParams(PageParams):
+    """The HTML parameters of the income statement."""
+
+    def __init__(self, currency: Currency,
+                 period: Period,
+                 has_data: bool,
+                 sections: list[IncomeStatementSection],):
+        """Constructs the HTML parameters of the income statement.
+
+        :param currency: The currency.
+        :param period: The period.
+        :param has_data: True if there is any data, or False otherwise.
+        """
+        self.currency: Currency = currency
+        """The currency."""
+        self.period: Period = period
+        """The period."""
+        self.__has_data: bool = has_data
+        """True if there is any data, or False otherwise."""
+        self.sections: list[IncomeStatementSection] = sections
+        self.period_chooser: IncomeStatementPeriodChooser \
+            = IncomeStatementPeriodChooser(currency)
+        """The period chooser."""
+
+    @property
+    def has_data(self) -> bool:
+        """Returns whether there is any data on the page.
+
+        :return: True if there is any data, or False otherwise.
+        """
+        return self.__has_data
+
+    @property
+    def report_chooser(self) -> ReportChooser:
+        """Returns the report chooser.
+
+        :return: The report chooser.
+        """
+        return ReportChooser(ReportType.INCOME_STATEMENT,
+                             currency=self.currency,
+                             period=self.period)
+
+    @property
+    def currency_options(self) -> list[OptionLink]:
+        """Returns the currency options.
+
+        :return: The currency options.
+        """
+        def get_url(currency: Currency):
+            if self.period.is_default:
+                return url_for("accounting.report.income-statement-default",
+                               currency=currency)
+            return url_for("accounting.report.income-statement",
+                           currency=currency, period=self.period)
+
+        in_use: set[str] = set(db.session.scalars(
+            sa.select(JournalEntry.currency_code)
+            .group_by(JournalEntry.currency_code)).all())
+        return [OptionLink(str(x), get_url(x), x.code == self.currency.code)
+                for x in Currency.query.filter(Currency.code.in_(in_use))
+                .order_by(Currency.code).all()]
+
+
+class IncomeStatement:
+    """The income statement."""
+
+    def __init__(self, currency: Currency, period: Period):
+        """Constructs an income statement.
+
+        :param currency: The currency.
+        :param period: The period.
+        """
+        self.__currency: Currency = currency
+        """The currency."""
+        self.__period: Period = period
+        """The period."""
+        self.__has_data: bool
+        """True if there is any data, or False otherwise."""
+        self.__sections: list[IncomeStatementSection]
+        """The sections."""
+        self.__set_data()
+
+    def __set_data(self) -> None:
+        """Queries and sets data sections in the income statement.
+
+        :return: None.
+        """
+        balances: list[IncomeStatementAccount] = self.__query_balances()
+
+        titles: list[BaseAccount] = BaseAccount.query\
+            .filter(BaseAccount.code.in_({"4", "5", "6", "7", "8", "9"})).all()
+        subtitles: list[BaseAccount] = BaseAccount.query\
+            .filter(BaseAccount.code.in_({x.account.base_code[:2]
+                                          for x in balances})).all()
+
+        total_titles: dict[str, str] \
+            = {"4": gettext("total revenue"),
+               "5": gettext("gross income"),
+               "6": gettext("operating income"),
+               "7": gettext("before tax income"),
+               "8": gettext("after tax income"),
+               "9": gettext("net income or loss for current period")}
+
+        sections: dict[str, IncomeStatementSection] \
+            = {x.code: IncomeStatementSection(x, total_titles[x.code])
+               for x in titles}
+        subsections: dict[str, IncomeStatementSubsection] \
+            = {x.code: IncomeStatementSubsection(x) for x in subtitles}
+        for subsection in subsections.values():
+            sections[subsection.title.code[0]].subsections.append(subsection)
+        for balance in balances:
+            subsections[balance.account.base_code[:2]].accounts.append(balance)
+
+        self.__has_data = len(balances) > 0
+        self.__sections = sorted(sections.values(), key=lambda x: x.title.code)
+        total: Decimal = Decimal("0")
+        for section in self.__sections:
+            total = total + section.total
+            section.accumulated.amount = total
+
+    def __query_balances(self) -> list[IncomeStatementAccount]:
+        """Queries and returns the balances.
+
+        :return: The balances.
