#2154 lots of rewrite between viewmodels, working now but should be possible to improve

core/src/main/java/org/kiwix/kiwixmobile/core/page/PageActivity.kt

@@ -50,7 +50,7 @@ import javax.inject.Inject
 
 abstract class PageActivity : OnItemClickListener, BaseActivity() {
   val activityComponent by lazy { coreActivityComponent }
-  abstract val pageViewModel: PageViewModel<PageState>
+  abstract val pageViewModel: PageViewModel
   @Inject lateinit var viewModelFactory: ViewModelProvider.Factory
   private var actionMode: ActionMode? = null
   val compositeDisposable = CompositeDisposable()

core/src/main/java/org/kiwix/kiwixmobile/core/page/adapter/Page.kt

@@ -26,6 +26,6 @@ interface Page : PageRelated {
   val zimFilePath: String?
   val url: String
   val title: String
-  val isSelected: Boolean
+  var isSelected: Boolean
   val favicon: String?
 }

core/src/main/java/org/kiwix/kiwixmobile/core/page/bookmark/BookmarksActivity.kt

@@ -1,7 +1,6 @@
 package org.kiwix.kiwixmobile.core.page.bookmark
 
 import org.kiwix.kiwixmobile.core.R
-import org.kiwix.kiwixmobile.core.di.components.CoreComponent
 import org.kiwix.kiwixmobile.core.extensions.ActivityExtensions.viewModel
 import org.kiwix.kiwixmobile.core.page.PageActivity
 import org.kiwix.kiwixmobile.core.page.adapter.PageAdapter
@@ -15,10 +14,6 @@ class BookmarksActivity : PageActivity() {
     PageAdapter(PageItemDelegate(this))
   }
 
-  override fun injection(coreComponent: CoreComponent) {
-    activityComponent.inject(this)
-  }
-
   override val title: String by lazy { getString(R.string.bookmarks) }
   override val noItemsString: String by lazy { getString(R.string.no_bookmarks) }
   override val switchString: String by lazy { getString(R.string.bookmarks_from_current_book) }

core/src/main/java/org/kiwix/kiwixmobile/core/page/bookmark/viewmodel/BookmarkState.kt

@@ -28,20 +28,13 @@ data class BookmarkState(
   override val showAll: Boolean,
   override val currentZimId: String?,
   override val searchTerm: String = ""
-) : PageState {
-
-  override val isInSelectionState = pageItems.any(BookmarkItem::isSelected)
-  override val numberOfSelectedItems = pageItems.filter(BookmarkItem::isSelected).size
+) : PageState() {
+  override val numberOfSelectedItems: Int = pageItems.filter(Page::isSelected).size
 
   override val filteredPageItems: List<PageRelated> = pageItems
     .filter { it.zimId == currentZimId || showAll }
     .filter { it.title.contains(searchTerm, true) }
 
-  override fun toggleSelectionOfItem(page: Page): BookmarkState {
-    page as BookmarkItem
-    val newList = pageItems.map {
-      if (it.databaseId == page.databaseId) it.apply { isSelected = !isSelected } else it
-    }
-    return BookmarkState(newList, showAll, currentZimId, searchTerm)
-  }
+  override fun copyWithNewItems(newItems: List<Page>): PageState =
+    copy(pageItems = (newItems as List<BookmarkItem>))
 }

core/src/main/java/org/kiwix/kiwixmobile/core/page/bookmark/viewmodel/BookmarkViewModel.kt

@@ -18,6 +18,7 @@
 
 package org.kiwix.kiwixmobile.core.page.bookmark.viewmodel
 
+import androidx.lifecycle.MutableLiveData
 import io.reactivex.schedulers.Schedulers
 import org.kiwix.kiwixmobile.core.dao.NewBookmarksDao
 import org.kiwix.kiwixmobile.core.page.bookmark.adapter.BookmarkItem
@@ -34,10 +35,14 @@ class BookmarkViewModel @Inject constructor(
   bookmarksDao: NewBookmarksDao,
   override val zimReaderContainer: ZimReaderContainer,
   override val sharedPreferenceUtil: SharedPreferenceUtil
-) : PageViewModel<BookmarkState>(bookmarksDao) {
+) : PageViewModel(bookmarksDao) {
 
