refactor(comments): convert internal representation to a tree

common/src/main/kotlin/dev/msfjarvis/claw/common/comments/CommentEntry.kt

@@ -26,10 +26,8 @@ import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
-import androidx.compose.runtime.mutableStateOf
 import androidx.compose.runtime.produceState
 import androidx.compose.runtime.remember
-import androidx.compose.runtime.setValue
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.platform.LocalUriHandler
 import androidx.compose.ui.text.AnnotatedString
@@ -43,7 +41,6 @@ import dev.msfjarvis.claw.common.posts.TagRow
 import dev.msfjarvis.claw.common.res.ClawIcons
 import dev.msfjarvis.claw.common.ui.NetworkImage
 import dev.msfjarvis.claw.common.ui.ThemedRichText
-import dev.msfjarvis.claw.model.Comment
 import dev.msfjarvis.claw.model.LinkMetadata
 import dev.msfjarvis.claw.model.LobstersPostDetails
 import java.time.Instant
@@ -134,17 +131,18 @@ private val CommentEntryPadding = 16f.dp
 @OptIn(ExperimentalAnimationApi::class)
 @Composable
 fun CommentEntry(
-  comment: Comment,
+  commentNode: CommentNode,
   htmlConverter: HTMLConverter,
+  toggleExpanded: (CommentNode) -> Unit,
   modifier: Modifier = Modifier,
 ) {
-  var expanded by remember(comment) { mutableStateOf(true) }
   val uriHandler = LocalUriHandler.current
+  val comment = commentNode.comment
   Box(
     modifier =
       modifier
         .fillMaxWidth()
-        .clickable { expanded = !expanded }
+        .clickable { toggleExpanded(commentNode) }
         .background(MaterialTheme.colorScheme.background)
         .padding(
           start = CommentEntryPadding * comment.indentLevel,
@@ -167,7 +165,7 @@ fun CommentEntry(
         modifier =
           Modifier.clickable { uriHandler.openUri("https://lobste.rs/u/${comment.user.username}") },
       )
-      AnimatedContent(targetState = expanded) { expandedState ->
+      AnimatedContent(targetState = commentNode.isExpanded) { expandedState ->
         if (expandedState) {
           ThemedRichText(
             text = htmlConverter.convertHTMLToMarkdown(comment.comment),

common/src/main/kotlin/dev/msfjarvis/claw/common/comments/CommentNode.kt

@@ -0,0 +1,66 @@
+/*
+ * Copyright © 2022 Harsh Shandilya.
+ * Use of this source code is governed by an MIT-style
+ * license that can be found in the LICENSE file or at
+ * https://opensource.org/licenses/MIT.
+ */
+package dev.msfjarvis.claw.common.comments
+
+import androidx.compose.material3.Divider
+import androidx.compose.runtime.Composable
+import dev.msfjarvis.claw.model.Comment
+
+data class CommentNode(
+  val comment: Comment,
+  var parent: CommentNode? = null,
+  val children: MutableList<CommentNode> = mutableListOf(),
+  var isExpanded: Boolean = true
+) {
+  fun addChild(child: CommentNode) {
+    if (comment.indentLevel + 1 == child.comment.indentLevel) {
+      children.add(child)
+      child.parent = this
+    } else {
+      children.last().addChild(child)
+    }
+  }
+}
+
+fun createListNode(comments: List<Comment>): MutableList<CommentNode> {
+  val commentNodes = mutableListOf<CommentNode>()
+
+  for (i in comments.indices) {
+    if (comments[i].indentLevel == 1) {
+      commentNodes.add(CommentNode(comment = comments[i]))
+    } else {
+      commentNodes.last().addChild(CommentNode(comment = comments[i]))
+    }
+  }
+
+  return commentNodes
+}
+
+@Composable
+fun DisplayListNode(
+  comments: List<CommentNode>,
+  htmlConverter: HTMLConverter,
+  updateComments: (CommentNode) -> Unit,
+) {
+  comments.forEach {
+    CommentEntry(commentNode = it, htmlConverter = htmlConverter, updateComments)
+    Divider()
+
+    if (it.children.isNotEmpty()) {
+      DisplayListNode(comments = it.children, htmlConverter = htmlConverter, updateComments)
+    }
+  }
+}
+
+fun toggleAllExpanded(commentNode: CommentNode): CommentNode {
+  commentNode.isExpanded = !commentNode.isExpanded
+
+  if (commentNode.children.isNotEmpty()) {
+    commentNode.children.forEach { toggleAllExpanded(it) }
+  }
+  return commentNode
+}

common/src/main/kotlin/dev/msfjarvis/claw/common/comments/Comments.kt

@@ -11,14 +11,13 @@ import androidx.compose.foundation.layout.fillMaxSize
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.padding
 import androidx.compose.foundation.lazy.LazyColumn
-import androidx.compose.foundation.lazy.itemsIndexed
-import androidx.compose.material3.Divider
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.Surface
 import androidx.compose.material3.Text
 import androidx.compose.runtime.Composable
 import androidx.compose.runtime.getValue
 import androidx.compose.runtime.produceState
+import androidx.compose.runtime.toMutableStateList
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.text.font.FontWeight
 import androidx.compose.ui.text.style.TextAlign
@@ -39,6 +38,8 @@ private fun CommentsPageInternal(
   htmlConverter: HTMLConverter,
   modifier: Modifier = Modifier,
 ) {
+  val commentNodes = createListNode(details.comments).toMutableStateList()
+
   Surface(color = MaterialTheme.colorScheme.surfaceVariant) {
     LazyColumn(modifier = modifier, contentPadding = PaddingValues(bottom = 24.dp)) {
       item {
@@ -49,7 +50,7 @@ private fun CommentsPageInternal(
         )
       }
 
-      if (details.comments.isNotEmpty()) {
+      if (commentNodes.isNotEmpty()) {
         item {
           Text(
             text = "Comments",
@@ -58,11 +59,18 @@ private fun CommentsPageInternal(
           )
         }
 
-        itemsIndexed(details.comments) { index, item ->
-          if (index != 0) {
-            Divider()
+        item {
+          DisplayListNode(comments = commentNodes, htmlConverter = htmlConverter) { node ->
+            val newNode = toggleAllExpanded(node)
+            val index =
+              commentNodes.indexOf(commentNodes.find { it.comment.url == node.comment.url })
+            if (index == -1) {
+              error("Failed to find node for comment: ${node.comment}")
+            } else {
+              commentNodes.removeAt(index)
+              commentNodes.add(index, newNode)
+            }
           }
-          CommentEntry(comment = item, htmlConverter = htmlConverter)
         }
       } else {
         item {