"""Amplitude → mouth openness, from PCM samples to the drawn frame.

Two halves, tested separately because only one of them needs a display:
`tts.level_of`/`envelope` turn samples into a 0..1 loudness, and
`PetWindow._mouth_frame` turns that loudness into a frame index. They meet at
the `mouth` signal, which the pipeline smoke test covers end to end.
"""

import sys
import time
from pathlib import Path

import numpy as np
import pytest

sys.path.insert(0, str(Path(__file__).resolve().parent.parent))

from bolt_pet.audio import tts


def frame(amplitude: int, samples: int = 480) -> np.ndarray:
    return np.full(samples, amplitude, dtype=np.int16)


# ── loudness ────────────────────────────────────────────────────────────────

def test_silence_closes_the_mouth():
    assert tts.level_of(np.zeros(480, dtype=np.int16)) == 0.0


def test_a_loud_frame_opens_it_fully():
    assert tts.level_of(frame(30000)) == 1.0


def test_the_level_never_leaves_zero_to_one():
    """It indexes a frame list; out of range is an IndexError on the UI thread."""
    for amplitude in (0, 1, 500, 6000, 20000, 32767):
        assert 0.0 <= tts.level_of(frame(amplitude)) <= 1.0


def test_it_rises_with_amplitude():
    quiet, middling, loud = (tts.level_of(frame(a)) for a in (800, 4000, 12000))
    assert quiet < middling < loud


def test_quiet_speech_still_moves_the_mouth_visibly():
    """The sqrt curve is the whole point. Speech spends most of its time well
    below peak, so a linear map leaves the mouth barely open for normal talking
    and the pet looks like it's mumbling."""
    assert tts.level_of(frame(1500)) > 0.15


def test_an_empty_frame_is_silence_not_a_crash():
    assert tts.level_of(np.zeros(0, dtype=np.int16)) == 0.0


# ── the envelope of a whole clip ────────────────────────────────────────────

def test_an_envelope_has_one_value_per_frame_at_the_requested_rate():
    one_second = np.zeros(16000, dtype=np.int16)
    assert len(tts.envelope(one_second, 16000, fps=30)) == pytest.approx(30, abs=1)


def test_an_envelope_tracks_loud_and_quiet_stretches():
    pcm = np.concatenate([np.zeros(8000, dtype=np.int16), frame(20000, 8000)])
    levels = tts.envelope(pcm, 16000, fps=10)
    assert max(levels[:4]) == 0.0      # the silent half
    assert min(levels[-4:]) > 0.5      # the loud half


def test_an_empty_clip_has_an_empty_envelope():
    assert tts.envelope(np.zeros(0, dtype=np.int16), 16000) == []


# ── the drawn frame ─────────────────────────────────────────────────────────

@pytest.fixture
def window():
    """Needs a QApplication; run with QT_QPA_PLATFORM=offscreen."""
    from PySide6.QtWidgets import QApplication

    from bolt_pet.ui.pet_window import PetWindow

    _app = QApplication.instance() or QApplication(["test"])
    win = PetWindow()
    yield win
    win.close()


class FakeAnimation:
    """Stands in for sprite.Animation — _mouth_frame only wants `.frames`."""

    def __init__(self, frames):
        self.frames = list(frames)


def test_the_talking_frame_follows_the_level(window):
    """The talking frames are an openness ramp — closed first, widest last —
    specifically so loudness can index them directly."""
    animation = FakeAnimation(["closed", "a", "b", "c", "d", "open"])

    assert window._mouth_frame(animation) is None      # no level set yet

    window.set_mouth(0.0)
    assert window._mouth_frame(animation) == "closed"

    window.set_mouth(1.0)
    assert window._mouth_frame(animation) == "open"

    window.set_mouth(0.5)
    assert window._mouth_frame(animation) not in ("closed", "open")


def test_a_stale_level_gives_the_animation_back(window):
    """If the audio thread stops sending levels — TTS died, the clip ended
    without a final zero — the mouth must not freeze half-open forever. After a
    moment it falls back to the ordinary looping animation."""
    animation = FakeAnimation(["a", "b", "c"])
    window.set_mouth(0.9)
    assert window._mouth_frame(animation) is not None

    window._mouth_at = time.monotonic() - 5.0
    assert window._mouth_frame(animation) is None


def test_a_single_frame_animation_falls_back_instead_of_indexing(window):
    """Art with one talking frame can't lip-sync; it must not try."""
    window.set_mouth(1.0)
    assert window._mouth_frame(FakeAnimation(["only"])) is None
    assert window._mouth_frame(FakeAnimation([])) is None


def test_no_animation_at_all_is_handled(window):
    window.set_mouth(0.5)
    assert window._mouth_frame(None) is None