const std = @import("std");

pub const title = "Day 03: Lobby";

pub fn run(_: std.mem.Allocator) !void {
    const input = @embedFile("./input/day03.txt");
    var lines = std.mem.tokenizeScalar(u8, input, '\n');

    var accumulator: u32 = 0;

    while (lines.next()) |line| {
        var first_digit: u8 = 0;
        var first_digit_index: usize = 0;
        for (line[0..line.len - 1], 0..) |c, i| {
            const digit = try std.fmt.charToDigit(c, 10);
            if (digit > first_digit) {
                first_digit = digit;
                first_digit_index = i;
            }
        }
        std.debug.print("first = {d}\n", .{first_digit});

        var second_digit: u8 = 0;
        if (first_digit_index == line.len - 2) {
            const c = line[line.len - 1];
            second_digit = try std.fmt.charToDigit(c, 10);
        } else {
            for (line[first_digit_index + 1..]) |c| {
                const digit = try std.fmt.charToDigit(c, 10);
                if (digit > second_digit) {
                    second_digit = digit;
                }
            }
        }
        std.debug.print("second = {d}\n", .{second_digit});

        const joltage = first_digit * 10 + second_digit;
        accumulator += joltage;
    }

    var buffer: [8]u8 = undefined;
    var stdout_writer = std.fs.File.stdout().writer(&buffer);
    const stdout = &stdout_writer.interface;

    try stdout.print("{d}\n", .{accumulator});

    try stdout.flush();
}