nothin' good on the radio simulator

sample_music.ts

import { writeFileSync } from "fs";

const numberOfSongs = process.argv.slice(2).length;
const randomFile = process.argv
  .slice(2)
  .map((x) => ' -i "' + x + '" \\\n')
  .join("");

function rndInt(min: number, max: number) {
  return Math.floor(Math.random() * (max - min + 1)) + min;
}

function shuffle(array: any[]) {
  var currentIndex = array.length,
    temporaryValue: any,
    randomIndex: number;

  // While there remain elements to shuffle...
  while (0 !== currentIndex) {
    // Pick a remaining element...
    randomIndex = Math.floor(Math.random() * currentIndex);
    currentIndex -= 1;

    // And swap it with the current element.
    temporaryValue = array[currentIndex];
    array[currentIndex] = array[randomIndex];
    array[randomIndex] = temporaryValue;
  }

  return array;
}

const flatten = (arr: any[]): any[] =>
  arr.reduce((a, v) => {
    v instanceof Array ? a.push(...flatten(v)) : a.push(v);
    return a;
  }, []);

const output = () => {
  const filterInstFunc = (i: number) =>
    `
    [${i}]atrim=start=20,atrim=duration=8[${i + 1000}];
    [${i}]atrim=start=${rndInt(30, 40) + 5},atrim=duration=${rndInt(3, 21)}[${i + 2000}];
    [${i}]atrim=start=${rndInt(50, 90)},atrim=duration=12[${i + 3000}];`;

  const concatFunc = (i: number): string[] => [i + 1000, i + 2000, i + 3000].map(String);

  const filterInstances = Array.from(Array(numberOfSongs).keys()).map(filterInstFunc);
  const filterInstancesConcat = flatten(Array.from(Array(numberOfSongs).keys()).map(concatFunc));

  return (
    "ffmpeg " +
    randomFile +
    " -f lavfi -i anullsrc -filter_complex " +
    '" ' +
    filterInstances.join("") +
    "[" +
    shuffle(filterInstancesConcat).join("][") +
    "]" +
    `concat=n=${numberOfSongs * 3}:v=0:a=1` +
    '"' +
    " /tmp/out.oga; and mpv /tmp/out.oga --no-video"
  );
};

// # cut up method
writeFileSync("run.sh", "#!/bin/fish\n" + output());