fix: make --output and --updatepaths tell the truth about TTFolderPath

--output iterated all 156k active Blogs rows and printed a "does not exist or is
not set" skip line for each, which is nearly every blog in the crawl registry --
only the few hundred downloaded locally ever have a folder. The signal was
buried in six figures of noise.

GetAllBlogsWithTTFolderPath now selects only active blogs carrying a non-empty
path, so --output processes export targets and nothing else. When none exist it
says so once, names the database it read, points at --updatepaths, and returns
non-zero instead of reporting success. A stored path this machine cannot see is
now reported separately from an unset one, with the path shown, because the two
are fixed in different places. Paths are trimmed before Directory.Exists, which
stray whitespace in a .tumblr FileDownloadLocation would otherwise defeat.

Both writers counted optimistically. UpdateBlogPathsRunner printed its
per-blog success line and incremented its total from the metadata file parsing,
never checking whether the UPDATE matched a row; LegacyPostsDbImporter counted a
blog as copied even when the legacy TTFolderPath was NULL. Either could report
full success having written nothing -- which is consistent with TL.db holding
zero populated paths across all 156,492 active blogs despite 20,679 posts having
merged. SetBlogTTFolderPath now returns whether a row changed, and both callers
report written / already-correct / no-matching-row separately.

Verified against a throwaway database: no-paths case, export case (stale .txt
rotated to .bak, per-PostType files, date-sorted), missing-folder case,
--updatepaths honest counts, and an idempotent rerun reporting already-correct.

Co-Authored-By: Claude Opus 5 <[email protected]>

URLNotesGrabberCORE/DataAccess.cs

@@ -106,6 +106,10 @@ namespace URLNotesGrabberCORE
             }
         }
 
+        // The database every DataAccess call defaults to, exposed so modes can report
+        // which file they actually read when their results are surprising.
+        public static string GetActiveDbPath() => GetDefaultDbPath();
+
         private static string GetDefaultDbPath()
         {
             if (_cachedDbPath != null)
@@ -2304,7 +2308,11 @@ namespace URLNotesGrabberCORE
             };
         }
 
-        public static void SetBlogTTFolderPath(string blogName, string? path, string? DBPath = null)
+        // Returns true only when a row's TTFolderPath actually changed. A false means either
+        // the row already held this value or no row matched the name -- callers must not
+        // report a write they did not get, which is how a --updatepaths run could once print
+        // "Updated <blog>" for every metadata file while leaving the column entirely NULL.
+        public static bool SetBlogTTFolderPath(string blogName, string? path, string? DBPath = null)
         {
             DBPath ??= GetDefaultDbPath();
             try { AddBlog(blogName, false, DBPath); } catch { }
@@ -2317,7 +2325,21 @@ namespace URLNotesGrabberCORE
             cmd.Parameters.AddWithValue("@path", (object?)path ?? DBNull.Value);
             cmd.Parameters.AddWithValue("@modified", DateTime.Now.ToString("yyyy-MM-dd HH:mm:ss"));
             cmd.Parameters.AddWithValue("@name", blogName);
-            cmd.ExecuteNonQuery();
+            return cmd.ExecuteNonQuery() > 0;
+        }
+
+        // Whether a Blogs row exists under this exact name. BlogName is a BINARY-collated
+        // primary key, so a metadata filename that differs only in case is a different blog
+        // as far as the UPDATE above is concerned -- worth telling the user about.
+        public static bool BlogExists(string blogName, string? DBPath = null)
+        {
+            DBPath ??= GetDefaultDbPath();
+
+            using var connection = new SQLiteConnection("Data Source=" + DBPath);
+            connection.Open();
+            using var cmd = new SQLiteCommand("SELECT 1 FROM Blogs WHERE BlogName = @name", connection);
+            cmd.Parameters.AddWithValue("@name", blogName);
+            return cmd.ExecuteScalar() != null;
         }
 
         // Partial UPDATE used by the correct-apply path. fieldsToUpdate maps
@@ -2391,24 +2413,48 @@ namespace URLNotesGrabberCORE
             };
         }
 
-        public static List<(string BlogName, string? TTFolderPath)> GetAllBlogsWithTTFolderPath(string? DBPath = null)
+        // Export targets only: active blogs that actually carry a TTFolderPath.
+        // Blogs is a 144k-row crawl registry and only the few hundred blogs downloaded
+        // locally have a folder, so returning the unset rows made --output print a skip
+        // line for every blog Tumblr has ever handed us.
+        public static List<(string BlogName, string TTFolderPath)> GetAllBlogsWithTTFolderPath(string? DBPath = null)
         {
             DBPath ??= GetDefaultDbPath();
-            var results = new List<(string, string?)>();
+            var results = new List<(string, string)>();
 
             using var connection = new SQLiteConnection("Data Source=" + DBPath);
             connection.Open();
-            using var cmd = new SQLiteCommand("SELECT BlogName, TTFolderPath FROM Blogs WHERE IsActive = 1", connection);
+            using var cmd = new SQLiteCommand(
+                "SELECT BlogName, TRIM(TTFolderPath) FROM Blogs WHERE IsActive = 1 AND IFNULL(TRIM(TTFolderPath), '') <> '' ORDER BY BlogName",
+                connection);
             using var reader = cmd.ExecuteReader();
             while (reader.Read())
-            {
-                string name = reader.GetString(0);
-                string? path = reader.IsDBNull(1) ? null : reader.GetString(1);
-                results.Add((name, path));
-            }
+                results.Add((reader.GetString(0), reader.GetString(1)));
             return results;
         }
 
+        // Companion counts for the messages --output and --updatepaths print about coverage.
+        public static int CountActiveBlogs(string? DBPath = null)
+        {
+            DBPath ??= GetDefaultDbPath();
+
+            using var connection = new SQLiteConnection("Data Source=" + DBPath);
+            connection.Open();
+            using var cmd = new SQLiteCommand("SELECT COUNT(*) FROM Blogs WHERE IsActive = 1", connection);
+            return Convert.ToInt32(cmd.ExecuteScalar());
+        }
+
+        public static int CountBlogsWithTTFolderPath(string? DBPath = null)
+        {
+            DBPath ??= GetDefaultDbPath();
+
+            using var connection = new SQLiteConnection("Data Source=" + DBPath);
+            connection.Open();
+            using var cmd = new SQLiteCommand(
+                "SELECT COUNT(*) FROM Blogs WHERE IFNULL(TRIM(TTFolderPath), '') <> ''", connection);
+            return Convert.ToInt32(cmd.ExecuteScalar());
+        }
+
         private static string SafeStr(SQLiteDataReader reader, int ordinal)
         {
             return reader.IsDBNull(ordinal) ? string.Empty : reader.GetValue(ordinal)?.ToString() ?? string.Empty;