+        """
+        sub_conditions: list[sa.BinaryExpression] \
+            = [Account.base_code.startswith(str(x)) for x in range(4, 10)]
+        conditions: list[sa.BinaryExpression] \
+            = [JournalEntry.currency_code == self.__currency.code,
+               sa.or_(*sub_conditions)]
+        if self.__period.start is not None:
+            conditions.append(Transaction.date >= self.__period.start)
+        if self.__period.end is not None:
+            conditions.append(Transaction.date <= self.__period.end)
+        balance_func: sa.Function = sa.func.sum(sa.case(
+            (JournalEntry.is_debit, JournalEntry.amount),
+            else_=-JournalEntry.amount)).label("balance")
+        select_balance: sa.Select \
+            = sa.select(JournalEntry.account_id, balance_func)\
+            .join(Transaction).join(Account)\
+            .filter(*conditions)\
+            .group_by(JournalEntry.account_id)\
+            .order_by(Account.base_code, Account.no)
+        balances: list[sa.Row] = db.session.execute(select_balance).all()
+        accounts: dict[int, Account] \
+            = {x.id: x for x in Account.query
+               .filter(Account.id.in_([x.account_id for x in balances])).all()}
+
+        def get_url(account: Account) -> str:
+            """Returns the ledger URL of an account.
+
+            :param account: The account.
+            :return: The ledger URL of the account.
+            """
+            if self.__period.is_default:
+                return url_for("accounting.report.ledger-default",
+                               currency=self.__currency, account=account)
+            return url_for("accounting.report.ledger",
+                           currency=self.__currency, account=account,
+                           period=self.__period)
+
+        return [IncomeStatementAccount(account=accounts[x.account_id],
+                                       amount=x.balance,
+                                       url=get_url(accounts[x.account_id]))
+                for x in balances]
+
+    def csv(self) -> Response:
+        """Returns the report as CSV for download.
+
+        :return: The response of the report for download.
+        """
+        filename: str = "income-statement-{currency}-{period}.csv"\
+            .format(currency=self.__currency.code, period=self.__period.spec)
+        rows: list[CSVRow] = self.__get_csv_rows()
+        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 __get_csv_rows(self) -> list[CSVRow]:
+        """Composes and returns the CSV rows.
+
+        :return: The CSV rows.
+        """
+        total_str: str = gettext("Total")
+        rows: list[CSVRow] = [CSVRow(None, gettext("Amount"))]
+        for section in self.__sections:
+            rows.append(CSVRow(str(section.title).title(), None))
+            for subsection in section.subsections:
+                rows.append(CSVRow(f" {str(subsection.title).title()}", None))
+                for account in subsection.accounts:
+                    rows.append(CSVRow(f"  {str(account.account).title()}",
+                                       account.amount))
+                rows.append(CSVRow(f" {total_str}", subsection.total))
+            rows.append(CSVRow(section.accumulated.title.title(),
+                               section.accumulated.amount))
+            rows.append(CSVRow(None, None))
+        rows = rows[:-1]
+        return rows
+
+    def html(self) -> str:
+        """Composes and returns the report as HTML.
+
+        :return: The report as HTML.
+        """
+        params: IncomeStatementPageParams = IncomeStatementPageParams(
+            currency=self.__currency,
+            period=self.__period,
+            has_data=self.__has_data,
+            sections=self.__sections)
+        return render_template("accounting/report/income-statement.html",
+                               report=params)

src/accounting/report/reports/journal.py

@@ -0,0 +1,251 @@
+# 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 journal.
+
+"""
+import csv
+from datetime import date
+from decimal import Decimal
+from io import StringIO
+
+import sqlalchemy as sa
+from flask import render_template, Response
+
+from accounting import db
+from accounting.locale import gettext
+from accounting.models import Currency, Account, Transaction, JournalEntry
+from accounting.report.page_params import PageParams
+from accounting.report.period import Period
+from accounting.report.period_choosers import JournalPeriodChooser
+from accounting.report.report_chooser import ReportChooser
+from accounting.report.report_type import ReportType
+from accounting.utils.pagination import Pagination
+
+
+class Entry:
+    """An entry in the journal."""
+
+    def __init__(self, entry: JournalEntry | None = None):
+        """Constructs the entry in the journal.
+
+        :param entry: The journal entry.
+        """
+        self.entry: JournalEntry | None = None
+        """The journal entry."""
+        self.transaction: Transaction | None = None
+        """The transaction."""
+        self.is_total: bool = False
+        """Whether this is the total entry."""
+        self.currency: Currency | None = None
+        """The account."""
+        self.account: Account | None = None
+        """The account."""
+        self.summary: str | None = None
+        """The summary."""
+        self.debit: Decimal | None = None
+        """The debit amount."""
+        self.credit: Decimal | None = None
+        """The credit amount."""
+        self.amount: Decimal | None = None
+        """The amount."""
+        if entry is not None:
+            self.entry = entry
+            self.summary = entry.summary
+            self.debit = entry.amount if entry.is_debit else None
+            self.credit = None if entry.is_debit else entry.amount
+            self.amount = entry.amount
+
+
+class CSVRow:
+    """A row in the CSV journal."""
