From 3b4cef9fa2f6c044320b8209c0b36aefd161b7ce Mon Sep 17 00:00:00 2001
From: tsuzukihashi <tsudukihashi0817@gmail.com>
Date: Sat, 3 Jun 2023 00:15:41 +0900
Subject: [PATCH] feat: Add LinkPresentationView

---
 .../CapsuleButtonStyle.swift                  |  0
 .../{ => ButtonStyle}/PressButtonStyle.swift  |  0
 .../Representable/LinkPresentationView.swift  | 92 +++++++++++++++++++
 3 files changed, 92 insertions(+)
 rename Sources/TsuzuKit/{ => ButtonStyle}/CapsuleButtonStyle.swift (100%)
 rename Sources/TsuzuKit/{ => ButtonStyle}/PressButtonStyle.swift (100%)
 create mode 100644 Sources/TsuzuKit/Representable/LinkPresentationView.swift

diff --git a/Sources/TsuzuKit/CapsuleButtonStyle.swift b/Sources/TsuzuKit/ButtonStyle/CapsuleButtonStyle.swift
similarity index 100%
rename from Sources/TsuzuKit/CapsuleButtonStyle.swift
rename to Sources/TsuzuKit/ButtonStyle/CapsuleButtonStyle.swift
diff --git a/Sources/TsuzuKit/PressButtonStyle.swift b/Sources/TsuzuKit/ButtonStyle/PressButtonStyle.swift
similarity index 100%
rename from Sources/TsuzuKit/PressButtonStyle.swift
rename to Sources/TsuzuKit/ButtonStyle/PressButtonStyle.swift
diff --git a/Sources/TsuzuKit/Representable/LinkPresentationView.swift b/Sources/TsuzuKit/Representable/LinkPresentationView.swift
new file mode 100644
index 0000000..7dab2bf
--- /dev/null
+++ b/Sources/TsuzuKit/Representable/LinkPresentationView.swift
@@ -0,0 +1,92 @@
+import SwiftUI
+import LinkPresentation
+
+public struct LinkPresentationView: UIViewRepresentable {
+  public typealias UIViewType = LPLinkView
+
+  let url: URL
+  @Binding var redraw: Bool
+
+  public func makeUIView(context: UIViewRepresentableContext<LinkPresentationView>) -> UIViewType {
+    let view = LPLinkView(url: url)
+    view.isHidden = true
+    if let cachedData = MetaCache.shared.metadata(for: url) {
+      update(view: view, with: cachedData)
+    } else {
+      self.fetchMetadata(for: url) { result in
+        switch result {
+        case .success(let metadata):
+          MetaCache.shared.store(metadata)
+          self.update(view: view, with: metadata)
+        case .failure:
+          self.redraw = true
+        }
+      }
+    }
+    return view
+  }
+
+  public func updateUIView(_ uiView: UIViewType, context: UIViewRepresentableContext<LinkPresentationView>) {
+  }
+
+  private func fetchMetadata(for url: URL, completion: @escaping (Result<LPLinkMetadata, Error>) -> Void) {
+    let provider = LPMetadataProvider()
+
+    provider.startFetchingMetadata(for: url) { metadata, error in
+      if let error = error {
+        completion(.failure(error))
+      } else if let metadata = metadata {
+        completion(.success(metadata))
+      } else {
+        completion(.failure(LPError(.unknown)))
+      }
+    }
+  }
+
+  private func update(view: UIViewType, with metadata: LPLinkMetadata) {
+    DispatchQueue.main.async {
+      view.metadata = metadata
+      view.sizeToFit()
+      self.redraw = true
+      view.isHidden = false
+    }
+  }
+}
+
+public final class MetaCache {
+  public static let shared = MetaCache()
+  private init(){}
+
+  private let storage = UserDefaults.standard
+
+  private let key = "Metadata"
+
+  func store(_ metadata: LPLinkMetadata) {
+    do {
+      let data = try NSKeyedArchiver.archivedData(withRootObject: metadata, requiringSecureCoding: true)
+      var metadatas: [String: Data] = storage.dictionary(forKey: key) as? [String: Data] ?? [:]
+      metadatas[metadata.originalURL!.absoluteString] = data
+      storage.set(metadatas, forKey: key)
+    }
+    catch {
+      print("Failed storing metadata with error \(error as NSError)")
+    }
+  }
+
+  func metadata(for url: URL) -> LPLinkMetadata? {
+    guard let metadatas = storage.dictionary(forKey: key) as? [String: Data] else {
+      return nil
+    }
+
+    guard let data = metadatas[url.absoluteString] else {
+      return nil
+    }
+
+    do {
+      return try NSKeyedUnarchiver.unarchivedObject(ofClass: LPLinkMetadata.self, from: data)
+    } catch {
+      print("Failed to unarchive metadata with error \(error)")
+      return nil
+    }
+  }
+}