feat(compose): autocomplete To/Cc from local address history

Adds RawAutocomplete<EmailAddress> to the To and Cc fields in the
compose screen. As the user types (minimum 2 chars), suggestions are
fetched from the local DB by searching from/to/cc columns of cached
emails. Selecting a suggestion appends it to any existing addresses
already in the field (comma-separated).

New repository method searchAddresses() returns deduplicated
EmailAddress objects matching the query string.

Closes #11

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

lib/core/repositories/email_repository.dart

@@ -57,6 +57,14 @@ abstract class EmailRepository {
   /// accounts if null) whose from, to, or cc fields contain [address].
   Future<List<Email>> getEmailsByAddress(String? accountId, String address);
 
+  /// Returns unique email addresses from the local cache whose email or display
+  /// name contains [query]. Results are deduplicated and capped at [limit].
+  Future<List<EmailAddress>> searchAddresses(
+    String? accountId,
+    String query, {
+    int limit = 10,
+  });
+
   /// Sends any queued local mutations for [accountId] to the server.
   /// Returns the number of changes successfully applied.
   Future<int> flushPendingChanges(String accountId, String password);

lib/data/repositories/email_repository_impl.dart

@@ -2596,6 +2596,51 @@ class EmailRepositoryImpl implements EmailRepository {
     return rows.map(_toModel).toList();
   }
 
+  @override
+  Future<List<model.EmailAddress>> searchAddresses(
+    String? accountId,
+    String query, {
+    int limit = 10,
+  }) async {
+    if (query.length < 2) return [];
+    final pattern = '%${query.toLowerCase()}%';
+    final rows = await (_db.select(_db.emails)
+          ..where((t) {
+            Expression<bool> cond = const Constant(true);
+            if (accountId != null) cond = t.accountId.equals(accountId);
+            cond = cond &
+                (t.fromJson.like(pattern) |
+                    t.toAddresses.like(pattern) |
+                    t.ccJson.like(pattern));
+            return cond;
+          })
+          ..limit(100))
+        .get();
+
+    final seen = <String>{};
+    final results = <model.EmailAddress>[];
+    final lowerQuery = query.toLowerCase();
+    for (final row in rows) {
+      for (final jsonStr in [row.fromJson, row.toAddresses, row.ccJson]) {
+        final list = jsonDecode(jsonStr) as List<dynamic>;
+        for (final e in list) {
+          final map = e as Map<String, dynamic>;
+          final addr = model.EmailAddress(
+            name: map['name'] as String?,
+            email: map['email'] as String,
+          );
+          if ((addr.email.toLowerCase().contains(lowerQuery) ||
+                  (addr.name?.toLowerCase().contains(lowerQuery) ?? false)) &&
+              seen.add(addr.email.toLowerCase())) {
+            results.add(addr);
+            if (results.length >= limit) return results;
+          }
+        }
+      }
+    }
+    return results;
+  }
+
   @override
   Future<List<model.Email>> searchEmails(
     String accountId,

lib/ui/screens/compose_screen.dart

@@ -39,6 +39,8 @@ class ComposeScreen extends ConsumerStatefulWidget {
 class _ComposeScreenState extends ConsumerState<ComposeScreen> {
   final _to = TextEditingController();
   final _cc = TextEditingController();
+  final _toFocus = FocusNode();
+  final _ccFocus = FocusNode();
   final _subject = TextEditingController();
   final _body = TextEditingController();
   String? _accountId;
@@ -139,6 +141,8 @@ class _ComposeScreenState extends ConsumerState<ComposeScreen> {
       c.removeListener(_onTextChanged);
       c.dispose();
     }
+    _toFocus.dispose();
+    _ccFocus.dispose();
     // Flush any pending save synchronously — we can't await in dispose, but
     // scheduling a microtask still runs before the isolate exits.
     if (_draftDirty) {
@@ -330,8 +334,8 @@ class _ComposeScreenState extends ConsumerState<ComposeScreen> {
                 ),
               ),
             ),
-          _field(_to, 'To', keyboardType: TextInputType.emailAddress),
-          _field(_cc, 'Cc', keyboardType: TextInputType.emailAddress),
+          _addressField(_to, _toFocus, 'To'),
+          _addressField(_cc, _ccFocus, 'Cc'),
           _field(_subject, 'Subject'),
           const SizedBox(height: 8),
           TextFormField(
@@ -384,6 +388,89 @@ class _ComposeScreenState extends ConsumerState<ComposeScreen> {
     );
   }
 