+
+    def __init__(self, txn_date: str | date,
+                 currency: str,
+                 account: str,
+                 summary: str | None,
+                 debit: str | Decimal | None,
+                 credit: str | Decimal | None,
+                 note: str | None):
+        """Constructs a row in the CSV journal.
+
+        :param txn_date: The transaction date.
+        :param summary: The summary.
+        :param debit: The debit amount.
+        :param credit: The credit amount.
+        :param note: The note.
+        """
+        self.date: str | date = txn_date
+        """The date."""
+        self.currency: str = currency
+        """The currency."""
+        self.account: str = account
+        """The account."""
+        self.summary: str | None = summary
+        """The summary."""
+        self.debit: str | Decimal | None = debit
+        """The debit amount."""
+        self.credit: str | Decimal | None = credit
+        """The credit amount."""
+        self.note: str | None = note
+        """The note."""
+
+    @property
+    def values(self) -> list[str | Decimal | None]:
+        """Returns the values of the row.
+
+        :return: The values of the row.
+        """
+        return [self.date, self.currency, self.account, self.summary,
+                self.debit, self.credit, self.note]
+
+
+class JournalPageParams(PageParams):
+    """The HTML parameters of the journal."""
+
+    def __init__(self, period: Period,
+                 pagination: Pagination[Entry],
+                 entries: list[Entry]):
+        """Constructs the HTML parameters of the journal.
+
+        :param period: The period.
+        :param entries: The journal entries.
+        """
+        self.period: Period = period
+        """The period."""
+        self.pagination: Pagination[Entry] = pagination
+        """The pagination."""
+        self.entries: list[Entry] = entries
+        """The entries."""
+        self.period_chooser: JournalPeriodChooser \
+            = JournalPeriodChooser()
+        """The period chooser."""
+
+    @property
+    def has_data(self) -> bool:
+        """Returns whether there is any data on the page.
+
+        :return: True if there is any data, or False otherwise.
+        """
+        return len(self.entries) > 0
+
+    @property
+    def report_chooser(self) -> ReportChooser:
+        """Returns the report chooser.
+
+        :return: The report chooser.
+        """
+        return ReportChooser(ReportType.JOURNAL,
+                             period=self.period)
+
+
+def _populate_entries(entries: list[Entry]) -> None:
+    """Populates the journal entries with relative data.
+
+    :param entries: The journal entries.
+    :return: None.
+    """
+    transactions: dict[int, Transaction] \
+        = {x.id: x for x in Transaction.query.filter(
+           Transaction.id.in_({x.entry.transaction_id for x in entries}))}
+    accounts: dict[int, Account] \
+        = {x.id: x for x in Account.query.filter(
+           Account.id.in_({x.entry.account_id for x in entries}))}
+    currencies: dict[int, Currency] \
+        = {x.code: x for x in Currency.query.filter(
+           Currency.code.in_({x.entry.currency_code for x in entries}))}
+    for entry in entries:
+        entry.transaction = transactions[entry.entry.transaction_id]
+        entry.account = accounts[entry.entry.account_id]
+        entry.currency = currencies[entry.entry.currency_code]
+
+
+class Journal:
+    """The journal."""
+
+    def __init__(self, period: Period):
+        """Constructs a journal.
+
+        :param period: The period.
+        """
+        """The account."""
+        self.__period: Period = period
+        """The period."""
+        self.__entries: list[Entry] = self.__query_entries()
+        """The journal entries."""
+
+    def __query_entries(self) -> list[Entry]:
+        """Queries and returns the journal entries.
+
+        :return: The journal entries.
+        """
+        conditions: list[sa.BinaryExpression] = []
+        if self.__period.start is not None:
+            conditions.append(Transaction.date >= self.__period.start)
+        if self.__period.end is not None:
+            conditions.append(Transaction.date <= self.__period.end)
+        return [Entry(x) for x in db.session
+                .query(JournalEntry).join(Transaction).filter(*conditions)
+                .order_by(Transaction.date,
+                          JournalEntry.is_debit.desc(),
+                          JournalEntry.no).all()]
+
+    def csv(self) -> Response:
+        """Returns the report as CSV for download.
+
+        :return: The response of the report for download.
+        """
+        filename: str = f"journal-{self.__period.spec}.csv"
+        rows: list[CSVRow] = self.__get_csv_rows()
+        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 __get_csv_rows(self) -> list[CSVRow]:
+        """Composes and returns the CSV rows.
+
+        :return: The CSV rows.
