import * as R from "remeda";
import Victor from "@a-robu/victor";

import { readFile } from "../05/part1.js";
import { passthru } from '../08/part1.js'

const directions = {
    R: new Victor(1,0),
    L: new Victor(-1,0),
    U: new Victor(0,1),
    D: new Victor(0,-1),
}

const parseLine = R.createPipe(
    line => line.split(" "),
    ([direction,times]) => Array(parseInt(times)).fill(directions[direction])
);


const readInput = (...args) => R.pipe(
  readFile(...args),
  text => text.split("\n"),
  R.compact,
  R.map( parseLine ),
  R.flatten,
)

export const puzzleInput = readInput(import.meta.url, "input");
export const sample = readInput(import.meta.url, "sample");

const touching = (v1,v2) => [v1.distanceX(v2), v1.distanceY(v2)].every(
    x => x*x <= 1
);

export function moveOnce( head, tail, d ) {
    head.add(d);

    if( touching(head,tail) ) return tail.toString();

    const delta = head.clone().subtract(tail).normalize();

    if( delta.x * delta.y ) {
        delta.x = delta.x > 0 ? 1 : -1;
        delta.y = delta.y > 0 ? 1 : -1;
    }

    tail.add(delta);

    return tail.toString();
}

const moveAround = (directives) => {
    const head = new Victor(0,0);
    const tail = new Victor(0,0);

    const move = d => moveOnce(head,tail,d);
    return [
        tail.toString(),
        ...directives.map( move )
    ]
};

export default R.createPipe(
    moveAround,
    R.uniq,
    moves => moves.length
);