const sample = await Deno.readTextFile("sample.txt");
const input = await Deno.readTextFile("input.txt");

const parseStack = (stackData: string): string[][] => {
  const rotateMatrix = (matrix: string[][]): string[][] =>
    matrix[0].map((_, index) =>
      matrix
        .map((row2) => row2[index].trim())
        .reverse()
        .filter(Boolean)
    );

  return rotateMatrix(
    stackData
      .split("\n")
      // Filter out last line and empty lines
      .filter((line, index, arr) => Boolean(line) && index < arr.length - 1)
      .map((line) =>
        line
          .split("")
          .reduce((r, v, i) => {
            const p = Math.floor(i / 4);
            r[p] = r[p] || [];
            r[p].push(v);
            return r;
          }, [] as string[][])
          .map((row) => row[1])
      )
  );
};

const parseMoves = (
  moveData: string
): { amount: number; from: number; to: number }[] => {
  return moveData
    .split("\n")
    .filter(Boolean)
    .map(
      (line): number[] =>
        line
          .match(/move\ (\d+)\ from\ (\d+)\ to\ (\d+)/)
          ?.slice(1)
          .map((v) => parseInt(v, 10)) || []
    )
    .map(([amount, from, to]) => ({ amount, from: from - 1, to: to - 1 }));
};

const solvePart1 = (data: string): string => {
  const [stackData, moveData] = data.split("\n\n");
  const stacks = parseStack(stackData);
  const moves = parseMoves(moveData);
  return moves
    .reduce((stack, move) => {
      const length = stack[move.from].length;
      stack[move.to] = stack[move.to].concat(
        stack[move.from].splice(length - move.amount, length).reverse()
      );
      return stack;
    }, stacks)
    .map((stack) => stack.pop())
    .join("");
};

console.log("Sample:", solvePart1(sample));
console.log("Input", solvePart1(input));

const solvePart2 = (data: string): string => {
  const [stackData, moveData] = data.split("\n\n");
  const stacks = parseStack(stackData);
  const moves = parseMoves(moveData);
  return moves
    .reduce((stack, move) => {
      const length = stack[move.from].length;
      stack[move.to] = stack[move.to].concat(
        stack[move.from].splice(length - move.amount, length)
      );
      return stack;
    }, stacks)
    .map((stack) => stack.pop())
    .join("");
};
console.log("Sample:", solvePart2(sample));
console.log("Input", solvePart2(input));