// Copyright (c) RxSwiftCommunity

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// of this software and associated documentation files (the "Software"), to deal
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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import RxSwift
import RxCocoa

/// Default values for `UIPinchGestureRecognizer` configuration
private enum Defaults {
    static var configuration: ((UIPinchGestureRecognizer) -> Void)? = nil
}

/// A `GestureRecognizerFactory` for `UIPinchGestureRecognizer`
public struct PinchGestureRecognizerFactory: GestureRecognizerFactory {
    public typealias Gesture = UIPinchGestureRecognizer
    public let configuration: (UIPinchGestureRecognizer) -> Void

    /**
     Initialiaze a `GestureRecognizerFactory` for `UIPinchGestureRecognizer`
     - parameter configuration: A closure that allows to fully configure the gesture recognizer
     */
    public init(
        configuration: ((UIPinchGestureRecognizer) -> Void)? = Defaults.configuration
        ){
        self.configuration = configuration ?? { _ in }
    }
}

extension AnyGestureRecognizerFactory {

    /**
     Returns an `AnyGestureRecognizerFactory` for `UIPinchGestureRecognizer`
     - parameter configuration: A closure that allows to fully configure the gesture recognizer
     */
    public static func pinch(
        configuration: ((UIPinchGestureRecognizer) -> Void)? = Defaults.configuration
        ) -> AnyGestureRecognizerFactory {
        let gesture = PinchGestureRecognizerFactory(
            configuration: configuration
        )
        return AnyGestureRecognizerFactory(gesture)
    }
}

public extension Reactive where Base: UIView {

    /**
     Returns an observable `UIPinchGestureRecognizer` events sequence
     - parameter configuration: A closure that allows to fully configure the gesture recognizer
     */
    public func pinchGesture(
        configuration: ((UIPinchGestureRecognizer) -> Void)? = Defaults.configuration
        ) -> ControlEvent<UIPinchGestureRecognizer> {

        return gesture(PinchGestureRecognizerFactory(
            configuration: configuration
        ))
    }
}

public extension ObservableType where E: UIPinchGestureRecognizer {

    /**
     Maps the observable `GestureRecognizer` events sequence to an observable sequence of scale factors relative to the points of the two touches in screen coordinates alongside the gesture velocity.
     */
    public func asScale() -> Observable<(scale: CGFloat, velocity: CGFloat)> {
        return self.map { gesture in
            return (gesture.scale, gesture.velocity)
        }
    }
}
