import io
from pytest import raises
from .messages import Message
from .midifiles import MidiFile

HEADER_ONE_TRACK = """
4d 54 68 64  # MThd
00 00 00 06  # Chunk size
      00 01  # Type 1
      00 01  # 1 track
      00 78  # 120 ticks per beat
"""    


def parse_hexdump(hexdump):
    data = bytearray()
    for line in hexdump.splitlines():
        data += bytearray.fromhex(line.split('#')[0])
    return data


def read_file(hexdump):
    return MidiFile(file=io.BytesIO(parse_hexdump(hexdump)))


def test_no_tracks():
    assert read_file("""
    4d 54 68 64  # MThd
    00 00 00 06  # Chunk size
    00 01  # Type 1
    00 00  # 0 tracks
    00 78  # 120 ticks per beat
    """).tracks == []


def test_single_message():
    assert read_file(HEADER_ONE_TRACK + """
    4d 54 72 6b  # MTrk
    00 00 00 04
    20 90 40 40  # note_on
    """).tracks[0] == [Message('note_on', note=64, velocity=64, time=32)]


def test_two_tracks():
    mid = read_file("""
    4d54 6864 0000 0006 0001 0002 0040        # Header
    4d54 726b 0000 0008 00 90 40 10  40 80 40 10   # Track 0
    4d54 726b 0000 0008 00 90 47 10  40 80 47 10   # Track 1
    """)
    assert len(mid.tracks) == 2
    # Todo: add some more tests here.


def test_empty_file():
    with raises(EOFError):
        read_file("")
   

def test_eof_in_track():
    with raises(EOFError):
        read_file(HEADER_ONE_TRACK + """
        4d 54 72 6b  # MTrk
        00 00 00 01  # Chunk size
        # Oops, no data here.
        """)


def test_invalid_data_byte():
    # Todo: should this raise IOError?
    with raises(IOError):
        read_file(HEADER_ONE_TRACK + """
        4d 54 72 6b  # MTrk
        00 00 00 04  # Chunk size
        00 90 ff 40  # note_on note=255 velocity=64
        """)