ios: highlight URLs in texts (#272)

* ios: highlight URLs in texts

* Apply suggestions from code review

apps/ios/Shared/MyPlayground.playground/Contents.swift

@@ -12,3 +12,15 @@ var a = [1, 2, 3]
 a.removeAll(where: { $0 == 1} )
 
 print(a)
+
+let input = "This is a test with the привет 🙂 URL https://www.hackingwithswift.com to be detected."
+let detector = try! NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue)
+let matches = detector.matches(in: input, options: [], range: NSRange(location: 0, length: input.count))
+
+print(matches)
+
+for match in matches {
+    guard let range = Range(match.range, in: input) else { continue }
+    let url = input[range]
+    print(url)
+}

apps/ios/Shared/MyPlayground.playground/timeline.xctimeline

@@ -3,7 +3,7 @@
    version = "3.0">
    <TimelineItems>
       <LoggerValueHistoryTimelineItem
-         documentLocation = "file:///Users/evgeny/opensource/simplex-chat/simplex-chat/apps/ios/Shared/MyPlayground.playground#CharacterRangeLen=88&amp;CharacterRangeLoc=91&amp;EndingColumnNumber=0&amp;EndingLineNumber=7&amp;StartingColumnNumber=3&amp;StartingLineNumber=6&amp;Timestamp=665423482.97412"
+         documentLocation = "file:///Users/evgeny/opensource/simplex-chat/simplex-chat/apps/ios/Shared/MyPlayground.playground#CharacterRangeLen=88&amp;CharacterRangeLoc=91&amp;EndingColumnNumber=0&amp;EndingLineNumber=7&amp;StartingColumnNumber=3&amp;StartingLineNumber=6&amp;Timestamp=665788560.47885"
          selectedRepresentationIndex = "0"
          shouldTrackSuperviewWidth = "NO">
       </LoggerValueHistoryTimelineItem>

apps/ios/Shared/Views/Chat/ChatItem/TextItemView.swift

@@ -11,14 +11,14 @@ import SwiftUI
 struct TextItemView: View {
     var chatItem: ChatItem
     var width: CGFloat
+    private let codeFont = Font.custom("Courier", size: UIFont.preferredFont(forTextStyle: .body).pointSize)
 
     var body: some View {
         let sent = chatItem.chatDir.sent
         let minWidth = min(200, width)
         let maxWidth = min(300, width * 0.78)
-
         return VStack {
-            Text(chatItem.content.text)
+            messageText(chatItem.content.text, sent: sent)
                 .padding(.top, 8)
                 .padding(.horizontal, 12)
                 .frame(minWidth: minWidth, maxWidth: maxWidth, alignment: .leading)
@@ -42,13 +42,55 @@ struct TextItemView: View {
             alignment: sent ? .trailing : .leading
         )
     }
+
+    private func messageText(_ s: String, sent: Bool = false) -> Text {
+        if s == "" { return Text("") }
+        let parts = s.split(separator: " ")
+        print(parts)
+        var res = wordToText(parts[0], sent)
+        var i = 1
+        while i < parts.count {
+            res = res + Text(" ") + wordToText(parts[i], sent)
+            i = i + 1
+        }
+        return res
+    }
+
+    private func wordToText(_ s: String.SubSequence, _ sent: Bool) -> Text {
+        switch true {
+        case s.starts(with: "http://") || s.starts(with: "https://"):
+            let str = String(s)
+            return Text(AttributedString(str, attributes: AttributeContainer([
+                .link: NSURL(string: str) as Any,
+                .foregroundColor: (sent ? UIColor.white : nil) as Any
+            ]))).underline()
+        default:
+            if (s.count > 1) {
+                switch true {
+                case s.first == "*" && s.last == "*": return mdText(s).bold()
+                case s.first == "_" && s.last == "_": return mdText(s).italic()
+                case s.first == "+" && s.last == "+": return mdText(s).underline()
+                case s.first == "~" && s.last == "~": return mdText(s).strikethrough()
+                default: return Text(s)
+                }
+            } else {
+                return Text(s)
+            }
+        }
+    }
+
+    private func mdText(_ s: String.SubSequence) -> Text {
+        Text(s[s.index(s.startIndex, offsetBy: 1)..<s.index(s.endIndex, offsetBy: -1)])
+    }
 }
 
 struct TextItemView_Previews: PreviewProvider {
     static var previews: some View {
         Group{
             TextItemView(chatItem: chatItemSample(1, .directSnd, .now, "hello"), width: 360)
+            TextItemView(chatItem: chatItemSample(2, .directSnd, .now, "https://simplex.chat"), width: 360)
             TextItemView(chatItem: chatItemSample(2, .directRcv, .now, "hello there too"), width: 360)
+            TextItemView(chatItem: chatItemSample(2, .directRcv, .now, "https://simplex.chat"), width: 360)
         }
         .previewLayout(.fixed(width: 360, height: 70))
     }

apps/ios/Shared/Views/ChatList/ChatPreviewView.swift

@@ -10,6 +10,8 @@ import SwiftUI
 
 struct ChatPreviewView: View {
     @ObservedObject var chat: Chat
+    @Environment(\.colorScheme) var colorScheme
+    var darkGreen = Color(red: 0, green: 0.5, blue: 0)
 
     var body: some View {
         let cItem = chat.chatItems.last
@@ -21,7 +23,7 @@ struct ChatPreviewView: View {
                    chat.serverInfo.networkStatus == .connected {
                     Image(systemName: "circle.fill")
                         .resizable()
-                        .foregroundColor(.green)
+                        .foregroundColor(colorScheme == .dark ? darkGreen : .green)
                         .frame(width: 5, height: 5)
                         .padding([.bottom, .leading], 1)
                 }