[core] ChatWoot - conversation selector

fix #1216
fix #1357
fix #1237
close #1343
close #1213

src/apps/chatwoot/api/chatwoot.webhook.controller.ts

@@ -89,6 +89,7 @@ export class ChatwootWebhookController {
         return { success: true };
       default:
         // Ignore other events
+        await this.chatWootQueueService.addJobToQueue(body.event, data);
         return { success: true };
     }
   }

src/apps/chatwoot/chatwoot.module.ts

@@ -25,6 +25,8 @@ import { WAHASessionStatusConsumer } from './consumers/waha/session.status';
 import { ChatWootQueueService } from './services/ChatWootQueueService';
 import { ChatWootScheduleService } from './services/ChatWootScheduleService';
 import { ChatWootWAHAQueueService } from './services/ChatWootWAHAQueueService';
+import { ChatWootConversationCreatedConsumer } from './consumers/inbox/conversation_created';
+import { ChatWootConversationStatusChangedConsumer } from '@waha/apps/chatwoot/consumers/inbox/conversation_status_changed';
 
 const CONTROLLERS = [ChatwootWebhookController, ChatwootLocalesController];
 
@@ -65,6 +67,14 @@ const IMPORTS = lodash.flatten([
     name: QueueName.INBOX_MESSAGE_UPDATED,
     defaultJobOptions: merge(ExponentialRetriesJobOptions, JobRemoveOptions),
   }),
+  RegisterAppQueue({
+    name: QueueName.INBOX_CONVERSATION_CREATED,
+    defaultJobOptions: merge(NoRetriesJobOptions, JobRemoveOptions),
+  }),
+  RegisterAppQueue({
+    name: QueueName.INBOX_CONVERSATION_STATUS_CHANGED,
+    defaultJobOptions: merge(NoRetriesJobOptions, JobRemoveOptions),
+  }),
   RegisterAppQueue({
     name: QueueName.INBOX_MESSAGE_DELETED,
     defaultJobOptions: merge(ExponentialRetriesJobOptions, JobRemoveOptions),
@@ -79,6 +89,9 @@ const PROVIDERS = [
   ChatWootInboxMessageCreatedConsumer,
   ChatWootInboxMessageUpdatedConsumer,
   ChatWootInboxMessageDeletedConsumer,
+  // Conversation events
+  ChatWootConversationCreatedConsumer,
+  ChatWootConversationStatusChangedConsumer,
   ChatWootInboxCommandsConsumer,
   WAHASessionStatusConsumer,
   WAHAMessageAnyConsumer,

src/apps/chatwoot/client/ContactConversationService.ts

@@ -138,4 +138,26 @@ export class ContactConversationService {
   public async InboxNotifications() {
     return this.ConversationByContact(new InboxContactInfo(this.l));
   }
+
+  public ResetCache(chatIds: Array<string>) {
+    this.logger.info(`Resetting cache chat ids: ${chatIds.join(', ')}`);
+    for (const chatId of chatIds) {
+      this.cache.delete(chatId);
+    }
+  }
+
+  public ResetMismatchedCache(chatIds: Array<string>, value: ConversationId) {
+    for (const chatId of chatIds) {
+      if (!this.cache.has(chatId)) {
+        continue;
+      }
+      const current = this.cache.get(chatId);
+      if (current !== value) {
+        this.logger.info(
+          `Resetting cache for chat id: ${chatId}, value changed from ${current} to ${value}`,
+        );
+        this.cache.delete(chatId);
+      }
+    }
+  }
 }

src/apps/chatwoot/client/ConversationService.ts

@@ -5,7 +5,7 @@ import {
   ChatWootInboxAPI,
 } from '@waha/apps/chatwoot/client/interfaces';
 import type { conversation } from '@figuro/chatwoot-sdk/dist/models/conversation';
-import * as lodash from 'lodash';
+import { ConversationSelector } from '@waha/apps/chatwoot/services/ConversationSelector';
 
 export type ConversationResult = Pick<conversation, 'id' | 'account_id'>;
 
@@ -19,6 +19,7 @@ export class ConversationService {
     private config: ChatWootAPIConfig,
     private accountAPI: ChatwootClient,
     private inboxAPI: ChatWootInboxAPI,
+    private selector: ConversationSelector,
     private logger: ILogger,
   ) {}
 
