feat(search,settings): add search landing page and configurable start tab

shared/src/commonMain/composeResources/values-en/strings.xml

@@ -1,4 +1,5 @@
 <resources>
+    <string name="app_name">Bilby</string>
     <string name="action_back">Back</string>
     <string name="action_cancel">Cancel</string>
     <string name="nav_already_here">Already on this page</string>
@@ -396,6 +397,7 @@
     <string name="settings_theme_system">System</string>
     <string name="settings_theme_light">Light</string>
     <string name="settings_theme_dark">Dark</string>
+    <string name="settings_start_tab">Start page</string>
     <string name="settings_pure_black">Pure black</string>
     <string name="settings_pure_black_subtitle">Black background in dark theme</string>
     <string name="settings_theme_palette">Color</string>

shared/src/commonMain/composeResources/values/strings.xml

@@ -1,4 +1,6 @@
 <resources>
+    <string name="app_name">Bilby</string>
+
     <!-- 导航。 -->
     <string name="nav_already_here">已在当前页面</string>
 
@@ -479,6 +481,7 @@
     <string name="settings_theme_system">跟随系统</string>
     <string name="settings_theme_light">浅色</string>
     <string name="settings_theme_dark">深色</string>
+    <string name="settings_start_tab">默认启动页</string>
     <string name="settings_pure_black">纯黑背景</string>
     <string name="settings_pure_black_subtitle">深色时页面底色为纯黑</string>
     <string name="settings_theme_palette">配色</string>

shared/src/commonMain/kotlin/dev/bilby/data/SettingsStore.kt

@@ -237,9 +237,15 @@ class SettingsStore(private val store: DataStore<Preferences>) {
                 ?: ThemeMode.System,
             pureBlack = p[KEY_PURE_BLACK] ?: false,
             palette = p[KEY_THEME_PALETTE] ?: AppearancePrefs.DYNAMIC,
+            startTab = p[KEY_START_TAB]?.let { name -> StartTab.entries.firstOrNull { it.name == name } }
+                ?: StartTab.Search,
         )
     }
 
+    val startTab: Flow<StartTab?> = store.data.map { p ->
+        p[KEY_START_TAB]?.let { name -> StartTab.entries.firstOrNull { it.name == name } } ?: StartTab.Search
+    }
+
     suspend fun saveThemeMode(mode: ThemeMode) {
         store.edit { p -> p[KEY_THEME_MODE] = mode.name }
     }
@@ -253,6 +259,10 @@ class SettingsStore(private val store: DataStore<Preferences>) {
         store.edit { p -> p[KEY_THEME_PALETTE] = palette }
     }
 
+    suspend fun saveStartTab(tab: StartTab) {
+        store.edit { p -> p[KEY_START_TAB] = tab.name }
+    }
+
     /**
      * 同时下几条缓存。为什么默认 1、上限 3,见 [dev.bilby.offline.OfflineDownloader] 的
      * "并发度"一节 —— 这里只负责把用户选的那个数存下来。
@@ -452,6 +462,7 @@ class SettingsStore(private val store: DataStore<Preferences>) {
         private val KEY_THEME_MODE = stringPreferencesKey("theme_mode")
         private val KEY_PURE_BLACK = booleanPreferencesKey("theme_pure_black")
         private val KEY_THEME_PALETTE = stringPreferencesKey("theme_palette")
+        private val KEY_START_TAB = stringPreferencesKey("start_tab")
         private val KEY_SESSDATA = stringPreferencesKey("sessdata")
         private val KEY_BILI_JCT = stringPreferencesKey("bili_jct")
         private val KEY_DEDE_USER_ID = stringPreferencesKey("dede_user_id")
@@ -758,6 +769,9 @@ data class PlayerPrefs(
 /** 明暗。三档互斥;纯黑是深色之下的另一个开关,不是第四档,见 [AppearancePrefs.pureBlack]。 */
 enum class ThemeMode { System, Light, Dark }
 
