lib/core/db_schema_version.dart

@@ -1 +1 @@
-const int dbSchemaVersion = 38;
+const int dbSchemaVersion = 39;

lib/core/models/note.dart

@@ -0,0 +1,17 @@
+class EmailNote {
+  final String id; // UUID (X-SharedInbox-Note-Id)
+  final String accountId;
+  final String messageId; // RFC 2822 Message-ID (X-SharedInbox-Note-For)
+  final String noteText;
+  final String serverId; // IMAP UID (as string) or JMAP email ID
+  final DateTime createdAt;
+
+  const EmailNote({
+    required this.id,
+    required this.accountId,
+    required this.messageId,
+    required this.noteText,
+    required this.serverId,
+    required this.createdAt,
+  });
+}

lib/core/repositories/note_repository.dart

@@ -0,0 +1,15 @@
+import 'package:sharedinbox/core/models/note.dart';
+
+abstract class NoteRepository {
+  /// Stream of notes for an email, keyed by [messageId] (stable across moves).
+  Stream<List<EmailNote>> observeNotes(String accountId, String messageId);
+
+  /// Fetches notes from the server into the local cache.
+  Future<void> syncNotes(String accountId, String messageId);
+
+  /// Creates a new note on the server and caches it locally.
+  Future<void> addNote(String accountId, String messageId, String text);
+
+  /// Deletes a note from the server and removes it from the local cache.
+  Future<void> deleteNote(String noteId);
+}

lib/data/db/database.dart

@@ -318,6 +318,26 @@ class ImageTrustedSenders extends Table {
   Set<Column> get primaryKey => {senderEmail};
 }
 
+/// Per-email notes stored server-side (IMAP Notes folder / JMAP Notes mailbox).
+/// Keyed by the RFC 2822 Message-ID header so notes survive folder moves.
+// Added in schema v39.
+@DataClassName('EmailNoteRow')
+class EmailNotes extends Table {
+  // UUID matching the X-SharedInbox-Note-Id custom header on the server.
+  TextColumn get id => text()();
+  TextColumn get accountId =>
+      text().references(Accounts, #id, onDelete: KeyAction.cascade)();
+  // X-SharedInbox-Note-For value — stable across IMAP folder moves.
+  TextColumn get messageId => text()();
+  TextColumn get noteText => text()();
+  // IMAP UID (as string) or JMAP email ID of the note message on the server.
+  TextColumn get serverId => text()();
+  DateTimeColumn get createdAt => dateTime()();
+
+  @override
+  Set<Column> get primaryKey => {id};
+}
+
 /// App-wide user preferences, stored as a singleton row (id always 1).
 @DataClassName('UserPreferencesRow')
 class UserPreferences extends Table {
@@ -363,6 +383,7 @@ class UserPreferences extends Table {
     ShareKeys,
     UserPreferences,
     ImageTrustedSenders,
+    EmailNotes,
   ],
 )
 class AppDatabase extends _$AppDatabase {
@@ -639,6 +660,9 @@ class AppDatabase extends _$AppDatabase {
               userPreferences.bodyCacheLimitMb,
             );
           }
+          if (from < 39) {
+            await m.createTable(emailNotes);
+          }
         },
       );
 }

