feat(message-list): add new MessageListFragment and it's MVI contract

feature/mail/message/list/api/src/main/kotlin/net/thunderbird/feature/mail/message/list/ui/MessageListContract.kt

@@ -0,0 +1,31 @@
+package net.thunderbird.feature.mail.message.list.ui
+
+import app.k9mail.core.ui.compose.common.mvi.BaseViewModel
+import net.thunderbird.feature.mail.message.list.ui.effect.MessageListEffect
+import net.thunderbird.feature.mail.message.list.ui.event.MessageListEvent
+import net.thunderbird.feature.mail.message.list.ui.state.MessageListState
+
+/**
+ * Defines the contract between the View and the ViewModel for the message list screen.
+ *
+ * This contract follows the MVI (Model-View-Intent) pattern, specifying the structure for:
+ * - **State (`MessageListState`)**: Represents the UI state.
+ * - **Events (`MessageListEvent`)**: User actions or other events from the UI.
+ * - **Effects (`MessageListEffect`)**: One-time actions for the UI to perform (e.g., navigation, showing a toast).
+ */
+interface MessageListContract {
+    /**
+     * The view model for the message list screen.
+     *
+     * It is responsible for handling the business logic of the message list screen and for providing the
+     * [MessageListState] to the UI. It consumes [MessageListEvent]s and produces [MessageListEffect]s.
+     *
+     * @see BaseViewModel
+     * @see MessageListState
+     * @see MessageListEvent
+     * @see MessageListEffect
+     */
+    abstract class ViewModel : BaseViewModel<MessageListState, MessageListEvent, MessageListEffect>(
+        initialState = MessageListState.WarmingUp(),
+    )
+}

feature/mail/message/list/internal/src/main/kotlin/net/thunderbird/feature/mail/message/list/internal/FeatureMessageListModule.kt

@@ -5,8 +5,10 @@ import net.thunderbird.feature.mail.message.list.internal.domain.usecase.BuildSw
 import net.thunderbird.feature.mail.message.list.internal.domain.usecase.CreateArchiveFolder
 import net.thunderbird.feature.mail.message.list.internal.domain.usecase.GetAccountFolders
 import net.thunderbird.feature.mail.message.list.internal.domain.usecase.SetArchiveFolder
+import net.thunderbird.feature.mail.message.list.internal.ui.MessageListViewModel
 import net.thunderbird.feature.mail.message.list.internal.ui.dialog.SetupArchiveFolderDialogFragment
 import net.thunderbird.feature.mail.message.list.internal.ui.dialog.SetupArchiveFolderDialogViewModel
+import net.thunderbird.feature.mail.message.list.ui.MessageListContract
 import net.thunderbird.feature.mail.message.list.ui.dialog.SetupArchiveFolderDialogContract
 import net.thunderbird.feature.mail.message.list.ui.dialog.SetupArchiveFolderDialogFragmentFactory
 import org.koin.core.module.dsl.viewModel
@@ -47,4 +49,8 @@ val featureMessageListModule = module {
         ) as SetupArchiveFolderDialogContract.ViewModel
     }
     factory<SetupArchiveFolderDialogFragmentFactory> { SetupArchiveFolderDialogFragment.Factory }
+
+    viewModel<MessageListContract.ViewModel> { parameters ->
+        MessageListViewModel()
+    }
 }

feature/mail/message/list/internal/src/main/kotlin/net/thunderbird/feature/mail/message/list/internal/ui/MessageListViewModel.kt

@@ -0,0 +1,10 @@
+package net.thunderbird.feature.mail.message.list.internal.ui
+
+import net.thunderbird.feature.mail.message.list.ui.MessageListContract
+import net.thunderbird.feature.mail.message.list.ui.event.MessageListEvent
+
+class MessageListViewModel : MessageListContract.ViewModel() {
+    override fun event(event: MessageListEvent) {
+        // TODO(9497): Handle events.
+    }
+}

