refactor(message-list): introduce AbstractMessageListFragment and migrate all logic from LegacyMessageListFragment to it

legacy/ui/legacy/src/main/java/com/fsck/k9/activity/MainActivity.kt

@@ -42,9 +42,9 @@ import com.fsck.k9.ui.BuildConfig
 import com.fsck.k9.ui.R
 import com.fsck.k9.ui.base.BaseActivity
 import com.fsck.k9.ui.managefolders.ManageFoldersActivity
+import com.fsck.k9.ui.messagelist.AbstractMessageListFragment
+import com.fsck.k9.ui.messagelist.AbstractMessageListFragment.MessageListFragmentListener
 import com.fsck.k9.ui.messagelist.DefaultFolderProvider
-import com.fsck.k9.ui.messagelist.MessageListFragment
-import com.fsck.k9.ui.messagelist.MessageListFragment.MessageListFragmentListener
 import com.fsck.k9.ui.messageview.MessageViewContainerFragment
 import com.fsck.k9.ui.messageview.MessageViewContainerFragment.MessageViewContainerListener
 import com.fsck.k9.ui.messageview.MessageViewFragment.MessageViewFragmentListener
@@ -53,7 +53,6 @@ import com.fsck.k9.ui.settings.SettingsActivity
 import com.fsck.k9.view.ViewSwitcher
 import com.fsck.k9.view.ViewSwitcher.OnSwitchCompleteListener
 import com.google.android.material.textview.MaterialTextView
-import kotlin.getValue
 import net.thunderbird.core.android.account.LegacyAccount
 import net.thunderbird.core.android.account.LegacyAccountDto
 import net.thunderbird.core.android.account.LegacyAccountDtoManager
@@ -86,7 +85,7 @@ private const val TAG = "MainActivity"
  * "View Message" notification.
  *
  * `MainActivity` manages the overall layout, including the navigation drawer and the main content area,
- * which currently displays either a [MessageListFragment] or a [MessageViewContainerFragment]. It orchestrates
+ * which currently displays either a [AbstractMessageListFragment] or a [MessageViewContainerFragment]. It orchestrates
  * the interactions between these fragments and handles the back stack. The responsibilities for managing the
  * action bar, search functionality, and single-pane/split-view layout logic are currently handled here but
  * are intended to be refactored into more dedicated components over time.
@@ -121,7 +120,8 @@ open class MainActivity :
     private var openFolderTransaction: FragmentTransaction? = null
     private var progressBar: ProgressBar? = null
     private var messageViewPlaceHolder: PlaceholderFragment? = null
-    private var messageListFragment: MessageListFragment? = null
+    private val messageListFragmentFactory: AbstractMessageListFragment.Factory by inject()
+    private var messageListFragment: AbstractMessageListFragment? = null
     private var messageViewContainerFragment: MessageViewContainerFragment? = null
     private var account: LegacyAccountDto? = null
     private var search: LocalMessageSearch? = null
@@ -266,7 +266,9 @@ open class MainActivity :
 
     private fun findFragments() {
         val fragmentManager = supportFragmentManager
-        messageListFragment = fragmentManager.findFragmentById(R.id.message_list_container) as? MessageListFragment
+        messageListFragment = fragmentManager.findFragmentById(
+            R.id.message_list_container,
+        ) as? AbstractMessageListFragment
         messageViewContainerFragment =
             fragmentManager.findFragmentByTag(FRAGMENT_TAG_MESSAGE_VIEW_CONTAINER) as? MessageViewContainerFragment
 
@@ -283,10 +285,10 @@ open class MainActivity :
         val hasMessageListFragment = messageListFragment != null
         if (!hasMessageListFragment) {
             val fragmentTransaction = fragmentManager.beginTransaction()
-            val messageListFragment = MessageListFragment.newInstance(
-                search!!,
-                false,
-                generalSettingsManager.getConfig()
+            val messageListFragment = messageListFragmentFactory.newInstance(
+                search = search!!,
+                isThreadDisplay = false,
+                threadedList = generalSettingsManager.getConfig()
                     .display
                     .inboxSettings
                     .isThreadedViewEnabled &&
@@ -741,10 +743,10 @@ open class MainActivity :
         }
 
         val openFolderTransaction = fragmentManager.beginTransaction()
-        val messageListFragment = MessageListFragment.newInstance(
-            search,
-            false,
-            generalSettingsManager.getConfig().display.inboxSettings.isThreadedViewEnabled,
+        val messageListFragment = messageListFragmentFactory.newInstance(
+            search = search,
+            isThreadDisplay = false,
+            threadedList = generalSettingsManager.getConfig().display.inboxSettings.isThreadedViewEnabled,
         )
         openFolderTransaction.replace(R.id.message_list_container, messageListFragment)
 
