From a248bdbd95c2f2c2a310c2d5de7e1394c04fbb87 Mon Sep 17 00:00:00 2001
From: Mauro <34335419+Velin92@users.noreply.github.com>
Date: Mon, 11 Dec 2023 16:43:31 +0100
Subject: [PATCH] Fix for line breaks (#2224)

---
 .../Sources/Other/Extensions/String.swift     | 24 +++++++++++++++++++
 .../HTMLParsing/AttributedStringBuilder.swift |  6 +++--
 .../View/Timeline/FormattedBodyText.swift     |  3 ++-
 UnitTests/Sources/StringTests.swift           | 23 ++++++++++++++++++
 .../PreviewTests/test_formattedBodyText.1.png |  4 ++--
 5 files changed, 55 insertions(+), 5 deletions(-)

diff --git a/ElementX/Sources/Other/Extensions/String.swift b/ElementX/Sources/Other/Extensions/String.swift
index d319ab666..10aa796d9 100644
--- a/ElementX/Sources/Other/Extensions/String.swift
+++ b/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
+    }
+}
diff --git a/ElementX/Sources/Other/HTMLParsing/AttributedStringBuilder.swift b/ElementX/Sources/Other/HTMLParsing/AttributedStringBuilder.swift
index 07192873b..943e1b364 100644
--- a/ElementX/Sources/Other/HTMLParsing/AttributedStringBuilder.swift
+++ b/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
         }
diff --git a/ElementX/Sources/Screens/RoomScreen/View/Timeline/FormattedBodyText.swift b/ElementX/Sources/Screens/RoomScreen/View/Timeline/FormattedBodyText.swift
index a1a48c99e..3464362cd 100644
--- a/ElementX/Sources/Screens/RoomScreen/View/Timeline/FormattedBodyText.swift
+++ b/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())
diff --git a/UnitTests/Sources/StringTests.swift b/UnitTests/Sources/StringTests.swift
index 809f21b1b..b6920fa51 100644
--- a/UnitTests/Sources/StringTests.swift
+++ b/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)
+    }
 }
diff --git a/UnitTests/__Snapshots__/PreviewTests/test_formattedBodyText.1.png b/UnitTests/__Snapshots__/PreviewTests/test_formattedBodyText.1.png
index 4a37acb24..3ca67e193 100644
--- a/UnitTests/__Snapshots__/PreviewTests/test_formattedBodyText.1.png
+++ b/UnitTests/__Snapshots__/PreviewTests/test_formattedBodyText.1.png
@@ -1,3 +1,3 @@
 version https://git-lfs.github.com/spec/v1
-oid sha256:8388baf6d6dff565d85ce4e75053f465a923e3e3216649e860f8103fe2bf2293
-size 212392
+oid sha256:afb864a0a68877a81dc46f01add0830bb6de243de11c70181624bd48b3886916
+size 212427