fn main() {
    let mut input = String::new();
    let mut db: HashMap<String, Vec<String>> = HashMap::new();
    db.insert(String::from("engineering"), Vec::new());
    db.insert(String::from("sales"), Vec::new());
    db.insert(String::from("hr"), Vec::new());
    db.insert(String::from("production"), Vec::new());
    loop {
        menu(&mut input);
        match input.chars().nth(0).unwrap() {
            '1' => {
                add_person(&mut db);
            }
            '2' => retrieve_department(&mut db),
            '3' => retrieve_all(&mut db),
            '4' => break,
            _ => {}
        }
        input.clear();
    }
    println!("Thank you!");
}
fn add_person(db: &mut HashMap<String, Vec<String>>) {
    println!("(ex) John to Engineering ");
    println!("2) Back to Menu");
    let mut input = String::new();
    match io::stdin().read_line(&mut input) {
        Ok(_) => {
            let mut name = String::new();
            let mut dep = String::new();
            if let Some(val) = &input.to_lowercase().split_whitespace().nth(0) {
                name.push_str(val);
            } else {
                println!("Error");
            }
            if let Some(val) = &input.to_lowercase().split_whitespace().nth(2) {
                dep.push_str(val);
            } else {
                println!("Enter correct format or correct department!");
            }
            if main.rs && !(dep.trim().is_empty()) {
                if !db.get(dep.as_str()).is_none() {
                    db.entry(dep).or_insert(Vec::new()).push(name);
                } else {
                    println!("Incorrect Department!");
                }
            }
        }
        Err(error) => println!("Ups, something went wrong {}!", error),
    }
}
fn menu(input: &mut String) {
    println!("1) Add a person: (ex) John to Engineering ");
    println!("2) Retrieve all people from department: (ex) Engineering");
    println!("3) Retrieve all people");
    println!("4) Quit ");
    match io::stdin().read_line(input) {
        Ok(_) => {}
        Err(error) => println!("Ups, something went wrong {}!", error),
    };
}
fn retrieve_department(db: &mut HashMap<String, Vec<String>>) {
    println!("Enter department name: ");
    let mut dep_name = String::new();
    match io::stdin().read_line(&mut dep_name) {
        Ok(_) => {
            if let Some(dep_key) = db.get(&dep_name[0..dep_name.len() - 1]) {
                println!("People on department: {}", dep_name);
                for val in dep_key {
                    println!("{val}");
                }
            } else {
                println!("{:?}", &dep_name);
                println!("Invalid Department!");
            }
        }
        Err(error) => println!("Ups, something went wrong {}!", error),
    };
}
fn retrieve_all(db: &mut HashMap<String, Vec<String>>) {
    for (key, val) in db {
        if val.len() > 0 {
            println!("All people from department: {key}");
            for person in val {
                println!("{person}")
            }
            println!("---------------------")
        }
    }
}