View/logic improvements

composeApp/src/commonMain/kotlin/net/sergeych/toread/App.kt

@@ -103,6 +103,41 @@ private fun BookReaderApp(onThemeToggle: () -> Unit) {
         state = loadStartupState()
     }
 
+    fun navigateBack() {
+        imageViewer?.let {
+            imageViewer = null
+            return
+        }
+        state = when (val current = state) {
+            is AppState.BookInfo -> AppState.Reader(
+                fileId = current.fileId,
+                book = current.book,
+                libraryItems = current.libraryItems,
+                scanPath = current.scanPath,
+                message = current.message,
+            )
+            is AppState.Reader -> {
+                scope.launch { saveActiveReadingFileId(null) }
+                AppState.Library(current.libraryItems, current.scanPath, current.message)
+            }
+            is AppState.Scan -> AppState.Library(current.items, current.scanPath, current.message)
+            is AppState.Error -> AppState.LoadingLibrary
+            is AppState.Library, AppState.LoadingLibrary -> current
+        }
+    }
+
+    val navigationDepth = when (state) {
+        is AppState.BookInfo -> 2
+        is AppState.Error, is AppState.Reader, is AppState.Scan -> 1
+        is AppState.Library, AppState.LoadingLibrary -> 0
+    } + if (imageViewer != null) 1 else 0
+
+    PlatformBackHandler(
+        enabled = navigationDepth > 0,
+        navigationDepth = navigationDepth,
+        onBack = ::navigateBack,
+    )
+
     fun startScan(path: String) {
         if (scanJob?.isActive == true) return
         activeScan = LibraryScanProgress(0, 0, 0, 0)
@@ -126,7 +161,17 @@ private fun BookReaderApp(onThemeToggle: () -> Unit) {
             scanJob = null
             activeScan = null
             state = when (val current = state) {
-                is AppState.Library, is AppState.Scan, AppState.LoadingLibrary -> loadLibraryState(message, path)
+                is AppState.Library -> if (report.getOrNull()?.hasLibraryChanges() == true) {
+                    loadLibraryState(message, path)
+                } else {
+                    current.copy(scanPath = path, message = message)
+                }
+                is AppState.Scan -> if (report.getOrNull()?.hasLibraryChanges() == true) {
+                    loadLibraryState(message, path)
+                } else {
+                    AppState.Library(current.items, path, message)
+                }
+                AppState.LoadingLibrary -> loadLibraryState(message, path)
                 is AppState.Reader -> current.copy(message = message)
                 is AppState.BookInfo -> current.copy(message = message)
                 is AppState.Error -> current
@@ -169,31 +214,21 @@ private fun BookReaderApp(onThemeToggle: () -> Unit) {
             onDeleted = { message ->
                 state = AppState.Library(emptyList(), current.scanPath, message)
             },
-            onBack = {
-                state = AppState.Library(emptyList(), current.scanPath, current.message)
-            },
+            onBack = ::navigateBack,
         )
         is AppState.BookInfo -> BookInfoScreen(
             fileId = current.fileId,
             book = current.book,
             onImageOpen = { imageViewer = it },
-            onBack = {
-                state = AppState.Reader(
-                    fileId = current.fileId,
-                    book = current.book,
-                    libraryItems = current.libraryItems,
-                    scanPath = current.scanPath,
-                    message = current.message,
-                )
-            },
+            onBack = ::navigateBack,
         )
-        is AppState.Error -> ErrorScreen(current.message, onBack = { state = AppState.LoadingLibrary })
+        is AppState.Error -> ErrorScreen(current.message, onBack = ::navigateBack)
     }
 
     imageViewer?.let { image ->
         ImageViewer(
             image = image,
-            onBack = { imageViewer = null },
+            onBack = ::navigateBack,
         )
     }
 }
@@ -204,3 +239,6 @@ internal data class ViewedBookImage(
     val mimeType: String,
     val title: String,
 )
+
+private fun LibraryScanReport.hasLibraryChanges(): Boolean =
+    importedFiles > 0

composeApp/src/commonMain/kotlin/net/sergeych/toread/LibraryPlatform.kt

@@ -44,6 +44,12 @@ data class LibraryScanProgress(
     val totalFiles: Int? = null,
 )
 