@@ -28,13 +29,8 @@ export class ConversationService {
         accountId: this.config.accountId,
         id: contact.id,
       })) as any;
-    const conversationsForInbox = lodash.filter(result.payload, {
-      inbox_id: this.config.inboxId,
-    }) as contact_conversations;
-    if (conversationsForInbox.length == 0) {
-      return null;
-    }
-    return conversationsForInbox[0];
+    const conversations = result.payload;
+    return this.selector.select(conversations);
   }
 
   private async create(contact: ContactIds): Promise<ConversationResult> {

src/apps/chatwoot/client/ids.ts

@@ -15,6 +15,16 @@ export function GetChatID(contact: any): string | null {
   return contact?.custom_attributes?.[AttributeKey.WA_CHAT_ID];
 }
 
+export function GetAllChatIDs(contact: any): Array<string> {
+  const attrs = contact?.custom_attributes || {};
+  const ids = [
+    attrs[AttributeKey.WA_CHAT_ID],
+    attrs[AttributeKey.WA_JID],
+    attrs[AttributeKey.WA_LID],
+  ];
+  return ids.filter(Boolean);
+}
+
 export function FindChatID(contact: any): string | null {
   if (GetJID(contact)) {
     return GetJID(contact);

src/apps/chatwoot/client/types.ts

@@ -51,3 +51,10 @@ export enum CustomAttributeModel {
   CONVERSATION = 0,
   CONTACT = 1,
 }
+
+export enum ConversationStatus {
+  OPEN = 'open',
+  PENDING = 'pending',
+  SNOOZED = 'snoozed',
+  RESOLVED = 'resolved',
+}

src/apps/chatwoot/consumers/QueueName.ts

@@ -18,6 +18,8 @@ export enum QueueName {
   //
   INBOX_MESSAGE_CREATED = 'chatwoot.inbox | message_created',
   INBOX_MESSAGE_UPDATED = 'chatwoot.inbox | message_updated',
+  INBOX_CONVERSATION_CREATED = 'chatwoot.inbox | conversation_created',
+  INBOX_CONVERSATION_STATUS_CHANGED = 'chatwoot.inbox | conversation_status_changed',
   //
   // ChatWoot Events - Artificial
   //

src/apps/chatwoot/consumers/inbox/base.ts

@@ -58,13 +58,20 @@ export abstract class ChatWootInboxMessageConsumer extends AppConsumer {
     job: Job,
   ): Promise<any>;
 
+  protected GetConversationID(body) {
+    return body.conversation.id;
+  }
+
   /**
    * Process the job
    * This method is called by the queue processor
    */
   async processJob(job: Job<InboxData, any, EventName>): Promise<any> {
     const body = job.data.body;
-    const key = ChatWootConversationKey(job.data.app, body.conversation.id);
+    const key = ChatWootConversationKey(
+      job.data.app,
+      this.GetConversationID(body),
+    );
     return await this.withMutex(job, key, () =>
       this.ProcessAndReportStatus(job),
     );

src/apps/chatwoot/consumers/inbox/conversation_created.ts

@@ -0,0 +1,57 @@
+import { Processor } from '@nestjs/bullmq';
+import { JOB_CONCURRENCY } from '@waha/apps/app_sdk/constants';
+import { QueueName } from '@waha/apps/chatwoot/consumers/QueueName';
+import { ChatWootConversationKey } from '@waha/apps/chatwoot/consumers/mutex';
+import { ChatWootInboxMessageConsumer } from '@waha/apps/chatwoot/consumers/inbox/base';
+import { InboxData } from '@waha/apps/chatwoot/consumers/types';
+import { Job } from 'bullmq';
+import { GetAllChatIDs } from '@waha/apps/chatwoot/client/ids';
+import { DIContainer } from '@waha/apps/chatwoot/di/DIContainer';
+import { TKey } from '@waha/apps/chatwoot/i18n/templates';
+import { ContactConversationService } from '@waha/apps/chatwoot/client/ContactConversationService';
+import { SessionManager } from '@waha/core/abc/manager.abc';
+import { PinoLogger } from 'nestjs-pino';
+import { RMutexService } from '@waha/modules/rmutex';
+
+@Processor(QueueName.INBOX_CONVERSATION_CREATED, {
+  concurrency: JOB_CONCURRENCY,
+})
+export class ChatWootConversationCreatedConsumer extends ChatWootInboxMessageConsumer {
+  constructor(
+    protected readonly manager: SessionManager,
+    log: PinoLogger,
+    rmutex: RMutexService,
+  ) {
+    super(manager, log, rmutex, 'ChatWootConversationCreatedConsumer');
+  }
+  protected ErrorHeaderKey(): TKey | null {
+    return null;
+  }
+
+  protected GetConversationID(body) {
+    return body.id;
+  }
+
+  protected async Process(
+    container: DIContainer,
+    body: any,
+    job: Job,
+  ): Promise<any> {
+    const handler = new ConversationCreatedHandler(
+      container.ContactConversationService(),
+    );
+    return handler.handle(body);
+  }
+}
+
+class ConversationCreatedHandler {
+  constructor(private service: ContactConversationService) {}
+
+  async handle(body: any) {
+    const ids = GetAllChatIDs(body?.meta?.sender);
+    if (!ids || ids.length === 0) {
+      return;
+    }
+    this.service.ResetMismatchedCache(ids, body.id);
+  }
+}

