import uuid
from datetime import date
from sqlalchemy import String, ForeignKey, Date, Index
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.db.database import Base
from app.models.base import AuditMixin
from app.constants import BATCH_STATUS_ACTIVE
from app.models.student_batch import student_batch_table


class Batch(AuditMixin, Base):
    __tablename__ = "batches"
    __table_args__ = (
        Index("ix_batch_mentor_deleted", "mentor_id", "deleted_at"),
        Index("ix_batch_status_deleted", "status", "deleted_at"),
    )

    id: Mapped[str] = mapped_column(String(36), primary_key=True, default=lambda: str(uuid.uuid4()))
    name: Mapped[str] = mapped_column(String(200), nullable=False)
    course_id: Mapped[str] = mapped_column(String(36), ForeignKey("courses.id"), nullable=False)
    mentor_id: Mapped[str] = mapped_column(String(36), ForeignKey("mentors.id"), nullable=False)
    start_date: Mapped[date] = mapped_column(Date, nullable=False)
    # "Active" or "Completed"
    status: Mapped[str] = mapped_column(String(20), nullable=False, default=BATCH_STATUS_ACTIVE)

    course: Mapped["Course"] = relationship("Course", back_populates="batches")  # noqa: F821
    mentor: Mapped["Mentor"] = relationship("Mentor", back_populates="batches")  # noqa: F821
    students: Mapped[list["Student"]] = relationship(  # noqa: F821
        "Student", secondary=student_batch_table, back_populates="batches"
    )
    sessions: Mapped[list["Session"]] = relationship(  # noqa: F821
        "Session", back_populates="batch", cascade="all, delete-orphan"
    )