Add support for REDACT

References: ircv3/ircv3-specifications#524

Author: emersion

lib/client.dart

@@ -105,6 +105,7 @@ Set<String> _getDefaultCaps(ConnectParams params) {
 		'draft/chathistory',
 		'draft/extended-monitor',
 		'draft/pre-away',
+		'draft/message-redaction',
 		'draft/read-marker',
 
 		'soju.im/bouncer-networks',

lib/client_controller.dart

@@ -773,6 +773,17 @@ class ClientController {
 			}).then((unreadCount) {
 				buffer.unreadCount = unreadCount;
 			});
+		case 'REDACT':
+			var target = msg.params[0];
+			var msgid = msg.params[1];
+
+			var buffer = _bufferList.get(target, network);
+			if (buffer == null) {
+				break;
+			}
+
+			// TODO: handle REDACT in a chathistory batch
+			return _handleRedact(buffer, msgid);
 		case RPL_MONONLINE:
 		case RPL_MONOFFLINE:
 			var online = msg.cmd == RPL_MONONLINE;
@@ -905,6 +916,18 @@ class ClientController {
 		}
 	}
 
+	Future<void> _handleRedact(BufferModel buffer, String msgid) async {
+		var msg = await _db.fetchMessageByNetworkMsgid(buffer.id, msgid);
+		if (msg == null) {
+			log.print('Received REDACT for unknown msgid "$msgid"');
+			return;
+		}
+		msg.redacted = true;
+		await _db.storeMessages([msg]);
+
+		buffer.redactMessage(msgid);
+	}
+
 	Future<void> _handleBouncerNetworksBatch(ClientBatch batch) async {
 		for (var msg in batch.messages) {
 			await _handleBouncerNetwork(msg);

lib/database.dart

@@ -198,6 +198,7 @@ class MessageEntry {
 	final String? networkMsgid;
 	final int buffer;
 	final String raw;
+	bool redacted;
 
 	IrcMessage? _msg;
 	DateTime? _dateTime;
@@ -209,21 +210,24 @@ class MessageEntry {
 			'network_msgid': networkMsgid,
 			'buffer': buffer,
 			'raw': raw,
+			'redacted': redacted ? 1 : 0,
 		};
 	}
 
 	MessageEntry(IrcMessage msg, this.buffer) :
 		time = msg.tags['time'] ?? formatIrcTime(DateTime.now()),
 		networkMsgid = msg.tags['msgid'],
 		raw = msg.toString(),
+		redacted = false,
 		_msg = msg;
 
 	MessageEntry.fromMap(Map<String, dynamic> m) :
 		id = m['id'] as int,
 		time = m['time'] as String,
 		networkMsgid = m['network_msgid'] as String?,
 		buffer = m['buffer'] as int,
-		raw = m['raw'] as String;
+		raw = m['raw'] as String,
+		redacted = m['redacted'] == 1;
 
 	IrcMessage get msg {
 		_msg ??= IrcMessage.parse(raw);
@@ -435,6 +439,7 @@ const _schema = [
 			network_msgid TEXT,
 			buffer INTEGER NOT NULL,
 			raw TEXT NOT NULL,
+			redacted INTEGER NOT NULL DEFAULT 0,
 			FOREIGN KEY (buffer) REFERENCES Buffer(id) ON DELETE CASCADE
 		)
 	''',
@@ -538,6 +543,7 @@ const _migrations = [
 		)
 	''',
 	'CREATE INDEX index_reaction_reply_network_msgid on Reaction(reply_network_msgid)',
+	'ALTER TABLE Message ADD COLUMN redacted INTEGER NOT NULL DEFAULT 0',
 ];
 
 class DB {
@@ -784,6 +790,11 @@ class DB {
 		return messages;
 	}
 
+	Future<MessageEntry?> fetchMessageByNetworkMsgid(int buffer, String msgid) async {
+		var messages = await fetchMessageSetByNetworkMsgid(buffer, [msgid]);
+		return messages[msgid];
+	}
+
 	Future<void> storeMessages(List<MessageEntry> entries) async {
 		await _db.transaction((txn) async {
 			await Future.wait(entries.map((entry) async {

lib/models.dart

@@ -547,6 +547,16 @@ class BufferModel extends ChangeNotifier {
 		notifyListeners();
 	}
 
