import io
import json
import sys
import tempfile
from pathlib import Path

sys.path.insert(0, str(Path(__file__).resolve().parents[1]))

import numpy as np
import soundfile as sf
from fastapi.testclient import TestClient

import pipeline_runner as runner
from app import app


def make_wav_buffer() -> io.BytesIO:
    sr = 22050
    y = np.zeros(sr, dtype=np.float32)
    for pos in [0, sr // 4, sr // 2, 3 * sr // 4]:
        n = min(1600, len(y) - pos)
        t = np.arange(n) / sr
        y[pos:pos + n] += 0.7 * np.exp(-t * 42) * np.sin(2 * np.pi * 90 * t)
    buf = io.BytesIO()
    sf.write(buf, y, sr, format="WAV")
    buf.seek(0)
    return buf


def test_config_exposes_runtime_diagnostics() -> None:
    client = TestClient(app)
    payload = client.get("/api/config").json()
    assert "runtime" in payload
    assert payload["runtime"]["backends"]["none"]["available"] is True
    assert payload["defaults"]["separation_backend"] == "spleeter"


def test_invalid_upload_extension_is_actionable() -> None:
    client = TestClient(app)
    response = client.post(
        "/api/jobs",
        files={"file": ("not-audio.txt", b"hello", "text/plain")},
        data={"params": json.dumps({})},
    )
    assert response.status_code == 400
    assert "Unsupported audio file extension" in response.json()["detail"]


def test_spleeter_falls_back_to_full_mix_without_demucs() -> None:
    original_spleeter = runner._extract_spleeter_separation
    original_demucs = runner._extract_demucs_separation
    runner._extract_spleeter_separation = lambda *args, **kwargs: (_ for _ in ()).throw(RuntimeError("synthetic spleeter failure"))
    runner._extract_demucs_separation = lambda *args, **kwargs: (_ for _ in ()).throw(RuntimeError("demucs should not be used for Spleeter fallback"))
    try:
        with tempfile.TemporaryDirectory() as tmp:
            wav_path = Path(tmp) / "input.wav"
            wav_path.write_bytes(make_wav_buffer().getvalue())
            params = runner.PipelineParams(separation_backend="spleeter", stem="drums", use_disk_cache=False, allow_backend_fallback=True)
            audio, sr, detail, context = runner._load_or_extract_separation(wav_path, params)
            assert sr == 44100
            assert audio.size > 0
            assert context is None
            assert "fallback full mix" in detail
            assert "Spleeter failed" in detail
    finally:
        runner._extract_spleeter_separation = original_spleeter
        runner._extract_demucs_separation = original_demucs


if __name__ == "__main__":
    test_config_exposes_runtime_diagnostics()
    test_invalid_upload_extension_is_actionable()
    test_spleeter_falls_back_to_full_mix_without_demucs()
    print("upload/error/fallback contract passed")