#![allow(dead_code)]
use std::collections::HashMap;
use std::fs::File;
use std::io;
use std::io::BufRead;
use std::path::Path;
use std::time::Instant;

#[derive(Debug, Clone)]
struct ElfFile {
    name: String,
    size: u32,
}

#[derive(Debug, Clone)]
struct Folder<'a> {
    name: String,
    files: HashMap<String, ElfFile>,
    folders: HashMap<String, &'a Folder<'a>>,
}

fn main() {
    let now = Instant::now();
    part_one();
    let part_one_duration = now.elapsed();
    part_two();
    let part_two_duration = now.elapsed();
    println!(
        "p1: {}ms, p2: {}ms",
        part_one_duration.as_millis(),
        (part_two_duration - part_one_duration).as_millis()
    );
}

fn read_lines<P>(filename: P) -> io::Result<io::Lines<io::BufReader<File>>>
where
    P: AsRef<Path>,
{
    // note that this discards a final newline
    let file = File::open(filename)?;
    Ok(io::BufReader::new(file).lines())
}

fn ElfFile_FromStr(s: &str) -> ElfFile {
    let mut f = s.split(" ");
    return ElfFile {
        size: f.next().unwrap().parse::<u32>().unwrap(),
        name: f.next().unwrap().to_string(),
    };
}

fn newFolder(s: &str) -> Folder {
    return Folder {
        name: s.to_string(),
        files: HashMap::new(),
        folders: HashMap::new(),
    };
}

fn part_one() {
    if let Ok(lines) = read_lines("./inputs/input") {
        let mut tree = Folder {
            name: "/".to_string(),
            files: HashMap::new(),
            folders: HashMap::new(),
        };
        let mut stack: Vec<&mut Folder> = vec![&mut tree];
        for line in lines {
            if let Ok(command) = line {
                match command.as_str() {
                    "$ cd /" => continue, // skip start
                    "$ ls" => continue, // we can assume this if we're not moving between directories
                    "$ cd .." => {
                        // stack.pop();
                    }
                    s if s.starts_with("$ cd ") => {
                        println!("push {}\n", s.split(" ").nth(2).unwrap())
                    }
                    s if s.starts_with("dir ") => {
                        let f = stack.pop().unwrap();
                        let ef = newFolder(s.split(" ").nth(1).unwrap());
                        f.folders.insert(ef.name.clone(), &ef);
                        stack.push(f);
                    }
                    s => {
                        // otherwise it must be a file
                        let f = stack.pop().unwrap();
                        let ef = ElfFile_FromStr(s);
                        f.files.insert(ef.name.clone(), ef);
                        stack.push(f);
                    }
                };
            }
        }
        println!("{:?}", tree);
    }
}

fn part_two() {}