src/apps/chatwoot/consumers/inbox/conversation_status_changed.ts

@@ -0,0 +1,62 @@
+import { Processor } from '@nestjs/bullmq';
+import { JOB_CONCURRENCY } from '@waha/apps/app_sdk/constants';
+import { QueueName } from '@waha/apps/chatwoot/consumers/QueueName';
+import { ChatWootInboxMessageConsumer } from '@waha/apps/chatwoot/consumers/inbox/base';
+import { Job } from 'bullmq';
+import { DIContainer } from '../../di/DIContainer';
+import { TKey } from '../../i18n/templates';
+import { ContactConversationService } from '@waha/apps/chatwoot/client/ContactConversationService';
+import { AttributeKey } from '@waha/apps/chatwoot/const';
+import { ConversationSelector } from '@waha/apps/chatwoot/services/ConversationSelector';
+import { GetAllChatIDs } from '@waha/apps/chatwoot/client/ids';
+import { SessionManager } from '@waha/core/abc/manager.abc';
+import { PinoLogger } from 'nestjs-pino';
+import { RMutexService } from '@waha/modules/rmutex';
+
+@Processor(QueueName.INBOX_CONVERSATION_STATUS_CHANGED, {
+  concurrency: JOB_CONCURRENCY,
+})
+export class ChatWootConversationStatusChangedConsumer extends ChatWootInboxMessageConsumer {
+  constructor(
+    protected readonly manager: SessionManager,
+    log: PinoLogger,
+    rmutex: RMutexService,
+  ) {
+    super(manager, log, rmutex, 'ChatWootConversationStatusChangedConsumer');
+  }
+
+  protected ErrorHeaderKey(): TKey | null {
+    return null;
+  }
+
+  protected GetConversationID(body) {
+    return body.id;
+  }
+
+  protected async Process(
+    container: DIContainer,
+    body: any,
+    job: Job,
+  ): Promise<any> {
+    const handler = new ConversationStatusChangedHandler(
+      container.ContactConversationService(),
+      container.ConversationSelector(),
+    );
+    return await handler.handle(body);
+  }
+}
+
+class ConversationStatusChangedHandler {
+  constructor(
+    private service: ContactConversationService,
+    private selector: ConversationSelector,
+  ) {}
+
+  async handle(body) {
+    if (!this.selector.hasStatusFilter()) {
+      return;
+    }
+    const ids = GetAllChatIDs(body.meta?.sender);
+    this.service.ResetCache(ids);
+  }
+}

src/apps/chatwoot/di/DIContainer.ts

@@ -25,21 +25,17 @@ import {
 import { Job } from 'bullmq';
 import { Knex } from 'knex';
 import { i18n } from '@waha/apps/chatwoot/i18n';
+import { CacheSync } from '@waha/utils/Cache';
+import {
+  ConversationSelector,
+  ConversationSort,
+} from '@waha/apps/chatwoot/services/ConversationSelector';
 
 /**
  * Dependency Injection Container for ChatWoot
  * Manages the creation and caching of various clients and repositories
  */
 export class DIContainer {
-  private accountAPI: ChatwootClient;
-  private inboxAPI: ChatWootInboxAPI;
-  private contactService: ContactService;
-  private conversationService: ConversationService;
-  private contactConversationService: ContactConversationService;
-  private locale: Locale;
-  private messageMappingService: MessageMappingService;
-  private wahaSelf: WAHASelf;
-
   /**
    * Creates a new DIContainer with the given configuration
    */
@@ -68,123 +64,124 @@ export class DIContainer {
     return this.knex;
   }
 
