import { test, expect } from "bun:test";
import { features, pickOnsets } from "../../src/align/features.ts";
import type { Audio } from "../../src/core/types.ts";

const SR = 44100;
function tone(freqs: number[], sec: number): Audio {
  const x = new Float32Array(Math.round(sec * SR));
  for (let i = 0; i < x.length; i++) for (const f of freqs) x[i]! += 0.3 * Math.sin((2 * Math.PI * f * i) / SR);
  return { sampleRate: SR, channels: [x] };
}

test("features rate and length", () => {
  const f = features(tone([440], 3), 10);
  expect(f.rate).toBe(10);
  expect(Math.abs(f.chroma.length - 31)).toBeLessThanOrEqual(1);
  expect(f.onset.length).toBe(f.chroma.length);
  expect(f.chroma[0]!.length).toBe(12);
  const g = features(tone([440], 3), 50);
  expect(Math.abs(g.chroma.length - 151)).toBeLessThanOrEqual(1);
});

test("chroma peaks at the right pitch class and is unit-norm", () => {
  const f = features(tone([440], 2), 10); // A -> pitch class 9
  const c = f.chroma[10]!;
  let best = 0;
  for (let k = 1; k < 12; k++) if (c[k]! > c[best]!) best = k;
  expect(best).toBe(9);
  expect(Math.hypot(...c)).toBeCloseTo(1, 4);
  const fe = features(tone([261.63, 329.63, 392], 2), 10).chroma[10]!; // C E G
  const top = [...fe].map((v, k) => [v, k] as const).sort((a, b) => b[0] - a[0]).slice(0, 3).map((e) => e[1]).sort((a, b) => a - b);
  expect(top).toEqual([0, 4, 7]);
});

test("silent frames stay zero", () => {
  const f = features({ sampleRate: SR, channels: [new Float32Array(SR * 2)] }, 10);
  for (const c of f.chroma) expect(c.every((v) => v === 0)).toBe(true);
});

test("pickOnsets finds a click train within 10 ms", () => {
  const x = new Float32Array(SR * 4);
  const times = [0.5, 1.2, 2.0, 2.7, 3.3];
  for (const t of times) {
    const s = Math.round(t * SR);
    for (let k = 0; k < 200; k++) x[s + k] = Math.sin(k * 0.8) * Math.exp(-k / 40) * 0.8;
  }
  const f = features({ sampleRate: SR, channels: [x] }, 50);
  const got = pickOnsets(f.onset, f.rate);
  expect(got.length).toBe(times.length);
  times.forEach((t, k) => expect(Math.abs(got[k]! - t)).toBeLessThanOrEqual(0.01));
});

test("pickOnsets enforces 50 ms min gap and ignores flat input", () => {
  const o = new Float32Array(100);
  o[20] = 5; o[22] = 6; o[60] = 5;
  expect(pickOnsets(o, 100)).toEqual([0.22, 0.6]);
  expect(pickOnsets(new Float32Array(100), 100)).toEqual([]);
});

test("pickOnsets refines peaks to sub-frame times by parabolic interpolation", () => {
  const o = new Float32Array(100);
  o[30] = 4; o[31] = 8; o[32] = 6; // peak leans right: δ = ½(4 − 6)/(4 − 16 + 6) = 1/6 frame
  const got = pickOnsets(o, 50);
  expect(got).toHaveLength(1);
  expect(got[0]!).toBeCloseTo((31 + 1 / 6) / 50, 9);
  // min-gap competition still compares the peak heights, not the interpolated times
  const p = new Float32Array(100);
  p[40] = 5; p[41] = 3; p[42] = 7; p[43] = 1;
  expect(pickOnsets(p, 100)).toHaveLength(1);
  expect(pickOnsets(p, 100)[0]!).toBeCloseTo((42 + 0.5 * (3 - 1) / (3 - 14 + 1)) / 100, 9);
});