import secrets
from pathlib import Path
from typing import List, Optional

from pydantic import validator
from pydantic_settings import BaseSettings


class Settings(BaseSettings):
    """Application settings."""
    
    # API
    API_V1_STR: str = "/api/v1"
    PROJECT_NAME: str = "Ecommerce Authentication and Inventory API"
    
    # Security
    SECRET_KEY: str = secrets.token_urlsafe(32)
    ALGORITHM: str = "HS256"
    ACCESS_TOKEN_EXPIRE_MINUTES: int = 30
    
    # CORS
    BACKEND_CORS_ORIGINS: List[str] = ["*"]
    
    # Database
    DB_DIR: Path = Path("/app") / "storage" / "db"
    SQLALCHEMY_DATABASE_URL: Optional[str] = None
    
    @validator("SQLALCHEMY_DATABASE_URL", pre=True)
    def assemble_db_url(cls, v: Optional[str], values: dict) -> str:
        if v:
            return v
        
        db_dir = values.get("DB_DIR")
        db_dir.mkdir(parents=True, exist_ok=True)
        
        return f"sqlite:///{db_dir}/db.sqlite"
    
    class Config:
        env_file = ".env"
        case_sensitive = True


settings = Settings()