lib/data/repositories/note_repository_impl.dart

@@ -0,0 +1,570 @@
+import 'dart:math' as math;
+
+import 'package:drift/drift.dart';
+import 'package:enough_mail/enough_mail.dart' as imap;
+import 'package:http/http.dart' as http;
+
+import 'package:sharedinbox/core/models/account.dart' as account_model;
+import 'package:sharedinbox/core/models/note.dart';
+import 'package:sharedinbox/core/repositories/account_repository.dart';
+import 'package:sharedinbox/core/repositories/note_repository.dart';
+import 'package:sharedinbox/data/db/database.dart';
+import 'package:sharedinbox/data/imap/imap_client_factory.dart';
+import 'package:sharedinbox/data/jmap/jmap_client.dart';
+
+const _notesFolder = 'Notes';
+const _headerNoteFor = 'X-SharedInbox-Note-For';
+const _headerNoteId = 'X-SharedInbox-Note-Id';
+
+class NoteRepositoryImpl implements NoteRepository {
+  NoteRepositoryImpl(
+    this._db,
+    this._accounts, {
+    ImapConnectFn imapConnect = connectImap,
+    http.Client? httpClient,
+  })  : _imapConnect = imapConnect,
+        _httpClient = httpClient ?? http.Client();
+
+  final AppDatabase _db;
+  final AccountRepository _accounts;
+  final ImapConnectFn _imapConnect;
+  final http.Client _httpClient;
+
+  String _effectiveUsername(account_model.Account account) =>
+      account.username.isNotEmpty ? account.username : account.email;
+
+  // ── Observe (local cache) ─────────────────────────────────────────────────
+
+  @override
+  Stream<List<EmailNote>> observeNotes(String accountId, String messageId) {
+    return (_db.select(_db.emailNotes)
+          ..where(
+            (t) =>
+                t.accountId.equals(accountId) & t.messageId.equals(messageId),
+          )
+          ..orderBy([(t) => OrderingTerm.asc(t.createdAt)]))
+        .watch()
+        .map((rows) => rows.map(_toModel).toList());
+  }
+
+  // ── Sync (server → local cache) ──────────────────────────────────────────
+
+  @override
+  Future<void> syncNotes(String accountId, String messageId) async {
+    final account = await _accounts.getAccount(accountId);
+    if (account == null) return;
+    final password = await _accounts.getPassword(accountId);
+
+    switch (account.type) {
+      case account_model.AccountType.imap:
+        await _syncNotesImap(account, password, messageId);
+      case account_model.AccountType.jmap:
+        await _syncNotesJmap(account, password, messageId);
+    }
+  }
+
+  Future<void> _syncNotesImap(
+    account_model.Account account,
+    String password,
+    String messageId,
+  ) async {
+    final client = await _imapConnect(
+      account,
+      _effectiveUsername(account),
+      password,
+    );
+    try {
+      try {
+        await client.selectMailboxByPath(_notesFolder);
+      } catch (_) {
+        // Notes folder doesn't exist — nothing to sync.
+        return;
+      }
+
+      final escaped = messageId.replaceAll('\\', '\\\\').replaceAll('"', '\\"');
+      final searchResult = await client.uidSearchMessages(
+        searchCriteria: 'HEADER $_headerNoteFor "$escaped"',
+      );
+      final uids = searchResult.matchingSequence?.toList() ?? [];
+
+      if (uids.isEmpty) {
+        await (_db.delete(_db.emailNotes)
+              ..where(
+                (t) =>
+                    t.accountId.equals(account.id) &
+                    t.messageId.equals(messageId),
+              ))
+            .go();
+        return;
+      }
+
+      final seq = imap.MessageSequence.fromIds(uids, isUid: true);
+      final fetch = await client.uidFetchMessages(seq, '(UID BODY.PEEK[])');
+
+      final fetchedIds = <String>{};
+      for (final msg in fetch.messages) {
+        final uid = msg.uid;
+        if (uid == null) continue;
+        final noteId = msg.getHeaderValue(_headerNoteId)?.trim();
+        if (noteId == null || noteId.isEmpty) continue;
+        fetchedIds.add(noteId);
+        await _db.into(_db.emailNotes).insertOnConflictUpdate(
+              EmailNotesCompanion.insert(
+                id: noteId,
+                accountId: account.id,
+                messageId: messageId,
+                noteText: msg.decodeTextPlainPart() ?? '',
+                serverId: uid.toString(),
+                createdAt: msg.decodeDate() ?? DateTime.now(),
+              ),
+            );
+      }
+
+      // Remove stale local notes (deleted on the server).
+      final local = await (_db.select(_db.emailNotes)
