from .._receivebuffer import ReceiveBuffer

def test_receivebuffer():
    b = ReceiveBuffer()
    assert not b
    assert len(b) == 0
    assert bytes(b) == b""

    b += b"123"
    assert b
    assert len(b) == 3
    assert bytes(b) == b"123"

    b.compress()
    assert bytes(b) == b"123"

    assert b.maybe_extract_at_most(2) == b"12"
    assert b
    assert len(b) == 1
    assert bytes(b) == b"3"

    b.compress()
    assert bytes(b) == b"3"

    assert b.maybe_extract_at_most(10) == b"3"
    assert bytes(b) == b""

    assert b.maybe_extract_at_most(10) is None
    assert not b

    ################################################################
    # maybe_extract_until_next
    ################################################################

    b += b"12345a6789aa"

    assert b.maybe_extract_until_next(b"a") == b"12345a"
    assert bytes(b) == b"6789aa"

    assert b.maybe_extract_until_next(b"aaa") is None
    assert bytes(b) == b"6789aa"

    b += b"a12"
    assert b.maybe_extract_until_next(b"aaa") == b"6789aaa"
    assert bytes(b) == b"12"

    # check repeated searches for the same needle, triggering the
    # pickup-where-we-left-off logic
    b += b"345"
    assert b.maybe_extract_until_next(b"aaa") is None

    b += b"6789aaa123"
    assert b.maybe_extract_until_next(b"aaa") == b"123456789aaa"
    assert bytes(b) == b"123"

    ################################################################
    # maybe_extract_lines
    ################################################################

    b += b"\r\na: b\r\nfoo:bar\r\n\r\ntrailing"
    lines = b.maybe_extract_lines()
    assert lines == [b"123", b"a: b", b"foo:bar"]
    assert bytes(b) == b"trailing"

    assert b.maybe_extract_lines() is None

    b += b"\r\n\r"
    assert b.maybe_extract_lines() is None

    assert b.maybe_extract_at_most(100) == b"trailing\r\n\r"
    assert not b

    # Empty body case (as happens at the end of chunked encoding if there are
    # no trailing headers, e.g.)
    b += b"\r\ntrailing"
    assert b.maybe_extract_lines() == []
    assert bytes(b) == b"trailing"