From a4cb8df4340845faa008ab12d1c910e42dda0a09 Mon Sep 17 00:00:00 2001
From: "xTCry [Vladislav Kh]" <wolt6@mail.ru>
Date: Sun, 1 Aug 2021 07:31:09 +0300
Subject: [PATCH] feat(listeners): support for chaining method listeners

---
 lib/services/listeners-explorer.service.ts  | 35 +++++++++++----------
 lib/services/metadata-accessor.service.ts   |  6 ++--
 lib/telegraf.constants.ts                   |  2 +-
 lib/utils/create-listener-decorator.util.ts | 26 ++++++++++-----
 4 files changed, 41 insertions(+), 28 deletions(-)

diff --git a/lib/services/listeners-explorer.service.ts b/lib/services/listeners-explorer.service.ts
index 6a5dbc8..e4c145e 100644
--- a/lib/services/listeners-explorer.service.ts
+++ b/lib/services/listeners-explorer.service.ts
@@ -22,7 +22,8 @@ import { TelegrafModuleOptions } from '../interfaces';
 @Injectable()
 export class ListenersExplorerService
   extends BaseExplorerService
-  implements OnModuleInit {
+  implements OnModuleInit
+{
   private readonly telegrafParamsFactory = new TelegrafParamsFactory();
   private bot: Telegraf<any>;
 
@@ -123,7 +124,7 @@ export class ListenersExplorerService
   ): void {
     const methodRef = prototype[methodName];
     const metadata = this.metadataAccessor.getListenerMetadata(methodRef);
-    if (!metadata) {
+    if (!metadata || metadata.length < 1) {
       return undefined;
     }
 
@@ -133,22 +134,22 @@ export class ListenersExplorerService
       methodName,
     );
 
-    const { method, args } = metadata;
+    for (const { method, args } of metadata) {
+      /* Basic callback */
+      // composer[method](...args, listenerCallbackFn);
 
-    /* Basic callback */
-    // composer[method](...args, listenerCallbackFn);
-
-    /* Complex callback return value handing */
-    composer[method](
-      ...args,
-      async (ctx: Context, next: Function): Promise<void> => {
-        const result = await listenerCallbackFn(ctx, next);
-        if (result) {
-          await ctx.reply(String(result));
-        }
-        // TODO-Possible-Feature: Add more supported return types
-      },
-    );
+      /* Complex callback return value handing */
+      composer[method](
+        ...args,
+        async (ctx: Context, next: Function): Promise<void> => {
+          const result = await listenerCallbackFn(ctx, next);
+          if (result) {
+            await ctx.reply(String(result));
+          }
+          // TODO-Possible-Feature: Add more supported return types
+        },
+      );
+    }
   }
 
   createContextCallback<T extends Record<string, unknown>>(
diff --git a/lib/services/metadata-accessor.service.ts b/lib/services/metadata-accessor.service.ts
index 75fb79c..2e5b343 100644
--- a/lib/services/metadata-accessor.service.ts
+++ b/lib/services/metadata-accessor.service.ts
@@ -2,7 +2,7 @@ import { Injectable } from '@nestjs/common';
 import { Reflector } from '@nestjs/core';
 import {
   SCENE_METADATA,
-  LISTENER_METADATA,
+  LISTENERS_METADATA,
   UPDATE_METADATA,
 } from '../telegraf.constants';
 import { ListenerMetadata } from '../interfaces';
@@ -21,8 +21,8 @@ export class MetadataAccessorService {
     return !!this.reflector.get(SCENE_METADATA, target);
   }
 
-  getListenerMetadata(target: Function): ListenerMetadata | undefined {
-    return this.reflector.get(LISTENER_METADATA, target);
+  getListenerMetadata(target: Function): ListenerMetadata[] | undefined {
+    return this.reflector.get(LISTENERS_METADATA, target);
   }
 
   getSceneMetadata(target: Function): string | undefined {
diff --git a/lib/telegraf.constants.ts b/lib/telegraf.constants.ts
index 56e78f2..70c6a90 100644
--- a/lib/telegraf.constants.ts
+++ b/lib/telegraf.constants.ts
@@ -6,7 +6,7 @@ export const DEFAULT_BOT_NAME = 'DEFAULT_BOT_NAME';
 
 export const UPDATE_METADATA = 'UPDATE_METADATA';
 export const SCENE_METADATA = 'SCENE_METADATA';
-export const LISTENER_METADATA = 'LISTENER_METADATA';
+export const LISTENERS_METADATA = 'LISTENERS_METADATA';
 
 export const PARAM_ARGS_METADATA = ROUTE_ARGS_METADATA;
 
diff --git a/lib/utils/create-listener-decorator.util.ts b/lib/utils/create-listener-decorator.util.ts
index c423ff3..1b3cb9a 100644
--- a/lib/utils/create-listener-decorator.util.ts
+++ b/lib/utils/create-listener-decorator.util.ts
@@ -1,17 +1,29 @@
-import { SetMetadata } from '@nestjs/common';
 import { Composer } from 'telegraf';
 import { ComposerMethodArgs, OnlyFunctionPropertyNames } from '../types';
-import { LISTENER_METADATA } from '../telegraf.constants';
+import { LISTENERS_METADATA } from '../telegraf.constants';
 import { ListenerMetadata } from '../interfaces';
 
 export function createListenerDecorator<
   TComposer extends Composer<never>,
-  TMethod extends OnlyFunctionPropertyNames<TComposer> = OnlyFunctionPropertyNames<TComposer>
+  TMethod extends OnlyFunctionPropertyNames<TComposer> = OnlyFunctionPropertyNames<TComposer>,
 >(method: TMethod) {
   return (...args: ComposerMethodArgs<TComposer, TMethod>): MethodDecorator => {
-    return SetMetadata(LISTENER_METADATA, {
-      method,
-      args,
-    } as ListenerMetadata);
+    return (
+      _target: any,
+      _key?: string | symbol,
+      descriptor?: TypedPropertyDescriptor<any>,
+    ) => {
+      const metadata = [
+        {
+          method,
+          args,
+        } as ListenerMetadata,
+      ];
+          
+      const previousValue = Reflect.getMetadata(LISTENERS_METADATA, descriptor.value) || [];
+      const value = [...previousValue, ...metadata];
+      Reflect.defineMetadata(LISTENERS_METADATA, value, descriptor.value);
+      return descriptor;
+    };
   };
 }