From 807eed1c8cc069d00217f78fb815351f84ff3839 Mon Sep 17 00:00:00 2001
From: Charlie Scheer <charlie.scheer@automattic.com>
Date: Fri, 20 Dec 2024 12:29:13 -1000
Subject: [PATCH] Format text with TextKit2 content storage methods

---
 Simplenote/SPTextView.swift | 75 +++++++++++++++++++++++++++++++------
 1 file changed, 64 insertions(+), 11 deletions(-)

diff --git a/Simplenote/SPTextView.swift b/Simplenote/SPTextView.swift
index 86101ee0f..a34315b24 100644
--- a/Simplenote/SPTextView.swift
+++ b/Simplenote/SPTextView.swift
@@ -7,17 +7,6 @@
 //
 
 extension SPTextView {
-    /*
-     SPInteractiveTextStorage *textStorage = [[SPInteractiveTextStorage alloc] init];
-     NSLayoutManager *layoutManager = [[NSLayoutManager alloc] init];
-
-     NSTextContainer *container = [[NSTextContainer alloc] initWithSize:CGSizeMake(0, CGFLOAT_MAX)];
-     container.widthTracksTextView = YES;
-     container.heightTracksTextView = YES;
-     [layoutManager addTextContainer:container];
-     [textStorage addLayoutManager:layoutManager];
-     */
-
     @objc
     func setupTextContainer(with textStorage: SPInteractiveTextStorage) -> NSTextContainer {
         let container = NSTextContainer(size: .zero)
@@ -28,6 +17,7 @@ extension SPTextView {
         if #available(iOS 16.0, *) {
             let textLayoutManager = NSTextLayoutManager()
             let contentStorage = NSTextContentStorage()
+            contentStorage.delegate = self
             contentStorage.addTextLayoutManager(textLayoutManager)
             textLayoutManager.textContainer = container
 
@@ -39,3 +29,66 @@ extension SPTextView {
         return container
     }
 }
+
+// MARK: NSTextContentStorageDelegate
+//
+extension SPTextView: NSTextContentStorageDelegate {
+    public func textContentStorage(_ textContentStorage: NSTextContentStorage, textParagraphWith range: NSRange) -> NSTextParagraph? {
+        guard let originalText = textContentStorage.textStorage?.attributedSubstring(from: range) as? NSMutableAttributedString else {
+            return nil
+        }
+
+        let style = textInRangeIsHeader(range) ? headlineStyle : defaultStyle
+        originalText.addAttributes(style, range: originalText.fullRange)
+
+        return NSTextParagraph(attributedString: originalText)
+    }
+
+    func textInRangeIsHeader(_ range: NSRange) -> Bool {
+        range.location == .zero
+    }
+
+    // MARK: Styles
+    //
+    var headlineFont: UIFont {
+        UIFont.preferredFont(for: .title1, weight: .bold)
+    }
+
+    var defaultFont: UIFont {
+        UIFont.preferredFont(forTextStyle: .body)
+    }
+
+    var defaultTextColor: UIColor {
+        UIColor.simplenoteNoteHeadlineColor
+    }
+
+    var lineSpacing: CGFloat {
+        defaultFont.lineHeight * Metrics.lineSpacingMultipler
+    }
+
+    var defaultStyle: [NSAttributedString.Key: Any] {
+        [
+            .font: defaultFont,
+            .foregroundColor: defaultTextColor,
+            .paragraphStyle: NSMutableParagraphStyle(lineSpacing: lineSpacing)
+        ]
+    }
+
+    var headlineStyle: [NSAttributedString.Key: Any] {
+        [
+            .font: headlineFont,
+            .foregroundColor: defaultTextColor,
+        ]
+    }
+}
+
+// MARK: - Metrics
+//
+private enum Metrics {
+    static let lineSpacingMultiplerPad: CGFloat = 0.40
+    static let lineSpacingMultiplerPhone: CGFloat = 0.20
+
+    static var lineSpacingMultipler: CGFloat {
+        UIDevice.isPad ? lineSpacingMultiplerPad : lineSpacingMultiplerPhone
+    }
+}