"""Модель задачи (асинхронная единица работы)."""

import secrets
from datetime import datetime
from enum import Enum
from typing import TYPE_CHECKING
from uuid import uuid4

from sqlalchemy import JSON, ForeignKey, String, func
from sqlalchemy.orm import Mapped, mapped_column, relationship

from app.database import Base

if TYPE_CHECKING:
    from app.models.user import User


class TaskType(str, Enum):
    """Тип задачи."""

    SEARCH = "search"
    PLAGIARISM = "plagiarism"
    SUMMARIZE = "summarize"
    GOST = "gost"


class TaskStatus(str, Enum):
    """Статус задачи."""

    QUEUED = "queued"
    PROCESSING = "processing"
    DONE = "done"
    FAILED = "failed"


class Task(Base):
    """Задача пользователя, обрабатываемая воркерами Celery."""

    __tablename__ = "tasks"

    # Внутренний UUID — не светится в API/URL
    id: Mapped[str] = mapped_column(
        String(36),
        primary_key=True,
        default=lambda: str(uuid4()),
    )
    # Публичный ID для URL: /tasks/{public_id}
    # token_urlsafe(16) → 22 символа base64url, не угадываем, не связан с internal UUID
    public_id: Mapped[str] = mapped_column(
        String(32),
        unique=True,
        index=True,
        default=lambda: secrets.token_urlsafe(16),
    )
    user_id: Mapped[int] = mapped_column(ForeignKey("users.id"), index=True)
    type: Mapped[str] = mapped_column(String(20), nullable=False)
    status: Mapped[str] = mapped_column(String(20), default=TaskStatus.QUEUED)
    celery_task_id: Mapped[str | None] = mapped_column(String(255), nullable=True)
    # Входные данные: query, filename, doc_ids и т.д.
    input_data: Mapped[dict] = mapped_column(JSON, default=dict)
    # Результат работы воркера
    result: Mapped[dict | None] = mapped_column(JSON, nullable=True)
    error: Mapped[str | None] = mapped_column(nullable=True)
    queue_position: Mapped[int | None] = mapped_column(nullable=True)
    created_at: Mapped[datetime] = mapped_column(server_default=func.now())
    updated_at: Mapped[datetime | None] = mapped_column(
        nullable=True,
        onupdate=func.now(),
    )

    # Связи
    user: Mapped["User"] = relationship(back_populates="tasks")

    def __repr__(self) -> str:
        return f"<Task id={self.id!r} type={self.type!r} status={self.status!r}>"