import hashlib
import random
import uuid
import time
import math
import re

USERNAME_PATTERN: re.Pattern = re.compile("^[0-9A-Za-z]+$")
PASSWORD_PATTERN: re.Pattern = re.compile("^[!-~]+$")


def IsValidUsername(strl: str) -> bool:
    return USERNAME_PATTERN.match(strl) is not None


def IsValidPassword(strl: str) -> bool:
    return PASSWORD_PATTERN.match(strl) is not None


def ComputePasswordHash(password: str) -> str:
    s = hashlib.sha256()
    s.update(password.encode("utf-8"))
    return s.hexdigest()


def GenerateUUID() -> str:
    return str(uuid.uuid1())


def GenerateToken(username: str) -> str:
    s = hashlib.sha256()
    s.update(username.encode("utf-8"))
    s.update(GenerateUUID().encode("utf-8"))
    return s.hexdigest()


def GenerateSalt() -> int:
    return random.randint(0, 6172748)


def ComputePasswordHashWithSalt(passwordHashed: str, salt: int) -> str:
    s = hashlib.sha256()
    s.update((passwordHashed + str(salt)).encode("utf-8"))
    return s.hexdigest()


def GetCurrentTimestamp() -> int:
    return int(time.time())


def GetTokenExpireOn() -> int:
    return GetCurrentTimestamp() + 60 * 60 * 24 * 2  # add 2 day from now


def Str2Bool(strl: str) -> bool:
    return strl.lower() == "true"


def GCD(a: int, b: int) -> int:
    return math.gcd(a, b)


def LCM(a: int, b: int) -> int:
    return (a * b) // GCD(a, b)