fix(android): keep a code block's box inside a list item

packages/enriched-markdown-android/ui/src/main/java/com/swmansion/enriched/markdown/accessibility/MarkdownAccessibilityHelper.kt

@@ -571,6 +571,9 @@ class MarkdownAccessibilityHelper(
         .maxByOrNull { it.depth } ?: return null
 
     if (requireStart) {
+      // An item split around a code block starts only where its marker is drawn: the segments after
+      // the code block continue it.
+      if (!deepest.drawsMarker) return null
       val spanStart = spanned.getSpanStart(deepest)
       val firstChar =
         (spanStart until minOf(spanStart + 10, spanned.length))

packages/enriched-markdown-android/ui/src/main/java/com/swmansion/enriched/markdown/renderer/BlockStyleContext.kt

@@ -46,6 +46,7 @@ class BlockStyleContext {
   var listItemMarkerExtra = 0f
   var listItemMarkerWidth: Float? = null
   var taskItemCount = 0
+  var accumulatedIndent = 0
 
   private val orderedListItemNumbers = ArrayDeque<Int>()
 
@@ -158,6 +159,7 @@ class BlockStyleContext {
     listItemMarkerExtra = 0f
     listItemMarkerWidth = null
     taskItemCount = 0
+    accumulatedIndent = 0
     orderedListItemNumbers.clear()
   }
 }

packages/enriched-markdown-android/ui/src/main/java/com/swmansion/enriched/markdown/renderer/BlockquoteRenderer.kt

@@ -28,6 +28,10 @@ class BlockquoteRenderer(
     onLinkLongPress: ((String) -> Unit)?,
     factory: RendererFactory,
   ) {
+    if (builder.isNotEmpty() && builder.last() != '\n') {
+      builder.append("\n")
+    }
+
     val start = builder.length
     val style = config.style.blockquoteStyle
     val context = factory.blockStyleContext

packages/enriched-markdown-android/ui/src/main/java/com/swmansion/enriched/markdown/renderer/CodeBlockRenderer.kt

@@ -25,6 +25,10 @@ class CodeBlockRenderer(
     onLinkLongPress: ((String) -> Unit)?,
     factory: RendererFactory,
   ) {
+    if (builder.isNotEmpty() && builder.last() != '\n') {
+      builder.append("\n")
+    }
+
     val start = builder.length
     val style = config.style.codeBlockStyle
     val context = factory.blockStyleContext
@@ -49,7 +53,7 @@ class CodeBlockRenderer(
 
     // Apply background, borders, and horizontal padding to content only
     builder.setSpan(
-      CodeBlockSpan(style, factory.context, factory.styleCache),
+      CodeBlockSpan(style, factory.context, factory.styleCache, context.accumulatedIndent),
       contentStart,
       end,
       SPAN_FLAGS_EXCLUSIVE_EXCLUSIVE,

packages/enriched-markdown-android/ui/src/main/java/com/swmansion/enriched/markdown/renderer/HeadingRenderer.kt

@@ -21,6 +21,10 @@ class HeadingRenderer(
     onLinkLongPress: ((String) -> Unit)?,
     factory: RendererFactory,
   ) {
+    if (builder.isNotEmpty() && builder.last() != '\n') {
+      builder.append("\n")
+    }
+
     val level = node.getAttribute("level")?.toIntOrNull() ?: 1
     val start = builder.length
 

packages/enriched-markdown-android/ui/src/main/java/com/swmansion/enriched/markdown/renderer/ListItemRenderer.kt

@@ -39,7 +39,8 @@ class ListItemRenderer(
 
     val depth = styleContext.listDepth - 1
     val listStyle = config.style.listStyle
-    val span =
+
+    fun makeSpan(drawsMarker: Boolean): BaseListSpan =
       if (isTask) {
         TaskListSpan(
           taskStyle = config.style.taskListStyle,
@@ -49,6 +50,7 @@ class ListItemRenderer(
           styleCache = factory.styleCache,
           taskIndex = taskIndex,
           isChecked = isChecked,
+          drawsMarker = drawsMarker,
           ancestorMarkerOffset = styleContext.ancestorMarkerOffset,
           markerExtraWidth = styleContext.listMarkerExtra,
           parentMarkerWidth = styleContext.listItemMarkerWidth,
@@ -61,6 +63,7 @@ class ListItemRenderer(
               depth,
               factory.context,
               factory.styleCache,
+              drawsMarker,
               ancestorMarkerOffset = styleContext.ancestorMarkerOffset,
               parentMarkerWidth = styleContext.listItemMarkerWidth,
             )
@@ -72,6 +75,7 @@ class ListItemRenderer(
               depth,
               factory.context,
               factory.styleCache,
+              drawsMarker,
               markerExtraWidth = styleContext.listMarkerExtra,
               ancestorMarkerOffset = styleContext.ancestorMarkerOffset,
               parentMarkerWidth = styleContext.listItemMarkerWidth,
@@ -82,27 +86,66 @@ class ListItemRenderer(
         }
       }
 
