from .models import Portfolio


ACTION_FIELD_MAP = {
            'like': 'likers',
            'scrap': 'scrappers',
        }

class PortfolioBeforeRelCheckService:
    @staticmethod
    def check_user_portfolio_rel(action_type: str, portfolio: Portfolio, user):
        action = ACTION_FIELD_MAP.get(action_type)
        if not action:
            raise ValueError(f"'{action_type}' is unsupported action type")

        if getattr(portfolio, action).filter(id=user.id).exists():
            return True
        else:
            return False

class PortfolioStateChangeService:
    @staticmethod
    def change_user_portfolio_rel(action_type: str, portfolio: Portfolio, user, add=True):
        action = ACTION_FIELD_MAP.get(action_type)
        if not action:
            raise ValueError(f"'{action_type}' is unsupported action type")

        user_method = getattr(getattr(portfolio, action), 'add' if add else 'remove')
        user_method(user)

    @staticmethod
    def change_count_portfolio_state(action_type: str, portfolio: Portfolio, add=True):
        action = ACTION_FIELD_MAP.get(action_type)
        if not action:
            raise ValueError(f"'{action_type}' is unsupported action type")
        field_name = action_type + '_count'
        current_count = getattr(portfolio, field_name)
        now_count = current_count+1 if add else max(current_count-1, 0)
        setattr(portfolio, field_name, now_count)
        portfolio.save(update_fields=[field_name])