+/** 启动时默认落到哪一栏:动态、搜索着陆页或我的。 */
+enum class StartTab { Feed, Search, Profile }
+
 data class AppearancePrefs(
     val mode: ThemeMode = ThemeMode.System,
     /**
@@ -772,6 +786,7 @@ data class AppearancePrefs(
      * 指到别的颜色上。
      */
     val palette: String = DYNAMIC,
+    val startTab: StartTab = StartTab.Search,
 ) {
     companion object {
         const val DYNAMIC = "dynamic"

shared/src/commonMain/kotlin/dev/bilby/ui/BilbyApp.kt

@@ -108,6 +108,7 @@ import dev.bilby.stringResource
 import androidx.compose.ui.graphics.vector.ImageVector
 import androidx.lifecycle.compose.collectAsStateWithLifecycle
 import dev.bilby.data.AppearancePrefs
+import dev.bilby.data.StartTab
 import androidx.lifecycle.viewmodel.compose.viewModel
 import androidx.lifecycle.viewmodel.initializer
 import androidx.lifecycle.viewmodel.viewModelFactory
@@ -1115,24 +1116,38 @@ private fun RootTabs(
     /** 搜索框里的编号或链接直接打开的那一页,可以是任何一种目的地。 */
     onOpen: (NavKey) -> Unit,
 ) {
-    var selected by rememberSaveable { mutableStateOf(RootTab.Feed) }
+    val persistedStartTab by container.settings.startTab.collectAsStateWithLifecycle(initialValue = null)
+    var selected by rememberSaveable { mutableStateOf(RootTab.Search) }
+    var appliedStartTab by rememberSaveable { mutableStateOf<StartTab?>(null) }
+    LaunchedEffect(persistedStartTab) {
+        val tab = persistedStartTab ?: return@LaunchedEffect
+        if (appliedStartTab != tab) {
+            appliedStartTab = tab
+            selected = when (tab) {
+                StartTab.Feed -> RootTab.Feed
+                StartTab.Search -> RootTab.Search
+                StartTab.Profile -> RootTab.Profile
+            }
+        }
+    }
     val windowSize = rememberBilbyWindowSize()
 
-    // 重按当前 tab 回到顶部,navigation-bar.md 的明文要求。
+    // 重按当前 tab 回到这一页的起点,navigation-bar.md 的明文要求。
     //
     // **每个 tab 一个计数器,不共用一个。** 共用的话,在动态页连点几下再切到个人页,
     // 个人页看到的是一个变过的计数器,会跟着滚一次它自己没被点过的。
     //
-    // 搜索页不接:那一页是对话式的,输入在下、一轮轮结果往上滚,顶端是最早的一轮,
-    // 回到顶不是"重来一次",而是翻到最旧的地方。
+    // 搜索页的"起点"是着陆页不是顶端:那一页是对话式的,没有"回到顶",搜过之后
+    // 重按是清掉查询翻回居中的框 —— 与回顶同一件事,都是回到进来的那一屏。
     var feedScrollToTop by remember { mutableIntStateOf(0) }
     var profileScrollToTop by remember { mutableIntStateOf(0) }
+    var searchHomeClicks by remember { mutableIntStateOf(0) }
     val onTabClick: (RootTab) -> Unit = { tab ->
         if (selected == tab) {
             when (tab) {
                 RootTab.Feed -> feedScrollToTop++
                 RootTab.Profile -> profileScrollToTop++
-                RootTab.Search -> Unit
+                RootTab.Search -> searchHomeClicks++
             }
         } else {
             selected = tab
@@ -1181,6 +1196,7 @@ private fun RootTabs(
                 feedScrollToTop = feedScrollToTop,
                 profileScrollToTop = profileScrollToTop,
                 focusSearchNonce = focusSearchNonce,
+                searchHomeClicks = searchHomeClicks,
                 container = container,
                 onVideoClick = onVideoClick,
                 onVideoInContext = onVideoInContext,
@@ -1218,6 +1234,7 @@ private fun RootTabs(
                     feedScrollToTop = feedScrollToTop,
                     profileScrollToTop = profileScrollToTop,
                     focusSearchNonce = focusSearchNonce,
+                    searchHomeClicks = searchHomeClicks,
                     container = container,
                     onVideoClick = onVideoClick,
                     onVideoInContext = onVideoInContext,
@@ -1343,6 +1360,8 @@ private fun RootTabsContent(
     feedScrollToTop: Int,
     profileScrollToTop: Int,
     focusSearchNonce: Int,
+    /** 每变一次就翻回着陆页,与回顶同一语义(搜索页没有"顶端"可回)。 */
+    searchHomeClicks: Int,
     container: AppContainer,
     onVideoClick: (String) -> Unit,
     onVideoInContext: (String, QueueContext) -> Unit,
@@ -1416,7 +1435,15 @@ private fun RootTabsContent(
                 )
 
