SwiftMessagesSegue.swift

//
//  SwiftMessagesSegue.swift
//  SwiftMessages
//
//  Created by Timothy Moose on 5/30/18.
//  Copyright © 2018 SwiftKick Mobile. All rights reserved.
//

import UIKit

/**
 `SwiftMessagesSegue` is a configurable subclass of `UIStoryboardSegue` that utilizes
 SwiftMessages to present and dismiss modal view controllers. It performs these transitions by
 becoming your view controller's `transitioningDelegate` and calling SwiftMessage's `show()`
 and `hide()` under the hood.

 To use `SwiftMessagesSegue` with Interface Builder, control-drag a segue, then select
 "swift messages" from the Segue Type dialog. This configures a default transition. There are
 two suggested ways to further configure the transition by setting options on `SwiftMessagesSegue`.
 First, and recommended, you may subclass `SwiftMessagesSegue` and override `init(identifier:source:destination:)`.
 Subclasses will automatically appear in the segue type dialog using an auto-generated name (for example, the
 name for "VeryNiceSegue" would be "very nice"). Second, you may override `prepare(for:sender:)` in the
 presenting view controller and downcast the segue to `SwiftMessagesSegue`.

 `SwiftMessagesSegue` can be used without an associated storyboard or segue by doing the following in
 the presenting view controller.

     let destinationVC = ... // make a reference to a destination view controller
     let segue = SwiftMessagesSegue(identifier: nil, source: self, destination: destinationVC)
     ... // do any configuration here
     segue.perform()

 To dismiss, call the UIKit API on the presenting view controller:

     dismiss(animated: true, completion: nil)

 It is not necessary to retain `segue` because it retains itself until dismissal. However, you can
 retain it if you plan to `perform()` more than once.

 #### Present the controller on top of all controllers

 If you don't know the presenter or you don't want to pass it as a source, like when you
 have a completely separated message controller, you can pass a `WindowViewController`
 as the `source` argument of the segue's initializer.

 By default, the window will be shown in the current window scene at `.normal` window level.
 However, these parameters can be customized by initializing the view controller with a `SwiftMessages.Config` that has the `SwiftMessages.Config.presentationContext` set to either `.window` or `.windowScene`:

 + note: Some additional details:
 1. Your view controller's view will be embedded in a `SwiftMessages.BaseView` in order to
 utilize some SwiftMessages features. This view can be accessed and configured via the
 `SwiftMessagesSegue.messageView` property. For example, you may configure a default drop
 shadow by calling `segue.messageView.configureDropShadow()`.
 2. SwiftMessagesSegue provides static default view controller sizing based on device.
 However, it is recommended that you specify sizing appropriate for your content using
 one of the following methods.
    1. Define sufficient width and height constraints in your view controller.
    2. Set `preferredContentSize` (a.k.a "Use Preferred Explicit Size" in Interface Builder's
       attribute inspector). Zeros are ignored, e.g. `CGSize(width: 0, height: 350)` only
       affects the height.
    3. Add explicit width and/or height constraints to `segue.messageView.backgroundView`.
    Note that `Layout.topMessage` and `Layout.bottomMessage` are always full screen width.
    For other layouts, the there is a maximum 500pt width on iPad (regular horizontal size class)
    at 950 priority, which can be overridden by adding higher-priority constraints.
 
 See the "View Controllers" selection in the Demo app for examples.
 */

open class SwiftMessagesSegue: UIStoryboardSegue {

    /**
     Specifies one of the pre-defined layout configurations.
     */
    public enum Layout {

        /// The standard message view layout that slides down from the top edge.
        case topMessage

        /// The standard message view layout that slides up from the bottom edge.
        case bottomMessage

        /// The standard message view layout that slides in from the leading edge.
        case leadingMessage

        /// The standard message view layout that slides in from the trailing edge.
        case trailingMessage

        /// A floating card-style view with rounded corners that slides down from the top edge.
        case topCard

