refactor: consolidate duplicated helpers into internal/util

internal/config/config.go

@@ -690,27 +690,6 @@ func (cfg CacheConfig) Validate() error {
 	return nil
 }
 
-func valueOrDefault(value string, fallback string) string {
-	if value == "" {
-		return fallback
-	}
-	return value
-}
-
-func intOrDefault(value int, fallback int) int {
-	if value == 0 {
-		return fallback
-	}
-	return value
-}
-
-func boolOrDefault(value *bool, fallback bool) bool {
-	if value == nil {
-		return fallback
-	}
-	return *value
-}
-
 func (cfg Config) validateExtensions() error {
 	for _, spec := range cfg.extensionSpecs {
 		if spec.Validate == nil {

internal/config/config_loader.go

@@ -9,6 +9,8 @@ import (
 	"path/filepath"
 	"strings"
 
+	"moonbridge/internal/util"
+
 	"gopkg.in/yaml.v3"
 )
 
@@ -444,26 +446,26 @@ func FromFileConfigWithOptions(fileConfig FileConfig, opts LoadOptions) (Config,
 
 	cfg := Config{
 		Mode:             mode,
-		Addr:             valueOrDefault(strings.TrimSpace(fileConfig.Server.Addr), DefaultAddr),
+		Addr:             util.OrDefault(strings.TrimSpace(fileConfig.Server.Addr), DefaultAddr),
 		AuthToken:        strings.TrimSpace(fileConfig.Server.AuthToken),
-		MaxSessions:      intOrDefault(fileConfig.Server.MaxSessions, 0),
-		SessionTTL:       valueOrDefault(strings.TrimSpace(fileConfig.Server.SessionTTL), "24h"),
+		MaxSessions:      util.OrDefault(fileConfig.Server.MaxSessions, 0),
+		SessionTTL:       util.OrDefault(strings.TrimSpace(fileConfig.Server.SessionTTL), "24h"),
 		TraceRequests:    traceEnabled,
-		LogLevel:         valueOrDefault(strings.TrimSpace(fileConfig.Log.Level), "info"),
-		LogFormat:        valueOrDefault(strings.TrimSpace(fileConfig.Log.Format), "text"),
+		LogLevel:         util.OrDefault(strings.TrimSpace(fileConfig.Log.Level), "info"),
+		LogFormat:        util.OrDefault(strings.TrimSpace(fileConfig.Log.Format), "text"),
 		SystemPrompt:     defaults.SystemPrompt,
 		DefaultModel:     defaults.Model,
 		Defaults:         defaults,
 		Models:           models,
 		Routes:           routes,
 		ProviderDefs:     providerDefs,
 		WebSearchSupport: webSearchSupport,
-		WebSearchMaxUses: intOrDefault(fileConfig.WebSearch.MaxUses, 8),
+		WebSearchMaxUses: util.OrDefault(fileConfig.WebSearch.MaxUses, 8),
 		TavilyAPIKey:     strings.TrimSpace(fileConfig.WebSearch.TavilyAPIKey),
 		FirecrawlAPIKey:  strings.TrimSpace(fileConfig.WebSearch.FirecrawlAPIKey),
-		SearchMaxRounds:  intOrDefault(fileConfig.WebSearch.SearchMaxRounds, 5),
+		SearchMaxRounds:  util.OrDefault(fileConfig.WebSearch.SearchMaxRounds, 5),
 		WebSearchExtra:   cloneAnyMap(fileConfig.WebSearch.Extra),
-		DefaultMaxTokens: intOrDefault(defaults.MaxTokens, 1024),
+		DefaultMaxTokens: util.OrDefault(defaults.MaxTokens, 1024),