+    val markerSpan = makeSpan(drawsMarker = true)
+
     // Nested lists inside this item shift by its extra marker width and measure their indent from its column.
+    // Code blocks inside it start at its text column, since the item's spans leave their lines (see below).
     val previousMarkerExtra = styleContext.listItemMarkerExtra
-    styleContext.listItemMarkerExtra = span.markerExtraWidth
+    styleContext.listItemMarkerExtra = markerSpan.markerExtraWidth
     val previousMarkerWidth = styleContext.listItemMarkerWidth
-    styleContext.listItemMarkerWidth = span.baselineMarkerWidth
+    styleContext.listItemMarkerWidth = markerSpan.baselineMarkerWidth
+    val previousIndent = styleContext.accumulatedIndent
+    styleContext.accumulatedIndent = previousIndent + markerSpan.getLeadingMargin(false)
     try {
       factory.renderChildren(node, builder, onLinkPress, onLinkLongPress)
     } finally {
+      styleContext.accumulatedIndent = previousIndent
       styleContext.listItemMarkerExtra = previousMarkerExtra
       styleContext.listItemMarkerWidth = previousMarkerWidth
     }
 
     if (builder.length == start || builder.substring(start).isBlank()) return
 
-    while (builder.length > start && builder.last() == '\n') {
-      builder.delete(builder.length - 1, builder.length)
+    if (builder.last() != '\n') {
+      builder.append("\n")
     }
-    builder.append("\n")
 
     val itemEnd = builder.length
-    builder.setSpan(span, start, itemEnd, SPAN_FLAGS_LIST_ITEM)
+
+    val codeBlocks = builder.getSpans(start, itemEnd, CodeBlockSpan::class.java)
+    // Nested items render first, so a code block keeps the innermost item that holds it.
+    for (block in codeBlocks) {
+      if (block.listItem == null) block.listItem = markerSpan
+    }
+
+    val codeBlockRanges =
+      codeBlocks
+        .map { builder.getSpanStart(it) to builder.getSpanEnd(it) }
+        .filter { it.first < it.second }
+        .sortedBy { it.first }
+
+    var segmentStart = start
+    var isFirstSegment = true
+    for ((codeStart, codeEnd) in codeBlockRanges) {
+      if (segmentStart < codeStart) {
+        builder.setSpan(
+          if (isFirstSegment) markerSpan else makeSpan(drawsMarker = false),
+          segmentStart,
+          codeStart,
+          SPAN_FLAGS_LIST_ITEM,
+        )
+        isFirstSegment = false
+      }
+      segmentStart = maxOf(segmentStart, codeEnd)
+    }
+    if (segmentStart < itemEnd) {
+      builder.setSpan(
+        if (isFirstSegment) markerSpan else makeSpan(drawsMarker = false),
+        segmentStart,
+        itemEnd,
+        SPAN_FLAGS_LIST_ITEM,
+      )
+    }
 
     if (isChecked) {
       applyCheckedDecorations(builder, start, itemEnd, depth)

packages/enriched-markdown-android/ui/src/main/java/com/swmansion/enriched/markdown/spans/BaseListSpan.kt

@@ -22,6 +22,7 @@ abstract class BaseListSpan(
   protected val blockStyle: BlockStyle,
   protected val marginLeft: Float,
   protected val gapWidth: Float,
+  internal val drawsMarker: Boolean = true,
   internal val ancestorMarkerOffset: Float = 0f,
   internal val parentMarkerWidth: Float? = null,
 ) : MetricAffectingSpan(),
@@ -76,6 +77,7 @@ abstract class BaseListSpan(
     first: Boolean,
     layout: Layout?,
   ) {
+    if (!drawsMarker) return
     if (!first || shouldSkipDrawing(text, start) || !hasContent(text, start, end)) return
 
     // Only draw the marker on the true first line of this span.

packages/enriched-markdown-android/ui/src/main/java/com/swmansion/enriched/markdown/spans/CodeBlockSpan.kt