+        """
+        _populate_entries(self.__entries)
+        rows: list[CSVRow] = [CSVRow(gettext("Date"), gettext("Currency"),
+                                     gettext("Account"), gettext("Summary"),
+                                     gettext("Debit"), gettext("Credit"),
+                                     gettext("Note"))]
+        rows.extend([CSVRow(x.transaction.date, x.currency.code,
+                            str(x.account).title(), x.summary,
+                            x.debit, x.credit, x.transaction.note)
+                     for x in self.__entries])
+        return rows
+
+    def html(self) -> str:
+        """Composes and returns the report as HTML.
+
+        :return: The report as HTML.
+        """
+        pagination: Pagination[Entry] = Pagination[Entry](self.__entries)
+        page_entries: list[Entry] = pagination.list
+        _populate_entries(page_entries)
+        params: JournalPageParams = JournalPageParams(
+            period=self.__period,
+            pagination=pagination,
+            entries=page_entries)
+        return render_template("accounting/report/journal.html",
+                               report=params)

src/accounting/report/reports/ledger.py

@@ -0,0 +1,443 @@
+# 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 ledger.
+
+"""
+import csv
+from datetime import date
+from decimal import Decimal
+from io import StringIO
+
+import sqlalchemy as sa
+from flask import url_for, render_template, Response
+
+from accounting import db
+from accounting.locale import gettext
+from accounting.models import Currency, Account, Transaction, JournalEntry
+from accounting.report.option_link import OptionLink
+from accounting.report.page_params import PageParams
+from accounting.report.period import Period
+from accounting.report.period_choosers import LedgerPeriodChooser
+from accounting.report.report_chooser import ReportChooser
+from accounting.report.report_type import ReportType
+from accounting.utils.pagination import Pagination
+
+
+class Entry:
+    """An entry in the ledger."""
+
+    def __init__(self, entry: JournalEntry | None = None):
+        """Constructs the entry in the ledger.
+
+        :param entry: The journal entry.
+        """
+        self.entry: JournalEntry | None = None
+        """The journal entry."""
+        self.transaction: Transaction | None = None
+        """The transaction."""
+        self.is_brought_forward: bool = False
+        """Whether this is the brought-forward entry."""
+        self.is_total: bool = False
+        """Whether this is the total entry."""
+        self.date: date | None = None
+        """The date."""
+        self.account: Account | None = None
+        """The account."""
+        self.summary: str | None = None
+        """The summary."""
+        self.debit: Decimal | None = None
+        """The debit amount."""
+        self.credit: Decimal | None = None
+        """The credit amount."""
+        self.balance: Decimal | None = None
+        """The balance."""
+        self.note: str | None = None
+        """The note."""
+        if entry is not None:
+            self.entry = entry
+            self.summary = entry.summary
+            self.debit = entry.amount if entry.is_debit else None
+            self.credit = None if entry.is_debit else entry.amount
+
+
+class EntryCollector:
+    """The ledger entry collector."""
+
+    def __init__(self, currency: Currency, account: Account, period: Period):
+        """Constructs the ledger entry collector.
+
+        :param currency: The currency.
+        :param account: The account.
+        :param period: The period.
+        """
+        self.__currency: Currency = currency
+        """The currency."""
+        self.__account: Account = account
+        """The account."""
+        self.__period: Period = period
+        """The period"""
+        self.brought_forward: Entry | None
+        """The brought-forward entry."""
+        self.entries: list[Entry]
+        """The ledger entries."""
+        self.total: Entry
+        """The total entry."""
+        self.brought_forward = self.__get_brought_forward_entry()
+        self.entries = self.__query_entries()
+        self.total = self.__get_total_entry()
+        self.__populate_balance()
+
+    def __get_brought_forward_entry(self) -> Entry | None:
+        """Queries, composes and returns the brought-forward entry.
+
+        :return: The brought-forward entry, or None if the ledger starts from
+            the beginning.
+        """
+        if self.__period.start is None:
+            return None
+        balance_func: sa.Function = sa.func.sum(sa.case(
+            (JournalEntry.is_debit, JournalEntry.amount),
+            else_=-JournalEntry.amount))
+        select: sa.Select = sa.Select(balance_func).join(Transaction)\
+            .filter(JournalEntry.currency_code == self.__currency.code,
+                    JournalEntry.account_id == self.__account.id,
+                    Transaction.date < self.__period.start)
+        balance: int | None = db.session.scalar(select)
+        if balance is None:
+            return None
+        entry: Entry = Entry()
+        entry.is_brought_forward = True
+        entry.date = self.__period.start
+        entry.summary = gettext("Brought forward")
+        if balance > 0:
+            entry.debit = balance
+        elif balance < 0:
+            entry.credit = -balance
+        entry.balance = balance
+        return entry
+
+    def __query_entries(self) -> list[Entry]:
+        """Queries and returns the ledger entries.