+  @CacheSync()
   public Locale(): Locale {
-    if (!this.locale) {
-      this.locale = i18n.locale(this.config.locale || DEFAULT_LOCALE);
-      this.locale = this.locale.override(this.ChatWootConfig().templates);
-    }
-    return this.locale;
+    let locale = i18n.locale(this.config.locale || DEFAULT_LOCALE);
+    locale = locale.override(this.ChatWootConfig().templates);
+    return locale;
   }
 
   /**
    * Gets the AccountAPI client
    * @returns ChatwootClient instance
    */
+  @CacheSync()
   public AccountAPI(): ChatwootClient {
-    if (!this.accountAPI) {
-      this.accountAPI = new ChatwootClient({
-        config: {
-          basePath: this.config.url,
-          with_credentials: true,
-          credentials: 'include',
-          token: this.config.accountToken,
-        },
-      });
-    }
-    return this.accountAPI;
+    return new ChatwootClient({
+      config: {
+        basePath: this.config.url,
+        with_credentials: true,
+        credentials: 'include',
+        token: this.config.accountToken,
+      },
+    });
   }
 
   /**
    * Gets the InboxAPI client
    * @returns ChatWootInboxAPI instance
    */
+  @CacheSync()
   public InboxAPI(): ChatWootInboxAPI {
-    if (!this.inboxAPI) {
-      const chatwootClientAPI = new ChatwootClient({
-        config: {
-          basePath: this.config.url,
-          with_credentials: true,
-          credentials: 'include',
-          token: this.config.inboxIdentifier,
-        },
-      });
-      this.inboxAPI = chatwootClientAPI.client as ChatWootInboxAPI;
-    }
-    return this.inboxAPI;
+    const chatwootClientAPI = new ChatwootClient({
+      config: {
+        basePath: this.config.url,
+        with_credentials: true,
+        credentials: 'include',
+        token: this.config.inboxIdentifier,
+      },
+    });
+    return chatwootClientAPI.client as ChatWootInboxAPI;
   }
 
   /**
    * Gets the ContactService
    * @returns ContactService instance
    */
+  @CacheSync()
   private ContactService(): ContactService {
-    if (!this.contactService) {
-      this.contactService = new ContactService(
-        this.config,
-        this.AccountAPI(),
-        this.InboxAPI(),
-        this.logger,
-      );
-    }
-    return this.contactService;
+    return new ContactService(
+      this.config,
+      this.AccountAPI(),
+      this.InboxAPI(),
+      this.logger,
+    );
+  }
+
+  @CacheSync()
+  public ConversationSelector() {
+    const config = this.ChatWootConfig();
+    return new ConversationSelector({
+      sort: config.conversations.sort,
+      status: config.conversations.status,
+      inboxId: this.config.inboxId,
+    });
   }
 
   /**
    * Gets the ConversationService
    * @returns ConversationService instance
    */
+  @CacheSync()
   private ConversationService(): ConversationService {
-    if (!this.conversationService) {
-      this.conversationService = new ConversationService(
-        this.config,
-        this.AccountAPI(),
-        this.InboxAPI(),
-        this.logger,
-      );
-    }
-    return this.conversationService;
+    return new ConversationService(
+      this.config,
+      this.AccountAPI(),
+      this.InboxAPI(),
+      this.ConversationSelector(),
+      this.logger,
+    );
   }
 
   /**
    * Gets the ContactConversationService
    * @returns ContactConversationService instance
    */
+  @CacheSync()
   public ContactConversationService(): ContactConversationService {
-    if (!this.contactConversationService) {
-      this.contactConversationService = new ContactConversationService(
-        this.config,
-        this.ContactService(),
-        this.ConversationService(),
-        this.AccountAPI(),
-        this.logger,
-        this.Locale(),
-      );
-    }
-    return this.contactConversationService;
+    return new ContactConversationService(
+      this.config,
+      this.ContactService(),
+      this.ConversationService(),
+      this.AccountAPI(),
+      this.logger,
+      this.Locale(),
+    );
   }
 
+  @CacheSync()
   private ChatwootMessageRepository(): ChatwootMessageRepository {
     return new ChatwootMessageRepository(this.Knex(), this.AppPk());
   }
 
+  @CacheSync()
   private WhatsAppMessageRepository(): WhatsAppMessageRepository {
     return new WhatsAppMessageRepository(this.Knex(), this.AppPk());
   }
 
