from uuid import uuid4
from enum import IntEnum
from datetime import datetime
from collections import namedtuple

from telethon.utils import get_display_name

Command = namedtuple(
  'Command', 
  'name argc args args_string'
)

Age = namedtuple(
  'Age',
  'days_until age age_now date_string'
)

class Kind(IntEnum):
  CANNOT_APPLY_TO_SELF = 0
  CAN_APPLY_TO_SELF    = 1
  NO_TARGET            = 2

class WordKind(IntEnum):
  FIRST  = 0 # «год» / «день».
  SECOND = 1 # «лет» / «дней».
  THIRD  = 2 # «года» / «дня».

WORDS_TABLE = {
 'год': ('год', 'лет', 'года'),
 'день': ('день', 'дней', 'дня')
}

def parse_command(text):
  text = text.strip()

  if not text.startswith('/'):
    raise ValueError

  text = text.split(' ')

  if len(text) < 1:
    raise ValueError

  command = text[0][1:].lower()

  if '@' in command:
    command = command.split('@')
    command = command[0]

  args = text[1:]
  argc = len(args)
  args_string = ' '.join(args)

  return Command(
    name=command, 
    argc=argc, 
    args=args, 
    args_string=args_string
  )

def get_user_name(user):
  full_name = get_display_name(user)
  if not full_name:
    full_name = user.username
  
  if not full_name:
    full_name = '?'

  return full_name

def get_link_to_user(user):
  full_name = get_user_name(user)

  if user.username:
    return f'[{full_name}](@{user.username})'

  return f'[{full_name}](tg://user?id={user.id})'

def is_valid_name(name):
  return name.isidentifier()

def make_temporary_filename(ext):
  uid = uuid4().hex

  return f'tmp_{uid}.{ext}'

def parse_kind(kind):
  kind = int(kind)

  if kind < 0 or kind > 2:
    raise ValueError

  return kind

# Bruh?
def get_word_kind(number):
  if number == 0 or 5 <= number <= 20:
    return WordKind.SECOND

  last_digit = number % 10

  if last_digit == 0:
    return WordKind.SECOND

  if last_digit == 1:
    return WordKind.FIRST

  if 5 <= last_digit <= 9:
    return WordKind.SECOND

  return WordKind.THIRD

def get_word_for(word, number):
  return f'{number} {WORDS_TABLE[word][get_word_kind(number)]}'

def calculate_age(date):
  now = datetime.now().date()
  birthday_date = date.replace(year=now.year)

  if now > birthday_date:
    birthday_date = date.replace(year=now.year + 1)

  delta = birthday_date - now
  age = (birthday_date - date).days // 365
  age_now = age - 1

  return Age(
    days_until=delta.days,
    age=age,
    age_now=age_now,
    date_string=date.strftime('%d.%m.%Y')
  )