tax calculator

taxcalculator.py

import numpy as np
from typing import Callable
from dataclasses import dataclass
import random

gen = np.random.default_rng()


@dataclass
class Simulation:
    name: str
    calculator: Callable


def get_ranges(years=30):
    ranges = []

    for i in range(len(historical_results) - years + 1):
        result = reversed(historical_results[i : i + years])
        result = map(lambda s: s / 100, result)
        ranges.append(list(result))

    return ranges


def get_random_range(years=30):
    start = random.randint(0, len(historical_results) - years)
    result = reversed(historical_results[start : start + years])
    result = map(lambda s: s / 100, result)

    return list(result)


def calculate_new_taxes(previous_value, current_value):
    return max(0, current_value - previous_value - 800) * 0.34


def calculate_old_taxes(previous_value, current_value):
    return current_value * (1.2 / 100)


def calculate_no_taxes(previous_value, current_value):
    return 0


def cagr(begin, end, years):
    return (end / begin) ** (1 / years) - 1


simulations = [
    Simulation("new taxes", calculate_new_taxes),
    Simulation("old taxes", calculate_old_taxes),
    Simulation("no taxes", calculate_no_taxes),
]


def run():

    for simulation in simulations:
        results = []
        for i in get_ranges(30):
            results.append(run_simulation(simulation.calculator, i))

        df = np.array(results)

        start_amount = 100000
        contributions = df[:, 0].mean()
        final_amount = df[:, 2].mean()
        taxes_paid = df[:, 1].mean()
        nett_gains = final_amount - start_amount
        return_rate = cagr(start_amount, final_amount, 30)

        print("=====", simulation.name, "=====")
        print("total investments", start_amount + contributions)
        print("final amount", final_amount)
        print("total taxes paid", taxes_paid)
        print("nett gainz", nett_gains)
        print("return rate", return_rate)


def run_simulation(calculator, returns):
    money = 100000
    # yearly = 10000
    yearly = 0
    total_taxes = 0
    total_contributions = 0

    for i in returns:
        returns = money * i
        taxes = calculator(money, money + returns)

        money = money + returns - taxes + yearly

        total_taxes += taxes
        total_contributions += yearly

    return (total_contributions, total_taxes, money)


historical_results = [
    7.77,
    -19.44,
    26.89,
    16.26,
    28.88,
    -6.24,
    19.42,
    9.54,
    -0.73,
    11.39,
    29.60,
    13.41,
    0.00,
    12.78,
    23.45,
    -38.49,
    3.53,
    13.62,
    3.00,
    8.99,
    26.38,
    -23.37,
    -13.04,
    -10.14,
    19.53,
    26.67,
    31.01,
    20.26,
    34.11,
    -1.54,
    7.06,
    4.46,
    26.31,
    -6.56,
    27.25,
    12.40,
    2.03,
    14.62,
    26.33,
    1.40,
    17.27,
    14.76,
    -9.73,
    25.77,
    12.31,
    1.06,
    -11.50,
    19.15,
    31.55,
    -29.72,
    -17.37,
    15.63,
    10.79,
    0.10,
    -11.36,
    7.66,
    20.09,
    -13.09,
    9.06,
    12.97,
    18.89,
    -11.81,
    23.13,
    -2.97,
    8.48,
    38.06,
    -14.31,
    2.62,
    26.40,
    45.02,
    -6.62,
    11.78,
    16.46,
    21.78,
    10.26,
    -0.65,
    0.00,
    -11.87,
    30.72,
    13.80,
    19.45,
    12.43,
    -17.86,
    -15.29,
    -5.45,
    25.21,
    -38.59,
    27.92,
    41.37,
    -5.94,
    46.59,
    -15.15,
    -47.07,
    -28.48,
    -11.91,
    37.88,
]

run()