import { promises as fsPromises } from "node:fs";

async function asyncReadFile(filename) {
    try {
        const contents = await fsPromises.readFile(filename, "utf-8");

        const arr = contents.split(/\r?\n/);

        return arr;
    } catch (err) {
        console.error(err);
    }
}

const findDividers = (rows) => {
    let spaceIndexes = [];
    rows.forEach((row, rowIndex) => {
        if (row == "") return;
        if (rowIndex === 0) {
            Array.from(row).forEach((theChar, charIndex) => {
                if (theChar === " ") spaceIndexes.push(charIndex);
            });
            return;
        }
        const rowArray = Array.from(row);
        spaceIndexes = spaceIndexes.filter(
            (spaceIndex) => rowArray[spaceIndex] === " "
        );
    });
    return spaceIndexes;
};

const calculateValues = (operands, operation) => {
    if (operation === "+")
        return operands.reduce((acc, curr) => acc + curr * 1, 0);
    else if (operation === "*")
        return operands.reduce((acc, curr) => acc * curr, 1);
};

/*
const data = `
123 328  51 64 
 45 64  387 23 
  6 98  215 314
*   +   *   +  
`
    .trim()
    .split("\n");
*/

const data = await asyncReadFile("../input.txt");

let total = 0;

const dividers = findDividers(data);

let newOperands = [];
let operation = "";

for (let c = data[0].length - 1; c >= 0; c--) {
    if (dividers.includes(c) || c === -1) {
        const result = calculateValues(newOperands, operation);
        total += result;
        console.log(`> result: ${result}`);
        operation = "";
        newOperands = [];
    }

    let newOperandParts = [];
    data.forEach((row) => {
        const charArray = Array.from(row);
        if (/\d+/.test(charArray[c])) newOperandParts.push(charArray[c]);
        else if (["+", "*"].includes(charArray[c])) operation = charArray[c];
    });
    if (newOperandParts.join("") !== "")
        newOperands.push(newOperandParts.join(""));
}
const result = calculateValues(newOperands, operation);
total += result;

console.log(`>> total: ${total}`);