+data class LibraryRescanReport(
+    val scannedFiles: Int,
+    val updatedFiles: Int,
+    val failedFiles: Int,
+)
+
 data class PlatformOpenBookRequest(
     val id: String,
     val displayName: String,
@@ -100,6 +106,10 @@ expect suspend fun scanLibrarySubtree(path: String, onProgress: (LibraryScanProg
 
 expect suspend fun openLibraryBook(fileId: String): ByteArray?
 
+expect suspend fun refreshLibraryItemFromParsedBook(fileId: String, book: Fb2Book): LibraryItem?
+
+expect suspend fun rescanAllLibraryBooks(): LibraryRescanReport
+
 expect suspend fun deleteLibraryItem(fileId: String): Boolean
 
 expect suspend fun loadLibraryReadingPosition(fileId: String): ReadingPosition?

composeApp/src/commonMain/kotlin/net/sergeych/toread/LibraryScreen.kt

@@ -27,7 +27,6 @@ import androidx.compose.material.icons.filled.Add
 import androidx.compose.material.icons.filled.Close
 import androidx.compose.material.icons.filled.KeyboardArrowDown
 import androidx.compose.material.icons.filled.MoreVert
-import androidx.compose.material.icons.filled.Refresh
 import androidx.compose.material.icons.filled.Search
 import androidx.compose.material3.Card
 import androidx.compose.material3.Checkbox
@@ -62,6 +61,7 @@ import androidx.compose.ui.input.key.onPreviewKeyEvent
 import androidx.compose.ui.input.key.type
 import androidx.compose.ui.layout.ContentScale
 import androidx.compose.ui.text.font.FontWeight
+import androidx.compose.ui.text.style.TextOverflow
 import androidx.compose.ui.text.style.TextAlign
 import androidx.compose.ui.unit.dp
 import net.sergeych.toread.fb2.Fb2Format
@@ -103,18 +103,28 @@ internal fun LibraryScreen(
     suspend fun loadPage(reset: Boolean = false) {
         if (loadingPage) return
         loadingPage = true
+        val previousItems = items
         if (reset) {
-            items = emptyList()
             nextOffset = 0
             endReached = false
-            coverCache.clear()
         }
         val offset = if (reset) 0 else nextOffset
         try {
-            val page = loadLibraryItemsPage(LibraryPageSize, offset)
-            items = if (reset) page else items + page
+            val limit = if (reset) maxOf(LibraryPageSize, previousItems.size) else LibraryPageSize
+            val page = loadLibraryItemsPage(limit, offset)
+            if (reset) {
+                if (page != previousItems) {
+                    items = page
+                }
+                val visibleFileIds = page.mapTo(mutableSetOf()) { it.fileId }
+                coverCache.keys.toList().forEach { fileId ->
+                    if (fileId !in visibleFileIds) coverCache.remove(fileId)
+                }
+            } else {
+                items = items + page
+            }
             nextOffset = offset + page.size
-            endReached = page.size < LibraryPageSize
+            endReached = page.size < limit
         } catch (t: Throwable) {
             message = t.message ?: "Could not load library."
             endReached = true
@@ -136,6 +146,24 @@ internal fun LibraryScreen(
         }
     }
 
