Improved the caching mechanism for the language list.

* Improved the language list UI according to new approach.
* Fixed: codeFactor and lint issues.

app/src/main/java/org/kiwix/kiwixmobile/language/composables/LanguageItemRow.kt

@@ -26,7 +26,6 @@ import androidx.compose.foundation.layout.Spacer
 import androidx.compose.foundation.layout.fillMaxWidth
 import androidx.compose.foundation.layout.height
 import androidx.compose.foundation.layout.padding
-import androidx.compose.material3.Checkbox
 import androidx.compose.material3.MaterialTheme
 import androidx.compose.material3.RadioButton
 import androidx.compose.material3.Text

app/src/main/java/org/kiwix/kiwixmobile/language/viewmodel/LanguageViewModel.kt

@@ -125,20 +125,30 @@ class LanguageViewModel @Inject constructor(
 
   private fun observeLanguages() = viewModelScope.launch {
     state.value = Loading
-    if (connectivityBroadcastReceiver.networkStates.value == NetworkState.NOT_CONNECTED) {
-      actions.emit(Error(context.getString(R.string.no_network_connection)))
+
+    val cachedLanguageList = sharedPreferenceUtil.getCachedLanguageList()
+    val isOnline = connectivityBroadcastReceiver.networkStates.value != NetworkState.NOT_CONNECTED
+
+    if (LanguageSessionCache.hasFetched && !cachedLanguageList.isNullOrEmpty()) {
+      actions.emit(UpdateLanguages(cachedLanguageList))
       return@launch
     }
-    try {
-      val languages = fetchLanguages()
-      if (languages?.isNotEmpty() == true) {
-        actions.emit(UpdateLanguages(languages))
-      } else {
-        Log.w("LanguageViewModel", "Fetched empty language list.")
-        actions.emit(Error(context.getString(R.string.no_language_available)))
-      }
-    } catch (e: Exception) {
-      Log.e("LanguageViewModel", "Error fetching languages", e)
+
+    if (isOnline) {
+      runCatching {
+        val fetched = fetchLanguages()
+        if (!fetched.isNullOrEmpty()) {
+          sharedPreferenceUtil.saveLanguageList(fetched)
+          LanguageSessionCache.hasFetched = true
+          actions.emit(UpdateLanguages(fetched))
+          return@launch
+        }
+      }.onFailure { it.printStackTrace() }
+    }
+
+    if (!cachedLanguageList.isNullOrEmpty()) {
+      actions.emit(UpdateLanguages(cachedLanguageList))
+    } else {
       actions.emit(Error(context.getString(R.string.no_language_available)))
     }
   }
@@ -222,3 +232,7 @@ class LanguageViewModel @Inject constructor(
     .addNetworkInterceptor(UserAgentInterceptor(USER_AGENT))
     .build()
 }
+
+object LanguageSessionCache {
+  var hasFetched: Boolean = false
+}

app/src/main/java/org/kiwix/kiwixmobile/nav/destination/library/online/OnlineLibraryScreen.kt

@@ -219,7 +219,7 @@ private fun OnlineLibraryList(state: OnlineLibraryScreenState, lazyListState: La
         val layoutInfo = lazyListState.layoutInfo
         val totalItems = layoutInfo.totalItemsCount
         val lastVisibleItemIndex = layoutInfo.visibleItemsInfo.lastOrNull()?.index ?: ZERO
-        (totalItems > ZERO && lastVisibleItemIndex >= (totalItems - FIVE)) to totalItems
+        (totalItems > ZERO && lastVisibleItemIndex >= totalItems.minus(FIVE)) to totalItems
       }.value
     }
       .distinctUntilChanged()

app/src/main/java/org/kiwix/kiwixmobile/zimManager/OnlineLibraryManager.kt

@@ -18,9 +18,9 @@
 
 package org.kiwix.kiwixmobile.zimManager
 
+import kotlinx.coroutines.CoroutineDispatcher
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.withContext
-import org.kiwix.kiwixmobile.core.data.remote.KiwixService.Companion.ITEMS_PER_PAGE
 import org.kiwix.kiwixmobile.core.data.remote.KiwixService.Companion.OPDS_LIBRARY_ENDPOINT
 import org.kiwix.kiwixmobile.core.downloader.downloadManager.ZERO
 import org.kiwix.kiwixmobile.core.entity.LibkiwixBook
@@ -34,11 +34,11 @@ import java.io.StringReader
 import javax.inject.Inject
 import javax.inject.Named
 
+@Suppress("UnusedPrivateProperty")
 class OnlineLibraryManager @Inject constructor(
   @Named(ONLINE_BOOKS_LIBRARY) private val library: Library,
   @Named(ONLINE_BOOKS_MANAGER) private val manager: Manager,
 ) {
-
   var totalResult = 0
   suspend fun parseOPDSStreamAndGetBooks(
     content: String?,
@@ -124,7 +124,10 @@ class OnlineLibraryManager @Inject constructor(
    */
   fun getStartOffset(pageIndex: Int, pageSize: Int): Int = pageIndex * pageSize
 
