From 1156af3d4c5215f475283d90566fc78f976da95d Mon Sep 17 00:00:00 2001
From: CMK <cirno.mainasuk@gmail.com>
Date: Mon, 21 Jun 2021 01:38:13 +0800
Subject: [PATCH] feat: add multiplex image nodes to StatusNode with progress
 loading supports

---
 .../Share/View/Node/Status/StatusNode.swift   | 65 ++++++++++++++++++-
 .../ViewModel/MosaicImageViewModel.swift      |  9 ++-
 2 files changed, 67 insertions(+), 7 deletions(-)

diff --git a/Mastodon/Scene/Share/View/Node/Status/StatusNode.swift b/Mastodon/Scene/Share/View/Node/Status/StatusNode.swift
index c4ec3e680..9ddbcf87b 100644
--- a/Mastodon/Scene/Share/View/Node/Status/StatusNode.swift
+++ b/Mastodon/Scene/Share/View/Node/Status/StatusNode.swift
@@ -10,6 +10,7 @@ import Combine
 import AsyncDisplayKit
 import CoreDataStack
 import ActiveLabel
+import func AVFoundation.AVMakeRect
 
 protocol StatusNodeDelegate: AnyObject {
     func statusNode(_ node: StatusNode, statusContentTextNode: ASMetaEditableTextNode, didSelectActiveEntityType type: ActiveEntityType)
@@ -20,6 +21,7 @@ final class StatusNode: ASCellNode {
     var disposeBag = Set<AnyCancellable>()
     var timestamp: Date
     var timestampSubscription: AnyCancellable?
+
     weak var delegate: StatusNodeDelegate?      // needs assign on main queue
 
     static let avatarImageSize = CGSize(width: 42, height: 42)
@@ -51,7 +53,6 @@ final class StatusNode: ASCellNode {
         // node.shouldRenderProgressImages = true
         return node
     }()
-
     let nameTextNode = ASTextNode()
     let nameDotTextNode = ASTextNode()
     let dateTextNode = ASTextNode()
@@ -62,10 +63,29 @@ final class StatusNode: ASCellNode {
         return node
     }()
 
+    let mosaicImageViewModel: MosaicImageViewModel
+    let mediaMultiplexImageNodes: [ASMultiplexImageNode]
+
     init(status: Status) {
         timestamp = (status.reblog ?? status).createdAt
+        let _mosaicImageViewModel: MosaicImageViewModel = {
+            let mediaAttachments = Array((status.reblog ?? status).mediaAttachments ?? []).sorted { $0.index.compare($1.index) == .orderedAscending }
+            return MosaicImageViewModel(mediaAttachments: mediaAttachments)
+        }()
+        mosaicImageViewModel = _mosaicImageViewModel
+        mediaMultiplexImageNodes = {
+            var imageNodes: [ASMultiplexImageNode] = []
+            for _ in 0..<_mosaicImageViewModel.metas.count {
+                let imageNode = ASMultiplexImageNode()   // TODO: adapt downloader
+                imageNode.downloadsIntermediateImages = true
+                imageNode.imageIdentifiers = ["url", "previewURL"].map { $0 as NSString }      // quality in descending order
+                imageNodes.append(imageNode)
+            }
+            return imageNodes
+        }()
         super.init()
 
+        print("meta: \(mosaicImageViewModel.metas.count), nodes: \(mediaMultiplexImageNodes.count)")
         automaticallyManagesSubnodes = true
 
         if let url = (status.reblog ?? status).author.avatarImageURL() {
@@ -98,6 +118,10 @@ final class StatusNode: ASCellNode {
         ) {
             statusContentTextNode.attributedText = parseResult.trimmedAttributedString(appearance: StatusNode.statusContentAppearance)
         }
+
+        for imageNode in mediaMultiplexImageNodes {
+            imageNode.dataSource = self
+        }
     }
 
     override func didEnterDisplayState() {
@@ -112,6 +136,7 @@ final class StatusNode: ASCellNode {
                 ])
             }
 