+  @CacheSync()
   private MessageMappingRepository(): MessageMappingRepository {
     return new MessageMappingRepository(this.Knex(), this.AppPk());
   }
 
+  @CacheSync()
   public MessageMappingService(): MessageMappingService {
-    if (!this.messageMappingService) {
-      this.messageMappingService = new MessageMappingService(
-        this.Knex(),
-        this.WhatsAppMessageRepository(),
-        this.ChatwootMessageRepository(),
-        this.MessageMappingRepository(),
-      );
-    }
-    return this.messageMappingService;
+    return new MessageMappingService(
+      this.Knex(),
+      this.WhatsAppMessageRepository(),
+      this.ChatwootMessageRepository(),
+      this.MessageMappingRepository(),
+    );
   }
 
   public ChatWootErrorReporter(job: Job): ChatWootErrorReporter {
@@ -195,19 +192,20 @@ export class DIContainer {
    * Gets the WAHASelf instance
    * @returns WAHASelf instance
    */
+  @CacheSync()
   public WAHASelf(): WAHASelf {
-    if (!this.wahaSelf) {
-      this.wahaSelf = new WAHASelf();
-      const logging = new AxiosLogging(this.Logger());
-      logging.applyTo(this.wahaSelf.client);
-    }
-    return this.wahaSelf;
+    const self = new WAHASelf();
+    const logging = new AxiosLogging(this.Logger());
+    logging.applyTo(self.client);
+    return self;
   }
 
+  @CacheSync()
   public CustomAttributesService() {
     return new CustomAttributesService(this.config, this.AccountAPI());
   }
 
+  @CacheSync()
   public ChatWootConfig(): ChatWootConfig {
     const defaults: ChatWootConfig = {
       templates: {},
@@ -215,6 +213,10 @@ export class DIContainer {
       commands: {
         server: true,
       },
+      conversations: {
+        sort: ConversationSort.created_newest,
+        status: null,
+      },
     };
     return lodash.defaults({}, this.config, defaults);
   }

src/apps/chatwoot/dto/config.dto.ts

@@ -9,6 +9,11 @@ import {
 } from 'class-validator';
 import { Type } from 'class-transformer';
 import { IsDynamicObject } from '@waha/nestjs/validation/IsDynamicObject';
+import {
+  ConversationSelectorConfig,
+  ConversationSort,
+} from '@waha/apps/chatwoot/services/ConversationSelector';
+import { ConversationStatus } from '@waha/apps/chatwoot/client/types';
 
 export const DEFAULT_LOCALE = 'en-US';
 
@@ -23,10 +28,20 @@ export enum LinkPreview {
   HQ = 'HG',
 }
 
+export class ChatWootConversationsConfig {
+  @IsEnum(ConversationSort)
+  sort: ConversationSort;
+
+  @IsOptional()
+  @IsEnum(ConversationStatus, { each: true })
+  status: Array<ConversationStatus> | null;
+}
+
 export interface ChatWootConfig {
   templates: Record<string, string>;
   linkPreview: LinkPreview;
   commands: ChatWootCommandsConfig;
+  conversations: ChatWootConversationsConfig;
 }
 
 export class ChatWootAppConfig implements ChatWootAPIConfig {
@@ -56,7 +71,13 @@ export class ChatWootAppConfig implements ChatWootAPIConfig {
   @IsDynamicObject()
   templates?: Record<string, string>;
 
+  @IsOptional()
   @ValidateNested()
   @Type(() => ChatWootCommandsConfig)
   commands?: ChatWootCommandsConfig;
+
+  @IsOptional()
+  @ValidateNested()
+  @Type(() => ChatWootConversationsConfig)
+  conversations?: ChatWootConversationsConfig;
 }

