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

async function Part1() {
    const file = await Deno.open("./Day9/input.txt");
    const lines = readLines(file);
    
    let map: number[][] = [];

    for await (const line of lines) {
        map.push([]);
        for (const n of line) {
            map[map.length -1].push(+n);
        }
    }

    let result = 0;

    for (const i in map) {
        for (const j in map[i]) {
            if (+i > 0 && map[i][j] >= map[+i-1][j]) {
                continue
            } else if (+j > 0 && map[i][j] >= map[i][+j - 1]) {
                continue
            } else if (+i < map.length - 1 && map[i][j] >= map[+i + 1][j]) {
                continue
            } else if (+j < map[i].length - 1 && map[i][j] >= map[i][+j + 1]) {
                continue
            }
            //console.log(i,j)
            result += map[i][j] + 1;
        }
    }
    return result
}

async function Part2() {
    const file = await Deno.open("./Day9/input.txt");
    const lines = readLines(file);
    
    let map: number[][] = [];
    const seen: boolean[][] = [];

    for await (const line of lines) {
        map.push([]);
        seen.push([]);
        for (const n of line) {
            map[map.length -1].push(+n);
            seen[seen.length -1].push(false);
        }
    }

    const basinSizes = [];

    for (const i in map) {
        for (const j in map[i]) {
            if (!seen[i][j] && map[i][j] != 9) {
                let size = 1;
                seen[i][j] = true;
                const neigbours = getNeighbours(map,+i,+j);
                while (neigbours.length != 0) {
                    const [a,b] = neigbours.pop()!;
                    if (map[a][b] == 9 || seen[a][b]) {
                        continue
                    } 
                    size++
                    seen[a][b] = true;
                    for (const n of getNeighbours(map,a,b)) {
                        const [c,d] = n;
                        if (!seen[c][d]) {
                            neigbours.push([c,d]);
                        }
                    }
                }
                basinSizes.push(size);
            }
        }
    }
    basinSizes.sort((a,b) => a-b);
    return basinSizes[basinSizes.length -1] * basinSizes[basinSizes.length -2] * basinSizes[basinSizes.length -3];
    
}

console.log("Part1: " + await Part1());
console.log("Part2: " + await Part2())

function getNeighbours(map: number[][],i:number,j:number) {
    const neighbours: [number,number][] = [];
    if (+i > 0) {
        neighbours.push([i-1,j])
    }
    if (+j > 0) {
        neighbours.push([i,j-1])
    }
    if (+i < map.length - 1) {
        neighbours.push([i+1,j])
    }
    if (+j < map[i].length - 1) {
        neighbours.push([i,j+1])
    }
    return neighbours
}