Fix(FlowiseChatGoogleGenerativeAI): Prevent "parts must not be empty" API error in Seq Agents (#4292)

* Fix(FlowiseChatGoogleGenerativeAI): Prevent "parts must not be empty" API error in Seq Agents

* Fix: Update pnpm-lock.yaml to resolve CI issues

* convert role function and tool to function

* remove comment

---------

Co-authored-by: Henry <hzj94@hotmail.com>

packages/components/nodes/chatmodels/ChatGoogleGenerativeAI/FlowiseChatGoogleGenerativeAI.ts

@@ -415,24 +415,18 @@ function getMessageAuthor(message: BaseMessage) {
 }
 
 function convertAuthorToRole(author: string) {
-    switch (author) {
-        /**
-         *  Note: Gemini currently is not supporting system messages
-         *  we will convert them to human messages and merge with following
-         * */
+    switch (author.toLowerCase()) {
         case 'ai':
-        case 'model': // getMessageAuthor returns message.name. code ex.: return message.name ?? type;
+        case 'assistant':
+        case 'model':
             return 'model'
-        case 'system':
-        case 'human':
-            return 'user'
         case 'function':
         case 'tool':
             return 'function'
+        case 'system':
+        case 'human':
         default:
-            // Instead of throwing, we return model (Needed for Multi Agent)
-            // throw new Error(`Unknown / unsupported author: ${author}`)
-            return 'model'
+            return 'user'
     }
 }
 
@@ -520,17 +514,29 @@ function convertMessageContentToParts(message: BaseMessage, isMultimodalModel: b
 
 function checkIfEmptyContentAndSameRole(contents: Content[]) {
     let prevRole = ''
-    const removedContents: Content[] = []
+    const validContents: Content[] = []
+
     for (const content of contents) {
-        const role = content.role
-        if (content.parts.length && content.parts[0].text === '' && role === prevRole) {
-            removedContents.push(content)
+        // Skip only if completely empty
+        if (!content.parts || !content.parts.length) {
+            continue
         }
 
-        prevRole = role
+        // Ensure role is always either 'user' or 'model'
+        content.role = content.role === 'model' ? 'model' : 'user'
+
+        // Handle consecutive messages
+        if (content.role === prevRole && validContents.length > 0) {
+            // Merge with previous content if same role
+            validContents[validContents.length - 1].parts.push(...content.parts)
+            continue
+        }
+
+        validContents.push(content)
+        prevRole = content.role
     }
 
-    return contents.filter((content) => !removedContents.includes(content))
+    return validContents
 }
 
 function convertBaseMessagesToContent(messages: BaseMessage[], isMultimodalModel: boolean) {
@@ -568,7 +574,7 @@ function convertBaseMessagesToContent(messages: BaseMessage[], isMultimodalModel
                 }
             }
             let actualRole = role
-            if (actualRole === 'function') {
+            if (actualRole === 'function' || actualRole === 'tool') {
                 // GenerativeAI API will throw an error if the role is not "user" or "model."
                 actualRole = 'user'
             }