import { join } from 'https://deno.land/std@0.167.0/path/mod.ts';

type Directory = { type: 'directory' };
type File = { type: 'file'; size: number };
type Tree = Record<string, Record<string, Directory | File>>;

function buildTree(shellLog: string): Tree {
  const tree: Tree = {};
  let curPath = '';
  for (const line of shellLog.split('\n')) {
    if (line.startsWith('$')) {
      if (line === '$ ls') {
        continue;
      }
      curPath = join(curPath, line.split(' ').at(-1)!);
      tree[curPath] ??= {};
      continue;
    }
    if (line.startsWith('dir')) {
      const dirName = line.split(' ').at(-1)!;
      tree[curPath][dirName] = {
        type: 'directory',
      };
      continue;
    }
    // only option left is file
    const [fileSize, fileName] = line.split(' ') as [string, string];
    tree[curPath][fileName] = {
      type: 'file',
      size: parseInt(fileSize),
    };
  }
  return tree;
}

function duRec(tree: Tree, entryPath = '/'): Record<string, number> {
  let result: Record<string, number> = {};
  let curSize = 0;
  for (const [name, entry] of Object.entries(tree[entryPath as keyof typeof tree])) {
    if (entry.type === 'directory') {
      const newEntry = join(entryPath, name);
      result = Object.assign(result, duRec(tree, newEntry)) as Record<string, number>;
      curSize += result[newEntry];
    } else curSize += entry.size;
  }
  result[entryPath] = curSize;
  return result;
}

const input = Deno.readTextFileSync('./input.txt').trimEnd();
const tree = buildTree(input);
const dirSizes = Object.values(duRec(tree));
const p1 = dirSizes.filter((size) => (size <= 100000))
  .reduce((prev, cur) => prev + cur, 0);
console.log('Solution Part 1:', p1);
dirSizes.sort((a, b) => a - b);
const free = 70000000 - dirSizes.at(-1)!;
const p2 = dirSizes.find((size) => (free + size) >= 30000000);
console.log('Solution Part 2:', p2);