-  override fun initialState(): BookmarkState =
-    BookmarkState(emptyList(), true, null)
+  override val state by lazy {
+    MutableLiveData<PageState>().apply {
+      value =
+        BookmarkState(emptyList(), sharedPreferenceUtil.showHistoryAllBooks, zimReaderContainer.id)
+    }
+  }
 
   init {
     compositeDisposable.addAll(

core/src/main/java/org/kiwix/kiwixmobile/core/page/history/HistoryActivity.kt

@@ -1,7 +1,6 @@
 package org.kiwix.kiwixmobile.core.page.history
 
 import org.kiwix.kiwixmobile.core.R
-import org.kiwix.kiwixmobile.core.di.components.CoreComponent
 import org.kiwix.kiwixmobile.core.extensions.ActivityExtensions.viewModel
 import org.kiwix.kiwixmobile.core.page.PageActivity
 import org.kiwix.kiwixmobile.core.page.adapter.PageAdapter
@@ -18,10 +17,6 @@ class HistoryActivity : PageActivity() {
     PageAdapter(PageItemDelegate(this), HistoryDateDelegate())
   }
 
-  override fun injection(coreComponent: CoreComponent) {
-    activityComponent.inject(this)
-  }
-
   override val noItemsString: String by lazy { getString(R.string.no_history) }
   override val switchString: String by lazy { getString(R.string.history_from_current_book) }
   override val title: String by lazy { getString(R.string.history) }

core/src/main/java/org/kiwix/kiwixmobile/core/page/history/viewmodel/HistoryState.kt

@@ -30,9 +30,8 @@ data class HistoryState(
   override val showAll: Boolean,
   override val currentZimId: String?,
   override val searchTerm: String = ""
-) : PageState {
-  override val isInSelectionState = pageItems.any(HistoryItem::isSelected)
-  override val numberOfSelectedItems = pageItems.filter(HistoryItem::isSelected).size
+) : PageState() {
+  override val numberOfSelectedItems: Int = pageItems.filter(Page::isSelected).size
 
   override val filteredPageItems: List<HistoryListItem> =
     HeaderizableList<HistoryListItem, HistoryItem, DateItem>(pageItems
@@ -43,13 +42,6 @@ data class HistoryState(
         { current, next -> current.dateString != next.dateString }
       )
 
-  override fun toggleSelectionOfItem(historyItem: Page): HistoryState {
-    historyItem as HistoryItem
-    val newList = pageItems.map {
-      if (it.id == historyItem.id) it.apply {
-        isSelected = !isSelected
-      } else it
-    }
-    return copy(pageItems = newList)
-  }
+  override fun copyWithNewItems(newItems: List<Page>): PageState =
+    copy(pageItems = (newItems as List<HistoryItem>))
 }

core/src/main/java/org/kiwix/kiwixmobile/core/page/history/viewmodel/HistoryViewModel.kt

@@ -18,6 +18,8 @@
 
 package org.kiwix.kiwixmobile.core.page.history.viewmodel
 
+import androidx.lifecycle.MutableLiveData
+import io.reactivex.schedulers.Schedulers
 import org.kiwix.kiwixmobile.core.dao.HistoryDao
 import org.kiwix.kiwixmobile.core.page.history.adapter.HistoryListItem.HistoryItem
 import org.kiwix.kiwixmobile.core.page.history.viewmodel.effects.ShowDeleteHistoryDialog
@@ -30,13 +32,25 @@ import org.kiwix.kiwixmobile.core.utils.SharedPreferenceUtil
 import javax.inject.Inject
 
 class HistoryViewModel @Inject constructor(
+  historyDao: HistoryDao,
   override val zimReaderContainer: ZimReaderContainer,
-  override val sharedPreferenceUtil: SharedPreferenceUtil,
-  historyDao: HistoryDao
-) : PageViewModel<HistoryState>(historyDao) {
+  override val sharedPreferenceUtil: SharedPreferenceUtil
+) : PageViewModel(pageDao = historyDao) {
 
