from twnet_parser.packet import \
    ChunkHeaderParser
from twnet_parser.chunk_header import \
    ChunkHeader

from tests.helper import cmp_bytes_as_bin

def test_chunk_header_unpack_vital1() -> None:
    parser = ChunkHeaderParser()
    header: ChunkHeader = parser.parse_header7(b'\x40\x10\x0a')

    assert header.flags.resend is False
    assert header.flags.vital is True

    assert header.size == 16
    assert header.seq == 10

def test_chunk_header_pack_vital1() -> None:
    header: ChunkHeader = ChunkHeader()

    header.flags.resend = False
    header.flags.vital = True
    header.size = 16
    header.seq = 10

    assert bytes([0b01000000, 0b00010000, 0b00001010]) == b'\x40\x10\x0a'

    cmp_bytes_as_bin(header.pack(), b'\x40\x10\x0a')
    assert header.pack() == b'\x40\x10\x0a'

def test_chunk_header_pack_resend() -> None:
    header: ChunkHeader = ChunkHeader()

    header.flags.resend = True
    header.flags.vital = False
    header.size = 16
    header.seq = 0

    assert bytes([0b10000000, 0b00010000]) == b'\x80\x10'

    cmp_bytes_as_bin(header.pack(), b'\x80\x10')
    assert header.pack() == b'\x80\x10'

def test_chunk_header_pack_no_flags1() -> None:
    header: ChunkHeader = ChunkHeader()

    header.flags.resend = False
    header.flags.vital = False
    header.size = 16
    header.seq = 0

    assert bytes([0b00000000, 0b00010000]) == b'\x00\x10'

    cmp_bytes_as_bin(header.pack(), b'\x00\x10')
    assert header.pack() == b'\x00\x10'

def test_chunk_header_pack_no_flags2() -> None:
    header: ChunkHeader = ChunkHeader()

    header.flags.resend = False
    header.flags.vital = False
    header.seq = 0

    header.size = 17
    assert bytes([0b00000000, 0b00010001]) == b'\x00\x11'
    cmp_bytes_as_bin(header.pack(), b'\x00\x11')
    assert header.pack() == b'\x00\x11'

    header.size = 18
    assert bytes([0b00000000, 0b00010010]) == b'\x00\x12'
    cmp_bytes_as_bin(header.pack(), b'\x00\x12')
    assert header.pack() == b'\x00\x12'

    header.size = 19
    assert bytes([0b00000000, 0b00010011]) == b'\x00\x13'
    cmp_bytes_as_bin(header.pack(), b'\x00\x13')
    assert header.pack() == b'\x00\x13'

    header.size = 20
    assert bytes([0b00000000, 0b00010100]) == b'\x00\x14'
    cmp_bytes_as_bin(header.pack(), b'\x00\x14')
    assert header.pack() == b'\x00\x14'

    header.size = 21
    assert bytes([0b00000000, 0b00010101]) == b'\x00\x15'
    cmp_bytes_as_bin(header.pack(), b'\x00\x15')
    assert header.pack() == b'\x00\x15'

def test_chunk_header_pack_no_flags_max_size() -> None:
    header: ChunkHeader = ChunkHeader()

    header.flags.resend = False
    header.flags.vital = False
    header.seq = 0

    header.size = 4094
    #
    # from libtw2 docs
    # https://github.com/heinrich5991/libtw2/blob/7885c99974ee445ce13297b72ae3e7c6ea3b969d/doc/packet7.md
    #
    # chunk7_header_nonvital:
    #     [ 1] flag_resend
    #     [ 1] flag_vital
    #     [ 6] <----------
    #     [ 2] padding   |-- size
    #     [ 6] <----------
    #
    #               FFss ssss    PPss ssss
    assert bytes([0b0011_1111, 0b0011_1110]) == b'\x3f\x3e'
    cmp_bytes_as_bin(header.pack(), b'\x3f\x3e')
    assert header.pack() == b'\x3f\x3e'

    header.size = 4095
    #
    # from libtw2 docs
    # https://github.com/heinrich5991/libtw2/blob/7885c99974ee445ce13297b72ae3e7c6ea3b969d/doc/packet7.md
    #
    # chunk7_header_nonvital:
    #     [ 1] flag_resend
    #     [ 1] flag_vital
    #     [ 6] <----------
    #     [ 2] padding   |-- size
    #     [ 6] <----------
    #
    #               FFss ssss    PPss ssss
    assert bytes([0b0011_1111, 0b0011_1111]) == b'\x3f\x3f'
    cmp_bytes_as_bin(header.pack(), b'\x3f\x3f')
    assert header.pack() == b'\x3f\x3f'


def test_chunk_header_pack_no_flags_out_of_bounds_size() -> None:
    header: ChunkHeader = ChunkHeader()

    header.flags.resend = False
    header.flags.vital = False
    header.seq = 0

    header.size = 4096
    #
    # from libtw2 docs
    # https://github.com/heinrich5991/libtw2/blob/7885c99974ee445ce13297b72ae3e7c6ea3b969d/doc/packet7.md
    #
    # chunk7_header_nonvital:
    #     [ 1] flag_resend
    #     [ 1] flag_vital
    #     [ 6] <----------
    #     [ 2] padding   |-- size
    #     [ 6] <----------
    #
    #               FFss ssss    PPss ssss
    assert bytes([0b0000_0000, 0b0000_0000]) == b'\x00\x00'
    #                 ^
    #                 does overflow to zero
    #                 should we error here instead?
    #                 TODO: https://gitlab.com/teeworlds-network/twnet_parser/-/issues/2
    cmp_bytes_as_bin(header.pack(), b'\x00\x00')
    assert header.pack() == b'\x00\x00'


def test_chunk_header_unpack_vital2() -> None:
    parser = ChunkHeaderParser()
    header: ChunkHeader = parser.parse_header7(b'\x40\x10\x09')

    assert header.flags.resend is False
    assert header.flags.vital is True

    assert header.size == 16
    assert header.seq == 9