"""Tests fuer den lokalen Piper-TTS-Provider (offline, mit Fake-Binary)."""

import asyncio
import json
import shutil
import stat

import pytest

import app.providers.tts.piper as piper_mod
from app.providers.tts.piper import PiperTTSProvider


@pytest.fixture(autouse=True)
def _force_binary_path(monkeypatch):
    """Diese Tests pruefen den Binary-Fallback (Fake-piper). Ist die piper-Python-Lib
    installiert, wuerde sonst der In-Process-Pfad das Fake-Modell zu laden versuchen."""
    monkeypatch.setattr(piper_mod, "_PIPER_LIB", False)


# PCM-Nutzlast des Fake-Binaries. 4000 Bytes = 2000 s16le-Samples.
FAKE_PCM = b"\x01\x02" * 2000


def _run(coro):
    return asyncio.run(coro)


def _make_fake_voice(tmp_path, sample_rate):
    """Legt ein Fake-piper-Binary + Stimmmodell (.onnx/.onnx.json) an."""
    voices = tmp_path / "voices"
    voices.mkdir()
    (voices / "de_DE-test.onnx").write_bytes(b"fake-model")
    (voices / "de_DE-test.onnx.json").write_text(
        json.dumps({"audio": {"sample_rate": sample_rate}})
    )

    # Fake-Binary: ignoriert Argumente, schreibt feste Roh-PCM-Bytes nach stdout.
    binp = tmp_path / "piper"
    binp.write_text(
        "#!/usr/bin/env python3\n"
        "import sys\n"
        f"sys.stdout.buffer.write({FAKE_PCM!r})\n"
    )
    binp.chmod(binp.stat().st_mode | stat.S_IEXEC | stat.S_IXGRP | stat.S_IXOTH)
    return str(binp), str(voices)


def test_piper_returns_pcm_without_resampling(tmp_path):
    # Native Rate == Ziel-Rate -> kein ffmpeg noetig, Bytes unveraendert.
    binp, voices = _make_fake_voice(tmp_path, sample_rate=24000)
    provider = PiperTTSProvider(binp, voices, "de_DE-test", target_rate=24000)
    pcm = _run(provider.synthesize("Hallo Welt"))
    assert pcm == FAKE_PCM


def test_piper_wraps_wav_on_request(tmp_path):
    binp, voices = _make_fake_voice(tmp_path, sample_rate=24000)
    provider = PiperTTSProvider(binp, voices, "de_DE-test", target_rate=24000)
    wav = _run(provider.synthesize("Hallo", audio_format="wav"))
    assert wav.startswith(b"RIFF") and b"WAVE" in wav[:16]


def test_piper_rejects_empty_text(tmp_path):
    binp, voices = _make_fake_voice(tmp_path, sample_rate=24000)
    provider = PiperTTSProvider(binp, voices, "de_DE-test")
    with pytest.raises(ValueError):
        _run(provider.synthesize("   "))


def test_piper_unknown_voice_raises(tmp_path):
    binp, voices = _make_fake_voice(tmp_path, sample_rate=24000)
    provider = PiperTTSProvider(binp, voices, "gibt-es-nicht")
    with pytest.raises(RuntimeError):
        _run(provider.synthesize("Hallo"))


@pytest.mark.skipif(not shutil.which("ffmpeg"), reason="ffmpeg nicht installiert")
def test_piper_resamples_when_rates_differ(tmp_path):
    # Native 16000 -> Ziel 24000: ffmpeg laeuft, Ergebnis ist gueltiges (nicht leeres) PCM.
    binp, voices = _make_fake_voice(tmp_path, sample_rate=16000)
    provider = PiperTTSProvider(binp, voices, "de_DE-test", target_rate=24000)
    pcm = _run(provider.synthesize("Hallo"))
    assert isinstance(pcm, bytes) and len(pcm) > 0