+
+        :return: The ledger entries.
+        """
+        conditions: list[sa.BinaryExpression] \
+            = [JournalEntry.currency_code == self.__currency.code,
+               JournalEntry.account_id == self.__account.id]
+        if self.__period.start is not None:
+            conditions.append(Transaction.date >= self.__period.start)
+        if self.__period.end is not None:
+            conditions.append(Transaction.date <= self.__period.end)
+        return [Entry(x) for x in JournalEntry.query.join(Transaction)
+                .filter(*conditions)
+                .order_by(Transaction.date,
+                          JournalEntry.is_debit.desc(),
+                          JournalEntry.no).all()]
+
+    def __get_total_entry(self) -> Entry:
+        """Composes the total entry.
+
+        :return: None.
+        """
+        entry: Entry = Entry()
+        entry.is_total = True
+        entry.summary = gettext("Total")
+        entry.debit = sum([x.debit for x in self.entries
+                           if x.debit is not None])
+        entry.credit = sum([x.credit for x in self.entries
+                            if x.credit is not None])
+        entry.balance = entry.debit - entry.credit
+        if self.brought_forward is not None:
+            entry.balance = self.brought_forward.balance + entry.balance
+        return entry
+
+    def __populate_balance(self) -> None:
+        """Populates the balance of the entries.
+
+        :return: None.
+        """
+        balance: Decimal = 0 if self.brought_forward is None \
+            else self.brought_forward.balance
+        for entry in self.entries:
+            if entry.debit is not None:
+                balance = balance + entry.debit
+            if entry.credit is not None:
+                balance = balance - entry.credit
+            entry.balance = balance
+
+
+class CSVRow:
+    """A row in the CSV ledger."""
+
+    def __init__(self, txn_date: date | str | None,
+                 summary: str | None,
+                 debit: str | Decimal | None,
+                 credit: str | Decimal | None,
+                 balance: str | Decimal | None,
+                 note: str | None):
+        """Constructs a row in the CSV ledger.
+
+        :param txn_date: The transaction date.
+        :param summary: The summary.
+        :param debit: The debit amount.
+        :param credit: The credit amount.
+        :param balance: The balance.
+        :param note: The note.
+        """
+        self.date: date | str | None = txn_date
+        """The date."""
+        self.summary: str | None = summary
+        """The summary."""
+        self.debit: str | Decimal | None = debit
+        """The debit amount."""
+        self.credit: str | Decimal | None = credit
+        """The credit amount."""
+        self.balance: str | Decimal | None = balance
+        """The balance."""
+        self.note: str | None = note
+        """The note."""
+
+    @property
+    def values(self) -> list[str | Decimal | None]:
+        """Returns the values of the row.
+
+        :return: The values of the row.
+        """
+        return [self.date, self.summary,
+                self.debit, self.credit, self.balance, self.note]
+
+
+class LedgerPageParams(PageParams):
+    """The HTML parameters of the ledger."""
+
+    def __init__(self, currency: Currency,
+                 account: Account,
+                 period: Period,
+                 has_data: bool,
+                 pagination: Pagination[Entry],
+                 brought_forward: Entry | None,
+                 entries: list[Entry],
+                 total: Entry | None):
+        """Constructs the HTML parameters of the ledger.
+
+        :param currency: The currency.
+        :param account: The account.
+        :param period: The period.
+        :param has_data: True if there is any data, or False otherwise.
+        :param brought_forward: The brought-forward entry.
+        :param entries: The ledger entries.
+        :param total: The total entry.
+        """
+        self.currency: Currency = currency
+        """The currency."""
+        self.account: Account = account
+        """The account."""
+        self.period: Period = period
+        """The period."""
+        self.__has_data: bool = has_data
+        """True if there is any data, or False otherwise."""
+        self.pagination: Pagination[Entry] = pagination
+        """The pagination."""
+        self.brought_forward: Entry | None = brought_forward
+        """The brought-forward entry."""
+        self.entries: list[Entry] = entries
+        """The entries."""
+        self.total: Entry | None = total
+        """The total entry."""
+        self.period_chooser: LedgerPeriodChooser \
+            = LedgerPeriodChooser(currency, account)
+        """The period chooser."""
+
+    @property
+    def has_data(self) -> bool:
+        """Returns whether there is any data on the page.
+
+        :return: True if there is any data, or False otherwise.
+        """
+        return self.__has_data
+
+    @property
+    def report_chooser(self) -> ReportChooser:
+        """Returns the report chooser.
+
+        :return: The report chooser.
