session-ios/Session/Media Viewing & Editing/Transitions/MediaPresentationContext.swift

// Copyright © 2022 Rangeproof Pty Ltd. All rights reserved.

import Foundation

enum Media {
    case gallery(MediaGalleryViewModel.Item)
    case image(UIImage)

    var image: UIImage? {
        switch self {
            case let .gallery(item):
                // For videos attempt to load a large thumbnail, for other items just try to load
                // the source file directly
                guard !item.isVideo else { return item.attachment.existingThumbnail(size: .large) }
                guard let originalFilePath: String = item.attachment.originalFilePath else { return nil }
                
                return UIImage(contentsOfFile: originalFilePath)
                
            case let .image(image): return image
        }
    }
}

struct MediaPresentationContext {
    let mediaView: UIView
    let presentationFrame: CGRect
    let cornerRadius: CGFloat
    let cornerMask: CACornerMask
}

// There are two kinds of AnimationControllers that interact with the media detail view. Both
// appear to transition the media view from one VC to it's corresponding location in the
// destination VC.
//
// MediaPresentationContextProvider is either a target or destination VC which can provide the
// details necessary to facilite this animation.
//
// First, the MediaZoomAnimationController is non-interactive. We use it whenever we're going to
// show the Media detail pager.
//
//  We can get there several ways:
//    From conversation settings, this can be a push or a pop from the tileView.
//    From conversationView/MessageDetails this can be a modal present or a pop from the tile view.
//
// The other animation controller, the MediaDismissAnimationController is used when we're going to
// stop showing the media pager. This can be a pop to the tile view, or a modal dismiss.
protocol MediaPresentationContextProvider {
    func mediaPresentationContext(mediaItem: Media, in coordinateSpace: UICoordinateSpace) -> MediaPresentationContext?

    // The transitionView will be presented below this view.
    // If nil, the transitionView will be presented above all
    func snapshotOverlayView(in coordinateSpace: UICoordinateSpace) -> (UIView, CGRect)?
}