"""Base SQLModel configuration for WealthWise database models.

This module provides the base model class with common fields and utilities
for all database entities.
"""

from datetime import datetime
from typing import Optional
from uuid import UUID, uuid4

from sqlalchemy import func
from sqlmodel import Field, SQLModel


class BaseModel(SQLModel):
    """Base model with common fields for all database tables.
    
    All models should inherit from this class to get:
    - UUID primary key
    - Created and updated timestamps
    - Soft delete support
    
    Attributes:
        id: Unique identifier (UUID)
        created_at: Timestamp when record was created
        updated_at: Timestamp when record was last updated
        deleted_at: Timestamp for soft deletes (None if active)
    """
    
    id: Optional[UUID] = Field(
        default_factory=uuid4,
        primary_key=True,
        index=True,
        description="Unique identifier",
    )
    
    created_at: Optional[datetime] = Field(
        default=None,
        sa_column_kwargs={
            "server_default": func.now(),
            "nullable": False,
        },
        description="Timestamp when record was created",
    )
    
    updated_at: Optional[datetime] = Field(
        default=None,
        sa_column_kwargs={
            "server_default": func.now(),
            "onupdate": func.now(),
            "nullable": False,
        },
        description="Timestamp when record was last updated",
    )
    
    deleted_at: Optional[datetime] = Field(
        default=None,
        description="Timestamp for soft delete (None if record is active)",
    )
    
    class Config:
        """Pydantic configuration."""
        # Allow arbitrary types for UUID handling
        arbitrary_types_allowed = True


class TimestampMixin(SQLModel):
    """Mixin for models that only need timestamp fields (no ID).
    
    Use this for association tables or when ID is handled differently.
    """
    
    created_at: Optional[datetime] = Field(
        default=None,
        sa_column_kwargs={
            "server_default": func.now(),
            "nullable": False,
        },
    )
    
    updated_at: Optional[datetime] = Field(
        default=None,
        sa_column_kwargs={
            "server_default": func.now(),
            "onupdate": func.now(),
            "nullable": False,
        },
    )