/**
 * Synthetic snippet library for the node tests: three event types (low
 * ringing tone, high short tone, repeatable noise burst) standing in for
 * recorded taps. A tap excites the struck object's impulse response, so
 * instances of one type are highly repeatable up to gain and small
 * decay/pitch drift; the burst type reuses one fixed noise pattern (the
 * "object") rather than fresh noise per instance.
 */
import { mulberry32 } from '../src/bench/rng.ts';
import { FS, type SnippetLibrary } from '../src/bench/types.ts';

export const PRE_S = 0.02, POST_S = 0.18;

export function makeSyntheticLibrary(perType = 120, seed = 42): SnippetLibrary {
  const pre = Math.round(PRE_S * FS), post = Math.round(POST_S * FS);
  const snipLen = pre + post;
  const rng = mulberry32(seed);

  const burstBase = new Float32Array(post);
  {
    const brng = mulberry32(7);
    for (let i = 0; i < post; i++) burstBase[i] = brng() * 2 - 1;
  }

  function makeSnippet(kind: number): Float32Array {
    const s = new Float32Array(snipLen);
    const jitF = 1 + 0.01 * (rng() - 0.5);
    const jitT = 1 + 0.2 * (rng() - 0.5);
    if (kind === 0) {
      const f = 300 * jitF, tau = 0.06 * jitT;
      for (let i = 0; i < post; i++) {
        const t = i / FS;
        s[pre + i] = Math.exp(-t / tau) * Math.sin(2 * Math.PI * f * t) * 0.8;
      }
    } else if (kind === 1) {
      const f = 1400 * jitF, tau = 0.025 * jitT;
      for (let i = 0; i < post; i++) {
        const t = i / FS;
        s[pre + i] = Math.exp(-t / tau) * Math.sin(2 * Math.PI * f * t) * 0.8;
      }
    } else {
      const tau = 0.012 * jitT;
      for (let i = 0; i < post; i++) {
        const t = i / FS;
        s[pre + i] = Math.exp(-t / tau) * (burstBase[i] + 0.15 * (rng() * 2 - 1)) * 0.7;
      }
    }
    for (let i = 0; i < snipLen; i++) s[i] += (rng() * 2 - 1) * 0.002;
    return s;
  }

  const lib: SnippetLibrary = { names: ['low', 'high', 'burst'], pre, post, snippets: [] };
  for (let k = 0; k < 3; k++) {
    for (let e = 0; e < perType; e++) lib.snippets.push({ typeIndex: k, samples: makeSnippet(k) });
  }
  return lib;
}