From 5fbf806e7328dd07f0928c2009e100809d3533cd Mon Sep 17 00:00:00 2001
From: Shadowfacts <me@shadowfacts.net>
Date: Wed, 22 May 2024 17:48:29 -0400
Subject: [PATCH] Handle break tags at the beginning of paragraphs

---
 BlockState.dot                                  |  3 ++-
 Sources/HTMLStreamer/BlockState.swift           | 13 +++++++++++--
 .../AttributedStringConverterTests.swift        | 17 +++++++++++++++++
 3 files changed, 30 insertions(+), 3 deletions(-)

diff --git a/BlockState.dot b/BlockState.dot
index 245bdc1..72283f1 100644
--- a/BlockState.dot
+++ b/BlockState.dot
@@ -35,7 +35,8 @@ digraph blockstate  {
 	nonEmptyBlock -> beginListItem [label = "<li>"];
 	nonEmptyBlock -> endListItem [label = "</li>"];
 	emptyBlock -> nonEmptyBlock [label = "non-whitespace (block break)"];
-	emptyBlock -> emptyBlock [label = "whitespace (skip)\n<br>\n</pre>\nstart/end block"];
+	emptyBlock -> emptyBlock [label = "whitespace (skip)\n</pre>\nstart/end block"];
+	emptyBlock -> lineBreakTag [label = "<br> (append to tmp, block break)"];
 	emptyBlock -> afterPreStartTag [label = "<pre> (depth = 1)"];
 	emptyBlock -> beginListItem [label = "<li>"];
 	emptyBlock -> endListItem [label = "</li>"];
diff --git a/Sources/HTMLStreamer/BlockState.swift b/Sources/HTMLStreamer/BlockState.swift
index 3c5a46c..39491e6 100644
--- a/Sources/HTMLStreamer/BlockState.swift
+++ b/Sources/HTMLStreamer/BlockState.swift
@@ -19,7 +19,11 @@ import Foundation
  */
 
 struct BlockStateMachine {
-    var blockState: BlockState = .start
+    var blockState: BlockState = .start {
+        didSet {
+            print("new state: \(blockState)")
+        }
+    }
     let blockBreak: String
     let lineBreak: String
     let listIndentForContentOutsideItem: String
@@ -30,6 +34,7 @@ struct BlockStateMachine {
 
 extension BlockStateMachine {
     mutating func startOrEndBlock() {
+        print("start/end block")
         switch blockState {
         case .start:
             break
@@ -78,6 +83,7 @@ extension BlockStateMachine {
     }
     
     mutating func continueBlock(char: UnicodeScalar) -> Bool {
+        print("continue block: \(char.debugDescription)")
         let isNewline = char == "\n"
         let isWhitespace = isNewline || isWhitespace(char)
         switch blockState {
@@ -292,11 +298,14 @@ extension BlockStateMachine {
     }
     
     mutating func breakTag() {
+        print("break tag")
         switch blockState {
         case .start:
             break
         case .emptyBlock:
-            append(lineBreak)
+            blockState = .lineBreakTag
+            append(blockBreak)
+            temporaryBuffer.append(lineBreak)
         case .nonEmptyBlock:
             blockState = .lineBreakTag
             temporaryBuffer.append(lineBreak)
diff --git a/Tests/HTMLStreamerTests/AttributedStringConverterTests.swift b/Tests/HTMLStreamerTests/AttributedStringConverterTests.swift
index f1e2829..b413996 100644
--- a/Tests/HTMLStreamerTests/AttributedStringConverterTests.swift
+++ b/Tests/HTMLStreamerTests/AttributedStringConverterTests.swift
@@ -662,4 +662,21 @@ final class AttributedStringConverterTests: XCTestCase {
         XCTAssertEqual(convert(html, callbacks: Replace.self), result)
     }
     
+    func testLineBreakAtBeginningOfBlockElement() {
+        let result = NSAttributedString(string: "a\n\n\n\nb", attributes: [
+            .font: font,
+            .paragraphStyle: NSParagraphStyle.default,
+            .foregroundColor: color,
+        ])
+        XCTAssertEqual(convert("<p>a</p><p><br></p><p>b</p>"), result)
+        
+        let result2 = NSAttributedString(string: "a\n\n\nb\n\nc", attributes: [
+            .font: font,
+            .paragraphStyle: NSParagraphStyle.default,
+            .foregroundColor: color,
+        ])
+        XCTAssertEqual(convert("<p>a</p><p><br>b</p><p>c</p>"), result2)
+    }
+
+    
 }