src/apps/chatwoot/services/ChatWootQueueService.ts

@@ -19,6 +19,10 @@ export class ChatWootQueueService {
     private readonly messageUpdatedQueue: Queue,
     @InjectQueue(QueueName.INBOX_MESSAGE_DELETED)
     private readonly messageDeletedQueue: Queue,
+    @InjectQueue(QueueName.INBOX_CONVERSATION_CREATED)
+    private readonly conversationCreatedQueue: Queue,
+    @InjectQueue(QueueName.INBOX_CONVERSATION_STATUS_CHANGED)
+    private readonly conversationStatusChanged: Queue,
     @InjectQueue(QueueName.INBOX_COMMANDS)
     private readonly commandsQueue: Queue,
   ) {}
@@ -41,10 +45,14 @@ export class ChatWootQueueService {
    */
   private getQueueForEvent(event: string): Queue | null {
     switch (event) {
+      case EventName.CONVERSATION_CREATED:
+        return this.conversationCreatedQueue;
       case EventName.MESSAGE_CREATED:
         return this.messageCreatedQueue;
       case EventName.MESSAGE_UPDATED:
         return this.messageUpdatedQueue;
+      case EventName.CONVERSATION_STATUS_CHANGED:
+        return this.conversationStatusChanged;
       case 'message_deleted':
         return this.messageDeletedQueue;
       case 'commands':
@@ -95,9 +103,9 @@ export class ChatWootQueueService {
    */
   async addJobToQueue(event: string, data: InboxData): Promise<any> {
     const queue = this.getQueueForEvent(event);
-    if (queue) {
-      return await this.add(queue, event, data);
+    if (!queue) {
+      return;
     }
-    return { ignored: true, event };
+    await this.add(queue, event, data);
   }
 }

src/apps/chatwoot/services/ConversationSelector.ts

@@ -0,0 +1,72 @@
+import { ConversationStatus } from '@waha/apps/chatwoot/client/types';
+import { contact_conversations } from '@figuro/chatwoot-sdk/dist/models/contact_conversations';
+import * as lodash from 'lodash';
+import type { conversation } from '@figuro/chatwoot-sdk/dist/models/conversation';
+
+export enum ConversationSort {
+  activity_newest = 'activity_newest',
+  created_newest = 'created_newest',
+  created_oldest = 'created_oldest',
+  activity_oldest = 'activity_oldest',
+}
+
+export type ConversationSelectorConfig = {
+  sort: ConversationSort;
+  status?: Array<ConversationStatus>;
+  inboxId: number;
+};
+
+export type ConversationResult = Pick<conversation, 'id' | 'account_id'>;
+
+export class ConversationSelector {
+  constructor(private config: ConversationSelectorConfig) {}
+
+  hasStatusFilter() {
+    return this.config.status;
+  }
+
+  select(conversations: contact_conversations): ConversationResult | null {
+    conversations = this.filter(conversations);
+    conversations = this.sort(conversations);
+    return conversations[0] || null;
+  }
+
+  private filter(conversations: contact_conversations): contact_conversations {
+    // Filter by inbox id
+    conversations = lodash.filter(conversations, {
+      inbox_id: this.config.inboxId,
+    }) as contact_conversations;
+
+    // Filter by status
+    if (this.config.status && this.config.status.length > 0) {
+      conversations = lodash.filter(conversations, (conversation) => {
+        return this.config.status.includes(
+          conversation.status as ConversationStatus,
+        );
+      });
+    }
+    return conversations;
+  }
+
+  private sort(conversations: contact_conversations): contact_conversations {
+    let field = null;
+    let dir = null;
+    switch (this.config.sort) {
+      case ConversationSort.activity_newest:
+        [field, dir] = ['last_activity_at', 'desc'];
+        break;
+      case ConversationSort.created_newest:
+        [field, dir] = ['created_at', 'desc'];
+        break;
+      case ConversationSort.created_oldest:
+        [field, dir] = ['created_at', 'asc'];
+        break;
+      case ConversationSort.activity_oldest:
+        [field, dir] = ['last_activity_at', 'asc'];
+    }
+    if (!field || !dir) {
+      return conversations;
+    }
+    return lodash.orderBy(conversations, [field], [dir]);
+  }
+}

src/utils/Cache.ts

@@ -21,3 +21,34 @@ export function CacheAsync() {
     };
   };
 }
+
+export function CacheSync() {
+  return function (
+    _target: any,
+    propertyKey: string,
+    descriptor: PropertyDescriptor,
+  ) {
+    const original = descriptor.value as (...args: any[]) => any;
+    if (typeof original !== 'function') {
+      throw new Error('@CacheSync can only decorate methods');
+    }
+
+    const symbol = Symbol(`__cache_${propertyKey}`);
+
+    descriptor.value = function (...args: any[]) {
+      if (Object.prototype.hasOwnProperty.call(this, symbol)) {
+        return (this as any)[symbol];
+      }
+      const result = original.apply(this, args);
+      Object.defineProperty(this, symbol, {
+        value: result,
+        enumerable: false,
+        configurable: false,
+        writable: false,
+      });
+      return result;
+    };
+
+    return descriptor;
+  };
+}