const { createStore, compose, applyMiddleware } = Redux;
const { runSaga, eventChannel } = ReduxSaga;
const { call, take } = ReduxSaga.effects;

const reducer = ()=>({});
const sagaMiddleware = ReduxSaga.default();
const store = createStore(reducer, {}, compose(
    applyMiddleware(
        sagaMiddleware
    )
));
store.runSagas = sagaMiddleware.run;

// ------------ Worker

function createWorker(){
    const scripts = Array.from(document.querySelectorAll('script[type="text\/js-worker"]'));
    const blob = new Blob(
        scripts.map( script => script.textContent),
        {type: 'text/javascript'}
    );
    const url = window.URL.createObjectURL(blob);
    return new Worker(url);
}

// ------------ Sagas

function createWorkerChannel(worker) {
    return eventChannel(emit => {

        const onMessage = (event) => emit(event.data);
        worker.addEventListener('message', onMessage, false);
        
        const unsubscribe = () => worker.terminate();
        return unsubscribe
    })
}

function* outputHash(hash){
    const node = yield call([document, 'querySelector'], 'output');
    node.textContent = hash;
}

function* addListeners(worker){
    const node = yield call([document, 'querySelector'], 'input');
    node.addEventListener('input', (e)=> worker.postMessage(e.target.value));
    worker.postMessage(node.value);
}

function* initialize(){
    const worker = yield call(createWorker);
    const channel = yield call(createWorkerChannel, worker)
    yield call(addListeners, worker);
            
    while(true){
        const payload = yield take(channel);
        yield call(outputHash, payload);
    }
}

// ------------ Run

store.runSagas(initialize);