import time 
from pygui.backend.models.frame import Frame
from pygui.serialcomm.stream_reader import StreamReader

class FakeTransport:
    """Yield canned data then blocks (returns b'')."""
    def __init__(self, lines):
        self._data = b"".join(lines)
        self._pos = 0
        self.closed = False
    def read(self, n=1):
        time.sleep(0.001)
        if self._pos >= len(self._data):
            return b""
        res = self._data[self._pos:self._pos+n]
        self._pos += n
        return res
    def readline(self):
        time.sleep(0.001)
        if self._pos >= len(self._data):
            return b""
        idx = self._data.find(b"\n", self._pos)
        if idx == -1:
            res = self._data[self._pos:]
            self._pos = len(self._data)
            return res
        res = self._data[self._pos:idx+1]
        self._pos = idx + 1
        return res
    def close(self): self.closed = True
    
def parse_line(raw: str, seq: int) -> Frame:
    parts = [float(x) for x in raw.split(",")]
    return Frame(seq = seq, time = parts[0], values = parts[1:])

def test_reads_frames_and_counts_errors():
    got, errors = [], []
    transport = FakeTransport([b"0.0,149,148\n", b"garbage\n", b"0.5,150,149\n"])
    r = StreamReader(transport, parse_line,
                    on_frame = got.append, on_error = lambda e: errors.append(e))
    
    r.start()
    time.sleep(0.1)
    r.stop()
    assert [f.values for f in got] == [[149.0, 148.0], [150.0, 149.0]]
    assert r.error_count == 1
    assert transport.closed