"""SeriesPage — ordered image membership for a series-kind Tag.

A series IS a Tag with kind='series'; series_page gives it ordered pages.
An image belongs to at most one series (UNIQUE image_id). Cover = the
lowest page_number. page_number is an ordering key only (not unique) —
reorder rewrites 1..N wholesale.
"""

from datetime import datetime

from sqlalchemy import DateTime, ForeignKey, Integer, func
from sqlalchemy.orm import Mapped, mapped_column

from .base import Base


class SeriesPage(Base):
    __tablename__ = "series_page"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    series_tag_id: Mapped[int] = mapped_column(
        ForeignKey("tag.id", ondelete="CASCADE"), nullable=False, index=True
    )
    image_id: Mapped[int] = mapped_column(
        ForeignKey("image_record.id", ondelete="CASCADE"),
        nullable=False,
        unique=True,
    )
    page_number: Mapped[int] = mapped_column(Integer, nullable=False)
    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now()
    )
    updated_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True),
        nullable=False,
        server_default=func.now(),
        onupdate=func.now(),
    )