+        """
+        return ReportChooser(ReportType.LEDGER,
+                             currency=self.currency,
+                             account=self.account,
+                             period=self.period)
+
+    @property
+    def currency_options(self) -> list[OptionLink]:
+        """Returns the currency options.
+
+        :return: The currency options.
+        """
+        def get_url(currency: Currency):
+            if self.period.is_default:
+                return url_for("accounting.report.ledger-default",
+                               currency=currency, account=self.account)
+            return url_for("accounting.report.ledger",
+                           currency=currency, account=self.account,
+                           period=self.period)
+
+        in_use: set[str] = set(db.session.scalars(
+            sa.select(JournalEntry.currency_code)
+            .group_by(JournalEntry.currency_code)).all())
+        return [OptionLink(str(x), get_url(x), x.code == self.currency.code)
+                for x in Currency.query.filter(Currency.code.in_(in_use))
+                .order_by(Currency.code).all()]
+
+    @property
+    def account_options(self) -> list[OptionLink]:
+        """Returns the account options.
+
+        :return: The account options.
+        """
+        def get_url(account: Account):
+            if self.period.is_default:
+                return url_for("accounting.report.ledger-default",
+                               currency=self.currency, account=account)
+            return url_for("accounting.report.ledger",
+                           currency=self.currency, account=account,
+                           period=self.period)
+
+        in_use: sa.Select = sa.Select(JournalEntry.account_id)\
+            .filter(JournalEntry.currency_code == self.currency.code)\
+            .group_by(JournalEntry.account_id)
+        return [OptionLink(str(x), get_url(x), x.id == self.account.id)
+                for x in Account.query.filter(Account.id.in_(in_use))
+                .order_by(Account.base_code, Account.no).all()]
+
+
+def _populate_entries(entries: list[Entry]) -> None:
+    """Populates the ledger entries with relative data.
+
+    :param entries: The ledger entries.
+    :return: None.
+    """
+    transactions: dict[int, Transaction] \
+        = {x.id: x for x in Transaction.query.filter(
+           Transaction.id.in_({x.entry.transaction_id for x in entries
+                               if x.entry is not None}))}
+    for entry in entries:
+        if entry.entry is not None:
+            entry.transaction = transactions[entry.entry.transaction_id]
+            entry.date = entry.transaction.date
+            entry.note = entry.transaction.note
+
+
+class Ledger:
+    """The ledger."""
+
+    def __init__(self, currency: Currency, account: Account, period: Period):
+        """Constructs a ledger.
+
+        :param currency: The currency.
+        :param account: The account.
+        :param period: The period.
+        """
+        self.__currency: Currency = currency
+        """The currency."""
+        self.__account: Account = account
+        """The account."""
+        self.__period: Period = period
+        """The period."""
+        collector: EntryCollector = EntryCollector(
+            self.__currency, self.__account, self.__period)
+        self.__brought_forward: Entry | None = collector.brought_forward
+        """The brought-forward entry."""
+        self.__entries: list[Entry] = collector.entries
+        """The ledger entries."""
+        self.__total: Entry = collector.total
+        """The total entry."""
+
+    def csv(self) -> Response:
+        """Returns the report as CSV for download.
+
+        :return: The response of the report for download.
+        """
+        filename: str = "ledger-{currency}-{account}-{period}.csv"\
+            .format(currency=self.__currency.code, account=self.__account.code,
+                    period=self.__period.spec)
+        rows: list[CSVRow] = self.__get_csv_rows()
+        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 __get_csv_rows(self) -> list[CSVRow]:
+        """Composes and returns the CSV rows.
+
+        :return: The CSV rows.
+        """
+        _populate_entries(self.__entries)
+        rows: list[CSVRow] = [CSVRow(gettext("Date"), gettext("Summary"),
+                                     gettext("Debit"), gettext("Credit"),
+                                     gettext("Balance"), gettext("Note"))]
+        if self.__brought_forward is not None:
+            rows.append(CSVRow(self.__brought_forward.date,
+                               self.__brought_forward.summary,
+                               self.__brought_forward.debit,
+                               self.__brought_forward.credit,
+                               self.__brought_forward.balance,
+                               None))
+        rows.extend([CSVRow(x.date, x.summary,
+                            x.debit, x.credit, x.balance, x.note)
+                     for x in self.__entries])
+        rows.append(CSVRow(gettext("Total"), None,
+                           self.__total.debit, self.__total.credit,
+                           self.__total.balance, None))
+        return rows
+
+    def html(self) -> str:
+        """Composes and returns the report as HTML.
+
+        :return: The report as HTML.
