[OpenAI] [Assistants] Add fileIds to Thread messages (#29500)

Fix #29473 

### Packages impacted by this PR
@azure/openai-assistants

### Issues associated with this PR
#29473 

### Describe the problem that is addressed by this PR
Add fileIds to Thread messages

### What are the possible designs available to address the problem? If
there are more than one possible design, why was the one in this PR
chosen?


### Are there test cases added in this PR? _(If not, why?)_


### Provide a list of related PRs _(if any)_


### Command used to generate this PR:**_(Applicable only to SDK release
request PRs)_

### Checklists
- [ ] Added impacted package name to the issue description
- [ ] Does this PR needs any fixes in the SDK Generator?** _(If so,
create an Issue in the
[Autorest/typescript](https://github.com/Azure/autorest.typescript)
repository and link it here)_
- [ ] Added a changelog (if necessary)

sdk/openai/openai-assistants/review/openai-assistants-models.api.md

@@ -54,10 +54,7 @@ export interface AssistantThread {
 
 // @public
 export interface AssistantThreadCreationOptions {
-    messages?: {
-        role: string;
-        content: string;
-    }[];
+    messages?: ThreadInitializationMessage[];
     metadata?: Record<string, string>;
 }
 
@@ -502,7 +499,7 @@ export interface ThreadDeletionStatus extends DeletionStatus {
 export interface ThreadInitializationMessage {
     content: string;
     fileIds?: string[];
-    metadata: Record<string, string> | null;
+    metadata?: Record<string, string> | null;
     role: MessageRole;
 }
 

sdk/openai/openai-assistants/review/openai-assistants.api.md

@@ -103,10 +103,7 @@ export interface AssistantThread {
 
 // @public
 export interface AssistantThreadCreationOptions {
-    messages?: {
-        role: string;
-        content: string;
-    }[];
+    messages?: ThreadInitializationMessage[];
     metadata?: Record<string, string>;
 }
 
@@ -551,6 +548,14 @@ export interface SubmitToolOutputsToRunOptions extends OperationOptions {
 export interface ThreadDeletionStatus extends DeletionStatus {
 }
 
+// @public
+export interface ThreadInitializationMessage {
+    content: string;
+    fileIds?: string[];
+    metadata?: Record<string, string> | null;
+    role: MessageRole;
+}
+
 // @public
 export interface ThreadMessage {
     assistantId?: string;

sdk/openai/openai-assistants/src/index.ts

@@ -96,6 +96,7 @@ export {
   GetMessageFileOptions,
   GetMessageOptions,
   ThreadRun,
+  ThreadInitializationMessage,
   CancelRunOptions,
   CreateRunOptions,
   CreateRunRequestOptions,

sdk/openai/openai-assistants/src/models/models.ts

@@ -123,12 +123,7 @@ export interface AssistantFileDeletionStatus extends DeletionStatus {}
 /** The details used to create a new assistant thread. */
 export interface AssistantThreadCreationOptions {
   /** The messages to associate with the new thread. */
-  messages?: {
-    /** The role associated with the assistant thread message. */
-    role: string;
-    /** The list of content items associated with the assistant thread message. */
-    content: string;
-  }[];
+  messages?: ThreadInitializationMessage[];
   /** A set of key/value pairs used to store additional information about the object. */
   metadata?: Record<string, string>;
 }
@@ -145,7 +140,7 @@ export interface ThreadInitializationMessage {
    */
   fileIds?: string[];
   /** A set of up to 16 key/value pairs that can be attached to an object, used for storing additional information about that object in a structured format. Keys may be up to 64 characters in length and values may be up to 512 characters in length. */
-  metadata: Record<string, string> | null;
+  metadata?: Record<string, string> | null;
 }
 
 /** Information about a single thread associated with an assistant. */