Fix for line breaks (#2224)

ElementX/Sources/Other/Extensions/String.swift

@@ -87,3 +87,27 @@ extension String {
         return "\(prefix(length))…"
     }
 }
+
+extension String {
+    func replacingHtmlBreaksOccurrences() -> String {
+        var result = self
+        let pattern = #"</p>(\n+)<p>"#
+        
+        guard let regex = try? NSRegularExpression(pattern: pattern, options: []) else {
+            return result
+        }
+        let matches = regex.matches(in: self, options: [], range: NSRange(location: 0, length: utf16.count))
+        
+        for match in matches.reversed() {
+            guard let range = Range(match.range, in: self),
+                  let innerMatchRange = Range(match.range(at: 1), in: self) else {
+                continue
+            }
+            let numberOfBreaks = (self[innerMatchRange].components(separatedBy: "\n").count - 1)
+            let replacement = "<br>" + String(repeating: "<br>", count: numberOfBreaks)
+            result.replaceSubrange(range, with: replacement)
+        }
+        
+        return result
+    }
+}

ElementX/Sources/Other/HTMLParsing/AttributedStringBuilder.swift

@@ -73,14 +73,16 @@ struct AttributedStringBuilder: AttributedStringBuilderProtocol {
     // that could happen with the default HTML renderer of NSAttributedString which is a
     // webview.
     func fromHTML(_ htmlString: String?) -> AttributedString? {
-        guard let htmlString else {
+        guard var originalHTMLString = htmlString else {
             return nil
         }
         
-        if let cached = Self.caches[cacheKey]?.value(forKey: htmlString) {
+        if let cached = Self.caches[cacheKey]?.value(forKey: originalHTMLString) {
             return cached
         }
         
+        let htmlString = originalHTMLString.replacingHtmlBreaksOccurrences()
+        
         guard let data = htmlString.data(using: .utf8) else {
             return nil
         }

ElementX/Sources/Screens/RoomScreen/View/Timeline/FormattedBodyText.swift

@@ -204,7 +204,8 @@ struct FormattedBodyText_Previews: PreviewProvider, TestablePreview {
             <code>Hello world</code>
             """,
             "<p>This is a list</p>\n<ul>\n<li>One</li>\n<li>Two</li>\n<li>And number 3</li>\n</ul>\n",
-            "<ul><li>First item</li><li>Second item</li><li>Third item</li></ul>"
+            "<ul><li>First item</li><li>Second item</li><li>Third item</li></ul>",
+            "<p>test</p>\n<p>test</p>"
         ]
         
         let attributedStringBuilder = AttributedStringBuilder(permalinkBaseURL: ServiceLocator.shared.settings.permalinkBaseURL, mentionBuilder: MentionBuilder())

UnitTests/Sources/StringTests.swift

@@ -88,4 +88,27 @@ class StringTests: XCTestCase {
     func testEllipsizeNotNeeded() {
         XCTAssertEqual("ellipsize".ellipsize(length: 15), "ellipsize")
     }
+    
+    func testReplaceBreakOccurrences() {
+        let input0 = "</p><p>"
+        let input1 = "</p>\n<p>"
+        let input2 = "</p>\n\n<p>"
+        let input3 = "</p>\n\n\n\n<p>"
+        let input4 = "<p>a</p>\n<p>b</p>"
+        let input5 = "empty"
+        
+        let expectedOutput0 = input0
+        let expectedOutput1 = "<br><br>"
+        let expectedOutput2 = "<br><br><br>"
+        let expectedOutput3 = "<br><br><br><br><br>"
+        let expectedOutput4 = "<p>a<br><br>b</p>"
+        let expectedOutput5 = input5
+        
+        XCTAssertEqual(input0.replacingHtmlBreaksOccurrences(), expectedOutput0)
+        XCTAssertEqual(input1.replacingHtmlBreaksOccurrences(), expectedOutput1)
+        XCTAssertEqual(input2.replacingHtmlBreaksOccurrences(), expectedOutput2)
+        XCTAssertEqual(input3.replacingHtmlBreaksOccurrences(), expectedOutput3)
+        XCTAssertEqual(input4.replacingHtmlBreaksOccurrences(), expectedOutput4)
+        XCTAssertEqual(input5.replacingHtmlBreaksOccurrences(), expectedOutput5)
+    }
 }