#!/usr/bin/env python3

import random, datetime, os, math, decimal

MAX_SIMULATIONS = 100_000

class ProgressBar:
  def __init__(self, size=100, prompt=None):
    self.size = size
    self.prompt = prompt
    self.at = 0
    self.columns = os.get_terminal_size().columns
    self.space = self.columns - 9
    self.percent = None
    self.moved = None

    if self.prompt is not None:
      self.space -= len(self.prompt) + 1

    decimal.getcontext().prec = 4

  def move(self, amt=1):
    self.at += amt
    self.percent = decimal.Decimal.from_float(self.at / self.size)
    self.moved = math.floor(self.space * self.percent)

  def render_bar(self):
    return ("\u2588" * self.moved) + (" " * (self.space - self.moved))

  def progress(self):
    percent = self.percent * 100

    if percent.compare(decimal.Decimal(100)) == decimal.Decimal(-1):
      return f"{percent:05.2f}"
    else:
      return f"{percent:.1f}"

  def render(self):
    if self.prompt is not None:
      return f"{self.prompt} [{self.render_bar()}] {self.progress()}%"
    else:
      return f"[{self.render_bar()}] {self.progress()}%"

  def __str__(self):
    return self.render()

count = int(input(f"Total birthdays: "))
matches = 0
prog_bar = ProgressBar(size=MAX_SIMULATIONS, prompt="Running simulations")

for simulation in range(MAX_SIMULATIONS):
  birthdays = { }

  for idx in range(count):
    year = datetime.date(2001, 1, 1)
    days = datetime.timedelta(random.randint(0, 364))
    birthday = year + days

    if birthday in birthdays:
      matches += 1
      break
    else:
      birthdays[birthday] = 0

  prog_bar.move(1)
  end = ""

  if simulation == MAX_SIMULATIONS - 1:
    end = "\n"

  print(f"\r{prog_bar}", end=end)

percent = decimal.Decimal.from_float(matches / MAX_SIMULATIONS) * 100

if matches == MAX_SIMULATIONS:
  print(f"Calculated {percent:.1f}% people shared a birthday.")
else:
  print(f"Calculated {percent:05.2f}% people shared a birthday.")