+        """
+        all_entries: list[Entry] = []
+        if self.__brought_forward is not None:
+            all_entries.append(self.__brought_forward)
+        all_entries.extend(self.__entries)
+        all_entries.append(self.__total)
+        pagination: Pagination[Entry] = Pagination[Entry](all_entries)
+        page_entries: list[Entry] = pagination.list
+        has_data: bool = len(page_entries) > 0
+        _populate_entries(page_entries)
+        brought_forward: Entry | None = None
+        if page_entries[0].is_brought_forward:
+            brought_forward = page_entries[0]
+            page_entries = page_entries[1:]
+        total: Entry | None = None
+        if page_entries[-1].is_total:
+            total = page_entries[-1]
+            page_entries = page_entries[:-1]
+        params: LedgerPageParams = LedgerPageParams(
+            currency=self.__currency,
+            account=self.__account,
+            period=self.__period,
+            has_data=has_data,
+            pagination=pagination,
+            brought_forward=brought_forward,
+            entries=page_entries,
+            total=total)
+        return render_template("accounting/report/ledger.html",
+                               report=params)

src/accounting/report/reports/trial_balance.py

@@ -0,0 +1,272 @@
+# 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 trial balance.
+
+"""
+import csv
+from decimal import Decimal
+from io import StringIO
+
+import sqlalchemy as sa
+from flask import url_for, Response, render_template
+
+from accounting import db
+from accounting.locale import gettext
+from accounting.models import Currency, Account, Transaction, JournalEntry
+from accounting.report.option_link import OptionLink
+from accounting.report.page_params import PageParams
+from accounting.report.period import Period
+from accounting.report.period_choosers import TrialBalancePeriodChooser
+from accounting.report.report_chooser import ReportChooser
+from accounting.report.report_type import ReportType
+
+
+class TrialBalanceAccount:
+    """An account in the trial balance."""
+
+    def __init__(self, account: Account, amount: Decimal, url: str):
+        """Constructs an account in the trial balance.
+
+        :param account: The account.
+        :param amount: The amount.
+        :param url: The URL to the ledger of the account.
+        """
+        self.account: Account = account
+        """The account."""
+        self.debit: Decimal | None = amount if amount > 0 else None
+        """The debit amount."""
+        self.credit: Decimal | None = -amount if amount < 0 else None
+        """The credit amount."""
+        self.url: str = url
+        """The URL to the ledger of the account."""
+
+
+class TrialBalanceTotal:
+    """The total in the trial balance."""
+
+    def __init__(self, debit: Decimal, credit: Decimal):
+        """Constructs the total in the trial balance.
+
+        :param debit: The debit amount.
+        :param credit: The credit amount.
+        """
+        self.debit: Decimal | None = debit
+        """The debit amount."""
+        self.credit: Decimal | None = credit
+        """The credit amount."""
+
+
+class CSVRow:
+    """A row in the CSV trial balance."""
+
+    def __init__(self, text: str | None,
+                 debit: str | Decimal | None,
+                 credit: str | Decimal | None):
+        """Constructs a row in the CSV trial balance.
+
+        :param text: The text.
+        :param debit: The debit amount.
+        :param credit: The credit amount.
+        """
+        self.text: str | None = text
+        """The text."""
+        self.debit: str | Decimal | None = debit
+        """The debit amount."""
+        self.credit: str | Decimal | None = credit
+        """The credit amount."""
+
+    @property
+    def values(self) -> list[str | Decimal | None]:
+        """Returns the values of the row.
+
+        :return: The values of the row.
+        """
+        return [self.text, self.debit, self.credit]
+
+
+class TrialBalancePageParams(PageParams):
+    """The HTML parameters of the trial balance."""
+
+    def __init__(self, currency: Currency,
+                 period: Period,
+                 accounts: list[TrialBalanceAccount],
+                 total: TrialBalanceTotal):
+        """Constructs the HTML parameters of the trial balance.
+
+        :param currency: The currency.
+        :param period: The period.
+        :param accounts: The accounts in the trial balance.
+        :param total: The total of the trial balance.
+        """
+        self.currency: Currency = currency
+        """The currency."""
+        self.period: Period = period
+        """The period."""
+        self.accounts: list[TrialBalanceAccount] = accounts
+        """The accounts in the trial balance."""
+        self.total: TrialBalanceTotal = total
+        """The total of the trial balance."""
+        self.period_chooser: TrialBalancePeriodChooser \
+            = TrialBalancePeriodChooser(currency)
+        """The period chooser."""
+
+    @property
+    def has_data(self) -> bool:
+        """Returns whether there is any data on the page.
+
+        :return: True if there is any data, or False otherwise.
+        """
+        return len(self.accounts) > 0
+
+    @property
+    def report_chooser(self) -> ReportChooser:
+        """Returns the report chooser.