 		Cache:            fromCacheFileConfig(fileConfig.Cache),
 		Persistence:      FromPersistenceFileConfig(fileConfig.Persistence),
 		ResponseProxy:    responseProxy,
@@ -514,11 +516,11 @@ func fromModelDefFileConfig(fileConfig map[string]ModelDefFileConfig, specs exte
 				Description: strings.TrimSpace(p.Description),
 			})
 		}
-		supportsReasoning := boolOrDefault(
+		supportsReasoning := util.Deref(
 			m.SupportsReasoning,
 			len(reasoningPresets) > 0 ||
 				strings.TrimSpace(m.DefaultReasoningLevel) != "" ||
-				boolOrDefault(m.SupportsReasoningSummaries, false) ||
+				util.Deref(m.SupportsReasoningSummaries, false) ||
 				strings.TrimSpace(m.DefaultReasoningSummary) != "",
 		)
 		models[trimmedSlug] = ModelDef{
@@ -530,10 +532,10 @@ func fromModelDefFileConfig(fileConfig map[string]ModelDefFileConfig, specs exte
 			SupportsReasoning:           supportsReasoning,
 			DefaultReasoningLevel:       strings.TrimSpace(m.DefaultReasoningLevel),
 			SupportedReasoningLevels:    reasoningPresets,
-			SupportsReasoningSummaries:  boolOrDefault(m.SupportsReasoningSummaries, false),
+			SupportsReasoningSummaries:  util.Deref(m.SupportsReasoningSummaries, false),
 			DefaultReasoningSummary:     strings.TrimSpace(m.DefaultReasoningSummary),
 			InputModalities:             m.InputModalities,
-			SupportsImageDetailOriginal: boolOrDefault(m.SupportsImageDetailOriginal, false),
+			SupportsImageDetailOriginal: util.Deref(m.SupportsImageDetailOriginal, false),
 			WebSearch:                   ws,
 			Extensions:                  modelExtensions,
 		}
@@ -635,7 +637,7 @@ func fromProviderDefFileConfig(fileConfig map[string]ProviderDefFileConfig, spec
 		pd := ProviderDef{
 			BaseURL:          strings.TrimRight(strings.TrimSpace(def.BaseURL), "/"),
 			APIKey:           strings.TrimSpace(def.APIKey),
-			Version:          valueOrDefault(strings.TrimSpace(def.Version), "2023-06-01"),
+			Version:          util.OrDefault(strings.TrimSpace(def.Version), "2023-06-01"),
 			UserAgent:        strings.TrimSpace(def.UserAgent),
 			Protocol:         strings.TrimSpace(def.Protocol),
 			WebSearchSupport: wsSupport,
@@ -952,7 +954,7 @@ func FromAnthropicProxyFileConfig(fileConfig ProxyTargetFileConfig) AnthropicPro
 		Model:           strings.TrimSpace(fileConfig.Model),
 		ProviderBaseURL: strings.TrimRight(strings.TrimSpace(fileConfig.BaseURL), "/"),
 		ProviderAPIKey:  strings.TrimSpace(fileConfig.APIKey),
-		ProviderVersion: valueOrDefault(strings.TrimSpace(fileConfig.Version), "2023-06-01"),
+		ProviderVersion: util.OrDefault(strings.TrimSpace(fileConfig.Version), "2023-06-01"),
 	}
 }
 
@@ -964,16 +966,16 @@ func FromPersistenceFileConfig(fileConfig PersistenceFileConfig) PersistenceConf
 
