from datetime import datetime

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

from backend.database import Base


# 导入任务/文件项统一状态
JOB_STATUS_QUEUED = "queued"
JOB_STATUS_RUNNING = "running"
JOB_STATUS_SUCCESS = "success"
JOB_STATUS_FAILED = "failed"
JOB_STATUS_CANCELLED = "cancelled"
JOB_STATUS_RETRYING = "retrying"

JOB_STATUSES = (
    JOB_STATUS_QUEUED,
    JOB_STATUS_RUNNING,
    JOB_STATUS_SUCCESS,
    JOB_STATUS_FAILED,
    JOB_STATUS_CANCELLED,
    JOB_STATUS_RETRYING,
)


class Question(Base):
    __tablename__ = "questions"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, index=True)
    chapter: Mapped[str] = mapped_column(Text, default="")
    primary_knowledge: Mapped[str] = mapped_column(Text, default="")
    secondary_knowledge: Mapped[str] = mapped_column(Text, default="")
    question_type: Mapped[str] = mapped_column(Text, default="")
    difficulty: Mapped[str] = mapped_column(Text, default="")
    stem: Mapped[str] = mapped_column(Text)
    option_a: Mapped[str] = mapped_column(Text, default="")
    option_b: Mapped[str] = mapped_column(Text, default="")
    option_c: Mapped[str] = mapped_column(Text, default="")
    option_d: Mapped[str] = mapped_column(Text, default="")
    answer: Mapped[str] = mapped_column(Text, default="")
    explanation: Mapped[str] = mapped_column(Text, default="")
    notes: Mapped[str] = mapped_column(Text, default="")
    source_file: Mapped[str] = mapped_column(Text, default="")
    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
    updated_at: Mapped[datetime] = mapped_column(
        DateTime, default=datetime.utcnow, onupdate=datetime.utcnow
    )


class Category(Base):
    __tablename__ = "categories"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, index=True)
    name: Mapped[str] = mapped_column(Text, nullable=False)
    parent_id: Mapped[int | None] = mapped_column(ForeignKey("categories.id"), nullable=True)
    level: Mapped[int] = mapped_column(Integer, default=1)

    children: Mapped[list["Category"]] = relationship(
        "Category", backref="parent", remote_side=[id], lazy="joined"
    )


class ImportHistory(Base):
    __tablename__ = "import_history"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, index=True)
    filename: Mapped[str] = mapped_column(Text, default="")
    method: Mapped[str] = mapped_column(Text, default="manual")
    question_count: Mapped[int] = mapped_column(Integer, default=0)
    status: Mapped[str] = mapped_column(Text, default="success")
    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)


class ImportJob(Base):
    """导入任务（持久化队列项）。"""

    __tablename__ = "import_jobs"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, index=True)
    status: Mapped[str] = mapped_column(String(32), default=JOB_STATUS_QUEUED, index=True)
    method: Mapped[str] = mapped_column(String(32), nullable=False)
    total: Mapped[int] = mapped_column(Integer, default=0)
    processed: Mapped[int] = mapped_column(Integer, default=0)
    success_count: Mapped[int] = mapped_column(Integer, default=0)
    failed_count: Mapped[int] = mapped_column(Integer, default=0)
    current_index: Mapped[int] = mapped_column(Integer, default=0)
    current_file: Mapped[str] = mapped_column(Text, default="")
    error: Mapped[str] = mapped_column(Text, default="")
    attempt: Mapped[int] = mapped_column(Integer, default=1)
    created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow)
    started_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
    ended_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
    updated_at: Mapped[datetime] = mapped_column(
        DateTime, default=datetime.utcnow, onupdate=datetime.utcnow
    )

    items: Mapped[list["ImportJobItem"]] = relationship(
        "ImportJobItem", back_populates="job", order_by="ImportJobItem.seq", lazy="selectin"
    )


class ImportJobItem(Base):
    """导入任务内的单个文件项。"""

    __tablename__ = "import_job_items"

    id: Mapped[int] = mapped_column(Integer, primary_key=True, index=True)
    job_id: Mapped[int] = mapped_column(ForeignKey("import_jobs.id", ondelete="CASCADE"), nullable=False)
    seq: Mapped[int] = mapped_column(Integer, nullable=False)
    filename: Mapped[str] = mapped_column(Text, default="")
    stored_path: Mapped[str] = mapped_column(Text, default="")
    status: Mapped[str] = mapped_column(String(32), default=JOB_STATUS_QUEUED)
    attempt: Mapped[int] = mapped_column(Integer, default=1)
    error: Mapped[str] = mapped_column(Text, default="")
    question_count: Mapped[int] = mapped_column(Integer, default=0)
    started_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)
    ended_at: Mapped[datetime | None] = mapped_column(DateTime, nullable=True)

    job: Mapped["ImportJob"] = relationship("ImportJob", back_populates="items")