@@ -1159,7 +1161,7 @@ open class MainActivity :
         }
     }
 
-    private fun addMessageListFragment(fragment: MessageListFragment) {
+    private fun addMessageListFragment(fragment: AbstractMessageListFragment) {
         messageListFragment?.isActive = false
 
         supportFragmentManager.commit {
@@ -1229,7 +1231,11 @@ open class MainActivity :
 
         initializeFromLocalSearch(tmpSearch)
 
-        val fragment = MessageListFragment.newInstance(tmpSearch, true, false)
+        val fragment = messageListFragmentFactory.newInstance(
+            search = tmpSearch,
+            isThreadDisplay = true,
+            threadedList = false,
+        )
         addMessageListFragment(fragment)
     }
 
@@ -1459,7 +1465,7 @@ open class MainActivity :
         }
     }
 
-    private fun MessageListFragment.setFullyActive() {
+    private fun AbstractMessageListFragment.setFullyActive() {
         isActive = true
         onFullyActive()
     }

legacy/ui/legacy/src/main/java/com/fsck/k9/ui/KoinModule.kt

@@ -5,6 +5,8 @@ import app.k9mail.legacy.message.controller.MessagingControllerMailChecker
 import com.fsck.k9.controller.MessagingController
 import com.fsck.k9.ui.helper.DisplayHtmlUiFactory
 import com.fsck.k9.ui.helper.SizeFormatter
+import com.fsck.k9.ui.messagelist.AbstractMessageListFragment
+import com.fsck.k9.ui.messagelist.LegacyMessageListFragment
 import com.fsck.k9.ui.messageview.LinkTextHandler
 import com.fsck.k9.ui.share.ShareIntentBuilder
 import net.thunderbird.core.common.inject.getList
@@ -25,4 +27,8 @@ val uiModule = module {
     factory { (context: Context) -> SizeFormatter(context.resources) }
     factory { ShareIntentBuilder(resourceProvider = get(), textPartFinder = get(), quoteDateFormatter = get()) }
     factory { LinkTextHandler(context = get(), clipboardManager = get()) }
+    factory<AbstractMessageListFragment.Factory> {
+        // TODO(9497): verify if EnableMessageListNewState is enabled. If so, use the new MessageListFragment instead.
+        LegacyMessageListFragment.Factory
+    }
 }

legacy/ui/legacy/src/main/java/com/fsck/k9/ui/messagelist/MessageListFragment.kt → legacy/ui/legacy/src/main/java/com/fsck/k9/ui/messagelist/AbstractMessageListFragment.kt

@@ -12,14 +12,14 @@ import android.view.View
 import android.view.ViewGroup
 import android.widget.Toast
 import androidx.activity.result.ActivityResultLauncher
+import androidx.annotation.Discouraged
 import androidx.annotation.StringRes
 import androidx.appcompat.view.ActionMode
 import androidx.compose.animation.animateContentSize
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.layout.onSizeChanged
 import androidx.compose.ui.platform.ComposeView
 import androidx.coordinatorlayout.widget.CoordinatorLayout
-import androidx.core.os.bundleOf
 import androidx.core.view.ViewCompat
 import androidx.core.view.WindowInsetsCompat
 import androidx.core.view.WindowInsetsCompat.Type.systemBars
@@ -62,7 +62,7 @@ import com.fsck.k9.ui.changelog.RecentChangesViewModel
 import com.fsck.k9.ui.choosefolder.ChooseFolderActivity
 import com.fsck.k9.ui.choosefolder.ChooseFolderResultContract
 import com.fsck.k9.ui.helper.RelativeDateTimeFormatter
-import com.fsck.k9.ui.messagelist.MessageListFragment.MessageListFragmentListener.Companion.MAX_PROGRESS
+import com.fsck.k9.ui.messagelist.AbstractMessageListFragment.MessageListFragmentListener.Companion.MAX_PROGRESS
 import com.fsck.k9.ui.messagelist.debug.AuthDebugActions
 import com.fsck.k9.ui.messagelist.item.MessageViewHolder
 import com.google.android.material.floatingactionbutton.FloatingActionButton
@@ -94,14 +94,14 @@ import net.thunderbird.core.featureflag.FeatureFlagKey
 import net.thunderbird.core.featureflag.FeatureFlagProvider
 import net.thunderbird.core.featureflag.FeatureFlagResult
 import net.thunderbird.core.logging.Logger
-import net.thunderbird.core.logging.legacy.Log
 import net.thunderbird.core.outcome.Outcome
 import net.thunderbird.core.preference.GeneralSettingsManager
 import net.thunderbird.core.preference.display.visualSettings.message.list.DisplayMessageListSettings
 import net.thunderbird.core.preference.interaction.InteractionSettings
 import net.thunderbird.core.ui.theme.api.FeatureThemeProvider
 import net.thunderbird.feature.account.avatar.AvatarMonogramCreator
 import net.thunderbird.feature.mail.folder.api.OutboxFolderManager
+import net.thunderbird.feature.mail.message.list.MessageListFeatureFlags
 import net.thunderbird.feature.mail.message.list.domain.DomainContract
 import net.thunderbird.feature.mail.message.list.ui.dialog.SetupArchiveFolderDialogFragmentFactory
 import net.thunderbird.feature.notification.api.content.InAppNotification
@@ -124,15 +124,29 @@ private const val MAXIMUM_MESSAGE_SORT_OVERRIDES = 3
 private const val MINIMUM_CLICK_INTERVAL = 200L
 private const val RECENT_CHANGES_SNACKBAR_DURATION = 10 * 1000
 