+	void redactMessage(String msgid) {
+		var msg = _messagesByNetworkMsgid[msgid];
+		if (msg == null) {
+			return;
+		}
+
+		msg.entry.redacted = true;
+		notifyListeners();
+	}
+
 	void populateMessageHistory(List<MessageModel> l) {
 		// The messages passed here must be already sorted by the caller, and
 		// must always come before the existing messages

lib/page/buffer.dart

@@ -972,13 +972,23 @@ class _MessageItem extends StatelessWidget {
 				);
 			}
 
-			body = stripAnsiFormatting(body);
+			TextSpan bodyTextSpan;
+			if (entry.redacted) {
+				bodyTextSpan = TextSpan(
+					text: 'This message has been deleted.',
+					style: TextStyle(fontStyle: FontStyle.italic),
+				);
+			} else {
+				body = stripAnsiFormatting(body);
+				bodyTextSpan = linkify(context, body, linkStyle: linkStyle);
+			}
+
 			content = [
 				if (isFirstInGroup) senderTextSpan,
 				if (isFirstInGroup) TextSpan(text: '\n'),
 				if (replyChip != null) replyChip,
 				if (replyChip != null) WidgetSpan(child: SizedBox(width: 5, height: 5)),
-				linkify(context, body, linkStyle: linkStyle),
+				bodyTextSpan,
 			];
 
 			if (prefs.linkPreview) {

lib/widget/message_sheet.dart

@@ -5,6 +5,7 @@ import 'package:provider/provider.dart';
 import '../ansi.dart';
 import '../client.dart';
 import '../client_controller.dart';
+import '../irc.dart';
 import '../models.dart';
 import '../page/buffer.dart';
 
@@ -34,19 +35,23 @@ class MessageSheet extends StatelessWidget {
 
 	@override
 	Widget build(BuildContext context) {
-		var sender = message.msg.source!.name;
+		var ircMsg = message.msg;
+		var sender = ircMsg.source!.name;
 		var client = context.read<Client>();
+		var isOwn = client.isMyNick(sender);
+		// TODO: we can redact if we are channel operator too
+		var canRedact = client.caps.enabled.contains('draft/message-redaction') && ircMsg.tags['msgid'] != null && isOwn && !message.entry.redacted;
 
 		return Column(mainAxisSize: MainAxisSize.min, children: [
-			if (onReply != null && !client.isMyNick(sender)) ListTile(
+			if (onReply != null && !isOwn) ListTile(
 				title: Text('Reply'),
 				leading: Icon(Icons.reply),
 				onTap: () {
 					Navigator.pop(context);
 					onReply!();
 				},
 			),
-			if (!client.isMyNick(sender)) ListTile(
+			if (!isOwn) ListTile(
 				title: Text('Message $sender'),
 				leading: Icon(Icons.chat_bubble),
 				onTap: () {
@@ -59,14 +64,23 @@ class MessageSheet extends StatelessWidget {
 				title: Text('Copy'),
 				leading: Icon(Icons.content_copy),
 				onTap: () async {
-					var body = stripAnsiFormatting(message.msg.params[1]);
+					var body = stripAnsiFormatting(ircMsg.params[1]);
 					var text = '<$sender> $body';
 					await Clipboard.setData(ClipboardData(text: text));
 					if (context.mounted) {
 						Navigator.pop(context);
 					}
 				},
 			),
+			if (canRedact) ListTile(
+				title: Text('Delete'),
+				leading: Icon(Icons.delete),
+				onTap: () async {
+					var buffer = context.read<BufferModel>();
+					client.send(IrcMessage('REDACT', [buffer.name, ircMsg.tags['msgid']!]));
+					Navigator.pop(context);
+				},
+			),
 		]);
 	}
 }