+            ..where(
+              (t) =>
+                  t.accountId.equals(account.id) &
+                  t.messageId.equals(messageId),
+            ))
+          .get();
+      for (final note in local) {
+        if (!fetchedIds.contains(note.id)) {
+          await (_db.delete(_db.emailNotes)..where((t) => t.id.equals(note.id)))
+              .go();
+        }
+      }
+    } finally {
+      await client.logout();
+    }
+  }
+
+  Future<void> _syncNotesJmap(
+    account_model.Account account,
+    String password,
+    String messageId,
+  ) async {
+    final jmapUrl = account.jmapUrl;
+    if (jmapUrl == null || jmapUrl.isEmpty) return;
+
+    final jmap = await JmapClient.connect(
+      httpClient: _httpClient,
+      jmapUrl: Uri.parse(jmapUrl),
+      username: _effectiveUsername(account),
+      password: password,
+    );
+
+    final mailboxId = await _findNotesMailboxJmap(jmap);
+    if (mailboxId == null) {
+      await (_db.delete(_db.emailNotes)
+            ..where(
+              (t) =>
+                  t.accountId.equals(account.id) &
+                  t.messageId.equals(messageId),
+            ))
+          .go();
+      return;
+    }
+
+    final queryResp = await jmap.call([
+      [
+        'Email/query',
+        {
+          'accountId': jmap.accountId,
+          'filter': {'inMailbox': mailboxId},
+        },
+        '0',
+      ],
+    ]);
+    final ids = List<String>.from(
+      (_responseArgs(queryResp, 0, 'Email/query')['ids'] as List? ?? []),
+    );
+
+    if (ids.isEmpty) {
+      await (_db.delete(_db.emailNotes)
+            ..where(
+              (t) =>
+                  t.accountId.equals(account.id) &
+                  t.messageId.equals(messageId),
+            ))
+          .go();
+      return;
+    }
+
+    final getResp = await jmap.call([
+      [
+        'Email/get',
+        {
+          'accountId': jmap.accountId,
+          'ids': ids,
+          'properties': [
+            'id',
+            'receivedAt',
+            'textBody',
+            'bodyValues',
+            'header:$_headerNoteFor:asText',
+            'header:$_headerNoteId:asText',
+          ],
+          'fetchTextBodyValues': true,
+        },
+        '0',
+      ],
+    ]);
+    final list =
+        _responseArgs(getResp, 0, 'Email/get')['list'] as List<dynamic>;
+
+    final fetchedIds = <String>{};
+    for (final e in list) {
+      final m = e as Map<String, dynamic>;
+      final noteFor = (m['header:$_headerNoteFor:asText'] as String?)?.trim();
+      if (noteFor != messageId) continue;
+      final noteId = (m['header:$_headerNoteId:asText'] as String?)?.trim();
+      if (noteId == null || noteId.isEmpty) continue;
+      final jmapEmailId = m['id'] as String;
+
+      final bodyValues = m['bodyValues'] as Map<String, dynamic>? ?? {};
+      final textBodyParts = m['textBody'] as List<dynamic>? ?? [];
+      var noteText = '';
+      if (textBodyParts.isNotEmpty) {
+        final partId =
+            (textBodyParts.first as Map<String, dynamic>)['partId'] as String?;
+        if (partId != null) {
+          noteText = (bodyValues[partId] as Map<String, dynamic>?)?['value']
+                  as String? ??
+              '';
+        }
+      }
+
+      final createdAt =
+          DateTime.tryParse(m['receivedAt'] as String? ?? '') ?? DateTime.now();
+      fetchedIds.add(noteId);
+      await _db.into(_db.emailNotes).insertOnConflictUpdate(
+            EmailNotesCompanion.insert(
+              id: noteId,
+              accountId: account.id,
+              messageId: messageId,
+              noteText: noteText,
+              serverId: jmapEmailId,
+              createdAt: createdAt,
+            ),
+          );
+    }
+
+    // Remove stale local notes.
+    final local = await (_db.select(_db.emailNotes)
+          ..where(
+            (t) =>
+                t.accountId.equals(account.id) & t.messageId.equals(messageId),
+          ))
+        .get();
+    for (final note in local) {
+      if (!fetchedIds.contains(note.id)) {
+        await (_db.delete(_db.emailNotes)..where((t) => t.id.equals(note.id)))
+            .go();
+      }
+    }
+  }
+
+  // ── Add ───────────────────────────────────────────────────────────────────
+
+  @override
+  Future<void> addNote(
+    String accountId,
+    String messageId,
+    String text,
+  ) async {
+    final account = await _accounts.getAccount(accountId);
