Support say(message)

src/user/contact.ts

@@ -320,11 +320,12 @@ export class Contact extends Accessory implements Sayable {
     return `Contact<${identity}>`
   }
 
-  public async say (text:     string)      : Promise<void | Message>
-  public async say (contact:  Contact)     : Promise<void | Message>
-  public async say (file:     FileBox)     : Promise<void | Message>
-  public async say (mini:     MiniProgram) : Promise<void | Message>
-  public async say (url:      UrlLink)     : Promise<void | Message>
+  public say (text:     string)      : Promise<void | Message>
+  public say (message:  Message)     : Promise<void | Message>
+  public say (contact:  Contact)     : Promise<void | Message>
+  public say (file:     FileBox)     : Promise<void | Message>
+  public say (mini:     MiniProgram) : Promise<void | Message>
+  public say (url:      UrlLink)     : Promise<void | Message>
 
   /**
    * > Tips:
@@ -385,12 +386,18 @@ export class Contact extends Accessory implements Sayable {
    */
   public async say (
     something:  string
+              | Message
               | Contact
               | FileBox
               | MiniProgram
               | UrlLink
   ): Promise<void | Message> {
     log.verbose('Contact', 'say(%s)', something)
+
+    if (something instanceof Message) {
+      return something.forward(this)
+    }
+
     let msgId: string | void
     if (typeof something === 'string') {
       /**

src/user/message.ts

@@ -416,13 +416,14 @@ export class Message extends Accessory implements Sayable {
     }
   }
 
-  public async say (text:    string, mention?: Contact | Contact[]) : Promise<void | Message>
-  public async say (contact: Contact)                               : Promise<void | Message>
-  public async say (file:    FileBox)                               : Promise<void | Message>
-  public async say (url:     UrlLink)                               : Promise<void | Message>
-  public async say (mini:    MiniProgram)                           : Promise<void | Message>
-
-  public async say (...args: never[]): Promise<never>
+  public say (text:    string, mention?: Contact | Contact[]) : Promise<void | Message>
+  public say (message: Message)                               : Promise<void | Message>
+  public say (contact: Contact)                               : Promise<void | Message>
+  public say (file:    FileBox)                               : Promise<void | Message>
+  public say (url:     UrlLink)                               : Promise<void | Message>
+  public say (mini:    MiniProgram)                           : Promise<void | Message>
+
+  public say (...args: never[]): Promise<never>
   /**
    * Reply a Text or Media File message to the sender.
    * > Tips:
@@ -501,7 +502,12 @@ export class Message extends Accessory implements Sayable {
    * .start()
    */
   public async say (
-    textOrContactOrFileOrUrlOrMini : string | Contact | FileBox | UrlLink | MiniProgram,
+    textOrContactOrFileOrUrlOrMini :  string
+                                    | Message
+                                    | Contact
+                                    | FileBox
+                                    | UrlLink
+                                    | MiniProgram,
   ): Promise<void | Message> {
     log.verbose('Message', 'say(%s)', textOrContactOrFileOrUrlOrMini)
 
@@ -511,14 +517,24 @@ export class Message extends Accessory implements Sayable {
     const room = this.room()
 
     let conversationId: string
+    let conversation
     if (room) {
+      conversation = room
       conversationId = room.id
     } else if (from) {
+      conversation = from
       conversationId = from.id
     } else {
       throw new Error('neither room nor from?')
     }
 
+    /**
+     * Support say a existing message: just forward it.
+     */
+    if (textOrContactOrFileOrUrlOrMini instanceof Message) {
+      return textOrContactOrFileOrUrlOrMini.forward(conversation)
+    }
+
     let msgId: void | string
     if (typeof textOrContactOrFileOrUrlOrMini === 'string') {
       /**

src/user/room.ts

@@ -378,6 +378,7 @@ export class Room extends Accessory implements Sayable {
   }
 
   public say (text:     string)                                  : Promise<void | Message>
+  public say (message:  Message)                                 : Promise<void | Message>
   public say (text:     string, ...mentionList: Contact[])       : Promise<void | Message>
   public say (textList: TemplateStringsArray, ...varList: any[]) : Promise<void | Message>
   public say (file:     FileBox)                                 : Promise<void | Message>
@@ -458,6 +459,7 @@ export class Room extends Accessory implements Sayable {
    */
   public async say (
     something : string
+              | Message
               | Contact
               | FileBox
               | MiniProgram
@@ -474,12 +476,20 @@ export class Room extends Accessory implements Sayable {
     let text: string
     let msgId: string | void
 
+    if (something instanceof Message) {
+      return something.forward(this)
+    }
+
+    function isTemplateStringArray (tsa: any): tsa is TemplateStringsArray {
+      return tsa instanceof Array
+    }
+
     /**
      *
      * 0. TemplateStringArray
      *
      */
-    if (something instanceof Array) {
+    if (isTemplateStringArray(something)) {
       const msgId = await this.sayTemplateStringsArray(
         something as TemplateStringsArray,
         ...varList,