import os
import json
import pytest
from app.core.render_engine import PythonRenderEngine

def test_render_engine_init():
    engine = PythonRenderEngine()
    assert engine.sample_rate == 44100

def test_bars_to_samples():
    engine = PythonRenderEngine()
    samples = engine.bars_to_samples(4.0, 120.0, 4)
    assert samples == 352800

def test_render_session_container_empty():
    engine = PythonRenderEngine()
    session = {"tracks": []}
    buf = engine.render_session_container(session, {}, 120.0, 4, 1000)
    assert buf.shape == (2, 1000)
    assert (buf == 0.0).all()

def _midi_track(instrument_id, fx_type=None):
    return {
        "id": "t1",
        "type": "MIDI",
        "instrument_id": instrument_id,
        "instrument_source": "vsti",
        "fx_type": fx_type,
        "volume_db": 0.0,
        "pan": 0.0,
        "mute": False,
        "items": [{
            "type": "MIDI_ITEM",
            "start_bar": 0.0,
            "duration_bars": 1.0,
            "clip_start_offset_bars": 0.0,
            "source_data": {
                "notes": [
                    {"pitch": 60, "velocity": 0.8, "start_beat": 0.0, "duration_beats": 1.0}
                ]
            },
        }],
    }


def test_render_session_vsti_bridge_unknown_instrument_falls_back(monkeypatch):
    """SF_RENDER_ENGINE=bridge: track VSTi đi vào native_render; instrument lạ
    (404) → fallback oscillator, không crash, không cần pedalboard."""
    from app.api.v1 import plugins as pl
    monkeypatch.setattr(pl.settings, "RENDER_ENGINE", "bridge")
    engine = PythonRenderEngine()
    session = {"tracks": [_midi_track("__no_such_plugin__")]}
    buf = engine.render_session_container(session, {}, 120.0, 4, 44100)
    assert buf.shape == (2, 44100)
    # oscillator sinh âm thật (non-silent)
    assert (buf != 0.0).any()


def test_render_session_vsti_pedalboard_default_falls_back(monkeypatch):
    """Mặc định pedalboard: không có plugin load được → oscillator (không crash)."""
    from app.api.v1 import plugins as pl
    monkeypatch.setattr(pl.settings, "RENDER_ENGINE", "pedalboard")
    engine = PythonRenderEngine()
    session = {"tracks": [_midi_track("__no_such_plugin__")]}
    buf = engine.render_session_container(session, {}, 120.0, 4, 44100)
    assert buf.shape == (2, 44100)


def test_render_session_fx_chorus_scipy_fallback():
    """FX chorus: fallback scipy (không pedalboard) không crash, thay đổi âm."""
    from app.api.v1 import plugins as pl
    pl.settings.RENDER_ENGINE = "pedalboard"
    engine = PythonRenderEngine()
    session = {"tracks": [_midi_track("__no_such_plugin__", fx_type="chorus")]}
    buf = engine.render_session_container(session, {}, 120.0, 4, 44100)
    assert buf.shape == (2, 44100)
    assert (buf != 0.0).any()


def test_render_session_fx_reverb_scipy_fallback():
    """FX reverb: fallback scipy (không pedalboard) không crash, thay đổi âm."""
    from app.api.v1 import plugins as pl
    pl.settings.RENDER_ENGINE = "pedalboard"
    engine = PythonRenderEngine()
    session = {"tracks": [_midi_track("__no_such_plugin__", fx_type="reverb")]}
    buf = engine.render_session_container(session, {}, 120.0, 4, 44100)
    assert buf.shape == (2, 44100)
    assert (buf != 0.0).any()