+        // FIXME: needs move to other only once called callback in life cycle like: `viewDidLoad`
         statusContentTextNode.textView.isEditable = false
         statusContentTextNode.textView.textDragInteraction?.isEnabled = false
         statusContentTextNode.textView.linkTextAttributes = [
@@ -153,16 +178,34 @@ final class StatusNode: ASCellNode {
 
         let verticalStack = ASStackLayoutSpec.vertical()
         verticalStack.spacing = 10
-        verticalStack.children = [
+        var verticalStackChildren: [ASLayoutElement] = [
             headerStack,
             statusContentTextNode,
         ]
+        if !mediaMultiplexImageNodes.isEmpty {
+            for (imageNode, meta) in zip(mediaMultiplexImageNodes, mosaicImageViewModel.metas) {
+                imageNode.style.preferredSize = AVMakeRect(aspectRatio: meta.size, insideRect: CGRect(origin: .zero, size: constrainedSize.max)).size
+                let layout = ASRatioLayoutSpec(ratio: meta.size.height / meta.size.width, child: imageNode)
+                verticalStackChildren.append(layout)
+            }
+        }
+        verticalStack.children = verticalStackChildren
 
         return verticalStack
     }
 
 }
 
+//extension StatusNode: ASImageDownloaderProtocol {
+//    func downloadImage(with URL: URL, callbackQueue: DispatchQueue, downloadProgress: ASImageDownloaderProgress?, completion: @escaping ASImageDownloaderCompletion) -> Any? {
+//
+//    }
+//
+//    func cancelImageDownload(forIdentifier downloadIdentifier: Any) {
+//
+//    }
+//}
+
 // MARK: - ASEditableTextNodeDelegate
 extension StatusNode: ASMetaEditableTextNodeDelegate {
     func metaEditableTextNode(_ textNode: ASMetaEditableTextNode, shouldInteractWith URL: URL, in characterRange: NSRange, interaction: UITextItemInteraction) -> Bool {
@@ -175,3 +218,21 @@ extension StatusNode: ASMetaEditableTextNodeDelegate {
         return false
     }
 }
+
+// MARK: - ASMultiplexImageNodeDataSource
+extension StatusNode: ASMultiplexImageNodeDataSource {
+    func multiplexImageNode(_ imageNode: ASMultiplexImageNode, urlForImageIdentifier imageIdentifier: ASImageIdentifier) -> URL? {
+        guard let imageNodeIndex = mediaMultiplexImageNodes.firstIndex(of: imageNode) else { return nil }
+        guard imageNodeIndex < mosaicImageViewModel.metas.count else { return nil }
+        let meta = mosaicImageViewModel.metas[imageNodeIndex]
+        switch imageIdentifier {
+        case "url" as NSString:
+            return meta.url
+        case "previewURL" as NSString:
+            return meta.priviewURL
+        default:
+            assertionFailure()
+            return nil
+        }
+    }
+}
diff --git a/Mastodon/Scene/Share/ViewModel/MosaicImageViewModel.swift b/Mastodon/Scene/Share/ViewModel/MosaicImageViewModel.swift
index 888d4dffe..265ce245b 100644
--- a/Mastodon/Scene/Share/ViewModel/MosaicImageViewModel.swift
+++ b/Mastodon/Scene/Share/ViewModel/MosaicImageViewModel.swift
@@ -16,16 +16,14 @@ struct MosaicImageViewModel {
     init(mediaAttachments: [Attachment]) {
         var metas: [MosaicMeta] = []
         for element in mediaAttachments where element.type == .image {
-            // Display original on the iPad/Mac
-            guard let previewURL = element.previewURL else { continue }
-            let urlString = UIDevice.current.userInterfaceIdiom == .phone ? previewURL : element.url
             guard let meta = element.meta,
                   let width = meta.original?.width,
                   let height = meta.original?.height,
-                  let url = URL(string: urlString) else {
+                  let url = URL(string: element.url) else {
                 continue
             }
             let mosaicMeta = MosaicMeta(
+                priviewURL: element.previewURL.flatMap { URL(string: $0) },
                 url: url,
                 size: CGSize(width: width, height: height),
                 blurhash: element.blurhash,
@@ -40,7 +38,8 @@ struct MosaicImageViewModel {
 
 struct MosaicMeta {
     static let edgeMaxLength: CGFloat = 20
-    
+
+    let priviewURL: URL?
     let url: URL
     let size: CGSize
     let blurhash: String?