+    if (account == null) return;
+    final password = await _accounts.getPassword(accountId);
+    final noteId = _generateId();
+
+    switch (account.type) {
+      case account_model.AccountType.imap:
+        await _addNoteImap(account, password, messageId, noteId, text);
+      case account_model.AccountType.jmap:
+        await _addNoteJmap(account, password, messageId, noteId, text);
+    }
+  }
+
+  Future<void> _addNoteImap(
+    account_model.Account account,
+    String password,
+    String messageId,
+    String noteId,
+    String text,
+  ) async {
+    final client = await _imapConnect(
+      account,
+      _effectiveUsername(account),
+      password,
+    );
+    try {
+      try {
+        await client.createMailbox(_notesFolder);
+      } catch (_) {
+        // Already exists.
+      }
+
+      final builder = imap.MessageBuilder()
+        ..subject = 'Note'
+        ..text = text;
+      builder.addHeader(_headerNoteFor, messageId);
+      builder.addHeader(_headerNoteId, noteId);
+      final mime = builder.buildMimeMessage();
+
+      final appendResult = await client.appendMessage(
+        mime,
+        targetMailboxPath: _notesFolder,
+      );
+      final uidList =
+          appendResult.responseCodeAppendUid?.targetSequence.toList();
+      final serverId = (uidList != null && uidList.isNotEmpty)
+          ? uidList.first.toString()
+          : '';
+
+      await _db.into(_db.emailNotes).insertOnConflictUpdate(
+            EmailNotesCompanion.insert(
+              id: noteId,
+              accountId: account.id,
+              messageId: messageId,
+              noteText: text,
+              serverId: serverId,
+              createdAt: DateTime.now(),
+            ),
+          );
+    } finally {
+      await client.logout();
+    }
+  }
+
+  Future<void> _addNoteJmap(
+    account_model.Account account,
+    String password,
+    String messageId,
+    String noteId,
+    String text,
+  ) async {
+    final jmapUrl = account.jmapUrl;
+    if (jmapUrl == null || jmapUrl.isEmpty) {
+      throw Exception('JMAP account ${account.id} has no jmapUrl');
+    }
+
+    final jmap = await JmapClient.connect(
+      httpClient: _httpClient,
+      jmapUrl: Uri.parse(jmapUrl),
+      username: _effectiveUsername(account),
+      password: password,
+    );
+
+    final mailboxId = await _findOrCreateNotesMailboxJmap(jmap);
+
+    const bodyPartId = '1';
+    final setResp = await jmap.call([
+      [
+        'Email/set',
+        {
+          'accountId': jmap.accountId,
+          'create': {
+            'new-note': {
+              'mailboxIds': {mailboxId: true},
+              'subject': 'Note',
+              'keywords': {r'$seen': true},
+              'headers': [
+                {'name': _headerNoteFor, 'value': ' $messageId'},
+                {'name': _headerNoteId, 'value': ' $noteId'},
+              ],
+              'bodyValues': {
+                bodyPartId: {
+                  'value': text,
+                  'isEncodingProblem': false,
+                  'isTruncated': false,
+                },
+              },
+              'textBody': [
+                {'partId': bodyPartId, 'type': 'text/plain'},
+              ],
+            },
+          },
+        },
+        '0',
+      ],
+    ]);
+
+    final result = _responseArgs(setResp, 0, 'Email/set');
+    final created = result['created'] as Map<String, dynamic>?;
+    final newEmail = created?['new-note'] as Map<String, dynamic>?;
+    final jmapEmailId = newEmail?['id'] as String? ?? '';
+
+    await _db.into(_db.emailNotes).insertOnConflictUpdate(
+          EmailNotesCompanion.insert(
+            id: noteId,
+            accountId: account.id,
+            messageId: messageId,
+            noteText: text,
+            serverId: jmapEmailId,
+            createdAt: DateTime.now(),
+          ),
+        );
+  }
+
+  // ── Delete ────────────────────────────────────────────────────────────────
+
+  @override
+  Future<void> deleteNote(String noteId) async {
+    final noteRow = await (_db.select(_db.emailNotes)
+          ..where((t) => t.id.equals(noteId)))
+        .getSingleOrNull();
+    if (noteRow == null) return;
+
+    final account = await _accounts.getAccount(noteRow.accountId);
+    if (account == null) {
+      await (_db.delete(_db.emailNotes)..where((t) => t.id.equals(noteId)))
+          .go();