-private const val TAG = "MessageListFragment"
-
-@Suppress("LargeClass", "TooManyFunctions")
-class MessageListFragment :
+@Suppress(
+    "LargeClass",
+    "TooManyFunctions",
+    "CyclomaticComplexMethod",
+    "TooGenericExceptionCaught",
+    "TooGenericExceptionThrown",
+    "SwallowedException",
+    "ReturnCount",
+    "ForbiddenComment",
+)
+@Discouraged(
+    message = "This class is in maintenance mode. DO NOT introduce any new features in this class. " +
+        "Only bugfixes are allowed. New features must be introduced in the new MessageListFragment, " +
+        "following the MVI principle.",
+)
+abstract class AbstractMessageListFragment :
     Fragment(),
     ConfirmationDialogFragmentListener,
     MessageListItemActionListener,
     ErrorNotificationsDialogFragmentActionListener {
 
+    abstract val logTag: String
+
     val viewModel: MessageListViewModel by viewModel()
     private val recentChangesViewModel: RecentChangesViewModel by viewModel()
 
@@ -373,7 +387,7 @@ class MessageListFragment :
             contactRepository = contactRepository,
             avatarMonogramCreator = avatarMonogramCreator,
         ).apply {
-            activeMessage = this@MessageListFragment.activeMessage
+            activeMessage = this@AbstractMessageListFragment.activeMessage
         }
     }
 
@@ -383,10 +397,10 @@ class MessageListFragment :
                 setFragmentResultListener(
                     SetupArchiveFolderDialogFragmentFactory.RESULT_CODE_DISMISS_REQUEST_KEY,
                 ) { key, bundle ->
-                    Log.d(
+                    logger.debug(logTag) {
                         "SetupArchiveFolderDialogFragment fragment listener triggered with " +
-                            "key: $key and bundle: $bundle",
-                    )
+                            "key: $key and bundle: $bundle"
+                    }
                     loadMessageList(forceUpdate = true)
                 }
             }
@@ -901,7 +915,7 @@ class MessageListFragment :
             )
             lifecycleScope.launch(Dispatchers.IO) {
                 accountManager.saveAccount(updatedAccount)
-                this@MessageListFragment.account = updatedAccount
+                this@AbstractMessageListFragment.account = updatedAccount
             }
         } else {
             K9.sortType = this.sortType
@@ -1618,7 +1632,7 @@ class MessageListFragment :
         for ((folderId, messagesInFolder) in folderMap) {
             val account = accountManager.getAccount(messagesInFolder.first().accountUuid)
             if (account == null) {
-                logger.debug(TAG) {
+                logger.debug(logTag) {
                     "Account for message ${messagesInFolder.first()} not found, skipping copy/move operation"
                 }
                 continue
@@ -1743,12 +1757,12 @@ class MessageListFragment :
         // If we represent a remote search, then kill that before going back.
         if (isRemoteSearch && remoteSearchFuture != null) {
             try {
-                Log.i("Remote search in progress, attempting to abort...")
+                logger.info(logTag) { "Remote search in progress, attempting to abort..." }
 
                 // Canceling the future stops any message fetches in progress.
                 val cancelSuccess = remoteSearchFuture!!.cancel(true) // mayInterruptIfRunning = true
                 if (!cancelSuccess) {
-                    Log.e("Could not cancel remote search future.")
+                    logger.error(logTag) { "Could not cancel remote search future." }
                 }
 
                 // Closing the folder will kill off the connection if we're mid-search.
@@ -1763,7 +1777,7 @@ class MessageListFragment :
                 )
             } catch (e: Exception) {
                 // Since the user is going back, log and squash any exceptions.
-                Log.e(e, "Could not abort remote search before going back")
+                logger.error(logTag, e) { "Could not abort remote search before going back" }
             }
         }
 
