"""
Implementation of C# System.Guid

References:
    https://referencesource.microsoft.com/#mscorlib/system/guid.cs

    # TODO Add License
"""

from struct import Struct, pack
from math import log

# Constants for masking bytes
MAXINT64 = 0xFFFFFFFFFFFFFFFF
MAXINT16 = 0xFFFF
MAXINT8 = 0xFF


class Guid:
    """
    A Global Unique Identifier (Guid) based on the one provided in C#'s System package

    The Guid is stored as a tuple of length 11 for easy processing and comparisons

    Attributes:
        guid (tuple): A tuple containing the guid
    """
    def __init__(self, *args):
        """
        Initialize the Guid

        Arguments:
            Union[int, str, bytes, short(int will be masked to short)]:
                The arguments can be in any of the following formats:
                (bytes(len 16))
                (int(len <= 4), short, short, bytes(len 8))
                (int(len <= 8), int(len <= 8))
                (int(len <= 16))
                (str) - str must be formatted 00000000-0000-0000-0000-000000000000
        """
        # Guid will be stored as a tuple len 11
        if bool(args):
            self.get_guid(args)
        else:
            self.guid = (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)

    def get_guid(self, args) -> None:
        s = Struct('I2H8B')
        if len(args) == 1 and isinstance(args[0], bytes) and len(args[0]) == 16:
            b = args[0]
            guid = s.pack((int(b[3]) << 24) | (int(b[2]) << 16) | (int(b[1]) << 8) | b[0],
                          ((int(b[5]) << 8) | b[4]),
                          (int(b[7]) << 8) | b[6],
                          *b[8:16]
                          )
            self.guid = s.unpack(guid)
        elif len(args) == 4 and all(isinstance(arg, int) for arg in args[0:3]) \
                and isinstance(args[3], bytes) and len(args[3]) == 8:
            guid = s.pack(args[0], args[1] & MAXINT16, args[2] & MAXINT16, *args[3])
            self.guid = s.unpack(guid)
        elif len(args) == 2 and all(isinstance(arg, int) for arg in args):
            if all((self.bytes_needed(arg) <= 4) for arg in args):
                int1, int2 = (args[0] << 32), (args[1] & 0xFFFFFFFF)
                id_int = int1 | int2
                b = pack('Q8x', id_int)
            elif all((self.bytes_needed(arg) <= 8) for arg in args):
                b = pack('QQ', args[0], args[1])
            else:
                raise TypeError('Arguments don\'t match any allowed configuration')
            guid = s.pack((int(b[3]) << 24) | (int(b[2]) << 16) | (int(b[1]) << 8) | b[0],
                          ((int(b[5]) << 8) | b[4]),
                          ((int(b[7]) << 8) | b[6]),
                          *b[8:16]
                          )
            self.guid = s.unpack(guid)
        elif len(args) == 1 and isinstance(args[0], int):
            if self.bytes_needed(args[0]) <= 8:
                b = pack('Q8x', args[0])
            else:
                first = (args[0] >> 64) & MAXINT64
                second = args[0] & MAXINT64
                b = pack('QQ', first, second)
            guid = s.pack((int(b[3]) << 24) | (int(b[2]) << 16) | (int(b[1]) << 8) | b[0],
                          ((int(b[5]) << 8) | b[4]),
                          (int(b[7]) << 8) | b[6],
                          *b[8:16]
                          )
            self.guid = s.unpack(guid)
        elif len(args) == 1 and isinstance(args[0], str) and len(args[0]) == 36:
            self.parse_string(args[0])
        else:
            raise TypeError('Arguments don\'t match any allowed configuration')

