import { readFileSync } from 'node:fs';
import { resolve } from 'node:path';
import { afterEach, describe, expect, it } from 'vitest';
import { createPulseTap, readSwitchboard, setMusicPulseAudible } from '@/audio/music-pulse';
import { TRAFFIC_PASS_GAP_SECONDS, TRAFFIC_PASS_PAN, playTrafficPass } from '@/audio/traffic-pass';

/** A minimal audio graph that records what the swell builds. */
function fakeContext() {
  const pans: number[] = [];
  const param = () => ({ setValueAtTime: (v: number) => pans.push(v), exponentialRampToValueAtTime: () => undefined });
  const node = (extra: object = {}) => ({ connect: () => undefined, disconnect: () => undefined, ...extra });
  const context = {
    state: 'running',
    currentTime: 10,
    sampleRate: 8000,
    started: 0,
    createGain: () => node({ context, gain: { setValueAtTime: () => undefined, exponentialRampToValueAtTime: () => undefined } }),
    createAnalyser: () => {
      throw new Error('no analyser');
    },
    createBuffer: (_channels: number, length: number) => ({ sampleRate: 8000, getChannelData: () => new Float32Array(length) }),
    createBufferSource: () =>
      node({
        buffer: null,
        onended: null,
        start: () => {
          context.started += 1;
        },
        stop: () => undefined,
      }),
    createBiquadFilter: () =>
      node({
        type: '',
        Q: { setValueAtTime: () => undefined },
        frequency: { setValueAtTime: () => undefined, exponentialRampToValueAtTime: () => undefined },
      }),
    createStereoPanner: () => node({ pan: param() }),
  };
  return { context, pans };
}

describe('traffic pass swell', () => {
  afterEach(() => setMusicPulseAudible(false));

  it('is silent with no audible soundtrack', () => {
    expect(readSwitchboard()).toBeNull();
    expect(playTrafficPass(1)).toBe(false);
  });

  it('plays once per gap, panned to the passing side', () => {
    const { context, pans } = fakeContext();
    createPulseTap(context as unknown as BaseAudioContext, { connect: () => undefined } as unknown as AudioNode);
    setMusicPulseAudible(true);
    expect(playTrafficPass(-1)).toBe(true);
    expect(pans).toContain(-TRAFFIC_PASS_PAN);
    expect(playTrafficPass(1)).toBe(false);
    context.currentTime += TRAFFIC_PASS_GAP_SECONDS + 0.01;
    expect(playTrafficPass(1)).toBe(true);
    expect(pans).toContain(TRAFFIC_PASS_PAN);
    expect(context.started).toBe(2);
  });

  it('never plays on a suspended context', () => {
    const { context } = fakeContext();
    context.state = 'suspended';
    createPulseTap(context as unknown as BaseAudioContext, { connect: () => undefined } as unknown as AudioNode);
    setMusicPulseAudible(true);
    expect(playTrafficPass(1)).toBe(false);
  });

  it('stays out of the initial bundle: only the scene chunk imports it, lazily, never on lite', () => {
    const environment = readFileSync(resolve(process.cwd(), 'src/scene/world/environment.ts'), 'utf8');
    expect(environment).toContain("import('@/audio/traffic-pass')");
    expect(environment).not.toMatch(/from '@\/audio\/traffic-pass'/u);
    const budgets = readFileSync(resolve(process.cwd(), 'scripts/lib/bundle-budgets.mjs'), 'utf8');
    expect(budgets).toContain('traffic-pass-');
  });
});