const { Glib, BNMath: Math, fn } = require('../../lib');

const parse = (input) => {
  const [arrivalString, idStrings] = input.split('\n');
  return {
    arrival: BigInt(arrivalString),
    ids: Glib.fromSplit(idStrings, ',').map((s) =>
      s === 'x' ? 1n : BigInt(s),
    ),
  };
};

const departureAfter = (time, id) => {
  let next = (time / id) * id;
  return next < time ? next + id : next;
};

module.exports = {
  '1': (input) => {
    input = parse(input);
    return input.ids
      .flatMap((i) => {
        if (i === 1n) {
          return [];
        }
        return [[i, departureAfter(input.arrival, i) - input.arrival]];
      })
      .minScore()
      .glib.product();

    return id * (time - input.arrival);
  },
  '2': (input) => {
    input = parse(input).ids.array;

    let solved = 1n;
    let step = input[0];
    let start = departureAfter(0n, input[0]);
    while (true) {
      for (let i = solved; i < input.length; i++) {
        const currentBus = input[i];
        const currentTime = start + i;
        if (departureAfter(currentTime, currentBus) === currentTime) {
          solved += 1n;
          step *= currentBus;
        } else {
          break;
        }
      }
      if (solved == input.length) {
        return start;
      }
      start += step;
    }
  },
};