rx+avspeechsynthesizer.swift

//
//  RxAVSpeechSynthesizerDelegate.swift
//  Pomodoro
//
//  Created by Won on 17/12/2018.
//  Copyright © 2018 won. All rights reserved.
//

#if os(iOS)

import AVFoundation
import RxAtomic
import RxCocoa
import RxSwift

extension AVSpeechSynthesizer: HasDelegate {
    public typealias Delegate = AVSpeechSynthesizerDelegate
}

open class RxAVSpeechSynthesizerDelegateProxy: DelegateProxy<AVSpeechSynthesizer, AVSpeechSynthesizerDelegate>, DelegateProxyType, AVSpeechSynthesizerDelegate {

    /// Typed parent object.
    public weak private(set) var speechSynthesizer: AVSpeechSynthesizer?

    /// - parameter speechSynthesizer: Parent object for delegate proxy.
    public init(speechSynthesizer: ParentObject) {
        self.speechSynthesizer = speechSynthesizer
        super.init(parentObject: speechSynthesizer, delegateProxy: RxAVSpeechSynthesizerDelegateProxy.self)
    }

    // Register known implementationss
    public static func registerKnownImplementations() {
        self.register { RxAVSpeechSynthesizerDelegateProxy(speechSynthesizer: $0) }
    }
}

public extension Reactive where Base: AVSpeechSynthesizer {
    /// Reactive wrapper for `delegate`.
    /// For more information take a look at `DelegateProxyType` protocol documentation.
    var delegate: DelegateProxy<AVSpeechSynthesizer, AVSpeechSynthesizerDelegate> {
        return RxAVSpeechSynthesizerDelegateProxy.proxy(for: base)
    }

    /// Installs delegate as forwarding delegate on `delegate`.
    /// Delegate won't be retained.
    ///
    /// It enables using normal delegate mechanism with reactive delegate mechanism.
    ///
    /// - parameter delegate: Delegate object.
    /// - returns: Disposable object that can be used to unbind the delegate.
    func setDelegate(_ delegate: AVSpeechSynthesizerDelegate) -> Disposable {
            return RxAVSpeechSynthesizerDelegateProxy
                .installForwardDelegate(delegate, retainDelegate: false, onProxyForObject: self.base)
    }

    /**
     Reactive wrapper for `delegate` message `synthesizer:utterance:`
     */
    var started: ControlEvent<AVSpeechUtterance> {
        let source = delegate
            .methodInvoked(#selector(AVSpeechSynthesizerDelegate.speechSynthesizer(_:didStart:)))
            .map { try castOrThrow(AVSpeechUtterance.self, $0[1]) }
        return ControlEvent(events: source)
    }

    /**
     Reactive wrapper for `delegate` message `synthesizer:utterance:`
     */
    var finished: ControlEvent<AVSpeechUtterance> {
        let source = delegate
            .methodInvoked(#selector(AVSpeechSynthesizerDelegate.speechSynthesizer(_:didFinish:)))
            .map { try castOrThrow(AVSpeechUtterance.self, $0[1]) }
        return ControlEvent(events: source)
    }

    /**
     Reactive wrapper for `delegate` message `synthesizer:utterance:`
     */
    var paused: ControlEvent<AVSpeechUtterance> {
        let source = delegate
            .methodInvoked(#selector(AVSpeechSynthesizerDelegate.speechSynthesizer(_:didPause:)))
            .map { try castOrThrow(AVSpeechUtterance.self, $0[1]) }
        return ControlEvent(events: source)
    }

    /**
     Reactive wrapper for `delegate` message `synthesizer:utterance:`
     */
    var continued: ControlEvent<AVSpeechUtterance> {
        let source = delegate
            .methodInvoked(#selector(AVSpeechSynthesizerDelegate.speechSynthesizer(_:didContinue:)))
            .map { try castOrThrow(AVSpeechUtterance.self, $0[1]) }
        return ControlEvent(events: source)
    }

    /**
     Reactive wrapper for `delegate` message `synthesizer:utterance:`
     */
    var canceled: ControlEvent<AVSpeechUtterance> {
        let source = delegate
            .methodInvoked(#selector(AVSpeechSynthesizerDelegate.speechSynthesizer(_:didCancel:)))
            .map { try castOrThrow(AVSpeechUtterance.self, $0[1]) }
        return ControlEvent(events: source)
    }

    /**
     Reactive wrapper for `delegate` message `synthesizer:characterRange:utterance:`
     */
    var speekRange: ControlEvent<(characterRange: NSRange, utterance: AVSpeechUtterance)> {
        let source = delegate
            .methodInvoked(#selector(AVSpeechSynthesizerDelegate.speechSynthesizer(_:willSpeakRangeOfSpeechString:utterance:)))
            .map { (characterRange: try castOrThrow(NSRange.self, $0[1]), utterance: try castOrThrow(AVSpeechUtterance.self, $0[2])) }
        return ControlEvent(events: source)
    }
}

func castOrThrow<T>(_ resultType: T.Type, _ object: Any) throws -> T {
    guard let returnValue = object as? T else {
        throw RxCocoaError.castingError(object: object, targetType: resultType)
    }

    return returnValue
}

#endif