@@ -22,9 +22,13 @@ class CodeBlockSpan(
   private val codeBlockStyle: CodeBlockStyle,
   private val context: Context,
   private val styleCache: SpanStyleCache,
+  private val leadingIndent: Int = 0,
 ) : MetricAffectingSpan(),
   LineBackgroundSpan,
   LeadingMarginSpan {
+  /** The innermost list item holding this block, whose marker span this is; copy-as-markdown nests the block under it. */
+  internal var listItem: BaseListSpan? = null
+
   private val blockStyle =
     BlockStyle(
       fontSize = codeBlockStyle.fontSize,
@@ -59,7 +63,7 @@ class CodeBlockSpan(
       color = codeBlockStyle.borderColor
     }
 
-  override fun getLeadingMargin(first: Boolean): Int = codeBlockStyle.padding.toInt()
+  override fun getLeadingMargin(first: Boolean): Int = codeBlockStyle.padding.toInt() + leadingIndent
 
   override fun drawLeadingMargin(
     c: Canvas?,
@@ -105,11 +109,12 @@ class CodeBlockSpan(
     val inset = codeBlockStyle.borderWidth / 2f
 
     rect.set(
-      left.toFloat() + inset,
+      left.toFloat() + leadingIndent + inset,
       top.toFloat() + (if (isFirstLine) inset else 0f),
       right.toFloat() - inset,
       bottom.toFloat() - (if (isLastLine) inset else 0f),
     )
+    if (rect.left >= rect.right) return
 
     val radius = codeBlockStyle.borderRadius
     val adjRadius = if (radius > inset) radius - inset else radius

packages/enriched-markdown-android/ui/src/main/java/com/swmansion/enriched/markdown/spans/OrderedListSpan.kt

@@ -17,6 +17,7 @@ class OrderedListSpan(
   depth: Int,
   context: Context,
   styleCache: SpanStyleCache,
+  drawsMarker: Boolean = true,
   override val markerExtraWidth: Float = 0f,
   ancestorMarkerOffset: Float = 0f,
   parentMarkerWidth: Float? = null,
@@ -33,6 +34,7 @@ class OrderedListSpan(
       ),
     marginLeft = listStyle.marginLeft,
     gapWidth = listStyle.gapWidth,
+    drawsMarker = drawsMarker,
     ancestorMarkerOffset = ancestorMarkerOffset,
     parentMarkerWidth = parentMarkerWidth,
   ) {

packages/enriched-markdown-android/ui/src/main/java/com/swmansion/enriched/markdown/spans/TaskListSpan.kt

@@ -26,6 +26,7 @@ class TaskListSpan(
    * moves it to the end of that order and shifts where its marker lands.
    */
   var isChecked: Boolean,
+  drawsMarker: Boolean = true,
   ancestorMarkerOffset: Float = 0f,
   override val markerExtraWidth: Float = 0f,
   parentMarkerWidth: Float? = null,
@@ -42,6 +43,7 @@ class TaskListSpan(
       ),
     marginLeft = listStyle.marginLeft,
     gapWidth = listStyle.gapWidth,
+    drawsMarker = drawsMarker,
     ancestorMarkerOffset = ancestorMarkerOffset,
     parentMarkerWidth = parentMarkerWidth,
   ) {

packages/enriched-markdown-android/ui/src/main/java/com/swmansion/enriched/markdown/spans/UnorderedListSpan.kt

@@ -13,6 +13,7 @@ class UnorderedListSpan(
   depth: Int,
   context: Context,
   styleCache: SpanStyleCache,
+  drawsMarker: Boolean = true,
   ancestorMarkerOffset: Float = 0f,
   parentMarkerWidth: Float? = null,
 ) : BaseListSpan(
@@ -28,6 +29,7 @@ class UnorderedListSpan(
       ),
     marginLeft = listStyle.marginLeft,
     gapWidth = listStyle.gapWidth,
+    drawsMarker = drawsMarker,
     ancestorMarkerOffset = ancestorMarkerOffset,
     parentMarkerWidth = parentMarkerWidth,
   ) {

packages/enriched-markdown-android/ui/src/main/java/com/swmansion/enriched/markdown/utils/text/conversion/HTMLGenerator.kt

@@ -21,6 +21,7 @@ import com.swmansion.enriched.markdown.spans.HeadingSpan
 import com.swmansion.enriched.markdown.spans.HighlightSpan
 import com.swmansion.enriched.markdown.spans.ImageSpan
 import com.swmansion.enriched.markdown.spans.LinkSpan
+import com.swmansion.enriched.markdown.spans.MarginBottomSpan
 import com.swmansion.enriched.markdown.spans.OrderedListSpan
 import com.swmansion.enriched.markdown.spans.StrongSpan
 import com.swmansion.enriched.markdown.spans.TaskListSpan
@@ -334,6 +335,9 @@ object HTMLGenerator {
       return
     }
 
