const fs = require('fs/promises');

const createNode = (parent) => {
  return {
    parent,
    children: {},
    localSize: 0
  };
};

let answer = 0;

(async () => {
  const input = await fs.readFile("./input.txt", 'utf8');

  const lines = input.split("\n");

  const files = createNode();

  lines.reduce((node, line) => {
    console.log("NODE: ", node);
    const cd = line.match(/^\$ cd (.*)$/);
    if(cd) {
      console.log("CD: ", cd);
      if(cd[1] == "..") {
        return node.parent;
      }
      return node.children[cd[1]];
    }
    const dir = line.match(/^dir (.*)$/);
    if(dir) {
      console.log("DIR: ", dir);
      node.children[dir[1]] = createNode(node);
    }
    const file = line.match(/^(\d+) .*$/);
    if(file) {
      node.localSize += parseFloat(file[1]);
    }

    return node;

  }, files);

  console.log("FILES: ", files);

  const fullSize = totalSmallerDirs(files);

  console.log("FULL SIZE: ", fullSize);
  console.log("ANSWER: ", answer);

})();

const totalSmallerDirs = (node) => {
  let totalSize =  node.localSize;

  totalSize += sum(Object.values(node.children).map(totalSmallerDirs));

  if(totalSize <= 100000) {
    answer += totalSize;
  }
  return totalSize;
}

const sum = (arr) => arr.reduce((total, num) => total+num, 0);