feat(captain): align playground fallback

internal/service/captain_assistant_service.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
+	"strings"
 
 	"github.com/gochat/gochat/internal/llm"
 	"github.com/gochat/gochat/internal/model"
@@ -59,6 +60,17 @@ type UpdateAssistantRequest struct {
 	Status             string          `json:"status"`
 }
 
+type PlaygroundMessage struct {
+	Role      string `json:"role"`
+	Content   string `json:"content"`
+	AgentName string `json:"agent_name,omitempty"`
+}
+
+type PlaygroundRequest struct {
+	MessageContent string              `json:"message_content"`
+	MessageHistory []PlaygroundMessage `json:"message_history"`
+}
+
 // --- CRUD Operations ---
 
 // Create creates a new CaptainAssistant.
@@ -309,6 +321,118 @@ func (s *CaptainAssistantService) GenerateResponse(ctx context.Context, assistan
 	return resp.Choices[0].Message.Content, nil
 }
 
+const captainPlaygroundFallbackMessage = "Captain assistant response generation is not configured for this account."
+
+// GeneratePlaygroundResponse follows Chatwoot Captain assistant playground behavior.
+func (s *CaptainAssistantService) GeneratePlaygroundResponse(ctx context.Context, accountID, assistantID uint, req PlaygroundRequest) (map[string]any, error) {
+	assistant, err := s.assistantRepo.GetByAccountAndID(ctx, accountID, assistantID)
+	if err != nil {
+		return nil, fmt.Errorf("assistant not found: %w", err)
+	}
+
+	if s.captainV2Enabled(ctx, accountID) {
+		history := playgroundMessageHistory(req.MessageHistory, req.MessageContent)
+		content, err := s.generatePlaygroundLLMResponse(ctx, assistant, history)
+		if err != nil {
+			return nil, err
+		}
+		return map[string]any{"response": content}, nil
+	}
+
+	history := append([]PlaygroundMessage{}, req.MessageHistory...)
+	content, err := s.generatePlaygroundLLMResponse(ctx, assistant, appendAdditionalPlaygroundMessage(history, req.MessageContent))
+	if err != nil {
+		return nil, err
+	}
+	return map[string]any{"content": content}, nil
+}
+
+func (s *CaptainAssistantService) generatePlaygroundLLMResponse(ctx context.Context, assistant *model.CaptainAssistant, history []PlaygroundMessage) (string, error) {
+	if s.llmProvider == nil {
+		return captainPlaygroundFallbackMessage, nil
+	}
+
+	cfg, _ := assistant.GetConfig()
+	messages := []llm.ChatMessage{{Role: "system", Content: buildSystemPrompt(assistant, cfg)}}
+	for _, message := range history {
+		if message.Role == "" || message.Content == "" {
+			continue
+		}
+		messages = append(messages, llm.ChatMessage{Role: message.Role, Content: message.Content})
+	}
+
+	resp, err := s.llmProvider.ChatCompletion(ctx, llm.ChatRequest{
+		Model:       cfg.Model,
+		Messages:    messages,
+		Temperature: cfg.Temperature,
+		MaxTokens:   1024,
+	})
+	if err != nil {
+		applogger.L().Errorf("GeneratePlaygroundResponse LLM call: %v", err)
+		return "", fmt.Errorf("llm generation failed: %w", err)
+	}
+	if len(resp.Choices) == 0 {
+		return "", fmt.Errorf("no response from LLM")
+	}
+	return resp.Choices[0].Message.Content, nil
+}
+
+func (s *CaptainAssistantService) captainV2Enabled(ctx context.Context, accountID uint) bool {
+	flags, err := s.assistantRepo.GetAccountFeatureFlags(ctx, accountID)
+	if err != nil {
+		return false
+	}
+	return featureFlagStringEnabled(flags, "captain_integration_v2")
+}
+
+func featureFlagStringEnabled(raw, flag string) bool {
+	raw = strings.TrimSpace(raw)
+	if raw == "" {
+		return false
+	}
+	var objectFlags map[string]bool
+	if err := json.Unmarshal([]byte(raw), &objectFlags); err == nil {
+		return objectFlags[flag]
+	}
+	var arrayFlags []string
+	if err := json.Unmarshal([]byte(raw), &arrayFlags); err == nil {
+		for _, item := range arrayFlags {
+			if item == flag {
+				return true
+			}
+		}
+		return false
+	}
+	for _, item := range strings.Split(raw, ",") {
+		if strings.TrimSpace(item) == flag {
+			return true
+		}
+	}
+	return false
+}
+
+func playgroundMessageHistory(history []PlaygroundMessage, current string) []PlaygroundMessage {
+	result := append([]PlaygroundMessage{}, history...)
+	if strings.TrimSpace(current) == "" {
+		return result
+	}
+	currentMessage := PlaygroundMessage{Role: "user", Content: current}
+	if len(result) > 0 {
+		last := result[len(result)-1]
+		if last.Role == currentMessage.Role && last.Content == currentMessage.Content && last.AgentName == "" {
+			return result
+		}
+	}
+	return append(result, currentMessage)
+}
+
+func appendAdditionalPlaygroundMessage(history []PlaygroundMessage, current string) []PlaygroundMessage {
+	if strings.TrimSpace(current) == "" {
+		return history
+	}
+	return append(history, PlaygroundMessage{Role: "user", Content: current})
+}
+
 // buildSystemPrompt constructs the system prompt from assistant config and guidelines.
 func buildSystemPrompt(assistant *model.CaptainAssistant, cfg *model.AssistantConfig) string {
 	prompt := fmt.Sprintf("You are %s, an AI assistant.", assistant.Name)