+    fun rescanAllLibrary() {
+        settingsMenuOpen = false
+        scope.launch {
+            busy = true
+            message = "Rescanning library..."
+            try {
+                val report = rescanAllLibraryBooks()
+                refresh(
+                    "Rescanned ${report.scannedFiles}, updated ${report.updatedFiles}, failed ${report.failedFiles}.",
+                )
+            } catch (t: Throwable) {
+                message = t.message ?: "Library rescan failed."
+            } finally {
+                busy = false
+            }
+        }
+    }
+
     fun clearSearch() {
         searchText = ""
         searchResults = emptyList()
@@ -212,14 +240,17 @@ internal fun LibraryScreen(
                 },
                 colors = themedTopAppBarColors(),
                 actions = {
-                    IconButton(onClick = { refresh() }, enabled = !busy && !loadingPage) {
-                        Icon(Icons.Filled.Refresh, contentDescription = "Refresh library")
-                    }
                     Box {
                         IconButton(onClick = { settingsMenuOpen = true }) {
                             Icon(Icons.Filled.MoreVert, contentDescription = "Library options")
                         }
                         DropdownMenu(expanded = settingsMenuOpen, onDismissRequest = { settingsMenuOpen = false }) {
+//                            DropdownMenuItem(
+//                                text = { Text("Rescan all library") },
+//                                enabled = !busy && activeScan == null,
+//                                onClick = ::rescanAllLibrary,
+//                            )
+//                            HorizontalDivider()
                             DropdownMenuItem(
                                 leadingIcon = {
                                     Checkbox(checked = autoScanDownloads, onCheckedChange = null)
@@ -282,12 +313,19 @@ internal fun LibraryScreen(
                                     val next = runCatching {
                                         val bytes = openLibraryBook(item.fileId) ?: error("Book file is not available.")
                                         val book = Fb2Format.parse(bytes, item.storageUri ?: item.title)
+                                        var readerLibraryItems = visibleItems
+                                        refreshLibraryItemFromParsedBook(item.fileId, book)?.let { updatedItem ->
+                                            items = items.replaceLibraryItem(updatedItem)
+                                            searchResults = searchResults.replaceLibraryItem(updatedItem)
+                                            readerLibraryItems = readerLibraryItems.replaceLibraryItem(updatedItem)
+                                            coverCache[updatedItem.fileId] = loadLibraryItemCover(updatedItem.fileId)
+                                        }
                                         markLibraryReadingStatus(item.fileId, BookReadingStatus.READING)
                                         saveActiveReadingFileId(item.fileId)
                                         AppState.Reader(
                                             fileId = item.fileId,
                                             book = book,
-                                            libraryItems = visibleItems,
+                                            libraryItems = readerLibraryItems,
                                             scanPath = state.scanPath,
                                             message = message,
                                         )
@@ -639,12 +677,14 @@ private fun LibraryRow(
                     style = MaterialTheme.typography.titleMedium,
                     fontWeight = FontWeight.SemiBold,
                     maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
                 )
                 Text(
                     item.authors.joinToString().ifBlank { "Unknown author" },
                     style = MaterialTheme.typography.bodyMedium,
                     color = MaterialTheme.colorScheme.secondary,
                     maxLines = 1,
+                    overflow = TextOverflow.Ellipsis,
                 )
                 Text(
                     item.libraryMetadataLine(),
@@ -791,6 +831,9 @@ private fun Long.formatBytes(): String =
         else -> "$this B"
     }
 
+private fun List<LibraryItem>.replaceLibraryItem(item: LibraryItem): List<LibraryItem> =
+    map { current -> if (current.fileId == item.fileId) item else current }
+
 private fun LibraryScanProgress.toCatalogScanMessage(): String {
     val total = totalFiles ?: return "Scanned $scannedFiles books"
     val percent = if (total <= 0) {

composeApp/src/commonMain/kotlin/net/sergeych/toread/PlatformBackHandler.kt

@@ -0,0 +1,10 @@
+package net.sergeych.toread
+
+import androidx.compose.runtime.Composable
+
+@Composable
+internal expect fun PlatformBackHandler(
+    enabled: Boolean,
+    navigationDepth: Int,
+    onBack: () -> Unit,
+)