+  Widget _addressField(
+    TextEditingController ctrl,
+    FocusNode focusNode,
+    String label,
+  ) {
+    return Padding(
+      padding: const EdgeInsets.symmetric(vertical: 6),
+      child: RawAutocomplete<EmailAddress>(
+        textEditingController: ctrl,
+        focusNode: focusNode,
+        displayStringForOption: (option) {
+          final text = ctrl.text;
+          final lastComma = text.lastIndexOf(',');
+          final prefix =
+              lastComma >= 0 ? '${text.substring(0, lastComma + 1)} ' : '';
+          return '$prefix${option.email}, ';
+        },
+        optionsBuilder: (value) async {
+          final text = value.text;
+          final lastComma = text.lastIndexOf(',');
+          final token = lastComma >= 0
+              ? text.substring(lastComma + 1).trim()
+              : text.trim();
+          if (token.length < 2) return const [];
+          return ref.read(emailRepositoryProvider).searchAddresses(null, token);
+        },
+        fieldViewBuilder: (ctx, fieldCtrl, fieldFocusNode, onFieldSubmitted) {
+          return TextFormField(
+            controller: fieldCtrl,
+            focusNode: fieldFocusNode,
+            keyboardType: TextInputType.emailAddress,
+            decoration: InputDecoration(
+              labelText: label,
+              border: const OutlineInputBorder(),
+            ),
+            onFieldSubmitted: (_) => onFieldSubmitted(),
+          );
+        },
+        optionsViewBuilder: (ctx, onSelected, options) {
+          return Align(
+            alignment: Alignment.topLeft,
+            child: Material(
+              elevation: 4,
+              child: ConstrainedBox(
+                constraints: const BoxConstraints(maxHeight: 200),
+                child: ListView.builder(
+                  padding: EdgeInsets.zero,
+                  shrinkWrap: true,
+                  itemCount: options.length,
+                  itemBuilder: (ctx, i) {
+                    final option = options.elementAt(i);
+                    return InkWell(
+                      onTap: () => onSelected(option),
+                      child: Padding(
+                        padding: const EdgeInsets.symmetric(
+                          horizontal: 16,
+                          vertical: 8,
+                        ),
+                        child: option.name != null
+                            ? Column(
+                                crossAxisAlignment: CrossAxisAlignment.start,
+                                mainAxisSize: MainAxisSize.min,
+                                children: [
+                                  Text(option.name!),
+                                  Text(
+                                    option.email,
+                                    style: const TextStyle(fontSize: 12),
+                                  ),
+                                ],
+                              )
+                            : Text(option.email),
+                      ),
+                    );
+                  },
+                ),
+              ),
+            ),
+          );
+        },
+      ),
+    );
+  }
+
   Widget _field(
     TextEditingController ctrl,
     String label, {

test/integration/account_sync_manager_test.dart

@@ -236,6 +236,14 @@ class _FakeEmails implements EmailRepository {
   @override
   Future<List<Email>> getEmailsByAddress(String? a, String address) async => [];
 
+  @override
+  Future<List<EmailAddress>> searchAddresses(
+    String? a,
+    String q, {
+    int limit = 10,
+  }) async =>
+      [];
+
   @override
   Stream<void> watchJmapPush(String accountId, String password) =>
       const Stream.empty();

test/unit/account_sync_manager_test.dart

@@ -94,6 +94,13 @@ class FakeEmailRepository implements EmailRepository {
   @override
   Future<List<Email>> getEmailsByAddress(String? a, String address) async => [];
   @override
+  Future<List<EmailAddress>> searchAddresses(
+    String? a,
+    String q, {
+    int limit = 10,
+  }) async =>
+      [];
+  @override
   Stream<void> watchJmapPush(String a, String p) => const Stream.empty();
   @override
   Stream<List<FailedMutation>> observeFailedMutations(String a) =>

test/unit/reliability_runner_test.dart

@@ -119,6 +119,13 @@ class _CountingEmails implements EmailRepository {
   @override
   Future<List<Email>> getEmailsByAddress(String? a, String addr) async => [];
   @override
+  Future<List<EmailAddress>> searchAddresses(
+    String? a,
+    String q, {
+    int limit = 10,
+  }) async =>
+      [];
+  @override
   Stream<List<FailedMutation>> observeFailedMutations(String a) =>
       Stream.value([]);
   @override

test/widget/helpers.dart

@@ -273,6 +273,14 @@ class FakeEmailRepository implements EmailRepository {
   ) async =>
       [];
 
+  @override
+  Future<List<EmailAddress>> searchAddresses(
+    String? accountId,
+    String query, {
+    int limit = 10,
+  }) async =>
+      [];
+
   @override
   Stream<void> watchJmapPush(String accountId, String password) =>
       const Stream.empty();