refactor(article): warm up the blocks that are actually rendered

The screen merges small parser blocks into larger render blocks,
while the warm-up measured the unmerged parser blocks. Merge once in
the view model and keep the merged blocks in the article state, so
the screen and the warm-up share exactly what will be drawn.

app/src/main/java/com/example/research/feature/search/SearchViewModel.kt

@@ -14,8 +14,9 @@ import com.example.research.data.local.preferences.PreferencesManager
 import com.example.research.data.repository.LocalDictionaryRepository
 import com.example.research.ui.article.ArticleState
 import com.example.research.ui.article.ArticleTextWarmUp
-import com.example.research.ui.article.DslBlock
 import com.example.research.ui.article.DslAnnotatedParser
+import com.example.research.ui.article.HEAVY_ARTICLE_BLOCK_COUNT
+import com.example.research.ui.article.mergeDslBlocks
 import com.example.research.R
 import kotlinx.coroutines.*
 import kotlinx.coroutines.flow.*
@@ -63,7 +64,7 @@ class SearchViewModel(
     private var indexWarmupJob: Job? = null
     private var debounceSaveQueryJob: Job? = null
 
-    private val parseCache = java.util.LinkedHashMap<String, List<DslBlock>>(PARSE_CACHE_SIZE, 0.75f, true)
+    private val parseCache = java.util.LinkedHashMap<String, ArticleState.Success>(PARSE_CACHE_SIZE, 0.75f, true)
     private val articleHistory = ArrayDeque<ArticleState.Success>()
 
     private val activeDictionaries: StateFlow<List<com.example.research.core.domain.model.Dictionary>> =
@@ -211,12 +212,7 @@ class SearchViewModel(
             val cached = synchronized(parseCache) { parseCache[cacheKey] }
             if (cached != null) {
                 mutableSelectedArticle.update {
-                    ArticleState.Success(
-                        title = entry.originalWord,
-                        dslContent = cached,
-                        dictionaryName = entry.dictionaryName,
-                        dictionaryPath = entry.dictionaryPath,
-                    )
+                    cached.copy(title = entry.originalWord, dictionaryName = entry.dictionaryName)
                 }
                 return@launch
             }
@@ -228,6 +224,13 @@ class SearchViewModel(
                             colorScheme = DslAnnotatedParser.ARTICLE_COLOR_SCHEME,
                         )
                     }
+                    val article = ArticleState.Success(
+                        title = entry.originalWord,
+                        dslContent = mergeDslBlocks(annotatedStringList),
+                        dictionaryName = entry.dictionaryName,
+                        dictionaryPath = entry.dictionaryPath,
+                        isHeavy = annotatedStringList.size > HEAVY_ARTICLE_BLOCK_COUNT,
+                    )
                     synchronized(parseCache) {
                         if (parseCache.size >= PARSE_CACHE_SIZE) {
                             val iterator = parseCache.entries.iterator()
@@ -235,19 +238,12 @@ class SearchViewModel(
                                 iterator.next().run { iterator.remove() }
                             }
                         }
-                        parseCache[cacheKey] = annotatedStringList
+                        parseCache[cacheKey] = article
                     }
                     viewModelScope.launch(Dispatchers.Default) {
-                        ArticleTextWarmUp.warmUp(getApplication(), annotatedStringList)
-                    }
-                    mutableSelectedArticle.update {
-                        ArticleState.Success(
-                            title = entry.originalWord,
-                            dslContent = annotatedStringList,
-                            dictionaryName = entry.dictionaryName,
-                            dictionaryPath = entry.dictionaryPath,
-                        )
+                        ArticleTextWarmUp.warmUp(getApplication(), article.dslContent)
                     }
+                    mutableSelectedArticle.update { article }
                 }
                 .onError { message, exception ->
                     Log.e(TAG, "loadArticle() - error: $message", exception)
@@ -324,10 +320,6 @@ class SearchViewModel(
     companion object {
         private const val TAG = "SearchViewModel"
 
-        // Parse cache: stores parsed DslBlock lists to avoid re-parsing articles
-        // Size: 50 articles - typical user navigation depth in a session
-        // Memory estimate: ~50KB per article average (text + formatting)
-        // Total: ~2.5MB worst case
         private const val PARSE_CACHE_SIZE = 50
 
         private const val KEY_SEARCH_QUERY = "search_query"

app/src/main/java/com/example/research/ui/article/ArticleScreen.kt

@@ -44,7 +44,6 @@ import androidx.compose.ui.platform.testTag
 import androidx.compose.ui.res.stringResource
 import androidx.compose.ui.semantics.semantics
 import androidx.compose.ui.semantics.testTagsAsResourceId
-import androidx.compose.ui.text.AnnotatedString
 import androidx.compose.ui.text.style.LineHeightStyle
 import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.unit.IntSize
@@ -55,54 +54,6 @@ import com.example.research.common.ui.theme.dictionaryTitleLarge
 import com.example.research.ui.theme.AppWindowInsets
 import com.example.research.ui.theme.Spacing
 
