feat: добавить доменную логику задач

Что сделано:
- добавлена модель задачи с UUID и бизнес-полями
- добавлены pydantic-схемы для создания, чтения и обновления
- реализован репозиторий и сервисный слой для CRUD-операций
- добавлена безопасная логика PATCH через exclude_unset

Author: RomanVetrov

app/models/task.py

@@ -0,0 +1,52 @@
+from __future__ import annotations
+
+import uuid
+from datetime import date
+from enum import Enum
+from typing import TYPE_CHECKING
+
+from sqlalchemy import Date, ForeignKey, String, Text
+from sqlalchemy.dialects.postgresql import UUID
+from sqlalchemy.orm import Mapped, mapped_column, relationship
+
+from app.database import Base
+from app.models.mixins import CreatedAtMixin
+
+if TYPE_CHECKING:
+    from app.models.tag import Tag
+
+
+class StatusEnum(str, Enum):
+    todo = "todo"
+    in_progress = "in_progress"
+    done = "done"
+
+
+class PriorityEnum(str, Enum):
+    low = "low"
+    medium = "medium"
+    high = "high"
+
+
+class Task(CreatedAtMixin, Base):
+    __tablename__ = "tasks"
+
+    id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), primary_key=True, default=uuid.uuid4
+    )
+    title: Mapped[str] = mapped_column(String(255), nullable=False)
+    description: Mapped[str | None] = mapped_column(Text(), nullable=True)
+    status: Mapped[StatusEnum] = mapped_column(
+        String(20), nullable=False, default=StatusEnum.todo
+    )
+    priority: Mapped[PriorityEnum] = mapped_column(
+        String(10), nullable=False, default=PriorityEnum.medium
+    )
+    due_date: Mapped[date | None] = mapped_column(Date(), nullable=True)
+    user_id: Mapped[uuid.UUID] = mapped_column(
+        UUID(as_uuid=True), ForeignKey("users.id", ondelete="CASCADE"), nullable=False
+    )
+    tags: Mapped[list[Tag]] = relationship(
+        secondary="task_tags",
+        back_populates="tasks",
+    )

app/repositories/task_repo.py

@@ -0,0 +1,47 @@
+from __future__ import annotations
+
+from collections.abc import Sequence
+from uuid import UUID
+
+from sqlalchemy import select
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.task import Task
+from app.models.user import User
+
+
+async def get_task_by_id(session: AsyncSession, task_id: UUID) -> Task | None:
+    """Возвращает задачу по id или None."""
+    return await session.get(Task, task_id)
+
+
+async def get_tasks_by_user(session: AsyncSession, user: User) -> Sequence[Task]:
+    """Возвращает все задачи пользователя."""
+    result = await session.execute(select(Task).where(Task.user_id == user.id))
+    return result.scalars().all()
+
+
+async def create_task(session: AsyncSession, user: User, **data) -> Task:
+    """Создаёт задачу для пользователя."""
+    task = Task(**data, user_id=user.id)
+    session.add(task)
+    await session.commit()
+    await session.refresh(task)
+    return task
+
+
+async def update_task(session: AsyncSession, task: Task, **data) -> Task:
+    """Обновляет переданные поля задачи."""
+    for field, value in data.items():
+        setattr(task, field, value)
+    await session.commit()
+    await session.refresh(task)
+    return task
+
+
+async def delete_task(session: AsyncSession, task: Task) -> UUID:
+    """Удаляет задачу и возвращает её id."""
+    task_id = task.id
+    await session.delete(task)
+    await session.commit()
+    return task_id

app/schemas/task.py

@@ -0,0 +1,43 @@
+from __future__ import annotations
+
+from datetime import date, datetime
+from uuid import UUID
+
+from pydantic import BaseModel, ConfigDict, Field
+
+from app.models.task import PriorityEnum, StatusEnum
+
+
+class TaskCreate(BaseModel):
+    title: str = Field(min_length=1, max_length=255)
+    description: str | None = Field(None, max_length=2000)
+    status: StatusEnum = StatusEnum.todo
+    priority: PriorityEnum = PriorityEnum.medium
+    due_date: date | None = None
+
+
+class TaskUpdate(BaseModel):
+    model_config = ConfigDict(extra="forbid")
+
+    title: str | None = Field(None, min_length=1, max_length=255)
+    description: str | None = Field(None, max_length=2000)
+    status: StatusEnum | None = None
+    priority: PriorityEnum | None = None
+    due_date: date | None = None
+
+
+class TaskRead(BaseModel):
+    model_config = ConfigDict(from_attributes=True)
+
+    id: UUID
+    title: str
+    description: str | None
+    status: StatusEnum
+    priority: PriorityEnum
+    due_date: date | None
+    user_id: UUID
+    created_at: datetime
+
+
+class TaskDeleted(BaseModel):
+    id: UUID

app/services/task.py

@@ -0,0 +1,42 @@
+from __future__ import annotations
+
+from collections.abc import Sequence
+from datetime import date
+from uuid import UUID
+
+from sqlalchemy.ext.asyncio import AsyncSession
+
+from app.models.task import Task
+from app.models.user import User
+from app.repositories import task_repo
+from app.schemas.task import TaskCreate, TaskUpdate
+
+
+class InvalidDueDate(Exception):
+    """Дедлайн задачи не может быть в прошлом."""
+
+
+async def create_task(session: AsyncSession, user: User, payload: TaskCreate) -> Task:
+    """Создаёт задачу. Поднимает InvalidDueDate если дедлайн в прошлом."""
+    if payload.due_date and payload.due_date < date.today():
+        raise InvalidDueDate
+    return await task_repo.create_task(session, user, **payload.model_dump())
+
+
+async def get_user_tasks(session: AsyncSession, user: User) -> Sequence[Task]:
+    """Возвращает все задачи пользователя."""
+    return await task_repo.get_tasks_by_user(session, user)
+
+
+async def update_task(session: AsyncSession, task: Task, payload: TaskUpdate) -> Task:
+    """Обновляет задачу. Поднимает InvalidDueDate если дедлайн в прошлом."""
+    updates = payload.model_dump(exclude_unset=True)
+    due_date = updates.get("due_date")
+    if due_date is not None and due_date < date.today():
+        raise InvalidDueDate
+    return await task_repo.update_task(session, task, **updates)
+
+
+async def delete_task(session: AsyncSession, task: Task) -> UUID:
+    """Удаляет задачу и возвращает её id."""
+    return await task_repo.delete_task(session, task)