                 // 不限宽:宽屏结果是格子、助理是侧栏,搜索框自己限宽(见 SearchChatScreen)。
-                RootTab.Search -> SearchPane(container, focusSearchNonce, onVideoClick, onUserClick, onOpenArticle, onOpen)
+                RootTab.Search -> SearchPane(
+                    container = container,
+                    focusSearchNonce = focusSearchNonce,
+                    searchHomeClicks = searchHomeClicks,
+                    onVideoClick = onVideoClick,
+                    onUserClick = onUserClick,
+                    onOpenArticle = onOpenArticle,
+                    onOpen = onOpen,
+                )
 
                 // 不限宽:宽屏每节是一排卡片,宽度换成条数(见 ProfileScreen);窄屏账号卡自己限宽。
                 RootTab.Profile -> ProfilePane(
@@ -1518,6 +1545,8 @@ private fun FeedPane(
 private fun SearchPane(
     container: AppContainer,
     focusSearchNonce: Int,
+    /** 重按搜索 tab 的次数:每变一次回一次着陆页。 */
+    searchHomeClicks: Int,
     onVideoClick: (String) -> Unit,
     onUserClick: (Long) -> Unit,
     onOpenArticle: (ArticleRef) -> Unit,
@@ -1536,6 +1565,15 @@ private fun SearchPane(
             }
         },
     )
+    // **只认计数的变化,不认它的值。** 切走再切回来时 remember 重取当前值,effect 会再跑
+    // 一趟但两次读数相同 —— 没有那一下按下,就不该把结果页翻回着陆页。
+    var lastHomeClick by remember { mutableIntStateOf(searchHomeClicks) }
+    LaunchedEffect(searchHomeClicks) {
+        if (searchHomeClicks != lastHomeClick) {
+            lastHomeClick = searchHomeClicks
+            vm.backToLanding()
+        }
+    }
     val currentOnOpen by rememberUpdatedState(onOpen)
     LaunchedEffect(vm) { vm.open.collect { currentOnOpen(it) } }
     val state by vm.state.collectAsStateWithLifecycle()
@@ -1551,6 +1589,7 @@ private fun SearchPane(
         onHistoryRemove = vm::removeSearchHistory,
         onHistoryClear = vm::clearSearchHistory,
         onSuggestionClick = vm::searchSuggestion,
+        onBackToLanding = vm::backToLanding,
         onInputChange = vm::onInputChange,
         onSearch = vm::search,
         onAskAgent = vm::askAgent,
@@ -1765,6 +1804,7 @@ private fun SettingsPageRoute(
             onModeChange = vm::setThemeMode,
             onPureBlackChange = vm::setPureBlack,
             onPaletteChange = vm::setThemePalette,
+            onStartTabChange = vm::setStartTab,
             onLanguageChange = system::applyLanguage,
             onBack = onBack,
         )

shared/src/commonMain/kotlin/dev/bilby/ui/search/NormalSearchController.kt

@@ -255,6 +255,12 @@ class NormalSearchController(
         restart(userPager)
     }
 
+    /** 回到还没搜过的状态:三栏归零、查询抹掉,界面翻回着陆页。重按搜索 tab 走这里。 */
+    fun clear() {
+        _state.update { it.copy(query = "") }
+        SearchTab.entries.forEach { pagerFor(it).reset(keepVisible = false) }
+    }
+
     /** 重试和下拉刷新:当前栏从第一页重来,已有结果留在屏幕上等新页落地。 */
     fun retry() {
         val s = _state.value