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

const fuelFor = (mass) => mass / 3n - 2n;

function* tyrant(mass) {
  while ((mass = fuelFor(mass)) > 0n) {
    yield mass;
  }
}

const react = (input) => {
  let lastLength;
  do {
    lastLength = input.length;
    for (let i = 0; i < input.length - 1; i++) {
      if (
        input[i] !== input[i + 1] &&
        input[i].toUpperCase() === input[i + 1].toUpperCase()
      ) {
        input = input.splice(i, 2);
      }
    }
  } while (input.length < lastLength);
  return input;
};

module.exports = {
  '1': (input) => react(input).length,
  2: (input) => {
    // pre-reacting saves a ton of time and makes no moves that invalidate others
    input = react(input);
    return Glib.fromIterable(input)
      .map((i) => i.toLowerCase())
      .unique()
      .map((char) => {
        const reduced = react(input.replace(new RegExp(char, 'gi'), ''));
        return reduced.length;
      })
      .toInts()
      .min();
  },
};