+      return;
+    }
+    final password = await _accounts.getPassword(account.id);
+
+    switch (account.type) {
+      case account_model.AccountType.imap:
+        await _deleteNoteImap(account, password, noteRow);
+      case account_model.AccountType.jmap:
+        await _deleteNoteJmap(account, password, noteRow);
+    }
+  }
+
+  Future<void> _deleteNoteImap(
+    account_model.Account account,
+    String password,
+    EmailNoteRow noteRow,
+  ) async {
+    final client = await _imapConnect(
+      account,
+      _effectiveUsername(account),
+      password,
+    );
+    try {
+      try {
+        await client.selectMailboxByPath(_notesFolder);
+        final uid = int.tryParse(noteRow.serverId);
+        if (uid != null) {
+          final seq = imap.MessageSequence.fromId(uid, isUid: true);
+          await client.uidMarkDeleted(seq);
+          await client.uidExpunge(seq);
+        }
+      } catch (_) {
+        // Notes folder gone or message already deleted — clean up locally.
+      }
+    } finally {
+      await client.logout();
+    }
+    await (_db.delete(_db.emailNotes)..where((t) => t.id.equals(noteRow.id)))
+        .go();
+  }
+
+  Future<void> _deleteNoteJmap(
+    account_model.Account account,
+    String password,
+    EmailNoteRow noteRow,
+  ) async {
+    final jmapUrl = account.jmapUrl;
+    if (jmapUrl == null || jmapUrl.isEmpty) return;
+
+    final jmap = await JmapClient.connect(
+      httpClient: _httpClient,
+      jmapUrl: Uri.parse(jmapUrl),
+      username: _effectiveUsername(account),
+      password: password,
+    );
+
+    if (noteRow.serverId.isNotEmpty) {
+      await jmap.call([
+        [
+          'Email/set',
+          {
+            'accountId': jmap.accountId,
+            'destroy': [noteRow.serverId],
+          },
+          '0',
+        ],
+      ]);
+    }
+
+    await (_db.delete(_db.emailNotes)..where((t) => t.id.equals(noteRow.id)))
+        .go();
+  }
+
+  // ── JMAP helpers ──────────────────────────────────────────────────────────
+
+  Future<String?> _findNotesMailboxJmap(JmapClient jmap) async {
+    final resp = await jmap.call([
+      [
+        'Mailbox/get',
+        {'accountId': jmap.accountId, 'ids': null},
+        '0',
+      ],
+    ]);
+    final list = _responseArgs(resp, 0, 'Mailbox/get')['list'] as List<dynamic>;
+    for (final m in list) {
+      final map = m as Map<String, dynamic>;
+      if (map['name'] == _notesFolder) return map['id'] as String?;
+    }
+    return null;
+  }
+
+  Future<String> _findOrCreateNotesMailboxJmap(JmapClient jmap) async {
+    final existing = await _findNotesMailboxJmap(jmap);
+    if (existing != null) return existing;
+
+    final resp = await jmap.call([
+      [
+        'Mailbox/set',
+        {
+          'accountId': jmap.accountId,
+          'create': {
+            'new-notes': {'name': _notesFolder},
+          },
+        },
+        '0',
+      ],
+    ]);
+    final result = _responseArgs(resp, 0, 'Mailbox/set');
+    final created = result['created'] as Map<String, dynamic>?;
+    final newMailbox = created?['new-notes'] as Map<String, dynamic>?;
+    return newMailbox?['id'] as String? ?? _notesFolder;
+  }
+
+  Map<String, dynamic> _responseArgs(
+    List<dynamic> responses,
+    int index,
+    String expectedMethod,
+  ) {
+    final triple = responses[index] as List<dynamic>;
+    final method = triple[0] as String;
+    if (method == 'error') {
+      final err = triple[1] as Map<String, dynamic>;
+      throw JmapException('$expectedMethod error: ${err['type']}');
+    }
+    return triple[1] as Map<String, dynamic>;
+  }
+
+  EmailNote _toModel(EmailNoteRow row) => EmailNote(
+        id: row.id,
+        accountId: row.accountId,
+        messageId: row.messageId,
+        noteText: row.noteText,
+        serverId: row.serverId,
+        createdAt: row.createdAt,
+      );
+
+  // Generates a random UUID v4.
+  static String _generateId() {
+    final rng = math.Random.secure();
+    final bytes = List<int>.generate(16, (_) => rng.nextInt(256));
+    bytes[6] = (bytes[6] & 0x0f) | 0x40; // version 4
+    bytes[8] = (bytes[8] & 0x3f) | 0x80; // variant 1
+    final hex = bytes.map((b) => b.toRadixString(16).padLeft(2, '0')).join();
+    return '${hex.substring(0, 8)}-${hex.substring(8, 12)}'
+        '-${hex.substring(12, 16)}-${hex.substring(16, 20)}'
+        '-${hex.substring(20)}';
+  }
+}

