const { Glib, Maps } = require('../../lib');

const parse = (input) => {
  return new Glib(
    (function*() {
      let current = null;
      let awake = true;
      for (const line of Glib.fromLines(input).array.sort()) {
        const [datePortion, actionPortion] = line.split('] ');
        if (actionPortion.endsWith('begins shift')) {
          if (current != null) {
            yield current;
            current = null;
          }
          current = {
            guard: BigInt(actionPortion.split(' ')[1].slice(1)),
            schedule: [],
          };
          awake = true;
        } else if (actionPortion === 'wakes up') {
          if (awake) {
            continue;
          }
          awake = true;
          current.schedule.push(BigInt(datePortion.split(':')[1]));
        } else if (actionPortion === 'falls asleep') {
          if (!awake) {
            continue;
          }
          awake = false;
          current.schedule.push(BigInt(datePortion.split(':')[1]));
        } else {
          throw new Error('bad line');
        }
      }
      yield current;
    })(),
  );
};

module.exports = {
  '1': (input) => {
    input = parse(input).array;
    const chosen = input.glib
      .map(({ guard, schedule }) => [
        guard,
        schedule.glib
          .chunk(2)
          .map(([a, b]) => b - a)
          .sum(),
      ])
      .reduce((a, pair) => Maps.add(a, new Map([pair])), new Map())
      .glibEntries.reduce((a, b) => (a[1] > b[1] ? a : b))[0];

    return (
      chosen *
      input.glib
        .filter(({ guard }) => guard === chosen)
        .flatMap(({ schedule }) =>
          schedule.glib
            .chunk(2)
            .flatMap(([start, end]) => Glib.fromSequence(start, end - 1n)),
        )
        .frequency()
        .glibEntries.reduce((a, b) => (a[1] > b[1] ? a : b))[0]
    );
  },
  2: (input) =>
    parse(input)
      .flatMap(({ guard, schedule }) =>
        schedule.glib
          .chunk(2)
          .flatMap(([start, end]) => Glib.fromSequence(start, end - 1n))
          .map((minute) => `${guard},${minute}`),
      )
      .frequency()
      .glibEntries.reduce((a, b) => (a[1] > b[1] ? a : b))[0]
      .split(',')
      .glib.toInts()
      .product(),
};