    def parse_string(self, string):
        if len(string) == 36:
            if string[8] == '-' and string[13] == '-' and string[18] == '-' and string[23] == '-':
                guid_str = string.split('-')
                try:
                    self.guid = (int(guid_str[0], 16),
                                 int(guid_str[1], 16),
                                 int(guid_str[2], 16),
                                 int(guid_str[3], 16) >> 8,
                                 int(guid_str[3], 16) & MAXINT8,
                                 int(guid_str[4], 16) >> 40,
                                 int(guid_str[4], 16) >> 32,
                                 int(guid_str[4], 16) >> 24,
                                 int(guid_str[4], 16) >> 16,
                                 int(guid_str[4], 16) >> 8,
                                 int(guid_str[4], 16) & MAXINT8,
                                 )
                except ValueError:
                    raise TypeError('String is not formatted properly must be in format '
                                    '00000000-0000-0000-0000-000000000000')

    def to_string(self):
        output = ''
        output += self.hexs_to_chars(self.guid[0] >> 24, self.guid[0] >> 16)
        output += self.hexs_to_chars(self.guid[0] >> 8, self.guid[0])
        output += '-'
        output += self.hexs_to_chars(self.guid[1] >> 8, self.guid[1])
        output += '-'
        output += self.hexs_to_chars(self.guid[2] >> 8, self.guid[2])
        output += '-'
        output += self.hexs_to_chars(self.guid[3], self.guid[4])
        output += '-'
        output += self.hexs_to_chars(self.guid[5], self.guid[6])
        output += self.hexs_to_chars(self.guid[7], self.guid[8])
        output += self.hexs_to_chars(self.guid[9], self.guid[10])
        return output

    def to_byte_array(self):
        b = bytearray(16)
        b[0] = self.guid[0] & MAXINT8
        b[1] = (self.guid[0] >> 8) & MAXINT8
        b[2] = (self.guid[0] >> 16) & MAXINT8
        b[3] = (self.guid[0] >> 24) & MAXINT8
        b[4] = self.guid[1] & MAXINT8
        b[5] = (self.guid[1] >> 8) & MAXINT8
        b[6] = self.guid[2] & MAXINT8
        b[7] = (self.guid[2] >> 8) & MAXINT8
        b[8] = self.guid[3] & MAXINT8
        b[9] = self.guid[4] & MAXINT8
        b[10] = self.guid[5] & MAXINT8
        b[11] = self.guid[6] & MAXINT8
        b[12] = self.guid[7] & MAXINT8
        b[13] = self.guid[8] & MAXINT8
        b[14] = self.guid[9] & MAXINT8
        b[15] = self.guid[10] & MAXINT8
        return b

    def hexs_to_chars(self, _a, _b):
        out = f'{self.hex_to_char(_a>>4)}{self.hex_to_char(_a)}{self.hex_to_char(_b>>4)}{self.hex_to_char(_b)}'
        return out

    @staticmethod
    def bytes_needed(a):
        if a == 0:
            return 1
        return int(log(a, 256)) + 1

    @staticmethod
    def hex_to_char(a: int):
        a = a & 0xf
        out = chr(a - 10 + 0x61 if a > 9 else a + 0x30)
        return out

    def __hash__(self):
        t = self.guid
        return t[0] ^ ((int(t[1]) << 16) | int(t[2])) ^ ((int(t[5]) << 24) | t[10])

    def __eq__(self, other):
        if other is None or not isinstance(other, Guid):
            return False
        if other.guid[0] != self.guid[0]:
            return False
        if other.guid[1] != self.guid[1]:
            return False
        if other.guid[2] != self.guid[2]:
            return False
        if other.guid[3] != self.guid[3]:
            return False
        if other.guid[4] != self.guid[4]:
            return False
        if other.guid[5] != self.guid[5]:
            return False
        if other.guid[6] != self.guid[6]:
            return False
        if other.guid[7] != self.guid[7]:
            return False
        if other.guid[8] != self.guid[8]:
            return False
        if other.guid[9] != self.guid[9]:
            return False
        if other.guid[10] != self.guid[10]:
            return False
        return True

    def __bool__(self):
        return not (self.guid == (0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0))

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

    def __repr__(self):
        return f'<Guid hash={self.__hash__()}>'