tasks 00d, 006, 007: move test seams to struct fields, centralize Viper config, extract shared card-dir logic

task 00d: remove package-level var test seams from processor and gui packages;
  factory functions (newAudioProvider, newOpenAIImageClient, newNanoBananaImageClient)
  are now struct fields on Processor and Application, initialized with production
  defaults in constructors and replaced in tests without global mutation.

task 006: add viperConfig struct captured once in NewProcessor; no method body
  calls viper.GetString/IsSet/GetFloat64 directly any more — all config-file values
  are accessed via p.viperCfg fields.

task 007: extract FindCardDirectory and FindOrCreateCardDirectory into
  internal/utils.go; both Processor.findCardDirectory and
  Application.findCardDirectory now delegate to the shared implementation,
  which also handles the legacy _word.txt backward-compat fallback.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

4 files changed, 68 insertions, 141 deletions

diff --git a/internal/gui/app.go b/internal/gui/app.go
index 4f8311e..e5cc9dd 100644
--- a/internal/gui/app.go
+++ b/internal/gui/app.go
@@ -105,6 +105,11 @@ type Application struct {
 	// Active operations tracking
 	activeOperations map[string]int // Map of word -> count of active operations
 	activeOpMu       sync.Mutex     // Mutex for activeOperations map
+
+	// Injectable factory functions — replaced in tests to avoid real API calls.
+	newOpenAIImageClient    func(*image.OpenAIConfig) promptAwareImageClient
+	newNanoBananaImageClient func(*image.NanoBananaConfig) promptAwareImageClient
+	newAudioProvider        func(*audio.Config) (audio.Provider, error)
 }
 
 // Config holds GUI application configuration
@@ -218,6 +223,11 @@ func New(config *Config) *Application {
 		cardContexts:     make(map[string]context.CancelFunc),
 		activeOperations: make(map[string]int),
 		autoPlayEnabled:  config.AutoPlay, // Use config setting
+
+		// Production defaults for factory functions; replaced in tests.
+		newOpenAIImageClient:    func(c *image.OpenAIConfig) promptAwareImageClient { return image.NewOpenAIClient(c) },
+		newNanoBananaImageClient: func(c *image.NanoBananaConfig) promptAwareImageClient { return image.NewNanoBananaClient(c) },
+		newAudioProvider:        audio.NewProvider,
 	}
 
 	// Initialize the word processing queue
diff --git a/internal/gui/generator.go b/internal/gui/generator.go
index 4763149..4b55608 100644
--- a/internal/gui/generator.go
+++ b/internal/gui/generator.go
@@ -22,16 +22,6 @@ type promptAwareImageClient interface {
 	SetPromptCallback(func(prompt string))
 }
 
-var newOpenAIImageClient = func(config *image.OpenAIConfig) promptAwareImageClient {
-	return image.NewOpenAIClient(config)
-}
-
-var newNanoBananaImageClient = func(config *image.NanoBananaConfig) promptAwareImageClient {
-	return image.NewNanoBananaClient(config)
-}
-
-var newAudioProvider = audio.NewProvider
-
 func randomVoice(voices []string) string {
 	rng := rand.New(rand.NewSource(time.Now().UnixNano()))
 	return voices[rng.Intn(len(voices))]
@@ -123,7 +113,7 @@ func (a *Application) audioConfigForGeneration(voice string, speed float64) audi
 func (a *Application) generateAudioFile(ctx context.Context, text, outputFile, voice string, speed float64) error {
 	audioConfig := a.audioConfigForGeneration(voice, speed)
 
-	provider, err := newAudioProvider(&audioConfig)
+	provider, err := a.newAudioProvider(&audioConfig)
 	if err != nil {
 		return err
 	}
@@ -410,7 +400,7 @@ func (a *Application) newImageSearcher() (promptAwareImageClient, error) {
 			Style:   "natural",
 		}
 
-		return newOpenAIImageClient(openaiConfig), nil
+		return a.newOpenAIImageClient(openaiConfig), nil
 	case imageProviderNanoBanana:
 		config := a.config
 		if config == nil {
@@ -426,7 +416,7 @@ func (a *Application) newImageSearcher() (promptAwareImageClient, error) {
 			TextModel: config.NanoBananaTextModel,
 		}
 