@@ -2591,36 +2605,47 @@ class MessageListFragment :
         fun startSupportActionMode(callback: ActionMode.Callback): ActionMode?
         fun goBack()
 
-        companion object {
+        companion object Companion {
             const val MAX_PROGRESS = 10000
         }
     }
 
-    companion object {
-
-        private const val ARG_SEARCH = "searchObject"
-        private const val ARG_THREADED_LIST = "showingThreadedList"
-        private const val ARG_IS_THREAD_DISPLAY = "isThreadedDisplay"
-
-        private const val STATE_SELECTED_MESSAGES = "selectedMessages"
-        private const val STATE_ACTIVE_MESSAGES = "activeMessages"
-        private const val STATE_ACTIVE_MESSAGE = "activeMessage"
-        private const val STATE_REMOTE_SEARCH_PERFORMED = "remoteSearchPerformed"
-
+    /**
+     * A factory for creating instances of [AbstractMessageListFragment].
+     *
+     * This interface is a temporary solution to toggle between different fragment implementations
+     * based on a feature flag. It allows for the creation of either a modern [MessageListFragment] or a
+     * [LegacyMessageListFragment] depending on the state of [MessageListFeatureFlags.EnableMessageListNewState].
+     */
+    interface Factory {
+        /**
+         * Creates a new instance of a class that inherits from [AbstractMessageListFragment].
+         *
+         * The specific implementation returned ([MessageListFragment] or [LegacyMessageListFragment]) is determined
+         * by the [MessageListFeatureFlags.EnableMessageListNewState] feature flag.
+         *
+         * @param search The search query that defines which messages to display.
+         * @param isThreadDisplay `true` if the fragment is used to display a single thread, `false` otherwise.
+         * @param threadedList `true` to display the message list in a threaded conversation view, `false` otherwise.
+         *
+         * @return An instance of [MessageListFragment] if the new state feature flag is enabled;
+         *  otherwise, an instance of [LegacyMessageListFragment].
+         */
         fun newInstance(
             search: LocalMessageSearch,
             isThreadDisplay: Boolean,
             threadedList: Boolean,
-        ): MessageListFragment {
-            val searchBytes = LocalMessageSearchSerializer.serialize(search)
-
-            return MessageListFragment().apply {
-                arguments = bundleOf(
-                    ARG_SEARCH to searchBytes,
-                    ARG_IS_THREAD_DISPLAY to isThreadDisplay,
-                    ARG_THREADED_LIST to threadedList,
-                )
-            }
-        }
+        ): AbstractMessageListFragment
+    }
+
+    companion object {
+        protected const val ARG_SEARCH = "searchObject"
+        protected const val ARG_THREADED_LIST = "showingThreadedList"
+        protected const val ARG_IS_THREAD_DISPLAY = "isThreadedDisplay"
+
+        protected const val STATE_SELECTED_MESSAGES = "selectedMessages"
+        protected const val STATE_ACTIVE_MESSAGES = "activeMessages"
+        protected const val STATE_ACTIVE_MESSAGE = "activeMessage"
+        protected const val STATE_REMOTE_SEARCH_PERFORMED = "remoteSearchPerformed"
     }
 }

legacy/ui/legacy/src/main/java/com/fsck/k9/ui/messagelist/LegacyMessageListFragment.kt

@@ -0,0 +1,33 @@
+package com.fsck.k9.ui.messagelist
+
+import androidx.core.os.bundleOf
+import net.thunderbird.feature.search.legacy.LocalMessageSearch
+import net.thunderbird.feature.search.legacy.serialization.LocalMessageSearchSerializer
+
+private const val TAG = "LegacyMessageListFragment"
+
+@Deprecated(
+    message = "DO NOT introduce any new features in this class. " +
+        "This will be replaced by the new MessageListFragment and deleted in the future.",
+)
+class LegacyMessageListFragment : AbstractMessageListFragment() {
+    override val logTag: String = TAG
+
+    companion object Factory : AbstractMessageListFragment.Factory {
+        override fun newInstance(
+            search: LocalMessageSearch,
+            isThreadDisplay: Boolean,
+            threadedList: Boolean,
+        ): LegacyMessageListFragment {
+            val searchBytes = LocalMessageSearchSerializer.serialize(search)
+
+            return LegacyMessageListFragment().apply {
+                arguments = bundleOf(
+                    ARG_SEARCH to searchBytes,
+                    ARG_IS_THREAD_DISPLAY to isThreadDisplay,
+                    ARG_THREADED_LIST to threadedList,
+                )
+            }
+        }
+    }
+}