-  override fun initialState(): HistoryState =
-    HistoryState(emptyList(), true, null)
+  override val state by lazy {
+    MutableLiveData<PageState>().apply {
+      value =
+        HistoryState(emptyList(), sharedPreferenceUtil.showHistoryAllBooks, zimReaderContainer.id)
+    }
+  }
+
+  init {
+    compositeDisposable.addAll(
+      viewStateReducer(),
+      pageDao.pages().subscribeOn(Schedulers.io())
+        .subscribe({ actions.offer(Action.UpdatePages(it)) }, Throwable::printStackTrace)
+    )
+  }
 
   override fun updatePagesBasedOnFilter(state: PageState, action: Action.Filter): PageState =
     (state as HistoryState).copy(searchTerm = action.searchTerm)

core/src/main/java/org/kiwix/kiwixmobile/core/page/viewmodel/PageState.kt

@@ -21,13 +21,22 @@ package org.kiwix.kiwixmobile.core.page.viewmodel
 import org.kiwix.kiwixmobile.core.page.adapter.Page
 import org.kiwix.kiwixmobile.core.page.adapter.PageRelated
 
-interface PageState {
-  val pageItems: List<Page>
-  val filteredPageItems: List<PageRelated>
-  val showAll: Boolean
-  val currentZimId: String?
-  val searchTerm: String
-  val isInSelectionState: Boolean
-  val numberOfSelectedItems: Int
-  fun toggleSelectionOfItem(page: Page): PageState
+abstract class PageState {
+  abstract val pageItems: List<Page>
+  val isInSelectionState: Boolean by lazy { pageItems.any(Page::isSelected) }
+  abstract val numberOfSelectedItems: Int
+  abstract val filteredPageItems: List<PageRelated>
+  abstract val showAll: Boolean
+  abstract val currentZimId: String?
+  abstract val searchTerm: String
+  fun toggleSelectionOfItem(page: Page): PageState {
+    val newList = pageItems.map {
+      if (it.id == page.id) it.apply {
+        isSelected = !isSelected
+      } else it
+    }
+    return copyWithNewItems(newList)
+  }
+
+  abstract fun copyWithNewItems(newItems: List<Page>): PageState
 }

core/src/main/java/org/kiwix/kiwixmobile/core/page/viewmodel/PageViewModel.kt

@@ -23,7 +23,6 @@ import androidx.lifecycle.ViewModel
 import io.reactivex.disposables.CompositeDisposable
 import io.reactivex.disposables.Disposable
 import io.reactivex.processors.PublishProcessor
-import io.reactivex.schedulers.Schedulers
 import org.kiwix.kiwixmobile.core.base.SideEffect
 import org.kiwix.kiwixmobile.core.dao.PageDao
 import org.kiwix.kiwixmobile.core.page.viewmodel.Action.Exit
@@ -40,31 +39,22 @@ import org.kiwix.kiwixmobile.core.reader.ZimReaderContainer
 import org.kiwix.kiwixmobile.core.search.viewmodel.effects.Finish
 import org.kiwix.kiwixmobile.core.utils.SharedPreferenceUtil
 
-abstract class PageViewModel<out T : PageState>(val pageDao: PageDao) : ViewModel() {
+abstract class PageViewModel(
+  val pageDao: PageDao
+) : ViewModel() {
+
   abstract val zimReaderContainer: ZimReaderContainer
   abstract val sharedPreferenceUtil: SharedPreferenceUtil
-  val state = MutableLiveData<PageState>().apply {
-    value = initialState()
-  }
+  abstract val state: MutableLiveData<PageState>
 
   val compositeDisposable = CompositeDisposable()
   val effects = PublishProcessor.create<SideEffect<*>>()
   val actions = PublishProcessor.create<Action>()
 
-  init {
-    compositeDisposable.addAll(
-      viewStateReducer(),
-      pageDao.pages().subscribeOn(Schedulers.io())
-        .subscribe({ actions.offer(Action.UpdatePages(it)) }, Throwable::printStackTrace)
-    )
-  }
-
-  fun viewStateReducer(): Disposable =
+  protected fun viewStateReducer(): Disposable =
     actions.map { reduce(it, state.value!!) }
       .subscribe(state::postValue, Throwable::printStackTrace)
 
-  abstract fun initialState(): T
-
   private fun reduce(action: Action, state: PageState): PageState = when (action) {
     Exit -> finishActivity(state)
     ExitActionModeMenu -> deselectAllPages(state)