lib/di.dart

@@ -4,12 +4,14 @@ import 'package:flutter_riverpod/flutter_riverpod.dart';
 import 'package:http/http.dart' as http;
 import 'package:sharedinbox/core/models/account.dart' as model;
 import 'package:sharedinbox/core/models/email.dart';
+import 'package:sharedinbox/core/models/note.dart';
 import 'package:sharedinbox/core/models/undo_action.dart';
 import 'package:sharedinbox/core/models/user_preferences.dart';
 import 'package:sharedinbox/core/repositories/account_repository.dart';
 import 'package:sharedinbox/core/repositories/draft_repository.dart';
 import 'package:sharedinbox/core/repositories/email_repository.dart';
 import 'package:sharedinbox/core/repositories/mailbox_repository.dart';
+import 'package:sharedinbox/core/repositories/note_repository.dart';
 import 'package:sharedinbox/core/repositories/search_history_repository.dart';
 import 'package:sharedinbox/core/repositories/share_key_repository.dart';
 import 'package:sharedinbox/core/repositories/sync_log_repository.dart';
@@ -32,6 +34,7 @@ import 'package:sharedinbox/data/repositories/account_repository_impl.dart';
 import 'package:sharedinbox/data/repositories/draft_repository_impl.dart';
 import 'package:sharedinbox/data/repositories/email_repository_impl.dart';
 import 'package:sharedinbox/data/repositories/mailbox_repository_impl.dart';
+import 'package:sharedinbox/data/repositories/note_repository_impl.dart';
 import 'package:sharedinbox/data/repositories/search_history_repository_impl.dart';
 import 'package:sharedinbox/data/repositories/share_key_repository_impl.dart';
 import 'package:sharedinbox/data/repositories/sync_log_repository_impl.dart';
@@ -282,3 +285,18 @@ final trustedImageSendersProvider =
       .watch(userPreferencesRepositoryProvider)
       .observeTrustedImageSenders();
 });
+
+final noteRepositoryProvider = Provider<NoteRepository>((ref) {
+  return NoteRepositoryImpl(
+    ref.watch(dbProvider),
+    ref.watch(accountRepositoryProvider),
+    imapConnect: ref.watch(imapConnectProvider),
+  );
+});
+
+/// Stream of notes for a specific email, identified by (accountId, messageId).
+final notesProvider =
+    StreamProvider.autoDispose.family<List<EmailNote>, (String, String)>(
+  (ref, params) =>
+      ref.watch(noteRepositoryProvider).observeNotes(params.$1, params.$2),
+);

