From cc10a1378542382d0b5eb85d316c57c1a53ae76f Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Tue, 28 Jun 2022 23:05:52 -0700
Subject: [PATCH] TextKit 2, baby

---
 Tusker/Views/ContentTextView.swift | 58 +++++++++++++++++++++++++-----
 1 file changed, 49 insertions(+), 9 deletions(-)

diff --git a/Tusker/Views/ContentTextView.swift b/Tusker/Views/ContentTextView.swift
index bfb6084f..8f47a1ae 100644
--- a/Tusker/Views/ContentTextView.swift
+++ b/Tusker/Views/ContentTextView.swift
@@ -195,15 +195,38 @@ class ContentTextView: LinkTextView, BaseEmojiLabel {
 
     func getLinkAtPoint(_ point: CGPoint) -> (URL, NSRange)? {
         let locationInTextContainer = CGPoint(x: point.x - textContainerInset.left, y: point.y - textContainerInset.top)
-        var partialFraction: CGFloat = 0
-        let characterIndex = layoutManager.characterIndex(for: locationInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: &partialFraction)
-        if characterIndex < textStorage.length && partialFraction < 1 {
-            var range = NSRange()
-            if let link = textStorage.attribute(.link, at: characterIndex, longestEffectiveRange: &range, in: textStorage.fullRange) as? URL {
-                return (link, range)
+        if #available(iOS 16.0, *),
+           let textLayoutManager {
+            guard let fragment = textLayoutManager.textLayoutFragment(for: point),
+               let lineFragment = fragment.textLineFragments.first(where: { lineFragment in
+                   lineFragment.typographicBounds.offsetBy(dx: fragment.layoutFragmentFrame.minX, dy: fragment.layoutFragmentFrame.minY).contains(point)
+               }) else {
+                return nil
             }
+            let charIndex = lineFragment.characterIndex(for: point)
+            
+            var range = NSRange()
+            guard let link = lineFragment.attributedString.attribute(.link, at: charIndex, longestEffectiveRange: &range, in: lineFragment.attributedString.fullRange) as? URL else {
+                return nil
+            }
+            // lineFragment.attributedString is the NSTextLayoutFragment's string, and so range is in its index space
+            // but we need to return a range in our whole attributedString's space, so convert it
+            let textLayoutFragmentStart = textLayoutManager.offset(from: textLayoutManager.documentRange.location, to: fragment.rangeInElement.location)
+            let rangeInSelf = NSRange(location: range.location + textLayoutFragmentStart, length: range.length)
+            return (link, rangeInSelf)
+        } else {
+            var partialFraction: CGFloat = 0
+            let characterIndex = layoutManager.characterIndex(for: locationInTextContainer, in: textContainer, fractionOfDistanceBetweenInsertionPoints: &partialFraction)
+            guard characterIndex < textStorage.length && partialFraction < 1 else {
+                return nil
+            }
+            
+            var range = NSRange()
+            guard let link = textStorage.attribute(.link, at: characterIndex, longestEffectiveRange: &range, in: textStorage.fullRange) as? URL else {
+                return nil
+            }
+            return (link, range)
         }
-        return nil
     }
     
     func handleLinkTapped(url: URL, text: String) {
@@ -297,8 +320,25 @@ extension ContentTextView: UIContextMenuInteractionDelegate {
         
         // Determine the line rects that the link takes up in the coordinate space of this view.
         var rects = [CGRect]()
-        layoutManager.enumerateEnclosingRects(forGlyphRange: range, withinSelectedGlyphRange: NSRange(location: NSNotFound, length: 0), in: textContainer) { (rect, stop) in
-            rects.append(rect)
+        if #available(iOS 16.0, *),
+           let textLayoutManager,
+           let contentManager = textLayoutManager.textContentManager {
+            // convert from NSRange to NSTextRange
+            // i have no idea under what circumstances any of these calls could fail
+            guard let startLoc = contentManager.location(contentManager.documentRange.location, offsetBy: range.location),
+                  let endLoc = contentManager.location(startLoc, offsetBy: range.length),
+                  let textRange = NSTextRange(location: startLoc, end: endLoc) else {
+                return nil
+            }
+            // .standard because i have no idea what the difference is
+            textLayoutManager.enumerateTextSegments(in: textRange, type: .standard, options: []) { range, rect, float, textContainer in
+                rects.append(rect)
+                return true
+            }
+        } else {
+            layoutManager.enumerateEnclosingRects(forGlyphRange: range, withinSelectedGlyphRange: NSRange(location: NSNotFound, length: 0), in: textContainer) { (rect, stop) in
+                rects.append(rect)
+            }
         }
         
         // Try to create a snapshot view of this view to disply as the preview.