 func fromCacheFileConfig(fileConfig CacheFileConfig) CacheConfig {
 	return CacheConfig{
-		Mode:                     valueOrDefault(strings.TrimSpace(fileConfig.Mode), "automatic"),
-		TTL:                      valueOrDefault(strings.TrimSpace(fileConfig.TTL), "5m"),
-		PromptCaching:            boolOrDefault(fileConfig.PromptCaching, true),
-		AutomaticPromptCache:     boolOrDefault(fileConfig.AutomaticPromptCache, true),
-		ExplicitCacheBreakpoints: boolOrDefault(fileConfig.ExplicitCacheBreakpoints, true),
-		AllowRetentionDowngrade:  boolOrDefault(fileConfig.AllowRetentionDowngrade, false),
-		MaxBreakpoints:           intOrDefault(fileConfig.MaxBreakpoints, 4),
-		MinCacheTokens:           intOrDefault(fileConfig.MinCacheTokens, 1024),
-		ExpectedReuse:            intOrDefault(fileConfig.ExpectedReuse, 2),
-		MinimumValueScore:        intOrDefault(fileConfig.MinimumValueScore, 2048),
-		MinBreakpointTokens:      intOrDefault(fileConfig.MinBreakpointTokens, 1024),
+		Mode:                     util.OrDefault(strings.TrimSpace(fileConfig.Mode), "automatic"),
+		TTL:                      util.OrDefault(strings.TrimSpace(fileConfig.TTL), "5m"),
+		PromptCaching:            util.Deref(fileConfig.PromptCaching, true),
+		AutomaticPromptCache:     util.Deref(fileConfig.AutomaticPromptCache, true),
+		ExplicitCacheBreakpoints: util.Deref(fileConfig.ExplicitCacheBreakpoints, true),
+		AllowRetentionDowngrade:  util.Deref(fileConfig.AllowRetentionDowngrade, false),
+		MaxBreakpoints:           util.OrDefault(fileConfig.MaxBreakpoints, 4),
+		MinCacheTokens:           util.OrDefault(fileConfig.MinCacheTokens, 1024),
+		ExpectedReuse:            util.OrDefault(fileConfig.ExpectedReuse, 2),
+		MinimumValueScore:        util.OrDefault(fileConfig.MinimumValueScore, 2048),
+		MinBreakpointTokens:      util.OrDefault(fileConfig.MinBreakpointTokens, 1024),
 	}
 }

internal/config/convert.go

@@ -1,6 +1,8 @@
 package config
 
 import (
+	"moonbridge/internal/util"
+
 	"gopkg.in/yaml.v3"
 )
 
@@ -122,12 +124,12 @@ func toModelDefFileConfig(def ModelDef) ModelDefFileConfig {
 		WebSearch:                toWebSearchFileConfig(def.WebSearch),
 	}
 
-	m.SupportsReasoning = boolPtr(def.SupportsReasoning)
+	m.SupportsReasoning = util.Ptr(def.SupportsReasoning)
 	if def.SupportsReasoningSummaries {
-		m.SupportsReasoningSummaries = boolPtr(true)
+		m.SupportsReasoningSummaries = util.Ptr(true)
 	}
 	if def.SupportsImageDetailOriginal {
-		m.SupportsImageDetailOriginal = boolPtr(true)
+		m.SupportsImageDetailOriginal = util.Ptr(true)
 	}
 
 	if len(def.Extensions) > 0 {
@@ -251,18 +253,14 @@ func toCacheFileConfig(c CacheConfig) CacheFileConfig {
 	return CacheFileConfig{
 		Mode:                     c.Mode,
 		TTL:                      c.TTL,
-		PromptCaching:            boolPtr(c.PromptCaching),
-		AutomaticPromptCache:     boolPtr(c.AutomaticPromptCache),
-		ExplicitCacheBreakpoints: boolPtr(c.ExplicitCacheBreakpoints),
-		AllowRetentionDowngrade:  boolPtr(c.AllowRetentionDowngrade),
+		PromptCaching:            util.Ptr(c.PromptCaching),
+		AutomaticPromptCache:     util.Ptr(c.AutomaticPromptCache),
+		ExplicitCacheBreakpoints: util.Ptr(c.ExplicitCacheBreakpoints),
+		AllowRetentionDowngrade:  util.Ptr(c.AllowRetentionDowngrade),
 		MaxBreakpoints:           c.MaxBreakpoints,
 		MinCacheTokens:           c.MinCacheTokens,
 		ExpectedReuse:            c.ExpectedReuse,
 		MinimumValueScore:        c.MinimumValueScore,
 		MinBreakpointTokens:      c.MinBreakpointTokens,
 	}
 }
-
-func boolPtr(v bool) *bool {
-	return &v
-}

internal/extension/codex/catalog.go

@@ -16,6 +16,7 @@ import (
 	"moonbridge/internal/config"
 	"moonbridge/internal/extension/visual"
 	"moonbridge/internal/modelref"
+	"moonbridge/internal/util"
 )
 