-  private suspend fun extractTotalResults(xml: String): Int = withContext(Dispatchers.IO) {
+  private suspend fun extractTotalResults(
+    xml: String,
+    dispatcher: CoroutineDispatcher = Dispatchers.IO
+  ): Int = withContext(dispatcher) {
     val factory = XmlPullParserFactory.newInstance()
     val parser = factory.newPullParser()
     parser.setInput(StringReader(xml))

app/src/main/java/org/kiwix/kiwixmobile/zimManager/ZimManageViewModel.kt

@@ -38,7 +38,6 @@ import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.catch
 import kotlinx.coroutines.flow.combine
 import kotlinx.coroutines.flow.debounce
-import kotlinx.coroutines.flow.distinctUntilChanged
 import kotlinx.coroutines.flow.drop
 import kotlinx.coroutines.flow.filter
 import kotlinx.coroutines.flow.filterNotNull
@@ -134,7 +133,7 @@ const val MAX_PROGRESS = 100
 const val THREE = 3
 const val FOUR = 4
 
-@Suppress("LongParameterList")
+@Suppress("LongParameterList", "LargeClass")
 class ZimManageViewModel @Inject constructor(
   private val downloadDao: DownloadRoomDao,
   private val libkiwixBookOnDisk: LibkiwixBookOnDisk,

core/src/main/java/org/kiwix/kiwixmobile/core/data/remote/LanguageFeed.kt

@@ -45,4 +45,3 @@ class LanguageEntry {
   @Namespace(prefix = "thr", reference = "http://purl.org/syndication/thread/1.0")
   var count: Int = ZERO
 }
-

core/src/main/java/org/kiwix/kiwixmobile/core/utils/SharedPreferenceUtil.kt

@@ -30,10 +30,13 @@ import kotlinx.coroutines.flow.MutableStateFlow
 import kotlinx.coroutines.flow.asStateFlow
 import kotlinx.coroutines.flow.onStart
 import kotlinx.coroutines.runBlocking
+import org.json.JSONArray
+import org.json.JSONObject
 import org.kiwix.kiwixmobile.core.DarkModeConfig
 import org.kiwix.kiwixmobile.core.DarkModeConfig.Mode.Companion.from
 import org.kiwix.kiwixmobile.core.R
 import org.kiwix.kiwixmobile.core.extensions.isFileExist
+import org.kiwix.kiwixmobile.core.zim_manager.Language
 import java.io.File
 import java.util.Locale
 import javax.inject.Inject
@@ -205,6 +208,40 @@ class SharedPreferenceUtil @Inject constructor(val context: Context) {
   fun putPrefExternalLinkPopup(externalLinkPopup: Boolean) =
     sharedPreferences.edit { putBoolean(PREF_EXTERNAL_LINK_POPUP, externalLinkPopup) }
 
+  fun saveLanguageList(languages: List<Language>) {
+    runCatching {
+      val jsonArray = JSONArray()
+      languages.forEach { lang ->
+        val obj = JSONObject().apply {
+          put(KEY_LANGUAGE_CODE, lang.languageCode)
+          put(KEY_OCCURRENCES_OF_LANGUAGE, lang.occurencesOfLanguage)
+          put(KEY_LANGUAGE_ACTIVE, lang.active)
+          put(KEY_LANGUAGE_ID, lang.id)
+        }
+        jsonArray.put(obj)
+      }
+      sharedPreferences.edit {
+        putString(CACHED_LANGUAGE_CODES, jsonArray.toString())
+      }
+    }.onFailure { it.printStackTrace() }
+  }
+
+  fun getCachedLanguageList(): List<Language>? =
+    runCatching {
+      val jsonString =
+        sharedPreferences.getString(CACHED_LANGUAGE_CODES, null) ?: return@runCatching null
+      val jsonArray = JSONArray(jsonString)
+      List(jsonArray.length()) { i ->
+        val obj = jsonArray.getJSONObject(i)
+        Language(
+          languageCode = obj.getString(KEY_LANGUAGE_CODE),
+          occurrencesOfLanguage = obj.getInt(KEY_OCCURRENCES_OF_LANGUAGE),
+          active = selectedOnlineContentLanguage == obj.getString(KEY_LANGUAGE_CODE),
+          id = obj.getLong(KEY_LANGUAGE_ID)
+        )
+      }
+    }.onFailure { it.printStackTrace() }.getOrNull()
+
   fun showIntro(): Boolean = sharedPreferences.getBoolean(PREF_SHOW_INTRO, true)
 
   fun setIntroShown() = sharedPreferences.edit { putBoolean(PREF_SHOW_INTRO, false) }
@@ -372,5 +409,10 @@ class SharedPreferenceUtil @Inject constructor(val context: Context) {
     const val PREF_LAST_DONATION_POPUP_SHOWN_IN_MILLISECONDS =
       "pref_last_donation_shown_in_milliseconds"
     private const val SELECTED_ONLINE_CONTENT_LANGUAGE = "selectedOnlineContentLanguage"
+    private const val CACHED_LANGUAGE_CODES = "cachedLanguageCodes"
+    private const val KEY_LANGUAGE_CODE = "languageCode"
+    private const val KEY_OCCURRENCES_OF_LANGUAGE = "occurrencesOfLanguage"
+    private const val KEY_LANGUAGE_ACTIVE = "languageActive"
+    private const val KEY_LANGUAGE_ID = "languageId"
   }
 }