hash-maps exercise

main.rs

use std::collections::HashMap;
use std::io;

fn list_users(department: &str, user_map: &HashMap<String, Vec<String>>) {
    if department == "All" || department == "all" {
        for (key, value) in user_map {
            println!("Department - {}:", key);
            for user in value {
                println!(" •{}", user);
            }
        }
    } else {
        let users = user_map.get(department);

        match users {
            Some(info) => {
                for user in info {
                    println!(" •{}", user)
                }
            }
            None => println!("Department doesn't exist, or it's empty!"),
        }
    }
}

fn main() {
    // Using a hash map and vectors, create a text interface to allow
    // a user to add employee names to a department in a company.
    // For example, "Add Sally to Engineering" or "Add Amir to Sales."
    // Then let the user retrieve a list of all people in a department
    // or all people in the  ompany by department sorted alphabetically

    let mut user_map: HashMap<String, Vec<String>> = HashMap::new();

    loop {
        println!("Please enter a command: ");

        // Expected commands: Add [name] to [department] || View [all || department]
        let mut input = String::new();
        io::stdin()
            .read_line(&mut input)
            .expect("Failed to read line");

        let input: Vec<&str> = input.trim().split(' ').collect();
        let operator = input.get(0).map(|x| x.to_lowercase());

        match operator.as_deref() {
            Some("add") => match (input.get(1), input.get(3)) {
                (Some(name), Some(department)) => {
                    let user_vec = user_map.entry(department.to_string()).or_insert(Vec::new());
                    user_vec.push(name.to_string());
                    user_vec.sort();
                }
                (None, Some(_)) => println!("Please enter a name!"),
                (Some(_), None) => println!("Please enter a department!"),
                (None, None) => println!("Please enter a name and department!"),
            },
            Some("view") => match input.get(1) {
                Some(department) => list_users(department, &user_map),
                None => println!("Please enter all or a department!"),
            },
            Some("exit") => break,
            Some(_) | None => println!("Invalid command 😞"),
        }
    }
}