-private const val MERGED_BLOCK_MAX_CHARS = 1500
-private const val MERGED_BLOCK_MAX_ITEMS = 12
-
-private fun mergeDslBlocks(blocks: List<DslBlock>): List<DslBlock> {
-    if (blocks.size <= MERGED_BLOCK_MAX_ITEMS) return blocks
-    val merged = ArrayList<DslBlock>(blocks.size / 4)
-    var i = 0
-    while (i < blocks.size) {
-        val builder = AnnotatedString.Builder()
-        val refs = ArrayList<DslAnnotatedParser.LazyRef>()
-        var j = i
-        while (j < blocks.size) {
-            val block = blocks[j]
-            repeat(block.indent) { builder.append(' ') }
-            val paraStart = builder.length
-            builder.append(block.text)
-            block.lazyRefs.forEach { ref ->
-                refs.add(
-                    ref.copy(
-                        startIndex = ref.startIndex + paraStart,
-                        endIndex = ref.endIndex + paraStart
-                    )
-                )
-            }
-            val more = j + 1 < blocks.size &&
-                (j + 1 - i) < MERGED_BLOCK_MAX_ITEMS &&
-                builder.length < MERGED_BLOCK_MAX_CHARS
-            if (more) {
-                builder.append('\n')
-            }
-            j++
-            if (!more) {
-                break
-            }
-        }
-        merged.add(
-            DslBlock(
-                text = builder.toAnnotatedString(),
-                indent = 0,
-                lazyRefs = refs,
-                continuesPrevious = blocks[i].continuesPrevious
-            )
-        )
-        i = j
-    }
-    return merged
-}
-
 @Composable
 fun ArticleContent(
     articleState: ArticleState?,
@@ -183,8 +134,7 @@ fun ArticleContent(
                 }
             }
 
-            val isHeavyArticle =
-                articleState.dslContent.size > HEAVY_ARTICLE_BLOCK_COUNT
+            val isHeavyArticle = articleState.isHeavy
 
             val darkTheme = MaterialTheme.colorScheme.background.luminance() < 0.5f
             val displayBlocks = remember(
@@ -192,14 +142,12 @@ fun ArticleContent(
                 baseTextStyle,
                 darkTheme
             ) {
-                val merged =
-                    mergeDslBlocks(articleState.dslContent)
                 if (darkTheme) {
-                    merged.map {
+                    articleState.dslContent.map {
                         it.copy(text = DslAnnotatedParser.remapForDarkTheme(it.text))
                     }
                 } else {
-                    merged
+                    articleState.dslContent
                 }
             }
             val articleList: @Composable (Modifier) -> Unit = { listModifier ->

app/src/main/java/com/example/research/ui/article/ArticleState.kt

@@ -37,6 +37,7 @@ sealed class ArticleState {
         val dictionaryPath: String = "",
         val scrollIndex: Int = 0,
         val scrollOffset: Int = 0,
+        val isHeavy: Boolean = false,
     ) : ArticleState()
     @Immutable
     data class Error(

app/src/main/java/com/example/research/ui/article/MergeDslBlocks.kt

@@ -0,0 +1,51 @@
+package com.example.research.ui.article
+
+import androidx.compose.ui.text.AnnotatedString
+
+private const val MERGED_BLOCK_MAX_CHARS = 1500
+private const val MERGED_BLOCK_MAX_ITEMS = 12
+
+internal fun mergeDslBlocks(blocks: List<DslBlock>): List<DslBlock> {
+    if (blocks.size <= MERGED_BLOCK_MAX_ITEMS) return blocks
+    val merged = ArrayList<DslBlock>(blocks.size / 4)
+    var i = 0
+    while (i < blocks.size) {
+        val builder = AnnotatedString.Builder()
+        val refs = ArrayList<DslAnnotatedParser.LazyRef>()
+        var j = i
+        while (j < blocks.size) {
+            val block = blocks[j]
+            repeat(block.indent) { builder.append(' ') }
+            val paraStart = builder.length
+            builder.append(block.text)
+            block.lazyRefs.forEach { ref ->
+                refs.add(
+                    ref.copy(
+                        startIndex = ref.startIndex + paraStart,
+                        endIndex = ref.endIndex + paraStart
+                    )
+                )
+            }
+            val more = j + 1 < blocks.size &&
+                (j + 1 - i) < MERGED_BLOCK_MAX_ITEMS &&
+                builder.length < MERGED_BLOCK_MAX_CHARS
+            if (more) {
+                builder.append('\n')
+            }
+            j++
+            if (!more) {
+                break
+            }
+        }
+        merged.add(
+            DslBlock(
+                text = builder.toAnnotatedString(),
+                indent = 0,
+                lazyRefs = refs,
+                continuesPrevious = blocks[i].continuesPrevious
+            )
+        )
+        i = j
+    }
+    return merged
+}