src/services/task_service.py - master - tegdif/cism

src/services/task_service.py
101 строка4 KB
tegdif
first_commit
28 июл 2026, 08:54
28 июл 2026, 08:548ecbd07
import uuid
from datetime import datetime, timezone
from typing import Optional

from sqlalchemy import select, func
from sqlalchemy.ext.asyncio import AsyncSession

from src.models.task import Task, TaskStatus, TaskPriority
from src.schemas.task import TaskCreate, TaskResponse, TaskStatusResponse, TaskListResponse


class TaskService:
    """Сервисный слой для CRUD-операций над задачами и управления статусами."""

    def __init__(self, session: AsyncSession) -> None:
        self.session = session

    async def create_task(self, task_data: TaskCreate) -> Task:
        """Создаёт новую задачу со статусом NEW и возвращает её."""
        task = Task(
            title=task_data.title,
            description=task_data.description or "",
            priority=task_data.priority,
            status=TaskStatus.NEW,
        )
        self.session.add(task)
        await self.session.commit()
        await self.session.refresh(task)
        return task

    async def get_task(self, task_id: uuid.UUID) -> Optional[Task]:
        """Возвращает задачу по UUID или None, если не найдена."""
        result = await self.session.execute(select(Task).where(Task.id == task_id))
        return result.scalar_one_or_none()

    async def get_tasks(
        self,
        page: int = 1,
        page_size: int = 10,
        status: Optional[TaskStatus] = None,
        priority: Optional[TaskPriority] = None,
    ) -> TaskListResponse:
        """Возвращает список задач с пагинацией и фильтрацией, отсортированный по дате создания (сначала новые)."""
        query = select(Task)
        count_query = select(func.count(Task.id))

        if status:
            query = query.where(Task.status == status)
            count_query = count_query.where(Task.status == status)
        if priority:
            query = query.where(Task.priority == priority)
            count_query = count_query.where(Task.priority == priority)

        total_result = await self.session.execute(count_query)
        total = total_result.scalar() or 0

        offset = (page - 1) * page_size
        query = query.order_by(Task.created_at.desc()).offset(offset).limit(page_size)
        result = await self.session.execute(query)
        tasks = list(result.scalars().all())

        items = [TaskResponse.model_validate(t) for t in tasks]
        return TaskListResponse(items=items, total=total, page=page, page_size=page_size)

    async def cancel_task(self, task_id: uuid.UUID) -> Optional[Task]:
        """Отменяет задачу. Вызывает ValueError, если задача уже в терминальном состоянии."""
        task = await self.get_task(task_id)
        if not task:
            return None
        if task.status in (TaskStatus.COMPLETED, TaskStatus.CANCELLED, TaskStatus.FAILED):
            raise ValueError(f"Невозможно отменить задачу в статусе {task.status.value}")
        task.status = TaskStatus.CANCELLED
        task.completed_at = datetime.now(timezone.utc)
        await self.session.commit()
        await self.session.refresh(task)
        return task

    async def update_task_status(
        self,
        task_id: uuid.UUID,
        status: TaskStatus,
        result: Optional[str] = None,
        error_info: Optional[str] = None,
    ) -> Optional[Task]:
        """Обновляет статус задачи и устанавливает временные метки (started_at / completed_at)."""
        task = await self.get_task(task_id)
        if not task:
            return None
        task.status = status
        now = datetime.now(timezone.utc)
        if status == TaskStatus.IN_PROGRESS:
            task.started_at = now
        elif status in (TaskStatus.COMPLETED, TaskStatus.FAILED, TaskStatus.CANCELLED):
            task.completed_at = now
        if result is not None:
            task.result = result
        if error_info is not None:
            task.error_info = error_info
        await self.session.commit()
        await self.session.refresh(task)
        return task