        /// A floating card-style view with rounded corners that slides up from the bottom edge.
        case bottomCard

        /// A floating card-style view with rounded corners that slides in from the leading edge.
        case leadingCard

        /// A floating card-style view with rounded corners that slides in from the trailing edge.
        case trailingCard

        /// A floating tab-style view with rounded leading corners that slides down from the top edge.
        case topTab

        /// A floating tab-style view with rounded leading corners that slides up from the bottom edge.
        case bottomTab

        /// A floating tab-style view with rounded leading corners that slides in from the leading edge.
        case leadingTab

        /// A floating tab-style view with rounded leading corners that slides in from the traling edge.
        case trailingTab

        /// A floating card-style view typically used with `.center` presentation style.
        case centered
    }

    /// The presentation style to use. See the SwiftMessages.PresentationStyle for details.
    public var presentationStyle: SwiftMessages.PresentationStyle {
        get { return messenger.defaultConfig.presentationStyle }
        set { messenger.defaultConfig.presentationStyle = newValue }
    }

    /// The dim mode to use. See the SwiftMessages.DimMode for details.
    public var dimMode: SwiftMessages.DimMode {
        get { return messenger.defaultConfig.dimMode}
        set { messenger.defaultConfig.dimMode = newValue }
    }
    
    // duration
    public var duration: SwiftMessages.Duration {
        get { return messenger.defaultConfig.duration}
        set { messenger.defaultConfig.duration = newValue }
    }

    /// Specifies whether or not the interactive pan-to-hide gesture is enabled
    /// on the message view. The default value is `true`, but may not be appropriate
    /// for view controllers that use swipe or pan gestures.
    public var interactiveHide: Bool {
        get { return messenger.defaultConfig.interactiveHide }
        set { messenger.defaultConfig.interactiveHide = newValue }
    }

    /// Specifies an optional array of event listeners.
    public var eventListeners: [SwiftMessages.EventListener] {
        get { return messenger.defaultConfig.eventListeners }
        set { messenger.defaultConfig.eventListeners = newValue }
    }

    /**
     Normally, the destination view controller's `modalPresentationStyle` is changed
     to `.custom` in the `perform()` function. Set this property to `false` to prevent it from
     being overridden.
    */
    public var overrideModalPresentationStyle: Bool = true

    /**
     The view that is passed to `SwiftMessages.show(config:view:)` during presentation.
     The view controller's view is installed into `containerView`, which is itself installed
     into `messageView`. `SwiftMessagesSegue` does this installation automatically based on the
     value of the `containment` property. `BaseView` is the parent of `MessageView` and provides a
     number of configuration options that you may use. For example, you may configure a default drop
     shadow by calling `messageView.configureDropShadow()`.
     */
    public var messageView = BaseView()

    /**
     The view controller's view is embedded in `containerView` before being installed into
     `messageView`. This view provides configurable continuous rounded corners (see the parent
     class `CornerRoundingView`).
    */
    public var containerView: CornerRoundingView = CornerRoundingView()

    /**
     Supply an instance of `KeyboardTrackingView` to have the message view avoid the keyboard.
     */
    public var keyboardTrackingView: KeyboardTrackingView? {
        get {
            return messenger.defaultConfig.keyboardTrackingView
        }
        set {
            messenger.defaultConfig.keyboardTrackingView = newValue
        }
    }

    private var messenger = SwiftMessages()
    private var selfRetainer: SwiftMessagesSegue? = nil
    private lazy var hider = { return TransitioningDismisser(segue: self) }()

    private lazy var presenter = {
        return Presenter(config: messenger.defaultConfig, view: messageView, delegate: messenger)
    }()

    override open func perform() {
        (source as? WindowViewController)?.install()
        selfRetainer = self
        if overrideModalPresentationStyle {
            destination.modalPresentationStyle = .custom
        }
        destination.transitioningDelegate = self
        source.present(destination, animated: true, completion: nil)
    }

