Changeset 0.7.0 (#37)

server/handlers/completion.go

@@ -21,6 +21,7 @@ type completionRequest struct {
 	ChatID      string   `json:"chat_id"`    // deprecated alias — maps to channel_id
 	Content     string   `json:"content" binding:"required"`
 	Model       string   `json:"model,omitempty"`
+	PresetID    string   `json:"preset_id,omitempty"` // if set, unwraps preset → base model + config
 	APIConfigID string   `json:"api_config_id,omitempty"`
 	MaxTokens   int      `json:"max_tokens,omitempty"`
 	Temperature *float64 `json:"temperature,omitempty"`
@@ -72,6 +73,32 @@ func (h *CompletionHandler) Complete(c *gin.Context) {
 		return
 	}
 
+	// ── Preset unwrap: preset overrides defaults, explicit request fields win ──
+	var presetSystemPrompt string
+	if req.PresetID != "" {
+		preset := ResolvePreset(req.PresetID, userID)
+		if preset == nil {
+			c.JSON(http.StatusBadRequest, gin.H{"error": "preset not found or not accessible"})
+			return
+		}
+		// Preset provides defaults; explicit request fields take priority
+		if req.Model == "" {
+			req.Model = preset.BaseModelID
+		}
+		if req.APIConfigID == "" && preset.APIConfigID != nil {
+			req.APIConfigID = *preset.APIConfigID
+		}
+		if req.Temperature == nil && preset.Temperature != nil {
+			req.Temperature = preset.Temperature
+		}
+		if req.MaxTokens == 0 && preset.MaxTokens != nil {
+			req.MaxTokens = *preset.MaxTokens
+		}
+		if preset.SystemPrompt != "" {
+			presetSystemPrompt = preset.SystemPrompt
+		}
+	}
+
 	// Resolve provider config
 	providerCfg, providerID, model, configID, err := h.resolveConfig(userID, channelID, req)
 	if err != nil {
@@ -86,7 +113,7 @@ func (h *CompletionHandler) Complete(c *gin.Context) {
 	}
 
 	// Load conversation history
-	messages, err := h.loadConversation(channelID)
+	messages, err := h.loadConversation(channelID, presetSystemPrompt)
 	if err != nil {
 		c.JSON(http.StatusInternalServerError, gin.H{"error": "failed to load conversation"})
 		return
@@ -367,7 +394,7 @@ func (h *CompletionHandler) resolveConfig(userID string, channelID string, req c
 
 // ── Conversation Loader ─────────────────────
 
-func (h *CompletionHandler) loadConversation(channelID string) ([]providers.Message, error) {
+func (h *CompletionHandler) loadConversation(channelID string, presetSystemPrompt string) ([]providers.Message, error) {
 	// Load system prompt from channel
 	var systemPrompt *string
 	_ = database.DB.QueryRow(
@@ -376,7 +403,13 @@ func (h *CompletionHandler) loadConversation(channelID string) ([]providers.Mess
 
 	messages := make([]providers.Message, 0)
 
-	if systemPrompt != nil && *systemPrompt != "" {
+	// Preset system prompt takes priority; channel system prompt is fallback
+	if presetSystemPrompt != "" {
+		messages = append(messages, providers.Message{
+			Role:    "system",
+			Content: presetSystemPrompt,
+		})
+	} else if systemPrompt != nil && *systemPrompt != "" {
 		messages = append(messages, providers.Message{
 			Role:    "system",
 			Content: *systemPrompt,