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

@@ -273,7 +273,7 @@ open class MainActivity :
             fragmentManager.findFragmentByTag(FRAGMENT_TAG_MESSAGE_VIEW_CONTAINER) as? MessageViewContainerFragment
 
         messageListFragment?.let { messageListFragment ->
-            messageViewContainerFragment?.setViewModel(messageListFragment.viewModel)
+            messageViewContainerFragment?.setViewModel(messageListFragment.legacyViewModel)
             initializeFromLocalSearch(messageListFragment.localSearch)
         }
     }
@@ -1110,7 +1110,7 @@ open class MainActivity :
             messageViewContainerFragment = fragment
 
             messageListFragment?.let { messageListFragment ->
-                fragment.setViewModel(messageListFragment.viewModel)
+                fragment.setViewModel(messageListFragment.legacyViewModel)
             }
 
             if (displayMode == DisplayMode.SPLIT_VIEW) {

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

@@ -7,10 +7,13 @@ 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.messagelist.MessageListFragment
 import com.fsck.k9.ui.messageview.LinkTextHandler
 import com.fsck.k9.ui.settings.AboutViewModel
 import com.fsck.k9.ui.share.ShareIntentBuilder
 import net.thunderbird.core.common.inject.getList
+import net.thunderbird.core.featureflag.FeatureFlagProvider
+import net.thunderbird.feature.mail.message.list.MessageListFeatureFlags
 import org.koin.core.module.dsl.viewModel
 import org.koin.core.qualifier.named
 import org.koin.dsl.module
@@ -31,7 +34,11 @@ val uiModule = module {
     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
+        val featureFlagProvider = get<FeatureFlagProvider>()
+        if (featureFlagProvider.provide(MessageListFeatureFlags.EnableMessageListNewState).isEnabled()) {
+            MessageListFragment.Factory
+        } else {
+            LegacyMessageListFragment.Factory
+        }
     }
 }

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

@@ -147,7 +147,8 @@ abstract class AbstractMessageListFragment :
 
     abstract val logTag: String
 
-    val viewModel: MessageListViewModel by viewModel()
+    val legacyViewModel: MessageListViewModel by viewModel()
+    private val viewModel: MessageListViewModel get() = legacyViewModel
     private val recentChangesViewModel: RecentChangesViewModel by viewModel()
 
     private val generalSettingsManager: GeneralSettingsManager by inject()
@@ -201,7 +202,8 @@ abstract class AbstractMessageListFragment :
 
     private lateinit var adapter: MessageListAdapter
 
-    private lateinit var accountUuids: Array<String>
+    protected lateinit var accountUuids: Array<String>
+        private set
     private var accounts: List<LegacyAccount> = emptyList()
 
     private var account: LegacyAccount? = null
@@ -333,7 +335,7 @@ abstract class AbstractMessageListFragment :
         rememberedSelected = savedInstanceState.getLongArray(STATE_SELECTED_MESSAGES)?.toSet()
     }
 
-    private fun decodeArguments(): Error? {
+    protected fun decodeArguments(): Error? {
         val arguments = requireArguments()
         showingThreadedList = arguments.getBoolean(ARG_THREADED_LIST, false)
         isThreadDisplay = arguments.getBoolean(ARG_IS_THREAD_DISPLAY, false)
@@ -2590,7 +2592,7 @@ abstract class AbstractMessageListFragment :
     }
 
     @Suppress("detekt.UnnecessaryAnnotationUseSiteTarget") // https://github.com/detekt/detekt/issues/8212
-    private enum class Error(@param:StringRes val errorText: Int) {
+    protected enum class Error(@param:StringRes val errorText: Int) {
         FolderNotFound(R.string.message_list_error_folder_not_found),
     }
 

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

@@ -0,0 +1,42 @@
+package com.fsck.k9.ui.messagelist
+
+import androidx.core.os.bundleOf
+import net.thunderbird.feature.account.AccountIdFactory
+import net.thunderbird.feature.mail.message.list.ui.MessageListContract
+import net.thunderbird.feature.search.legacy.LocalMessageSearch
+import net.thunderbird.feature.search.legacy.serialization.LocalMessageSearchSerializer
+import org.koin.android.ext.android.inject
+import org.koin.core.parameter.parameterSetOf
+
+private const val TAG = "MessageListFragment"
+
+// TODO(10322): Move this fragment to :feature:mail:message:list once all migration to the new
+//              MessageListFragment to MVI is done.
+class MessageListFragment : AbstractMessageListFragment() {
+    override val logTag: String = TAG
+
+    // TODO(9497): Remove suppression once we start use the new view model.
+    @Suppress("UnusedPrivateProperty")
+    private val viewModel: MessageListContract.ViewModel by inject {
+        decodeArguments()
+        parameterSetOf(accountUuids.map { AccountIdFactory.of(it) }.toSet())
+    }
+
+    companion object Factory : AbstractMessageListFragment.Factory {
+        override 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,
+                )
+            }
+        }
+    }
+}