fix: fix skylark format issue when the assistant role message is the first message (#155)

Co-Authored-By: Minghan Zhang <112773885+zmh-program@users.noreply.github.com>

adapter/skylark/chat.go

@@ -5,6 +5,7 @@ import (
 	"chat/globals"
 	"chat/utils"
 	"fmt"
+
 	"github.com/volcengine/volc-sdk-golang/service/maas"
 	"github.com/volcengine/volc-sdk-golang/service/maas/models/api"
 )
@@ -12,17 +13,41 @@ import (
 const defaultMaxTokens int64 = 1500
 
 func getMessages(messages []globals.Message) []*api.Message {
-	return utils.Each[globals.Message, *api.Message](messages, func(message globals.Message) *api.Message {
+	result := make([]*api.Message, 0)
+
+	for _, message := range messages {
 		if message.Role == globals.Tool {
 			message.Role = maas.ChatRoleOfFunction
 		}
 
-		return &api.Message{
+		msg := &api.Message{
 			Role:         message.Role,
 			Content:      message.Content,
 			FunctionCall: getFunctionCall(message.ToolCalls),
 		}
-	})
+
+		hasPrevious := len(result) > 0
+
+		//  a message should not followed by the same role message, merge them
+		if hasPrevious && result[len(result)-1].Role == message.Role {
+			prev := result[len(result)-1]
+			prev.Content += msg.Content
+			if message.ToolCalls != nil {
+				prev.FunctionCall = msg.FunctionCall
+			}
+
+			continue
+		}
+
+		// `assistant` message should follow a user or function message, if not has previous message, change the role to `user`
+		if !hasPrevious && message.Role == maas.ChatRoleOfAssistant {
+			msg.Role = maas.ChatRoleOfUser
+		}
+
+		result = append(result, msg)
+	}
+
+	return result
 }
 
 func (c *ChatInstance) GetMaxTokens(token *int) int64 {