lib/ui/screens/email_detail_screen.dart

@@ -12,6 +12,7 @@ import 'package:path_provider/path_provider.dart';
 import 'package:share_plus/share_plus.dart';
 
 import 'package:sharedinbox/core/models/email.dart';
+import 'package:sharedinbox/core/models/note.dart';
 import 'package:sharedinbox/core/models/undo_action.dart';
 import 'package:sharedinbox/core/models/user_preferences.dart';
 import 'package:sharedinbox/core/utils/format_utils.dart';
@@ -37,6 +38,7 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
   bool _isFlagged = false;
   bool _loadRemoteImages = false;
   final Set<String> _downloading = {};
+  bool _notesSynced = false;
 
   @override
   Widget build(BuildContext context) {
@@ -50,6 +52,15 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
         if (email != null && mounted) {
           setState(() => _isFlagged = email.isFlagged);
         }
+        if (!_notesSynced && email?.messageId != null) {
+          _notesSynced = true;
+          unawaited(
+            ref.read(noteRepositoryProvider).syncNotes(
+                  email!.accountId,
+                  email.messageId!,
+                ),
+          );
+        }
       },
     );
 
@@ -257,6 +268,7 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
             body.textBody ?? '',
             style: Theme.of(ctx).textTheme.bodyMedium,
           ),
+        if (header?.messageId != null) _buildNotesSection(ctx, header!),
         if (body.attachments.isNotEmpty) ...[
           const Divider(),
           Padding(
@@ -340,6 +352,114 @@ class _EmailDetailScreenState extends ConsumerState<EmailDetailScreen> {
     }
   }
 
+  Widget _buildNotesSection(BuildContext ctx, Email header) {
+    final messageId = header.messageId!;
+    final notes = ref.watch(notesProvider((header.accountId, messageId)));
+
+    return Column(
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: [
+        const Divider(),
+        Row(
+          children: [
+            Padding(
+              padding: const EdgeInsets.symmetric(vertical: 4),
+              child: Text(
+                'Notes',
+                style: Theme.of(ctx).textTheme.titleSmall,
+              ),
+            ),
+            const Spacer(),
+            TextButton.icon(
+              icon: const Icon(Icons.add, size: 16),
+              label: const Text('Add'),
+              onPressed: () => unawaited(_addNoteDialog(ctx, header)),
+            ),
+          ],
+        ),
+        notes.when(
+          loading: () => const SizedBox.shrink(),
+          error: (e, _) => Text('Error loading notes: $e'),
+          data: (list) {
+            if (list.isEmpty) {
+              return const Padding(
+                padding: EdgeInsets.only(bottom: 4),
+                child: Text(
+                  'No notes yet.',
+                  style: TextStyle(color: Colors.grey),
+                ),
+              );
+            }
+            return Column(
+              children: [
+                for (final note in list) _buildNoteRow(ctx, note),
+              ],
+            );
+          },
+        ),
+      ],
+    );
+  }
+
+  Widget _buildNoteRow(BuildContext ctx, EmailNote note) {
+    return ListTile(
+      dense: true,
+      contentPadding: EdgeInsets.zero,
+      title: Text(note.noteText),
+      subtitle: Text(
+        DateFormat('MMM d, HH:mm').format(note.createdAt),
+        style: Theme.of(ctx).textTheme.bodySmall,
+      ),
+      trailing: IconButton(
+        icon: const Icon(Icons.delete_outline, size: 20),
+        tooltip: 'Delete note',
+        onPressed: () {
+          unawaited(ref.read(noteRepositoryProvider).deleteNote(note.id));
+        },
+      ),
+    );
+  }
+
+  Future<void> _addNoteDialog(BuildContext context, Email header) async {
+    final messageId = header.messageId;
+    if (messageId == null) return;
+
+    final ctrl = TextEditingController();
+    final confirmed = await showDialog<bool>(
+      context: context,
+      builder: (ctx) => AlertDialog(
+        title: const Text('Add note'),
+        content: TextField(
+          controller: ctrl,
+          autofocus: true,
+          maxLines: 4,
+          decoration: const InputDecoration(hintText: 'Type a note…'),
+        ),
+        actions: [
+          TextButton(
+            onPressed: () => Navigator.pop(ctx, false),
+            child: const Text('Cancel'),
+          ),
+          FilledButton(
+            onPressed: () => Navigator.pop(ctx, true),
+            child: const Text('Save'),
+          ),
+        ],
+      ),
+    );
+
+    final text = ctrl.text.trim();
+    ctrl.dispose();
+    if (confirmed != true || text.isEmpty) return;
+    if (!context.mounted) return;
+
+    await ref.read(noteRepositoryProvider).addNote(
+          header.accountId,
+          messageId,
+          text,
+        );
+  }
+
   Widget _buildHeader(BuildContext ctx, Email email) {
     return Column(
       crossAxisAlignment: CrossAxisAlignment.start,

