mia-accounting/src/accounting/models.py

# The Mia! Accounting Flask Project.
# Author: imacat@mail.imacat.idv.tw (imacat), 2023/1/25

#  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 data models.

"""
import re
import typing as t

import sqlalchemy as sa
from flask import current_app
from flask_babel import get_locale
from sqlalchemy import text

from accounting.database import db
from accounting.utils.user import user_cls, user_pk_column


class BaseAccount(db.Model):
    """A base account."""
    __tablename__ = "accounting_base_accounts"
    """The table name."""
    code = db.Column(db.String, nullable=False, primary_key=True)
    """The code."""
    title_l10n = db.Column("title", db.String, nullable=False)
    """The title."""
    l10n = db.relationship("BaseAccountL10n", back_populates="account",
                           lazy=False)
    """The localized titles."""
    accounts = db.relationship("Account", back_populates="base")
    """The descendant accounts under the base account."""

    def __str__(self) -> str:
        """Returns the string representation of the base account.

        :return: The string representation of the base account.
        """
        return F"{self.code} {self.title}"

    @property
    def title(self) -> str:
        """Returns the title in the current locale.

        :return: The title in the current locale.
        """
        current_locale = str(get_locale())
        if current_locale == current_app.config["BABEL_DEFAULT_LOCALE"]:
            return self.title_l10n
        for l10n in self.l10n:
            if l10n.locale == current_locale:
                return l10n.title
        return self.title_l10n


class BaseAccountL10n(db.Model):
    """A localized base account title."""
    __tablename__ = "accounting_base_accounts_l10n"
    """The table name."""
    account_code = db.Column(db.String, db.ForeignKey(BaseAccount.code,
                                                      ondelete="CASCADE"),
                             nullable=False, primary_key=True)
    """The code of the account."""
    account = db.relationship(BaseAccount, back_populates="l10n")
    """The account."""
    locale = db.Column(db.String, nullable=False, primary_key=True)
    """The locale."""
    title = db.Column(db.String, nullable=False)
    """The localized title."""


class Account(db.Model):
    """An account."""
    __tablename__ = "accounting_accounts"
    """The table name."""
    id = db.Column(db.Integer, nullable=False, primary_key=True)
    """The account ID."""
    base_code = db.Column(db.String, db.ForeignKey(BaseAccount.code,
                                                   ondelete="CASCADE"),
                          nullable=False)
    """The code of the base account."""
    base = db.relationship(BaseAccount, back_populates="accounts")
    """The base account."""
    no = db.Column(db.Integer, nullable=False, default=text("1"))
    """The account number under the base account."""
    title_l10n = db.Column("title", db.String, nullable=False)
    """The title."""
    is_offset_needed = db.Column(db.Boolean, nullable=False, default=False)
    """Whether the entries of this account need offsets."""
    created_at = db.Column(db.DateTime(timezone=True), nullable=False,
                           server_default=db.func.now())
    """The time of creation."""
    created_by_id = db.Column(db.Integer, db.ForeignKey(user_pk_column),
                              nullable=False)
    """The ID of the creator."""
    created_by = db.relationship(user_cls, foreign_keys=created_by_id)
    """The creator."""
    updated_at = db.Column(db.DateTime(timezone=True), nullable=False,
                           server_default=db.func.now())
    """The time of last update."""
    updated_by_id = db.Column(db.Integer, db.ForeignKey(user_pk_column),
                              nullable=False)
    """The ID of the updator."""
    updated_by = db.relationship(user_cls, foreign_keys=updated_by_id)
    """The updator."""
    l10n = db.relationship("AccountL10n", back_populates="account",
                           lazy=False)
    """The localized titles."""

    __CASH = "1111-001"
    """The code of the cash account,"""
    __RECEIVABLE = "1141-001"
    """The code of the receivable account,"""
    __PAYABLE = "2141-001"
    """The code of the payable account,"""
    __ACCUMULATED_CHANGE = "3351-001"
    """The code of the accumulated-change account,"""
    __BROUGHT_FORWARD = "3352-001"
    """The code of the brought-forward account,"""
    __NET_CHANGE = "3353-001"
    """The code of the net-change account,"""

    def __str__(self) -> str:
        """Returns the string representation of this account.

        :return: The string representation of this account.
        """
        return F"{self.base_code}-{self.no:03d} {self.title}"

    @property
    def code(self) -> str:
        """Returns the code.

        :return: The code.
        """
        return F"{self.base_code}-{self.no:03d}"

    @property
    def title(self) -> str:
        """Returns the title in the current locale.

