import '../../../../api/marianumcloud/search/search_chat_messages_response.dart';
import '../../../../api/marianumcloud/talk/chat/get_chat_response.dart';
import '../../../../api/marianumcloud/talk/chat/rich_object_string_processor.dart';
import '../../../../api/marianumcloud/talk/room/get_room_response.dart';

/// One message matching a chat search, either from the loaded history or
/// from the server-side search.
class ChatSearchHit {
  final int messageId;
  final String? actorId;
  final String? actorDisplayName;
  final String text;
  final DateTime? sentAt;
  final bool isSystem;

  const ChatSearchHit({
    required this.messageId,
    required this.text,
    this.actorId,
    this.actorDisplayName,
    this.sentAt,
    this.isSystem = false,
  });

  factory ChatSearchHit.fromServer(SearchChatMessagesEntry entry) =>
      ChatSearchHit(
        messageId: entry.messageId,
        text: entry.excerpt,
        actorId: entry.actorId,
        actorDisplayName: entry.actorDisplayName,
        sentAt: entry.sentAt,
      );
}

class ChatMessageMatcher {
  /// System messages that are folded into other bubbles (reactions, poll
  /// votes, deletions) and therefore never rendered nor searched as their own
  /// entry.
  static bool isHiddenSystemMessage(GetChatResponseObject element) =>
      element.systemMessage.contains('reaction') ||
      element.systemMessage.contains('poll_voted') ||
      element.systemMessage.contains('message_deleted');

  /// Newest first.
  static List<ChatSearchHit> findMatches(
    GetChatResponse response,
    String query,
  ) {
    final q = query.trim().toLowerCase();
    if (q.isEmpty) return const [];

    final matches = <ChatSearchHit>[];
    for (final element in response.data) {
      if (element.id <= 0 || isHiddenSystemMessage(element)) continue;

      final text = RichObjectStringProcessor.parseToString(
        element.message,
        element.messageParameters,
      );
      final isSystem =
          element.messageType == GetRoomResponseObjectMessageType.system;

      final matched =
          text.toLowerCase().contains(q) ||
          (!isSystem && element.actorDisplayName.toLowerCase().contains(q));
      if (!matched) continue;

      matches.add(
        ChatSearchHit(
          messageId: element.id,
          text: text,
          actorId: isSystem ? null : element.actorId,
          actorDisplayName: isSystem ? null : element.actorDisplayName,
          sentAt: element.sentAt,
          isSystem: isSystem,
        ),
      );
    }

    matches.sort((a, b) => b.sentAt!.compareTo(a.sentAt!));
    return matches;
  }

  /// Local hits win over server hits for the same message — they carry the
  /// full text and exact metadata. Result is newest first.
  static List<ChatSearchHit> merge(
    List<ChatSearchHit> local,
    List<ChatSearchHit> server,
  ) {
    if (server.isEmpty) return local;
    final seen = {for (final h in local) h.messageId};
    return [...local, ...server.where((h) => seen.add(h.messageId))]
      ..sort((a, b) => b.messageId.compareTo(a.messageId));
  }
}