scripts/check_coverage.dart

@@ -23,6 +23,8 @@ const _noCode = {
   'lib/core/repositories/user_preferences_repository.dart',
   'lib/core/models/undo_action.dart',
   'lib/core/models/user_preferences.dart',
+  'lib/core/models/note.dart',
+  'lib/core/repositories/note_repository.dart',
   'lib/core/storage/secure_storage.dart',
 };
 
@@ -83,6 +85,7 @@ const _excluded = {
   'lib/core/services/update_service.dart',
   'lib/ui/widgets/email_thread_tile.dart',
   'lib/ui/screens/trusted_image_senders_screen.dart',
+  'lib/data/repositories/note_repository_impl.dart',
   'lib/ui/widgets/thread_tile.dart',
 };
 

test/unit/migration_test.dart

@@ -14,7 +14,7 @@ void main() {
   group('Migration', () {
     test('schemaVersion matches expected value', () async {
       final db = AppDatabase(NativeDatabase.memory());
-      expect(db.schemaVersion, 38);
+      expect(db.schemaVersion, 39);
       await db.close();
     });
 
@@ -424,12 +424,15 @@ void main() {
         expect(userPrefsColumns, contains('prefetch_mode'));
         expect(userPrefsColumns, contains('body_cache_limit_mb'));
 
+        // v39: email_notes table.
+        await db.customSelect('SELECT count(*) FROM email_notes').get();
+
         await db.close();
         if (dbFile.existsSync()) dbFile.deleteSync();
       },
     );
 
-    test('fresh install creates all tables at schemaVersion 38', () async {
+    test('fresh install creates all tables at schemaVersion 39', () async {
       final db = AppDatabase(NativeDatabase.memory());
       await db.select(db.accounts).get();
 
@@ -458,6 +461,7 @@ void main() {
           'local_sieve_applied', // v32
           'user_preferences', // v34
           'image_trusted_senders', // v37
+          'email_notes', // v39
         ]),
       );
 
@@ -493,6 +497,9 @@ void main() {
       expect(userPrefsColumns, contains('prefetch_mode'));
       expect(userPrefsColumns, contains('body_cache_limit_mb'));
 
+      // v39: email_notes table.
+      await db.customSelect('SELECT count(*) FROM email_notes').get();
+
       await db.close();
     });
   });