 // ModelInfo represents a model entry in the OpenAI /v1/models response.
@@ -469,13 +470,6 @@ func WriteModelsCatalog(path string, providerCfg config.ProviderConfig, pluginCf
 	return os.WriteFile(path, data, 0644)
 }
 
-func valueOrDefault(value string, fallback string) string {
-	if value == "" {
-		return fallback
-	}
-	return value
-}
-
 // routeFor resolves a model alias to a RouteEntry from a ProviderConfig.
 func routeFor(providerCfg config.ProviderConfig, modelAlias string) config.RouteEntry {
 	if provider, upstream := modelref.Parse(modelAlias); provider != "" {
@@ -547,7 +541,7 @@ func GenerateConfigToml(output io.Writer, modelAlias string, baseURL string, cod
 	fmt.Fprintln(output)
 	fmt.Fprintln(output, "[model_providers.moonbridge]")
 	fmt.Fprintln(output, `name = "Moon Bridge"`)
-	fmt.Fprintf(output, "base_url = %q\n", valueOrDefault(baseURL, "http://"+config.DefaultAddr+"/v1"))
+	fmt.Fprintf(output, "base_url = %q\n", util.OrDefault(baseURL, "http://"+config.DefaultAddr+"/v1"))
 	if serverCfg.AuthToken != "" {
 		fmt.Fprintln(output, `requires_openai_auth = true`)
 	}

internal/extension/deepseek_v4/deepseek_v4.go

@@ -8,6 +8,7 @@ import (
 	"moonbridge/internal/format"
 	"moonbridge/internal/protocol/anthropic"
 	"moonbridge/internal/protocol/openai"
+	"moonbridge/internal/util"
 )
 
 // StripReasoningContent removes the reasoning_content field from message
@@ -112,7 +113,7 @@ func StreamDeltaForReasoning(delta anthropic.StreamDelta) string {
 		return delta.Text
 	}
 	if delta.Type == "thinking_delta" {
-		return firstNonEmpty(delta.Thinking, delta.Text)
+		return util.FirstNonEmpty(delta.Thinking, delta.Text)
 	}
 	return ""
 }
@@ -126,15 +127,6 @@ func IsReasoningContentBlock(block *format.CoreContentBlock) bool {
 	return block.Type == "reasoning" || block.Type == "reasoning_content"
 }
 
-func firstNonEmpty(values ...string) string {
-	for _, value := range values {
-		if value != "" {
-			return value
-		}
-	}
-	return ""
-}
-
 // ToAnthropicRequest mutates an Anthropic request for DeepSeek V4 quirks.
 // DeepSeek-compatible providers may reject or mis-handle sampling knobs here.
 // Codex/OpenAI reasoning effort maps to DeepSeek's Anthropic-compatible

internal/extension/deepseek_v4/state.go

@@ -10,6 +10,7 @@ import (
 
 	"moonbridge/internal/format"
 	"moonbridge/internal/protocol/anthropic"
+	"moonbridge/internal/util"
 )
 
 const persistedThinkingSummaryPrefix = "moonbridge:deepseek_v4_thinking:v1:"
@@ -173,7 +174,7 @@ func (stream *StreamState) Start(index int, block *format.CoreContentBlock) bool
 	if stream == nil || block == nil || !IsReasoningContentBlock(block) {
 		return false
 	}
-	stream.thinkingText[index] = firstNonEmpty(block.ReasoningText, block.Text)
+	stream.thinkingText[index] = util.FirstNonEmpty(block.ReasoningText, block.Text)
 	stream.thinkingSignature[index] = block.ReasoningSignature
 	return true
 }
@@ -184,10 +185,10 @@ func (stream *StreamState) Delta(index int, delta anthropic.StreamDelta) bool {
 	}
 	switch delta.Type {
 	case "thinking_delta", "reasoning_content_delta":
-		stream.thinkingText[index] += firstNonEmpty(delta.Thinking, delta.Text)
+		stream.thinkingText[index] += util.FirstNonEmpty(delta.Thinking, delta.Text)
 		return true
 	case "signature_delta":
-		stream.thinkingSignature[index] += firstNonEmpty(delta.Signature, delta.Text)
+		stream.thinkingSignature[index] += util.FirstNonEmpty(delta.Signature, delta.Text)
 		return true
 	default:
 		return false

internal/protocol/openai/adapter.go

@@ -17,6 +17,7 @@ import (
 
 	"moonbridge/internal/extension/codextool"
 	"moonbridge/internal/format"
+	"moonbridge/internal/util"
 )
 
