#![feature(vec_remove_item)]

use std::collections::HashSet;

pub fn get_perms(mut items: Vec<String>) -> Result<HashSet<String>, String> {

	let mut permutations: HashSet<String> = HashSet::new();

	// Handles instances where either one or less items are passed to the function
	if items.len() < 1 {
		return Err("The Items Vec must have items dawg...".to_string())
	} else if items.len() == 1 {
		permutations.insert(items.pop().unwrap());
		return Ok(permutations)
	}

	for item in &items {
		let mut items_copy = items.clone();
		permutations.insert(item.clone());
		items_copy.remove_item(item);
		complete_perms(&mut permutations, item, &items_copy);
	}

	Ok(permutations)
}

fn complete_perms(permutations: &mut HashSet<String>, prepended: &String, items: &[String]) {
	for item in items {
		let new_item = format!("{}{}", prepended, item);
		permutations.insert(new_item);
	}
	if items.len() > 1 {
		for item in items {
			let to_be_prepended = format!("{}{}", prepended, item);
			let mut items_copy = items.to_vec();
			items_copy.remove_item(&item);
			complete_perms(&mut *permutations, &to_be_prepended, &items_copy);
		}
	}
}

fn main() {
    let items = vec!["a".to_string(), "b".to_string(), "c".to_string()];
    let perms = get_perms(items).unwrap();

    let mut vec_of_items = Vec::new();

    for perm in perms {
        vec_of_items.push(perm);
    }
    vec_of_items.sort();
    for item in vec_of_items {
        println!("{:?}", item);
    }
}