"""CC11 expression curve (spec midi_note_cc11_expression).

Unit: _expression_events — grid 64 samples, nội suy tuyến tính, clamp 0..127.
Integration: render_soundfont_offline qua native_bridge — năng lượng output
theo curve (CC11 thấp -> âm nhỏ hơn rõ rệt). Skip nếu thiếu bridge/SF2."""
import os
import tempfile

import numpy as np
import pytest
import soundfile as sf

from app.core import native_render

SF2 = r"C:\Users\locpham\SonicForgeStudio\app\storage\soundfonts\518e850f-a5d3-4790-b1f9-0c90c203c524.sf2"


def _has_bridge():
    try:
        return bool(native_render.find_bridge_exe())
    except Exception:
        return False


# ── Unit: _expression_events ─────────────────────────────────────────────

def test_no_curve_no_events():
    assert native_render._expression_events([], 120, 48000) == []
    assert native_render._expression_events(None, 120, 48000) == []
    assert native_render._expression_events([{"pitch": 60, "start_beat": 0.0, "duration_beats": 1.0}], 120, 48000) == []


def test_flat_curve_grid():
    # bpm 120, 1 beat = 0.5s; @48k -> 24000 samples; grid 64 -> 376 points (0..24000 inclusive)
    events = native_render._expression_events(
        [{"start_beat": 0.0, "duration_beats": 1.0, "expression_curve": [{"position_ratio": 0.0, "value": 127}]}],
        120, 48000)
    assert len(events) == 24000 // 64 + 1
    assert events[0] == {"sample": 0, "kind": 2, "a": 11, "b": 127}
    assert events[-1]["sample"] == 24000
    assert all(e["kind"] == 2 and e["a"] == 11 and e["b"] == 127 for e in events)
    assert all(events[i]["sample"] < events[i + 1]["sample"] for i in range(len(events) - 1))


def test_ramp_interp():
    # curve 0 -> 127; @48k grid 64: tỉ lệ 0.5 tại sample 12000 -> value ~64
    events = native_render._expression_events(
        [{"start_beat": 0.0, "duration_beats": 1.0,
          "expression_curve": [{"position_ratio": 0.0, "value": 0}, {"position_ratio": 1.0, "value": 127}]}],
        120, 48000, grid=240)  # 240 chia hết 24000 -> sample 12000 (ratio 0.5) nằm trên grid
    by_sample = {e["sample"]: e["b"] for e in events}
    assert by_sample[0] == 0
    assert by_sample[24000] == 127
    assert abs(by_sample[12000] - 64) <= 1  # nội suy tuyến tính tại giữa


def test_curve_offset_and_clamp():
    # note bắt đầu beat 2 (sample 48000) + grid custom 128; value clamp 0..127
    events = native_render._expression_events(
        [{"start_beat": 2.0, "duration_beats": 0.5,
          "expression_curve": [{"position_ratio": 0.0, "value": 200}, {"position_ratio": 1.0, "value": -5}]}],
        120, 48000, grid=128)
    assert events[0]["sample"] == 48000
    assert events[0]["b"] == 127  # clamp trên
    # 12000 / 128 = 93.75 -> điểm cuối 93*128 = 11904 (pos += grid; 12032 > 12000 dừng)
    assert events[-1]["sample"] == 48000 + 11904
    assert events[-1]["b"] == 0  # clamp dưới
    assert all(0 <= e["b"] <= 127 for e in events)


def test_curve_sorted_by_sample_with_notes():
    # nhiều note cùng curve — events toàn cục sorted theo sample, không trùng key kind/a
    events = native_render._expression_events([
        {"start_beat": 0.0, "duration_beats": 1.0,
         "expression_curve": [{"position_ratio": 0.0, "value": 100}]},
        {"start_beat": 4.0, "duration_beats": 1.0,
         "expression_curve": [{"position_ratio": 0.0, "value": 50}]},
    ], 120, 48000, grid=1024)
    assert events
    assert all(events[i]["sample"] <= events[i + 1]["sample"] for i in range(len(events) - 1))
    assert events[0]["b"] == 100
    assert events[-1]["b"] == 50


# ── Integration: render_soundfont_offline, năng lượng theo curve ─────────

def test_render_energy_follows_curve():
    if not _has_bridge():
        pytest.skip("bridge exe missing")
    if not os.path.isfile(SF2):
        pytest.skip("SF2 fixture missing")
    with tempfile.TemporaryDirectory() as td:
        base = os.path.join(td, "n.wav")
        jobs = [
            ("flat", base + ".flat.wav", [{"position_ratio": 0.0, "value": 127}]),
            ("low", base + ".low.wav", [{"position_ratio": 0.0, "value": 20}]),
            ("ramp", base + ".ramp.wav",
             [{"position_ratio": 0.0, "value": 0}, {"position_ratio": 1.0, "value": 127}]),
        ]
        rms = {}
        for name, out, curve in jobs:
            notes = [{"pitch": 60, "velocity": 0.8, "start_beat": 0.0, "duration_beats": 1.0,
                      "expression_curve": curve}]
            out_path, _dur = native_render.render_soundfont_offline(
                SF2, notes, bpm=120.0, sample_rate=44100)
            try:
                data, sr = sf.read(out_path, always_2d=True)
                rms[name] = float(np.sqrt(np.mean(data ** 2)))
            finally:
                try:
                    os.remove(out_path)
                except OSError:
                    pass
        assert rms["flat"] > 0.001
        # CC11 thấp phải giảm năng lượng rõ rệt (>3x RMS)
        assert rms["flat"] > 3 * rms["low"], f"flat={rms['flat']:.5f} low={rms['low']:.5f}"
        # ramp (0 -> 127) yếu ở đầu -> năng lượng trung bình thấp hơn flat
        assert rms["flat"] > rms["ramp"], f"flat={rms['flat']:.5f} ramp={rms['ramp']:.5f}"