from datetime import datetime
from typing import Optional
from sqlmodel import SQLModel, Field, Relationship

class TaskBase(SQLModel):
    title: str = Field(index=True, min_length=1, max_length=200)
    description: Optional[str] = Field(default=None, max_length=2000)
    priority: str = Field(default="medium", index=True) # low, medium, high

class Task(TaskBase, table=True):
    id: Optional[int] = Field(default=None, primary_key=True)
    user_id: int = Field(foreign_key="user.id", index=True)
    completed: bool = Field(default=False, index=True)
    created_at: datetime = Field(default_factory=datetime.utcnow, index=True)
    updated_at: datetime = Field(default_factory=datetime.utcnow)
    completed_at: Optional[datetime] = None

    user: "User" = Relationship(back_populates="tasks")

class TaskCreate(TaskBase):
    pass

class TaskUpdate(SQLModel):
    title: Optional[str] = Field(default=None, min_length=1, max_length=200)
    description: Optional[str] = Field(default=None, max_length=2000)
    priority: Optional[str] = None
    completed: Optional[bool] = None

class TaskRead(TaskBase):
    id: int
    user_id: int
    completed: bool
    priority: str
    created_at: datetime
    updated_at: datetime
    completed_at: Optional[datetime]