"""Camera probe (edge/probe.py) — all with fakes, no hardware."""

import pytest

from edge import probe


class FakeFrame:
    def __init__(self, shape):
        self.shape = shape


class FakeSource:
    """Yields `blanks` empty reads, then frames. Records that close() was called."""

    def __init__(self, blanks=0, shape=(480, 640, 3)):
        self._blanks = blanks
        self._shape = shape
        self.closed = False

    def read(self):
        if self._blanks > 0:
            self._blanks -= 1
            return False, None
        return True, FakeFrame(self._shape)

    def close(self):
        self.closed = True


def test_probe_reports_frame_geometry():
    r = probe.probe_one("uvc", "0", "cam-02", build_source=lambda b, d: FakeSource())
    assert r.ok
    assert "640x480" in r.detail and "3 channel" in r.detail


def test_probe_retries_while_the_sensor_settles():
    # A UVC camera commonly returns nothing for the first reads; that is not a failure.
    src = FakeSource(blanks=probe._READ_ATTEMPTS - 1)
    r = probe.probe_one("uvc", "0", "cam-02", build_source=lambda b, d: src)
    assert r.ok


def test_probe_fails_when_no_frame_ever_arrives(monkeypatch):
    monkeypatch.setattr(probe, "_READ_DELAY_S", 0)
    src = FakeSource(blanks=probe._READ_ATTEMPTS)
    r = probe.probe_one("csi", "0", "cam-01", build_source=lambda b, d: src)
    assert not r.ok
    assert "no frame" in r.detail


def test_probe_fails_when_the_device_cannot_be_opened():
    def boom(backend, device):
        raise RuntimeError("UVC device 0 failed to open")

    r = probe.probe_one("uvc", "0", "cam-02", build_source=boom)
    assert not r.ok
    assert "open failed" in r.detail


def test_probe_closes_the_source_even_on_failure(monkeypatch):
    monkeypatch.setattr(probe, "_READ_DELAY_S", 0)
    src = FakeSource(blanks=probe._READ_ATTEMPTS)
    probe.probe_one("uvc", "0", "cam-02", build_source=lambda b, d: src)
    assert src.closed, "a probe that holds the device open would block the daemon start"


def test_probe_all_covers_every_configured_camera():
    env = {"CAMERAS": "csi:0:cam-01,uvc:0:cam-02"}
    results = probe.probe_all(env, build_source=lambda b, d: FakeSource())
    assert [r.camera_id for r in results] == ["cam-01", "cam-02"]
    assert [r.backend for r in results] == ["csi", "uvc"]
    assert all(r.ok for r in results)


def test_probe_all_rejects_a_malformed_cameras_value():
    with pytest.raises(ValueError):
        probe.probe_all({"CAMERAS": "csi:0"}, build_source=lambda b, d: FakeSource())