import { setupTest, startEngine, startClientInTmux, openCmdFifo, wait, ensureGenTone, exec, tmuxCapturePane, teardownTest } from './test_utils';
import * as globals from "./test_globals";

export async function testVUMeter(): Promise<void> {
  console.log("\nTest: VU METER RESPONDS TO AUDIO");
  setupTest();
  const engine = await startEngine();
  await startClientInTmux();
  openCmdFifo();
  await wait(500);

  // Capture initial VU line (should be empty/spaces)
  let pane = tmuxCapturePane("looper", "0");
  const paneLines = pane.split("\n");
  // Look for any line containing x or # – that is the VU meter line.
  const vuLineBefore = paneLines.find(l => /[x#]/.test(l)) || "";
  console.log(`  Initial VU line: "${vuLineBefore.trim()}"`);

  // Generate tone in background (does not block the test)
  ensureGenTone();
  const toneProc = exec(`${globals.GEN_TONE_BIN} 3.0 "looper:ch0in"`, { timeout: 8000 });

  // Wait for audio to start reaching the meter
  await wait(1500);

  // Capture pane while tone is playing
  pane = tmuxCapturePane("looper", "0");
  const paneLines2 = pane.split("\n");
  // Same detection as above
  const vuLineDuring = paneLines2.find(l => /[x#]/.test(l)) || "";
  console.log(`  VU line during tone: "${vuLineDuring.trim()}"`);

  // The VU meter should show non-space characters (at least one 'x' or '#')
  const hasSignal = /[x#]/.test(vuLineDuring);
  if (hasSignal) {
    console.log("  PASS: VU meter shows signal (non‑space characters)");
  } else {
    console.log("  FAIL: VU meter line does not show any signal characters");
    console.log("  Pane excerpt:\n" + pane.slice(0, 2000));
    engine.kill(); teardownTest();
    throw new Error("VU meter not responsive");
  }

  // Wait for tone process to finish
  try { toneProc.kill(); } catch {}

  engine.kill();
  teardownTest();
}