from pydantic import BaseModel, Field
from typing import Optional
from datetime import datetime


class TaskCreate(BaseModel):
    """Schema for creating a new task."""

    title: str = Field(..., min_length=1, max_length=200, description="Task title (required)")
    description: Optional[str] = Field(None, max_length=2000, description="Optional detailed description")

    class Config:
        json_schema_extra = {
            "example": {
                "title": "Buy groceries",
                "description": "Milk, eggs, bread, and vegetables"
            }
        }


class TaskUpdate(BaseModel):
    """Schema for updating an existing task."""

    title: Optional[str] = Field(None, min_length=1, max_length=200, description="Updated task title")
    description: Optional[str] = Field(None, max_length=2000, description="Updated description")
    completed: Optional[bool] = Field(None, description="Updated completion status")

    class Config:
        json_schema_extra = {
            "example": {
                "title": "Buy groceries and cook dinner",
                "description": "Updated shopping list",
                "completed": True
            }
        }


class TaskResponse(BaseModel):
    """Schema for task response."""

    id: int = Field(..., description="Unique task identifier")
    title: str = Field(..., description="Task title")
    description: Optional[str] = Field(None, description="Task description")
    completed: bool = Field(..., description="Whether task is marked as complete")
    user_id: int = Field(..., description="ID of user who owns this task")
    created_at: datetime = Field(..., description="Timestamp when task was created")
    updated_at: datetime = Field(..., description="Timestamp when task was last modified")

    class Config:
        from_attributes = True
        json_schema_extra = {
            "example": {
                "id": 1,
                "title": "Buy groceries",
                "description": "Milk, eggs, bread",
                "completed": False,
                "user_id": 42,
                "created_at": "2026-02-02T10:30:00Z",
                "updated_at": "2026-02-02T10:30:00Z"
            }
        }