        :return: The title in the current locale.
        """
        current_locale = str(get_locale())
        if current_locale == current_app.config["BABEL_DEFAULT_LOCALE"]:
            return self.title_l10n
        for l10n in self.l10n:
            if l10n.locale == current_locale:
                return l10n.title
        return self.title_l10n

    @title.setter
    def title(self, value: str) -> None:
        """Sets the title in the current locale.

        :param value: The new title.
        :return: None.
        """
        if self.title_l10n is None:
            self.title_l10n = value
            return
        current_locale = str(get_locale())
        if current_locale == current_app.config["BABEL_DEFAULT_LOCALE"]:
            self.title_l10n = value
            return
        for l10n in self.l10n:
            if l10n.locale == current_locale:
                l10n.title = value
                return
        self.l10n.append(AccountL10n(
            locale=current_locale, title=value))

    @classmethod
    def find_by_code(cls, code: str) -> t.Self | None:
        """Finds an accounting account by its code.

        :param code: The code.
        :return: The accounting account, or None if this account does not
            exist.
        """
        m = re.match("^([1-9]{4})-([0-9]{3})$", code)
        if m is None:
            return None
        return cls.query.filter(cls.base_code == m.group(1),
                                cls.no == int(m.group(2))).first()

    @classmethod
    def debit(cls) -> list[t.Self]:
        """Returns the debit accounts.

        :return: The debit accounts.
        """
        return cls.query.filter(sa.or_(cls.base_code.startswith("1"),
                                       cls.base_code.startswith("2"),
                                       cls.base_code.startswith("3"),
                                       cls.base_code.startswith("5"),
                                       cls.base_code.startswith("6"),
                                       cls.base_code.startswith("75"),
                                       cls.base_code.startswith("76"),
                                       cls.base_code.startswith("77"),
                                       cls.base_code.startswith("78"),
                                       cls.base_code.startswith("8"),
                                       cls.base_code.startswith("9")),
                                cls.base_code != "3351",
                                cls.base_code != "3353")\
            .order_by(cls.base_code, cls.no).all()

    @classmethod
    def credit(cls) -> list[t.Self]:
        """Returns the debit accounts.

        :return: The debit accounts.
        """
        return cls.query.filter(sa.or_(cls.base_code.startswith("1"),
                                       cls.base_code.startswith("2"),
                                       cls.base_code.startswith("3"),
                                       cls.base_code.startswith("4"),
                                       cls.base_code.startswith("71"),
                                       cls.base_code.startswith("72"),
                                       cls.base_code.startswith("73"),
                                       cls.base_code.startswith("74"),
                                       cls.base_code.startswith("8"),
                                       cls.base_code.startswith("9")),
                                cls.base_code != "3351",
                                cls.base_code != "3353")\
            .order_by(cls.base_code, cls.no).all()

    @classmethod
    def cash(cls) -> t.Self:
        """Returns the cash account.

        :return: The cash account
        """
        return cls.find_by_code(cls.__CASH)

    @classmethod
    def receivable(cls) -> t.Self:
        """Returns the receivable account.

        :return: The receivable account
        """
        return cls.find_by_code(cls.__RECEIVABLE)

    @classmethod
    def payable(cls) -> t.Self:
        """Returns the payable account.

        :return: The payable account
        """
        return cls.find_by_code(cls.__PAYABLE)

    @classmethod
    def accumulated_change(cls) -> t.Self:
        """Returns the accumulated-change account.

        :return: The accumulated-change account
        """
        return cls.find_by_code(cls.__ACCUMULATED_CHANGE)

    @classmethod
    def brought_forward(cls) -> t.Self:
        """Returns the brought-forward account.

        :return: The brought-forward account
        """
        return cls.find_by_code(cls.__BROUGHT_FORWARD)

    @classmethod
    def net_change(cls) -> t.Self:
        """Returns the net-change account.

        :return: The net-change account
        """
        return cls.find_by_code(cls.__NET_CHANGE)

    def delete(self) -> None:
        """Deletes this accounting account.

        :return: None.
        """
        AccountL10n.query.filter(AccountL10n.account == self).delete()
        cls: t.Type[t.Self] = self.__class__
        cls.query.filter(cls.id == self.id).delete()


class AccountL10n(db.Model):
    """A localized account title."""
    __tablename__ = "accounting_accounts_l10n"
    account_id = db.Column(db.Integer, db.ForeignKey(Account.id,
                                                     ondelete="CASCADE"),
                           nullable=False, primary_key=True)
    account = db.relationship(Account, back_populates="l10n")
    locale = db.Column(db.String, nullable=False, primary_key=True)
    title = db.Column(db.String, nullable=False)
    db.UniqueConstraint(account_id, locale)