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 ways to further configure the transition by setting configuration options on `SwiftMessagesSegue`.
 First, you may override `prepare(for:sender:)` in the presenting view controller and downcast the
 segue to `SwiftMessagesSegue`. Second, 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").

 The SwiftMessagesSegueExtras framework contains several pre-configured subclasses: `TopMessageSegue`,
 `BottomMessageSegue`, `TopCardSegue`, `BottomCardSegue`, `TopTabSegue`, `BottomTabSegue`, and
 `CenteredSegue`. These classes are not included in the SwiftMessages to avoid cluttering the Segue Type
 dialog by default. Therefore, SwiftMessagesSegueExtras must be explicitly added to the project
 (see the View Controller readme).

 `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.

 + 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. SwiftMessages relies on a view's `intrinsicContentSize` to determine the height of a message.
    However, some view controllers' views does not define a good `intrinsicContentSize`
    (`UINavigationController` is a common example). For these cases, there are a couple of ways
    to specify the preferred height. First, you may set the `preferredContentSize` on the destination
    view controller (available as "Use Preferred Explicit Size" in IB's attribute inspector). Second,
    you may set `SwiftMessagesSegue.messageView.backgroundHeight`.

 See the "View Controllers" selection in the Demo app for examples.
 */

open class SwiftMessagesSegue: UIStoryboardSegue {

    /**
     Specifies one of the pre-defined layouts, mirroring a subset of `MessageView.Layout`.
     */
    public enum Layout {

        /// The standard message view layout on top.
        case topMessage

        /// The standard message view layout on bottom.
        case bottomMessage

        /// A floating card-style view with rounded corners on top
        case topCard

        /// A floating tab-style view with rounded corners on bottom
        case topTab

        /// A floating card-style view with rounded corners on bottom
        case bottomCard

        /// A floating tab-style view with rounded corners on top
        case bottomTab

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

    /**
     Specifies how the view controller's view is installed into the
     containing message view.
     */
    public enum Containment {

        /**
         The view controller's view is installed for edge-to-edge display, extending into the safe areas
         to the device edges. This is done by calling `messageView.installContentView(:insets:)`
         See that method's documentation for additional details.
        */
        case content

        /**
         The view controller's view is installed for card-style layouts, inset from the margins
         and avoiding safe areas. This is done by calling `messageView.installBackgroundView(:insets:)`.
         See that method's documentation for details.
        */
        case background

        /**
         The view controller's view is installed for tab-style layouts, inset from the side margins, but extending
         to the device edge on the top or bottom. This is done by calling `messageView.installBackgroundVerticalView(:insets:)`.
         See that method's documentation for details.
         */
        case backgroundVertical
    }

    /**
     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 squircle (round) corners (see the parent
     class `CornerRoundingView`).
    */
    public var containerView = ViewControllerContainerView()

    /**
     Specifies how the view controller's view is installed into the
     containing message view. See `Containment` for details.
     */
    public var containment: Containment = .content

    /// 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 }
    }

    /// 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 }
    }

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

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

    override open func perform() {
        selfRetainer = self
        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
        messageView.statusBarOffset = 0
        messageView.safeAreaTopOffset = 0
        messageView.safeAreaBottomOffset = 0
        containment = .content
        containerView.cornerRadius = 0
        containerView.roundsLeadingCorners = false
        messageView.configureDropShadow()
        switch layout {
        case .topMessage:
            messageView.layoutMarginAdditions = UIEdgeInsetsMake(20, 20, 20, 20)
            messageView.collapseLayoutMarginAdditions = false
            let animation = TopBottomAnimation(style: .top)
            animation.springDamping = 1
            presentationStyle = .custom(animator: animation)
        case .bottomMessage:
            messageView.layoutMarginAdditions = UIEdgeInsetsMake(20, 20, 20, 20)
            messageView.collapseLayoutMarginAdditions = false
            let animation = TopBottomAnimation(style: .bottom)
            animation.springDamping = 1
            presentationStyle = .custom(animator: animation)
        case .topCard:
            containment = .background
            messageView.layoutMarginAdditions = UIEdgeInsetsMake(10, 10, 10, 10)
            messageView.collapseLayoutMarginAdditions = true
            containerView.cornerRadius = 15
            presentationStyle = .top
        case .bottomCard:
            containment = .background
            messageView.layoutMarginAdditions = UIEdgeInsetsMake(10, 10, 10, 10)
            messageView.collapseLayoutMarginAdditions = true
            containerView.cornerRadius = 15
            presentationStyle = .bottom
        case .topTab:
            containment = .backgroundVertical
            messageView.layoutMarginAdditions = UIEdgeInsetsMake(20, 10, 20, 10)
            messageView.collapseLayoutMarginAdditions = true
            containerView.cornerRadius = 15
            containerView.roundsLeadingCorners = true
            let animation = TopBottomAnimation(style: .top)
            animation.springDamping = 1
            presentationStyle = .custom(animator: animation)
        case .bottomTab:
            containment = .backgroundVertical
            messageView.layoutMarginAdditions = UIEdgeInsetsMake(20, 10, 20, 10)
            messageView.collapseLayoutMarginAdditions = true
            containerView.cornerRadius = 15
            containerView.roundsLeadingCorners = true
            let animation = TopBottomAnimation(style: .bottom)
            animation.springDamping = 1
            presentationStyle = .custom(animator: animation)
        case .centered:
            containment = .backgroundVertical
            messageView.layoutMarginAdditions = UIEdgeInsetsMake(20, 10, 20, 10)
            messageView.collapseLayoutMarginAdditions = true
            containerView.cornerRadius = 15
            presentationStyle = .center
        }
    }
}

extension SwiftMessagesSegue: UIViewControllerTransitioningDelegate {
    public func animationController(forPresented presented: UIViewController, presenting: UIViewController, source: UIViewController) -> UIViewControllerAnimatedTransitioning? {
        let shower = Shower(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 interinally hidden by SwiftMessages, such as with a
                    // dismiss gesture, rather than by view controller dismissal.
                    source.dismiss(animated: false, completion: nil)
                }
                self.selfRetainer = nil
            default: break
            }
        }
        return shower
    }

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

extension SwiftMessagesSegue {
    private class Shower: 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
            // Setup the layout of the `toView`
            do {
                toView.translatesAutoresizingMaskIntoConstraints = false
                segue.containerView.addSubview(toView)
                toView.topAnchor.constraint(equalTo: segue.containerView.topAnchor).isActive = true
                toView.bottomAnchor.constraint(equalTo: segue.containerView.bottomAnchor).isActive = true
                toView.leftAnchor.constraint(equalTo: segue.containerView.leftAnchor).isActive = true
                toView.rightAnchor.constraint(equalTo: segue.containerView.rightAnchor).isActive = true
            }
            // Install the `toView` into the message view.
            switch segue.containment {
            case .content:
                segue.messageView.installContentView(segue.containerView)
            case .background:
                segue.messageView.installBackgroundView(segue.containerView)
            case .backgroundVertical:
                segue.messageView.installBackgroundVerticalView(segue.containerView)
            }
            segue.containerView.viewController = transitionContext.viewController(forKey: .to)
            segue.presenter.config.presentationContext = .view(transitionContainer)
            segue.messenger.show(presenter: segue.presenter)
        }
    }
}

extension SwiftMessagesSegue {
    private class Hider: 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()
        }
    }
}