class Performance:

    @staticmethod
    def performance(time_step: int, portfolio_obj: portfolio):
        '''save to file'''
        equity = portfolio_obj.equity
        save_file = InitialConditions.get_save_file()
        record = {
                "time_step": time_step,
                "timestamp": (
                    InitialConditions.get_initial_time() + 
                    timedelta(seconds = InitialConditions.get_time_step_size() * time_step)
                ).isoformat(),
                "total equity": equity,
                "positions": portfolio_obj.positions
        }
        #append total to savefile, must exist
        with open(save_file, "a") as f:
            f.write(json.dumps(record) + "\n")


    @staticmethod
    def summary(portfolio_obj: portfolio):
        """plot equity curve"""
        save_file = InitialConditions.get_save_file()

        times = []
        equities = []

        with open(save_file, "r") as f:
            for line in f:
                record = json.loads(line)
                times.append(datetime.fromisoformat(record["timestamp"]))
                equities.append(record["total equity"])

        png_file = "plot.png"

        plt.figure()
        plt.plot(times, equities, 'o')
        plt.xlabel("Times")
        plt.ylabel("Equity")
        plt.title("Equity Curve")
        plt.grid(True)

        plt.savefig(png_file, dpi=150, bbox_inches="tight")
        plt.close()