"""ImportTask — a single source file to import as part of a batch.

State machine: pending -> queued -> processing -> complete | skipped | failed.
Workers crashing mid-task leave rows in 'processing'; the recovery sweep
(tasks/maintenance.py::recover_interrupted_tasks) re-queues rows that have
been processing longer than the stuck-task threshold.
"""

from datetime import datetime

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

from .base import Base


class ImportTask(Base):
    __tablename__ = "import_task"

    id: Mapped[int] = mapped_column(Integer, primary_key=True)
    batch_id: Mapped[int] = mapped_column(
        ForeignKey("import_batch.id", ondelete="CASCADE"), nullable=False, index=True
    )

    source_path: Mapped[str] = mapped_column(Text, nullable=False)
    task_type: Mapped[str] = mapped_column(String(16), nullable=False)  # media|archive
    status: Mapped[str] = mapped_column(String(16), nullable=False, default="pending", index=True)

    result_image_id: Mapped[int | None] = mapped_column(
        ForeignKey("image_record.id", ondelete="SET NULL"), nullable=True
    )
    error: Mapped[str | None] = mapped_column(Text, nullable=True)
    size_bytes: Mapped[int | None] = mapped_column(BigInteger, nullable=True)

    created_at: Mapped[datetime] = mapped_column(
        DateTime(timezone=True), nullable=False, server_default=func.now()
    )
    started_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)
    finished_at: Mapped[datetime | None] = mapped_column(DateTime(timezone=True), nullable=True)

    batch = relationship("ImportBatch", back_populates="tasks")