+
+        :return: The report chooser.
+        """
+        return ReportChooser(ReportType.TRIAL_BALANCE,
+                             currency=self.currency,
+                             period=self.period)
+
+    @property
+    def currency_options(self) -> list[OptionLink]:
+        """Returns the currency options.
+
+        :return: The currency options.
+        """
+        def get_url(currency: Currency):
+            if self.period.is_default:
+                return url_for("accounting.report.trial-balance-default",
+                               currency=currency)
+            return url_for("accounting.report.trial-balance",
+                           currency=currency, period=self.period)
+
+        in_use: set[str] = set(db.session.scalars(
+            sa.select(JournalEntry.currency_code)
+            .group_by(JournalEntry.currency_code)).all())
+        return [OptionLink(str(x), get_url(x), x.code == self.currency.code)
+                for x in Currency.query.filter(Currency.code.in_(in_use))
+                .order_by(Currency.code).all()]
+
+
+class TrialBalance:
+    """The trial balance."""
+
+    def __init__(self, currency: Currency, period: Period):
+        """Constructs a trial balance.
+
+        :param currency: The currency.
+        :param period: The period.
+        """
+        self.__currency: Currency = currency
+        """The currency."""
+        self.__period: Period = period
+        """The period."""
+        self.__accounts: list[TrialBalanceAccount]
+        """The accounts in the trial balance."""
+        self.__total: TrialBalanceTotal
+        """The total of the trial balance."""
+        self.__set_data()
+
+    def __set_data(self) -> None:
+        """Queries and sets data sections in the trial balance.
+
+        :return: None.
+        """
+        conditions: list[sa.BinaryExpression] \
+            = [JournalEntry.currency_code == self.__currency.code]
+        if self.__period.start is not None:
+            conditions.append(Transaction.date >= self.__period.start)
+        if self.__period.end is not None:
+            conditions.append(Transaction.date <= self.__period.end)
+        balance_func: sa.Function = sa.func.sum(sa.case(
+            (JournalEntry.is_debit, JournalEntry.amount),
+            else_=-JournalEntry.amount)).label("balance")
+        select_balances: sa.Select \
+            = sa.select(Account.id, balance_func)\
+            .join(Transaction).join(Account)\
+            .filter(*conditions)\
+            .group_by(JournalEntry.account_id)\
+            .order_by(Account.base_code, Account.no)
+        balances: list[sa.Row] = db.session.execute(select_balances).all()
+        accounts: dict[int, Account] \
+            = {x.id: x for x in Account.query
+               .filter(Account.id.in_([x.id for x in balances])).all()}
+
+        def get_url(account: Account) -> str:
+            """Returns the ledger URL of an account.
+
+            :param account: The account.
+            :return: The ledger URL of the account.
+            """
+            if self.__period.is_default:
+                return url_for("accounting.report.ledger-default",
+                               currency=self.__currency, account=account)
+            return url_for("accounting.report.ledger",
+                           currency=self.__currency, account=account,
+                           period=self.__period)
+
+        self.__accounts = [TrialBalanceAccount(account=accounts[x.id],
+                                               amount=x.balance,
+                                               url=get_url(accounts[x.id]))
+                           for x in balances]
+        self.__total = TrialBalanceTotal(
+            sum([x.debit for x in self.__accounts if x.debit is not None]),
+            sum([x.credit for x in self.__accounts if x.credit is not None]))
+
+    def csv(self) -> Response:
+        """Returns the report as CSV for download.
+
+        :return: The response of the report for download.
+        """
+        filename: str = "trial-balance-{currency}-{period}.csv"\
+            .format(currency=self.__currency.code, period=self.__period.spec)
+        rows: list[CSVRow] = self.__get_csv_rows()
+        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 __get_csv_rows(self) -> list[CSVRow]:
+        """Composes and returns the CSV rows.
+
+        :return: The CSV rows.
+        """
+        rows: list[CSVRow] = [CSVRow(gettext("Account"), gettext("Debit"),
+                                     gettext("Credit"))]
+        rows.extend([CSVRow(str(x.account).title(), x.debit, x.credit)
+                     for x in self.__accounts])
+        rows.append(CSVRow(gettext("Total"), self.__total.debit,
+                           self.__total.credit))
+        return rows
+
+    def html(self) -> str:
+        """Composes and returns the report as HTML.
+
+        :return: The report as HTML.
+        """
+        params: TrialBalancePageParams = TrialBalancePageParams(
+            currency=self.__currency,
+            period=self.__period,
+            accounts=self.__accounts,
+            total=self.__total)
+        return render_template("accounting/report/trial-balance.html",
+                               report=params)