 // ============================================================================
@@ -1262,7 +1263,7 @@ func convertInput(raw json.RawMessage, model string) ([]format.CoreMessage, []fo
 			}
 			pendingFCBlocks = append(pendingFCBlocks, format.CoreContentBlock{
 				Type:          "tool_use",
-				ToolUseID:     firstNonEmpty(item.CallID, item.ID),
+				ToolUseID:     util.FirstNonEmpty(item.CallID, item.ID),
 				ToolName:      item.Name,
 				ToolNamespace: item.Namespace,
 				ToolInput:     toolInput,
@@ -1287,7 +1288,7 @@ func convertInput(raw json.RawMessage, model string) ([]format.CoreMessage, []fo
 			}
 			pendingFCBlocks = append(pendingFCBlocks, format.CoreContentBlock{
 				Type:          "tool_use",
-				ToolUseID:     firstNonEmpty(item.CallID, item.ID),
+				ToolUseID:     util.FirstNonEmpty(item.CallID, item.ID),
 				ToolName:      item.Name,
 				ToolNamespace: item.Namespace,
 				ToolInput:     toolInput,
@@ -1488,16 +1489,6 @@ func convertToolChoice(raw json.RawMessage) (*format.CoreToolChoice, error) {
 // Utility
 // ============================================================================
 
-// firstNonEmpty returns the first non-empty string from the list.
-func firstNonEmpty(vals ...string) string {
-	for _, v := range vals {
-		if v != "" {
-			return v
-		}
-	}
-	return ""
-}
-
 // copyContentParts returns a shallow copy of a ContentPart slice.
 func copyContentParts(parts []ContentPart) []ContentPart {
 	out := make([]ContentPart, len(parts))

internal/service/provider/manager.go

@@ -466,13 +466,6 @@ func newHTTPClient(cfg HTTPConfig) *http.Client {
 	}
 }
 
-func valueOrDefault(value, fallback string) string {
-	if value == "" {
-		return fallback
-	}
-	return value
-}
-
 // ClientForKey returns the anthropic.Client for a given provider key.
 func (pm *ProviderManager) ClientForKey(key string) (ProviderClient, error) {
 	pm.mu.RLock()

internal/service/server/adapter_dispatch.go

@@ -23,6 +23,7 @@ import (
 	"moonbridge/internal/service/stats"
 	mbtrace "moonbridge/internal/service/trace"
 	"moonbridge/internal/session"
+	"moonbridge/internal/util"
 )
 
 // ============================================================================
@@ -827,7 +828,7 @@ func streamOutputItemToCoreBlocks(item openai.OutputItem) []format.CoreContentBl
 	case "reasoning":
 		return reasoningBlocksFromStreamOutput(item.Summary)
 	case "function_call", "custom_tool_call", "local_shell_call":
-		toolUseID := firstNonEmptyString(item.CallID, item.ID)
+		toolUseID := util.FirstNonEmpty(item.CallID, item.ID)
 		if toolUseID == "" {
 			return nil
 		}
@@ -890,15 +891,6 @@ func streamOutputToolInput(item openai.OutputItem) json.RawMessage {
 	return payload
 }
 
-func firstNonEmptyString(vals ...string) string {
-	for _, v := range vals {
-		if v != "" {
-			return v
-		}
-	}
-	return ""
-}
-
 // handleAdapterStream handles the streaming path through adapter dispatch.
 func (s *Server) handleAdapterStream(
 	w http.ResponseWriter,