Feed writes: bulk OPML upsert, targeted fetch-result update, shared toggle

- AddFeedScreen: OPML import no longer crashes the app on a
  non-XML/corrupt file (try/catch around the whole import). Bulk
  upsertAll() instead of a per-feed getById()+upsert() loop -- 2N
  sequential DB round-trips for N feeds otherwise, real cost at 100+
  feed subscription lists.
- FeedDao.updateFetchResult only writes the columns a fetch actually
  produces, instead of a full-row @Update built from a feed snapshot
  read before a (possibly slow) network round-trip -- the old path
  could silently revert a readerModeEnabled/folder edit made via
  FeedListScreen while that feed's fetch was still in flight.
- setReaderModeEnabled(feed, enabled) persists the toggle and returns
  the exact confirmation text, shared by FeedListScreen's per-row
  toggle and ReaderScreen's toggleFeedReaderMode -- previously two
  independently-typed copies of the same snackbar message.

1 files changed, 35 insertions, 23 deletions

diff --git a/app/src/main/java/org/terst/feedreader/ui/AddFeedScreen.kt b/app/src/main/java/org/terst/feedreader/ui/AddFeedScreen.kt
index 38b0f32..1e8814c 100644
--- a/app/src/main/java/org/terst/feedreader/ui/AddFeedScreen.kt
+++ b/app/src/main/java/org/terst/feedreader/ui/AddFeedScreen.kt
@@ -54,30 +54,42 @@ fun AddFeedScreen(onDone: () -> Unit) {
         if (uri == null) return@rememberLauncherForActivityResult
         isBusy = true
         scope.launch {
-            val imported = withContext(Dispatchers.IO) {
-                context.contentResolver.openInputStream(uri)?.use { stream -> Opml.parse(stream) } ?: emptyList()
-            }
-            // A feed cross-listed under multiple OPML category folders (common when
-            // exported from a reader with folders/labels) appears once per folder here --
-            // dedupe by feed URL before reporting a count, or "108 feeds" would be reported
-            // as some larger number even though upsert already collapses them to one row each.
-            val uniqueFeeds = imported.map { it.copy(xmlUrl = preferHttps(it.xmlUrl)) }.distinctBy { it.xmlUrl }
-            for (feed in uniqueFeeds) {
-                // upsert() REPLACEs the whole row -- for a feed that's already subscribed,
-                // building a bare FeedEntity here would silently wipe readerModeDisabled
-                // (and etag/lastModified/lastError) back to defaults on every re-import.
-                // Preserve the existing row's other fields; only title/siteUrl come from OPML.
-                val existing = db.feedDao().getById(feed.xmlUrl)
-                val entity = existing?.copy(
-                    title = feed.title,
-                    siteUrl = feed.htmlUrl ?: existing.siteUrl,
-                    folder = feed.folder ?: existing.folder
-                ) ?: FeedEntity(id = feed.xmlUrl, title = feed.title, siteUrl = feed.htmlUrl, folder = feed.folder)
-                db.feedDao().upsert(entity)
+            try {
+                val imported = withContext(Dispatchers.IO) {
+                    context.contentResolver.openInputStream(uri)?.use { stream -> Opml.parse(stream) } ?: emptyList()
+                }
+                // A feed cross-listed under multiple OPML category folders (common when
+                // exported from a reader with folders/labels) appears once per folder here --
+                // dedupe by feed URL before reporting a count, or "108 feeds" would be reported
+                // as some larger number even though upsert already collapses them to one row each.
+                val uniqueFeeds = imported.map { it.copy(xmlUrl = preferHttps(it.xmlUrl)) }.distinctBy { it.xmlUrl }
+                withContext(Dispatchers.IO) {
+                    // Loaded once, not one getById() per feed: upsert() REPLACEs the whole
+                    // row, and for a feed that's already subscribed, building a bare
+                    // FeedEntity here would silently wipe readerModeDisabled (and
+                    // etag/lastModified/lastError) back to defaults on every re-import --
+                    // preserve the existing row's other fields, only title/siteUrl come
+                    // from OPML.
+                    val existingById = db.feedDao().getAll().associateBy { it.id }
+                    val entities = uniqueFeeds.map { feed ->
+                        val existing = existingById[feed.xmlUrl]
+                        existing?.copy(
+                            title = feed.title,
+                            siteUrl = feed.htmlUrl ?: existing.siteUrl,
+                            folder = feed.folder ?: existing.folder
+                        ) ?: FeedEntity(id = feed.xmlUrl, title = feed.title, siteUrl = feed.htmlUrl, folder = feed.folder)
+                    }
+                    db.feedDao().upsertAll(entities)
+                }
+                FeedFetchWorker.fetchNow(context)
+                status = "Imported ${uniqueFeeds.size} feed(s)"
+            } catch (e: Exception) {
+                // A non-XML or corrupt/truncated file throws from Opml.parse -- without this,
+                // that crashed the whole app instead of just failing this one import.
+                status = "Couldn't import: ${e.message}"
+            } finally {
+                isBusy = false
             }
-            FeedFetchWorker.fetchNow(context)
-            status = "Imported ${uniqueFeeds.size} feed(s)"
-            isBusy = false
         }
     }