const fs = require("node:fs");
const Computer = require("../IntComp/Computer");

/* Set up the computer */
const input = fs.readFileSync("./15/input.dat", "utf8")
    .split(",")
    .map((x) => parseInt(x, 10));

const droid = new Computer(input);

/* Set up values for the simulation */
/**
 * Directions the droid can move in
 */
const Directions = {
    NORTH: 1,
    SOUTH: 2,
    EAST: 3,
    WEST: 4,
};
/**
 * Vectorized values for the Directions values
 */
const Vectors = {
    NORTH: 1,
    SOUTH: -1,
    EAST: 1,
    WEST: -1,
};
/**
 * Tile data for rendering the droid's internal map
 */
const mapTiles = {
    WALL: "█",
    EMPTY: ".",
    OXYGEN: "0",
};
/**
 * The current position of the droid
 * 
 * X and Y are relative to the droid's position at the start of the
 * simulation.
 */
const droidPosition = {
    x: 0,
    y: 0
};

const droidMap = new Map();

/**
 * Statuses output but the droid
 */
const STATUS = ["NO_MOVEMENT", "MOVEMENT_SUCCESSFUL", "OXYGEN_FOUND"];

/**
 * The last direction we had the droid move in
 */
let lastDirection = Directions.EAST;
/**
 * The last status code output by the droid
 */
let lastSignal = -1;

let mapLooped = false;

// Start the droid
droid.Run()
// Continue running of droid
do {
    // Handle input to the droid
    if (droid.awaitingInput) {
        // Get the new direction to move in
        let currDirection = updateMap(lastDirection, lastSignal);

        droid.Input(currDirection);
        lastDirection = currDirection;
    }
    // Handle the droid's output
    if (droid.HasOutput()) {
        lastSignal = droid.outputValues.pop()
        console.log(STATUS[lastSignal]);
    }
} while (droid.running && !mapLooped);

/**
 * Update the map data and return a new dirction to move in
 *
 * @param {1|2|3|4} lastDirection The last direction the droid moved in
 * @param {0|1|2} lastSignal The last signal output by the droid
 *
 * @returns {1|2|3|4} A new direction for the droid to move in
 */
function updateMap(lastDirection, lastSignal) {
    let newDirection = lastDirection;
    let mapX = droidPosition.x;
    let mapY = droidPosition.y;
    let foundTile = mapTiles.EMPTY;

    if (lastSignal == 0) {
        if (lastDirection == Directions.EAST) {
            mapX += Vectors.EAST;
            newDirection = Directions.NORTH;
        }
        else if (lastDirection == Directions.NORTH) {
            mapY += Vectors.NORTH;
            newDirection = Directions.WEST;
        }
        else if (lastDirection == Directions.WEST) {
            mapX += Vectors.WEST;
            newDirection = Directions.SOUTH;
        }
        else if (lastDirection == Directions.SOUTH) {
            mapY += Vectors.SOUTH;
            newDirection = Directions.EAST;
        }

        foundTile = mapTiles.WALL;
    }
    else if (lastSignal == 1) {
        if (lastDirection == Directions.EAST) {
            droidPosition.x += Vectors.EAST;
        }
        else if (lastDirection == Directions.NORTH) {
            droidPosition.y += Vectors.NORTH;
        }
        else if (lastDirection == Directions.WEST) {
            droidPosition.x += Vectors.WEST;
        }
        else if (lastDirection == Directions.SOUTH) {
            droidPosition.y += Vectors.SOUTH;
        }
        foundTile = mapTiles.EMPTY;
    }
    else if (lastSignal == 2) {
        foundTile = mapTiles.OXYGEN;
        console.log(STATUS[lastSignal]);
    }

    mapLooped = droidMap.has(`${mapX},${mapY}`) && mapX + mapY != 0;

    droidMap.set(`${mapX},${mapY}`, foundTile);

    return newDirection;
}