vertigo 0.11.4

use std::rc::Rc;

use crate::computed::{Computed, DropResource, struct_mut::ValueMut};

struct SubscribeValueVerInner<T> {
    version: ValueMut<u32>,
    value: ValueMut<Option<T>>,
}

impl<T> SubscribeValueVerInner<T> {
    pub fn new() -> Rc<SubscribeValueVerInner<T>> {
        Rc::new(SubscribeValueVerInner {
            version: ValueMut::new(0),
            value: ValueMut::new(None),
        })
    }
}

pub struct SubscribeValueVer<T> {
    client: Option<DropResource>,
    value: Rc<SubscribeValueVerInner<T>>,
}

impl<T: PartialEq + Clone + 'static> SubscribeValueVer<T> {
    pub fn new(com: Computed<T>) -> SubscribeValueVer<T> {
        let value = SubscribeValueVerInner::new();

        let client = {
            let value = value.clone();
            com.subscribe(move |new_value| {
                value.value.set(Some(new_value));
                let current = value.version.get();
                value.version.set(current + 1);
            })
        };

        SubscribeValueVer {
            client: Some(client),
            value,
        }
    }

    pub fn get(&self) -> (T, u32) {
        let value = self.value.value.get();

        let value = match value {
            Some(value) => value,
            None => {
                panic!("expected value");
            }
        };

        let version = self.value.version.get();

        (value, version)
    }

    pub fn off(&mut self) {
        self.client = None;
    }
}