jrtibbetts/Stylobate

//  Copyright © 2018 Poikile Creations. All rights reserved.

#if os(iOS) || os(tvOS)

import UIKit

/// Implemented by views that show a progress bar when an activity is executing.
/// The default implementation will add a `UIProgressView` if your
/// implementation doesn't set one.
public protocol ProgressBusyView: VisualIndicatorBusyView {

    /// The progress view to display. Your implementation must create a property
    /// or outlet for it, but doesn't have to initialize it or connect it in a
    /// storyboard or nib, because the default implementation can create one.
    var progressView: UIProgressView? { get }

}

// MARK: - ProgressBusyView Default Implementation

public extension ProgressBusyView where Self: UIView {

    var progressView: UIProgressView? {
        return busyIndicator as? UIProgressView
    }

    func startActivity(completion: BusyView.ActivityCompletion? = nil) {
        if busyIndicator == nil {
            busyIndicator = UIProgressView(progressViewStyle: .default)
        }

        if progressView?.superview == nil {
            addSubview(progressView!)
            progressView?.centerInSuperview()
            setNeedsUpdateConstraints()
            layoutIfNeeded()
        }

        if let progressView = progressView {
            summon(progressView)
        }

        completion?()
    }

    func stopActivity(completion: BusyView.ActivityCompletion?) {
        if let progressView = progressView {
            banish(progressView)
        }

        completion?()
    }

}

#endif