    override public init(identifier: String?, source: UIViewController, destination: UIViewController) {
        super.init(identifier: identifier, source: source, destination: destination)
        dimMode = .gray(interactive: true)
        messenger.defaultConfig.duration = .forever
    }

    fileprivate let safeAreaWorkaroundViewController = UIViewController()
}

extension SwiftMessagesSegue {
    /// A convenience method for configuring some pre-defined layouts that mirror a subset of `MessageView.Layout`.
    public func configure(layout: Layout) {
        messageView.bounceAnimationOffset = 0
        containerView.cornerRadius = 0
        containerView.roundsLeadingCorners = false
        messageView.configureDropShadow()
        switch layout {
        case .topMessage:
// TODO SIZE are these layout margin settings still relevant?
//            messageView.layoutMarginAdditions = UIEdgeInsets(top: 20, left: 20, bottom: 20, right: 20)
//            messageView.collapseLayoutMarginAdditions = false
            let animation = EdgeAnimation(style: .top)
            animation.springDamping = 1
            presentationStyle = .custom(animator: animation)
        case .bottomMessage:
//            messageView.layoutMarginAdditions = UIEdgeInsets(top: 20, left: 20, bottom: 20, right: 20)
//            messageView.collapseLayoutMarginAdditions = false
            let animation = EdgeAnimation(style: .bottom)
            animation.springDamping = 1
            presentationStyle = .custom(animator: animation)
        case .leadingMessage:
//            messageView.layoutMarginAdditions = UIEdgeInsets(top: 20, left: 20, bottom: 20, right: 20)
//            messageView.collapseLayoutMarginAdditions = false
            let animation = EdgeAnimation(style: .leading)
            animation.springDamping = 1
            presentationStyle = .custom(animator: animation)
        case .trailingMessage:
//            messageView.layoutMarginAdditions = UIEdgeInsets(top: 20, left: 20, bottom: 20, right: 20)
//            messageView.collapseLayoutMarginAdditions = false
            let animation = EdgeAnimation(style: .trailing)
            animation.springDamping = 1
            presentationStyle = .custom(animator: animation)
        case .topCard:
            messageView.layout.insets.top = .absolute(0, from: .safeArea)
            messageView.layout.insets.leading = .absolute(0, from: .safeArea)
            messageView.layout.insets.trailing = .absolute(0, from: .safeArea)
            messageView.layout.min.insets.top = .absolute(10, from: .superview)
            messageView.layout.min.insets.leading = .absolute(10, from: .superview)
            messageView.layout.min.insets.trailing = .absolute(10, from: .superview)
            messageView.layout.min.insets.bottom = .absolute(10, from: .safeArea)
            containerView.cornerRadius = 15
            presentationStyle = .top
        case .bottomCard:
            messageView.layout.insets.bottom = .absolute(0, from: .safeArea)
            messageView.layout.insets.leading = .absolute(0, from: .safeArea)
            messageView.layout.insets.trailing = .absolute(0, from: .safeArea)
            messageView.layout.min.insets.bottom = .absolute(10, from: .superview)
            messageView.layout.min.insets.leading = .absolute(10, from: .superview)
            messageView.layout.min.insets.trailing = .absolute(10, from: .superview)
            messageView.layout.min.insets.top = .absolute(10, from: .safeArea)
            containerView.cornerRadius = 15
            presentationStyle = .bottom
        case .leadingCard:
            messageView.layout.insets.leading = .absolute(0, from: .safeArea)
            messageView.layout.insets.top = .absolute(0, from: .safeArea)
            messageView.layout.insets.bottom = .absolute(0, from: .safeArea)
            messageView.layout.min.insets.leading = .absolute(10, from: .superview)
            messageView.layout.min.insets.top = .absolute(10, from: .superview)
            messageView.layout.min.insets.bottom = .absolute(10, from: .superview)
            messageView.layout.min.insets.trailing = .absolute(10, from: .safeArea)
            containerView.cornerRadius = 15
            let animation = EdgeAnimation(style: .leading)
