Make links clickable in profile view

damus/Util/Markdown.swift

@@ -0,0 +1,43 @@
+//
+//  Markdown.swift
+//  damus
+//
+//  Created by Lionello Lunesu on 2022-12-28.
+//
+
+import Foundation
+
+public struct Markdown {
+    private let detector = try! NSDataDetector(types: NSTextCheckingResult.CheckingType.link.rawValue)
+
+    /// Ensure the specified URL has a scheme by prepending "https://" if it's absent.
+    static func withScheme(_ url: any StringProtocol) -> any StringProtocol {
+        return url.contains("://") ? url : "https://" + url
+    }
+
+    static func parseMarkdown(content: String) -> AttributedString {
+        // Similar to the parsing in NoteContentView
+        let md_opts: AttributedString.MarkdownParsingOptions =
+            .init(interpretedSyntax: .inlineOnlyPreservingWhitespace)
+
+        if let txt = try? AttributedString(markdown: content, options: md_opts) {
+            return txt
+        } else {
+            return AttributedString(stringLiteral: content)
+        }
+    }
+
+    /// Process the input text and add markdown for any embedded URLs.
+    public func process(_ input: String) -> AttributedString {
+        let matches = detector.matches(in: input, options: [], range: NSRange(location: 0, length: input.utf16.count))
+        var output = input
+        // Start with the last match, because replacing the first would invalidate all subsequent indices
+        for match in matches.reversed() {
+            guard let range = Range(match.range, in: input) else { continue }
+            let url = input[range]
+            output.replaceSubrange(range, with: "[\(url)](\(Markdown.withScheme(url)))")
+        }
+        // TODO: escape unintentional markdown
+        return Markdown.parseMarkdown(content: output)
+    }
+}

damus/Views/ProfileView.swift

@@ -143,7 +143,9 @@ struct ProfileView: View {
                 }
         }
     }
-    
+
+    static let markdownHelper = Markdown()
+
     var DMButton: some View {
         let dm_model = damus_state.dms.lookup_or_create(profile.pubkey)
         let dmview = DMChatView(damus_state: damus_state, pubkey: profile.pubkey)
@@ -179,7 +181,6 @@ struct ProfileView: View {
                 
                 DMButton
                 
-                
                 if profile.pubkey != damus_state.pubkey {
                     FollowButtonView(
                         target: profile.get_follow_target(),
@@ -196,7 +197,7 @@ struct ProfileView: View {
             ProfileNameView(pubkey: profile.pubkey, profile: data, contacts: damus_state.contacts)
                 .padding(.bottom)
             
-            Text(data?.about ?? "")
+            Text(ProfileView.markdownHelper.process(data?.about ?? ""))
                 .font(.subheadline)
         
             Divider()

damusTests/MarkdownTests.swift

@@ -0,0 +1,43 @@
+//
+//  MarkdownTests.swift
+//  damusTests
+//
+//  Created by Lionello Lunesu on 2022-12-28.
+//
+
+import XCTest
+@testable import damus
+
+class MarkdownTests: XCTestCase {
+    let md_opts: AttributedString.MarkdownParsingOptions =
+        .init(interpretedSyntax: .inlineOnlyPreservingWhitespace)
+
+    override func setUpWithError() throws {
+        // Put setup code here. This method is called before the invocation of each test method in the class.
+    }
+
+    override func tearDownWithError() throws {
+        // Put teardown code here. This method is called after the invocation of each test method in the class.
+    }
+
+    func test_convert_link() throws {
+        let helper = Markdown()
+        let md = helper.process("prologue https://nostr.build epilogue")
+        let expected = try AttributedString(markdown: "prologue [https://nostr.build](https://nostr.build) epilogue", options: md_opts)
+        XCTAssertEqual(md, expected)
+    }
+
+    func test_convert_link_no_scheme() throws {
+        let helper = Markdown()
+        let md = helper.process("prologue damus.io epilogue")
+        let expected = try AttributedString(markdown: "prologue [damus.io](https://damus.io) epilogue", options: md_opts)
+        XCTAssertEqual(md, expected)
+    }
+
+    func test_convert_links() throws {
+        let helper = Markdown()
+        let md = helper.process("prologue damus.io https://nostr.build epilogue")
+        let expected = try AttributedString(markdown: "prologue [damus.io](https://damus.io) [https://nostr.build](https://nostr.build) epilogue", options: md_opts)
+        XCTAssertEqual(md, expected)
+    }
+}