import { readLines } from "https://deno.land/std@0.177.1/io/read_lines.ts";

async function Part1() {
    const file = await Deno.open("./Day3/input.txt");
    const lines = readLines(file);

    let line = (await lines.next()).value as string;
    const bits: number[] = new Array(line.length).fill(0);
    let NrOfLines = 1;

    for (let i = 0; i < line.length; i++) {
        if (line[i] == '1') {
            bits[i]++;
        }
    }

    for await (line of lines) {
        NrOfLines++;
        for (let i = 0; i < line.length; i++) {
            if (line[i] == '1') {
                bits[i]++;
            }
        }
    }

    let gamma = 0;
    let epsilon = 0;

    for (let i = bits.length - 1; i >= 0; i--) {
        if (bits[i] > NrOfLines/2) {
            gamma += 2**((bits.length - 1) - i);
        } else {
            epsilon += 2**((bits.length - 1) - i);
        }
    }

    return gamma * epsilon;
}

async function Part2() {
    const file = await Deno.open("./Day3/input.txt");
    const lines = readLines(file);

    let OxygenLines: string[] = [];
    let CO2Lines: string[] = [];

    for await (const line of lines) {
        OxygenLines.push(line);
        CO2Lines.push(line);
    }

    const ReadingLength = OxygenLines[0].length;

    for (let i = 0; i < ReadingLength; i++) {

        if (OxygenLines.length > 1) {
            const OxyBit = mostCommonBit(OxygenLines,i);
            OxygenLines = OxygenLines.filter(reading => +reading[i] == OxyBit);
        }

        if (CO2Lines.length > 1) {
            const CO2Bit = mostCommonBit(CO2Lines,i);
            CO2Lines = CO2Lines.filter(reading => +reading[i] != CO2Bit);
        }
    }
    
    const OxygenReading = OxygenLines[0];
    const CO2Reading = CO2Lines[0];

    let OxygenLevel = 0;
    let CO2Level = 0;

    for (let i = ReadingLength - 1; i >= 0; i--) {
        OxygenLevel += +OxygenReading[i] * 2**(ReadingLength - 1 - i);
        CO2Level += +CO2Reading[i] * 2**(ReadingLength - 1 - i);
    }

    return OxygenLevel * CO2Level;
}

function mostCommonBit(arr: string[], index: number): 0 | 1 {
    let count = 0;
    for (const line of arr) {
        if (line[index] == '1') {
            count++;
        }
    }
    if (count >= arr.length/2) {
        return 1
    }
    return 0
}

console.log("Part1: " + await Part1());

console.log("Part2: " + await Part2());