use std::env;
use std::cmp::max;
use std::fs::File;
use std::io::Read;
use std::process;

fn main() {
    let args: Vec<String> = env::args().collect();
    if args.len() < 2 {
        println!("Too few arguments.");
        process::exit(1);
    }
    let filename = &args[1];
    // Your code here :)
    let mut file =
        File::open(filename).expect(format!("Cannot open file: {}\n", filename).as_str());
    let mut buffer = [0; 1024];
    let mut line_count = 0;
    let mut word_count = 0;
    let mut byte_count = 0;
    let mut skip_ws = false;
    let mut in_word = false;
    loop {
        let rd_size = file
            .read(&mut buffer)
            .expect(format!("Error reading file: {}", filename).as_str());
        if rd_size == 0 {
            break;
        }
        byte_count += rd_size;
        for v in buffer {
            if v == b'\n' {
                line_count += 1;
            }
            if v.is_ascii_whitespace() {
                if in_word && !skip_ws {
                    skip_ws = true;
                    in_word = false;
                    word_count += 1;
                }
            } else {
                in_word = true;
                skip_ws = false;
            }
        }
    }
    let str_line_count = format!("{line_count}");
    let str_word_count = format!("{word_count}");
    let str_byte_count = format!("{byte_count}");
    let align = max(
        str_line_count.len(),
        max(str_word_count.len(), str_byte_count.len()),
    );
    println!(
        "{:>align$} {:>align$} {:>align$} {filename}",
        str_line_count, str_word_count, str_byte_count
    );
}