"""Watermark probe: abstain-by-default, and absence is never counter-evidence."""

from text_detection.detectors.watermark import WatermarkDetector
from text_detection.schema import Verdict


async def test_abstains_when_no_keys_configured(monkeypatch):
    from text_detection.config import settings

    monkeypatch.setattr(settings, "synthid_keys_path", None, raising=False)
    det = WatermarkDetector()
    res = await det.detect_text("Some ordinary text with no watermark at all.")
    assert res.detector == "text_watermark"
    assert res.confidence == 0.0          # abstain -> ignored by fusion
    assert res.verdict == Verdict.UNCERTAIN
    assert res.error is None              # abstain is NOT an error


async def test_absent_watermark_does_not_lower_p_fake(monkeypatch):
    # Absence of a watermark says nothing about authorship: p_fake must stay
    # neutral at 0.5, never drop toward "human".
    from text_detection.config import settings

    monkeypatch.setattr(settings, "synthid_keys_path", "/tmp/fake-keys", raising=False)
    det = WatermarkDetector()
    res = await det.detect_text("Some ordinary text with no watermark at all.")
    assert res.p_fake == 0.5
    assert res.confidence == 0.0


async def test_detected_watermark_is_high_confidence_ai(monkeypatch):
    from text_detection.detectors import watermark as wm

    monkeypatch.setattr(wm.settings, "synthid_keys_path", "/tmp/fake-keys", raising=False)
    monkeypatch.setattr(wm, "_synthid_detect", lambda text, keys: (True, 0.91))
    res = await wm.WatermarkDetector().detect_text("Watermarked output.")
    assert res.verdict == Verdict.AI_GENERATED
    assert res.p_fake > 0.9
    assert res.confidence > 0.9
    assert res.generator == "watermarked-LLM"


async def test_empty_text_returns_error():
    det = WatermarkDetector()
    res = await det.detect_text("")
    assert res.error is not None