"""
This is a pure Python implementation of Dynamic Programming solution to the fibonacci
sequence problem.
"""


class Fibonacci:
 def __init__(self) -> None:
 self.sequence = [0, 1]

 def get(self, index: int) -> list:
 """
 Get the Fibonacci number of `index`. If the number does not exist,
 calculate all missing numbers leading up to the number of `index`.

 >>> Fibonacci().get(10)
 [0, 1, 1, 2, 3, 5, 8, 13, 21, 34]
 >>> Fibonacci().get(5)
 [0, 1, 1, 2, 3]
 """
 difference = index - (len(self.sequence) - 2)
 if difference >= 1:
 for _ in range(difference):
 self.sequence.append(self.sequence[-1] + self.sequence[-2])
 return self.sequence[:index]


def main():
 print(
 "Fibonacci Series Using Dynamic Programming\n",
 "Enter the index of the Fibonacci number you want to calculate ",
 "in the prompt below. (To exit enter exit or Ctrl-C)\n",
 sep="",
 )
 fibonacci = Fibonacci()

 while True:
 prompt: str = input(">> ")
 if prompt in {"exit", "quit"}:
 break

 try:
 index: int = int(prompt)
 except ValueError:
 print("Enter a number or 'exit'")
 continue

 print(fibonacci.get(index))


if __name__ == "__main__":
 main()