extern crate rand; // 0.5.5

use std::collections::HashMap;
use std::sync::Arc;
use std::thread;

fn main() {
    //working_example();
}

/*
fn non_move_closure() {
    let map: HashMap<_, _> = [(1, "a"), (2, "b")].into_iter().cloned().collect();
    thread::spawn(|| println!("{:?}", map));
}
*/

/*
fn trying_to_share_after_move() {
    let map: HashMap<_, _> = [(1, "a"), (2, "b")].into_iter().cloned().collect();
    let shared_map = Arc::new(map);
    let mut handles = vec![];
    for _ in 0..5 {
        handles.push(thread::spawn(move || {
           println!("{:?}", shared_map);
        }));
    }
}
*/

/*
fn trying_to_access_mutably() {
    let map: HashMap<_, _> = [(1, "a"), (2, "b")].into_iter().cloned().collect();
    map.insert(3, "c");

    let shared_map = Arc::new(map);
    let mut handles = vec![];
    for _ in 0..5 {
        let map_clone = Arc::clone(&shared_map);
        handles.push(thread::spawn(move || {
           map_clone.insert(4, "d");
        }));
    }
}
*/

fn working_example() {
    use rand::Rng;
    use std::sync::Mutex;

    let mut map: HashMap<_, _> = [(1, "a"), (2, "b")].into_iter().cloned().collect();
    map.insert(3, "c");

    let shared_map = Arc::new(Mutex::new(map));
    let mut handles = vec![];
    for _ in 0..5 {
        let map_clone = Arc::clone(&shared_map);
        handles.push(thread::spawn(move || {
            map_clone
                .lock()
                .unwrap()
                .insert(rand::thread_rng().gen(), "d");
        }));
    }
    for h in handles {
        h.join().unwrap();
    }
    let map = Arc::try_unwrap(shared_map).unwrap().into_inner().unwrap();
    println!("{:#?}", map);
}