const std = @import("std");

pub fn main() !void {
    const path: [:0]const u8 = std.mem.span(std.os.argv[1]);
    var file = try std.fs.cwd().openFile(path, .{});
    defer file.close();

    var buffer: [32]u8 = undefined;
    var reader = file.reader(&buffer);

    var dial: i16 = 50;
    var part1: u64 = 0;
    var part2: u64 = 0;

    while (reader.interface.takeDelimiterInclusive('\n')) |line| {
        const value = try std.fmt.parseInt(i16, line[1 .. line.len - 1], 10);
        const v = if (line[0] == 'R') value else -value;
        const next = @mod(dial + v, 100);

        if (next == 0) {
            part1 += 1;
        }

        part2 += @abs(@divFloor(dial, 100) - @divFloor(dial + v, 100));
        if (dial == 0 and v < 0) {
            part2 -= 1;
        }
        if (next == 0 and v < 0) {
            part2 += 1;
        }

        dial = next;
    } else |err| switch (err) {
        error.EndOfStream => {},
        else => |e| return e,
    }

    std.debug.print("part1: {}\n", .{part1});
    std.debug.print("part2: {}\n", .{part2});
}