            presentationStyle = .custom(animator: animation)
        case .trailingCard:
            messageView.layout.insets.trailing = .absolute(0, from: .safeArea)
            messageView.layout.insets.top = .absolute(0, from: .safeArea)
            messageView.layout.insets.bottom = .absolute(0, from: .safeArea)
            messageView.layout.min.insets.trailing = .absolute(10, from: .superview)
            messageView.layout.min.insets.top = .absolute(10, from: .superview)
            messageView.layout.min.insets.bottom = .absolute(10, from: .superview)
            messageView.layout.min.insets.leading = .absolute(10, from: .safeArea)
            containerView.cornerRadius = 15
            let animation = EdgeAnimation(style: .trailing)
            presentationStyle = .custom(animator: animation)
        case .topTab:
            messageView.layout.insets.top = .absolute(0, from: .superview)
            messageView.layout.insets.leading = .absolute(0, from: .safeArea)
            messageView.layout.insets.trailing = .absolute(0, from: .safeArea)
            messageView.layout.min.insets.leading = .absolute(10, from: .superview)
            messageView.layout.min.insets.trailing = .absolute(10, from: .superview)
            messageView.layout.min.insets.bottom = .absolute(10, from: .safeArea)
            containerView.cornerRadius = 15
            containerView.roundsLeadingCorners = true
            let animation = EdgeAnimation(style: .top)
            animation.springDamping = 1
            presentationStyle = .custom(animator: animation)
        case .bottomTab:
            messageView.layout.insets.bottom = .absolute(0, from: .superview)
            messageView.layout.insets.leading = .absolute(0, from: .safeArea)
            messageView.layout.insets.trailing = .absolute(0, from: .safeArea)
            messageView.layout.min.insets.leading = .absolute(10, from: .superview)
            messageView.layout.min.insets.trailing = .absolute(10, from: .superview)
            messageView.layout.min.insets.top = .absolute(10, from: .safeArea)
            containerView.cornerRadius = 15
            containerView.roundsLeadingCorners = true
            let animation = EdgeAnimation(style: .bottom)
            animation.springDamping = 1
            presentationStyle = .custom(animator: animation)
        case .leadingTab:
            messageView.layout.insets.leading = .absolute(0, from: .superview)
            messageView.layout.insets.top = .absolute(0, from: .safeArea)
            messageView.layout.insets.bottom = .absolute(0, from: .safeArea)
            messageView.layout.min.insets.top = .absolute(10, from: .superview)
            messageView.layout.min.insets.bottom = .absolute(10, from: .superview)
            messageView.layout.min.insets.trailing = .absolute(10, from: .safeArea)
            containerView.cornerRadius = 15
            containerView.roundsLeadingCorners = true
            let animation = EdgeAnimation(style: .leading)
            animation.springDamping = 1
            presentationStyle = .custom(animator: animation)
        case .trailingTab:
            messageView.layout.insets.trailing = .absolute(0, from: .superview)
            messageView.layout.insets.top = .absolute(0, from: .safeArea)
            messageView.layout.insets.bottom = .absolute(0, from: .safeArea)
            messageView.layout.min.insets.top = .absolute(10, from: .superview)
            messageView.layout.min.insets.bottom = .absolute(10, from: .superview)
            messageView.layout.min.insets.leading = .absolute(10, from: .safeArea)
            containerView.cornerRadius = 15
            containerView.roundsLeadingCorners = true
            let animation = EdgeAnimation(style: .trailing)
            animation.springDamping = 1
            presentationStyle = .custom(animator: animation)
        case .centered:
            messageView.layout.min.insets.top = .absolute(10, from: .safeArea)
            messageView.layout.min.insets.bottom = .absolute(10, from: .safeArea)
            messageView.layout.min.insets.leading = .absolute(10, from: .safeArea)
            messageView.layout.min.insets.trailing = .absolute(10, from: .safeArea)
            containerView.cornerRadius = 15
            presentationStyle = .center
        }
    }
}

