models.py

import datetime
from typing import List

from sqlalchemy import (
    String,
    Integer,
    Date,
    create_engine,
    ForeignKey,
    UniqueConstraint,
    select,
)
from sqlalchemy.orm import (
    DeclarativeBase,
    Mapped,
    mapped_column,
    relationship,
    sessionmaker,
)

from flask_sqlalchemy import SQLAlchemy


class HRDBBase(DeclarativeBase):
    def __repr__(self):
        return f"{self.__class__.__name__}(id={self.id})"


class Employee(HRDBBase):
    __tablename__ = "hr_employees"
    __table_args__ = (UniqueConstraint("email"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    last_name: Mapped[str] = mapped_column(String(50))
    first_name: Mapped[str] = mapped_column(String(50))
    email: Mapped[str] = mapped_column(String(50))
    phone: Mapped[str] = mapped_column(String(50))
    title_id: Mapped[int] = mapped_column(ForeignKey("hr_designations.id"))
    title: Mapped["Designation"] = relationship(back_populates="employees")


class Designation(HRDBBase):
    __tablename__ = "hr_designations"
    __table_args__ = (UniqueConstraint("title"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    title: Mapped[str] = mapped_column(String(50))
    max_leaves: Mapped[int] = mapped_column(Integer)
    employees: Mapped[List["Employee"]] = relationship(back_populates="title")


class Leave(HRDBBase):
    __tablename__ = "hr_leaves"
    __table_args__ = (UniqueConstraint("employee_id", "date"),)
    id: Mapped[int] = mapped_column(primary_key=True)
    date: Mapped[datetime.date] = mapped_column(Date())
    employee_id: Mapped[int] = mapped_column(ForeignKey("hr_employees.id"))
    reason: Mapped[str] = mapped_column(String(200))


def create_all(db_uri):
    engine = create_engine(db_uri)
    HRDBBase.metadata.create_all(engine)


def get_session(db_uri):
    engine = create_engine(db_uri)
    Session = sessionmaker(bind=engine)
    session = Session()
    return session