import os
from string import ascii_letters

LETTERS_AND_SPACE = ascii_letters + " \t\n"


def load_dictionary() -> dict[str, None]:
 path = os.path.split(os.path.realpath(__file__))
 english_words: dict[str, None] = {}
 with open(path[0] + "/dictionary.txt") as dictionary_file:
 for word in dictionary_file.read().split("\n"):
 english_words[word] = None
 return english_words


ENGLISH_WORDS = load_dictionary()


def get_english_count(message: str) -> float:
 message = message.upper()
 message = remove_non_letters(message)
 possible_words = message.split()
 matches = len([word for word in possible_words if word in ENGLISH_WORDS])
 return float(matches) / len(possible_words)


def remove_non_letters(message: str) -> str:
 return "".join(symbol for symbol in message if symbol in LETTERS_AND_SPACE)


def is_english(
 message: str, word_percentage: int = 20, letter_percentage: int = 85
) -> bool:
 """
 >>> is_english('Hello World')
 True
 >>> is_english('llold HorWd')
 False
 """
 words_match = get_english_count(message) * 100 >= word_percentage
 num_letters = len(remove_non_letters(message))
 message_letters_percentage = (float(num_letters) / len(message)) * 100
 letters_match = message_letters_percentage >= letter_percentage
 return words_match and letters_match


if __name__ == "__main__":
 import doctest

 doctest.testmod()