extension SwiftMessagesSegue: UIViewControllerTransitioningDelegate {
    public func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        let shower = TransitioningPresenter(segue: self)
        messenger.defaultConfig.eventListeners.append { [unowned self] in
            switch $0 {
            case .didShow:
                shower.completeTransition?(true)
            case .didHide:
                if let completeTransition = self.hider.completeTransition {
                    completeTransition(true)
                } else {
                    // Case where message is internally hidden by SwiftMessages, such as with a
                    // dismiss gesture, rather than by view controller dismissal.
                    source.dismiss(animated: false, completion: nil)
                }
                (source as? WindowViewController)?.uninstall()
                self.selfRetainer = nil
            default: break
            }
        }
        return shower
    }

    public func animationController(forDismissed dismissed: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        return hider
    }
}

extension SwiftMessagesSegue {
    private class TransitioningPresenter: NSObject, UIViewControllerAnimatedTransitioning {

        fileprivate private(set) var completeTransition: ((Bool) -> Void)?
        private weak var segue: SwiftMessagesSegue?

        fileprivate init(segue: SwiftMessagesSegue) {
            self.segue = segue
        }

        func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
            return segue?.presenter.animator.showDuration ?? 0.5
        }

        func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
            guard let segue = segue,
                let toView = transitionContext.view(forKey: .to) else {
                transitionContext.completeTransition(false)
                return
            }
            if #available(iOS 12, *) {}
            else if #available(iOS 11.0, *) {
                // This works around a bug in iOS 11 where the safe area of `messageView` (
                // and all ancestor views) is not set except on iPhone X. By assigning `messageView`
                // to a view controller, its safe area is set consistently. This bug has been resolved as
                // of Xcode 10 beta 2.
                segue.safeAreaWorkaroundViewController.view = segue.presenter.maskingView
            }
            completeTransition = transitionContext.completeTransition
            let transitionContainer = transitionContext.containerView
            // Install the background and content views
            do {
                segue.messageView.installBackgroundView(segue.containerView)
                segue.messageView.installContentView(toView)
            }

            let toVC = transitionContext.viewController(forKey: .to)

            // Nav controller automatically includes height of nav bar in,
            // the `preferredContentSize` and our logic needs to consider this.
            var navInset: CGFloat = 0
            if let nav = toVC as? UINavigationController {
                navInset = nav.navigationBar.frame.height
            }

            if let preferredHeight = toVC?.preferredContentSize.height,
                preferredHeight - navInset > 0 {
                segue.containerView.heightAnchor.constraint(equalToConstant: preferredHeight)
                    .with(priority: .belowMessageSizeable - 1)
                    .isActive = true
            }
            if let preferredWidth = toVC?.preferredContentSize.width,
                preferredWidth > 0 {
                segue.containerView.widthAnchor.constraint(equalToConstant: preferredWidth)
                    .with(priority: .belowMessageSizeable - 1)
                    .isActive = true
            }
            segue.presenter.config.presentationContext = .view(transitionContainer)
            segue.messenger.show(presenter: segue.presenter)
        }
    }
}

extension SwiftMessagesSegue {
    private class TransitioningDismisser: NSObject, UIViewControllerAnimatedTransitioning {

        fileprivate private(set) var completeTransition: ((Bool) -> Void)?
        private weak var segue: SwiftMessagesSegue?

        fileprivate init(segue: SwiftMessagesSegue) {
            self.segue = segue
        }

        func transitionDuration(using transitionContext: UIViewControllerContextTransitioning?) -> TimeInterval {
            return segue?.presenter.animator.hideDuration ?? 0.5
        }

        func animateTransition(using transitionContext: UIViewControllerContextTransitioning) {
            guard let messenger = segue?.messenger else {
                transitionContext.completeTransition(false)
                return
            }
            completeTransition = transitionContext.completeTransition
            messenger.hide()
        }
    }
}