+    // A block's bottom-margin line inside a list item or a quote holds no content of its own.
+    if (paraText.isEmpty() && text.getSpans(para.start, para.start + 1, MarginBottomSpan::class.java).isNotEmpty()) return
+
     // Get content range (trim trailing newline)
     val contentEnd = if (para.end > para.start && text[para.end - 1] == '\n') para.end - 1 else para.end
     val isCodeBlock = para.type == TYPE_CODE_BLOCK

packages/enriched-markdown-android/ui/src/main/java/com/swmansion/enriched/markdown/utils/text/conversion/MarkdownExtractor.kt

@@ -171,7 +171,8 @@ object MarkdownExtractor {
 
     val codeBlockSpans = spannable.getSpans(segmentStart, segmentEnd, CodeBlockSpan::class.java)
     if (codeBlockSpans.isNotEmpty()) {
-      appendCodeBlock(segmentText, result, state)
+      val opensBlock = codeBlockSpans.any { spannable.getSpanStart(it) == segmentStart }
+      appendCodeBlock(spannable, codeBlockSpans[0], segmentText, opensBlock, result, state)
       return true
     }
 
@@ -291,7 +292,10 @@ object MarkdownExtractor {
   }
 
   private fun appendCodeBlock(
+    spannable: Spannable,
+    block: CodeBlockSpan,
     text: String,
+    opensBlock: Boolean,
     result: StringBuilder,
     state: ExtractionState,
   ) {
@@ -300,14 +304,42 @@ object MarkdownExtractor {
       state.needsBlankLine = false
     }
 
-    val needsFence = result.isEmpty() || result.endsWith("\n\n")
-    if (needsFence) result.append("```\n")
+    // A code block inside a list item lines up under the item's text.
+    val item = block.listItem
+
+    // When the block opens its item, the item's marker span is not attached at all or sits after the block.
+    val itemStart = item?.let { spannable.getSpanStart(it) } ?: -1
+    val markerSpanDetached = itemStart < 0
+    val markerSpanAfterBlock = itemStart >= spannable.getSpanEnd(block)
+    val blockOpensItem = item != null && (markerSpanDetached || markerSpanAfterBlock)
+
+    // The fence takes the item's marker only when the selection includes the block's first line.
+    val opensItem = opensBlock && blockOpensItem
+    val nestedItem = item?.takeIf { opensItem || result.isNotEmpty() }
+    val indent = nestedItem?.let { contentIndent(it) } ?: ""
+    if (nestedItem != null) state.listDepth = nestedItem.depth
+
+    val needsFence = result.isEmpty() || result.endsWith("\n\n") || opensBlock
+    if (needsFence) {
+      if (!result.isAtLineStart()) result.append("\n")
+      if (opensItem) {
+        result.append(listMarker(item))
+        state.itemOpenedByCode = item
+      } else {
+        result.append(indent)
+      }
+      result.append("```\n")
+    }
 
-    result.append(text)
+    text.split('\n').forEachIndexed { index, line ->
+      if (index > 0) result.append('\n')
+      if (line.isNotEmpty() && result.isAtLineStart()) result.append(indent)
+      result.append(line)
+    }
 
     if (text.endsWith("\n")) {
-      result.append("```\n")
-      state.needsBlankLine = true
+      result.append(indent).append("```\n")
+      state.needsBlankLine = nestedItem == null
     }
   }
 
@@ -346,6 +378,13 @@ object MarkdownExtractor {
     }
 
     state.listDepth = listSpan.depth
+
+    // Text after a code block continues its item rather than starting a new one.
+    val continuesItem = !listSpan.drawsMarker || listSpan === state.itemOpenedByCode
+    return if (continuesItem) contentIndent(listSpan) else listMarker(listSpan)
+  }
+
+  private fun listMarker(listSpan: BaseListSpan): String {
     val indent = "  ".repeat(listSpan.depth)
 
     return when (listSpan) {
@@ -355,6 +394,12 @@ object MarkdownExtractor {
     }
   }
 
+  /** The column an item's text starts at; a task item's checkbox is part of its text. */
+  private fun contentIndent(listSpan: BaseListSpan): String {
+    val markerWidth = if (listSpan is OrderedListSpan) "${listSpan.itemNumber}. ".length else 2
+    return " ".repeat(2 * listSpan.depth + markerWidth)
+  }
+
   private fun applyInlineFormatting(
     spannable: Spannable,
     text: String,
@@ -424,6 +469,7 @@ object MarkdownExtractor {
     var blockquoteDepth: Int = -1,
     var listDepth: Int = -1,
     var needsBlankLine: Boolean = false,
+    var itemOpenedByCode: BaseListSpan? = null,
   )
 
   private class HeadingAccumulator {