from datetime import datetime
from typing import Optional

from sqlalchemy import DateTime, ForeignKey, Integer, String, Text
from sqlalchemy.orm import Mapped, mapped_column, relationship

from .base import Base


class SnapshotContent(Base):
    """Stores unique file contents by SHA-256. One row per unique content."""

    __tablename__ = "snapshot_contents"

    sha256: Mapped[str] = mapped_column(String(64), primary_key=True)
    content: Mapped[str] = mapped_column(Text(), nullable=False)
    size: Mapped[int] = mapped_column(Integer(), nullable=False)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)

    snapshots: Mapped[list["ConfigSnapshot"]] = relationship(
        "ConfigSnapshot", back_populates="snapshot_content"
    )


class ConfigSnapshot(Base):
    """Each capture event: device + path + timestamp + content reference."""

    __tablename__ = "config_snapshots"

    id: Mapped[int] = mapped_column(Integer(), autoincrement=True, primary_key=True)
    device_id: Mapped[int] = mapped_column(
        Integer(), ForeignKey("devices.id", ondelete="CASCADE"), nullable=False
    )
    sha256: Mapped[str] = mapped_column(
        String(64), ForeignKey("snapshot_contents.sha256"), nullable=False
    )
    label: Mapped[Optional[str]] = mapped_column(String(255), nullable=True)
    created_at: Mapped[datetime] = mapped_column(DateTime(timezone=True), nullable=False)

    device: Mapped["Device"] = relationship("Device", back_populates="config_snapshots")
    snapshot_content: Mapped["SnapshotContent"] = relationship(
        "SnapshotContent", back_populates="snapshots"
    )