extension Observable {
    @warn_unused_result(message="http://git.io/rxs.uo")

    public static func zip<O1: ObservableType, O2: ObservableType, O3: ObservableType, O4: ObservableType, O5: ObservableType>
    (source1: O1, _ source2: O2, _ source3: O3, _ source4: O4, _ source5: O5, resultSelector: (O1.E, O2.E, O3.E, O4.E, O5.E) throws -> E)
    -> Observable<E> {
        return Zip5(
            source1: source1.asObservable(),   
            source2: source2.asObservable(), 
            source3: source3.asObservable(), 
            source4: source4.asObservable(), 
            source5: source5.asObservable(),

            resultSelector: resultSelector
        )
    }
}

class ZipSink5_<E1, E2, E3, E4, E5, O: ObserverType> : ZipSink<O> {
    typealias R = O.E
    typealias Parent = Zip5<E1, E2, E3, E4, E5, R>

    let _parent: Parent

    var _values1: Queue<E1> = Queue(capacity: 2)
    var _values2: Queue<E2> = Queue(capacity: 2)
    var _values3: Queue<E3> = Queue(capacity: 2)
    var _values4: Queue<E4> = Queue(capacity: 2)
    var _values5: Queue<E5> = Queue(capacity: 2)

    init(parent: Parent, observer: O) {
        _parent = parent
        super.init(arity: 5, observer: observer)
    }

    override func hasElements(index: Int) -> Bool {
        switch (index) {
        case 0: return _values1.count > 0
        case 1: return _values2.count > 0
        case 2: return _values3.count > 0
        case 3: return _values4.count > 0
        case 4: return _values5.count > 0

        default:
            rxFatalError("Unhandled case (Function)")
        }

        return false
    }

    func run() -> Disposable {
        let subscription1 = SingleAssignmentDisposable()
        let subscription2 = SingleAssignmentDisposable()
        let subscription3 = SingleAssignmentDisposable()
        let subscription4 = SingleAssignmentDisposable()
        let subscription5 = SingleAssignmentDisposable()

        let observer1 = ZipObserver(lock: _lock, parent: self, index: 0, setNextValue: { self._values1.enqueue($0) }, this: subscription1)
        let observer2 = ZipObserver(lock: _lock, parent: self, index: 1, setNextValue: { self._values2.enqueue($0) }, this: subscription2)
        let observer3 = ZipObserver(lock: _lock, parent: self, index: 2, setNextValue: { self._values3.enqueue($0) }, this: subscription3)
        let observer4 = ZipObserver(lock: _lock, parent: self, index: 3, setNextValue: { self._values4.enqueue($0) }, this: subscription4)
        let observer5 = ZipObserver(lock: _lock, parent: self, index: 4, setNextValue: { self._values5.enqueue($0) }, this: subscription5)

        subscription1.disposable = _parent.source1.subscribe(observer1)
        subscription2.disposable = _parent.source2.subscribe(observer2)
        subscription3.disposable = _parent.source3.subscribe(observer3)
        subscription4.disposable = _parent.source4.subscribe(observer4)
        subscription5.disposable = _parent.source5.subscribe(observer5)

        return CompositeDisposable(disposables: [
           subscription1,
           subscription2,
           subscription3,
           subscription4,
           subscription5
        ])
    }

    override func getResult() throws -> R {
        return try _parent._resultSelector(_values1.dequeue()!, _values2.dequeue()!, _values3.dequeue()!, _values4.dequeue()!, _values5.dequeue()!)
    }
}

class Zip5<E1, E2, E3, E4, E5, R> : Producer<R> {
    typealias ResultSelector = (E1, E2, E3, E4, E5) throws -> R

    let source1: Observable<E1>
    let source2: Observable<E2>
    let source3: Observable<E3>
    let source4: Observable<E4>
    let source5: Observable<E5>

    let _resultSelector: ResultSelector

    init(source1: Observable<E1>, source2: Observable<E2>, source3: Observable<E3>, source4: Observable<E4>, source5: Observable<E5>, resultSelector: ResultSelector) {
        self.source1 = source1
        self.source2 = source2
        self.source3 = source3
        self.source4 = source4
        self.source5 = source5

        _resultSelector = resultSelector
    }

    override func run<O: ObserverType where O.E == R>(observer: O) -> Disposable {
        let sink = ZipSink5_(parent: self, observer: observer)
        sink.disposable = sink.run()
        return sink
    }
}