-		return newNanoBananaImageClient(nanoBananaConfig), nil
+		return a.newNanoBananaImageClient(nanoBananaConfig), nil
 	default:
 		return nil, fmt.Errorf("unknown image provider: %s", a.config.ImageProvider)
 	}
diff --git a/internal/gui/generator_test.go b/internal/gui/generator_test.go
index 4e4e3cc..c8bcf42 100644
--- a/internal/gui/generator_test.go
+++ b/internal/gui/generator_test.go
@@ -93,29 +93,9 @@ func (f *fakeAudioProvider) BuildAttribution(params audio.AttributionParams) str
 }
 
 func TestGenerateImagesWithPromptUsesNanoBananaProvider(t *testing.T) {
-	originalNanoBananaClient := newNanoBananaImageClient
-	originalOpenAIClient := newOpenAIImageClient
-	t.Cleanup(func() {
-		newNanoBananaImageClient = originalNanoBananaClient
-		newOpenAIImageClient = originalOpenAIClient
-	})
-
 	fakeClient := &fakePromptAwareImageClient{}
 	var capturedConfig *image.NanoBananaConfig
 
-	newNanoBananaImageClient = func(config *image.NanoBananaConfig) promptAwareImageClient {
-		capturedConfig = &image.NanoBananaConfig{
-			APIKey:    config.APIKey,
-			Model:     config.Model,
-			TextModel: config.TextModel,
-		}
-		return fakeClient
-	}
-	newOpenAIImageClient = func(*image.OpenAIConfig) promptAwareImageClient {
-		t.Fatal("unexpected OpenAI image client construction")
-		return nil
-	}
-
 	tempDir := t.TempDir()
 	app := &Application{
 		config: &Config{
@@ -127,6 +107,18 @@ func TestGenerateImagesWithPromptUsesNanoBananaProvider(t *testing.T) {
 		},
 		currentWord: "друго",
 	}
+	app.newNanoBananaImageClient = func(config *image.NanoBananaConfig) promptAwareImageClient {
+		capturedConfig = &image.NanoBananaConfig{
+			APIKey:    config.APIKey,
+			Model:     config.Model,
+			TextModel: config.TextModel,
+		}
+		return fakeClient
+	}
+	app.newOpenAIImageClient = func(*image.OpenAIConfig) promptAwareImageClient {
+		t.Fatal("unexpected OpenAI image client construction")
+		return nil
+	}
 
 	outputPath, err := app.generateImagesWithPrompt(context.Background(), "ябълка", "custom prompt", "apple", tempDir)
 	if err != nil {
@@ -176,11 +168,6 @@ func TestGenerateImagesWithPromptUsesNanoBananaProvider(t *testing.T) {
 }
 
 func TestGenerateAudioUsesSharedOpenAIVoices(t *testing.T) {
-	originalFactory := newAudioProvider
-	t.Cleanup(func() {
-		newAudioProvider = originalFactory
-	})
-
 	originalVoices := append([]string(nil), audio.OpenAIVoices...)
 	t.Cleanup(func() {
 		audio.OpenAIVoices = originalVoices
@@ -190,11 +177,6 @@ func TestGenerateAudioUsesSharedOpenAIVoices(t *testing.T) {
 
 	fakeProvider := &fakeAudioProvider{}
 	var capturedConfig *audio.Config
-	newAudioProvider = func(config *audio.Config) (audio.Provider, error) {
-		copyConfig := *config
-		capturedConfig = &copyConfig
-		return fakeProvider, nil
-	}
 
 	tempDir := t.TempDir()
 	cardDir := filepath.Join(tempDir, "card")
@@ -215,6 +197,11 @@ func TestGenerateAudioUsesSharedOpenAIVoices(t *testing.T) {
 			OpenAIInstruction: "Speak clearly.",
 		},
 	}
+	app.newAudioProvider = func(config *audio.Config) (audio.Provider, error) {
+		copyConfig := *config
+		capturedConfig = &copyConfig
+		return fakeProvider, nil
+	}
 
 	outputPath, err := app.generateAudio(context.Background(), "ябълка", cardDir)
 	if err != nil {
@@ -267,11 +254,6 @@ func TestGenerateAudioUsesSharedOpenAIVoices(t *testing.T) {
 }
 
 func TestGenerateAudioUsesRandomGeminiVoiceAndAttribution(t *testing.T) {
-	originalFactory := newAudioProvider
-	t.Cleanup(func() {
-		newAudioProvider = originalFactory
-	})
-
 	originalVoices := append([]string(nil), audio.GeminiVoices...)
 	t.Cleanup(func() {
 		audio.GeminiVoices = originalVoices
@@ -281,11 +263,6 @@ func TestGenerateAudioUsesRandomGeminiVoiceAndAttribution(t *testing.T) {
 
 	fakeProvider := &fakeAudioProvider{}
 	var capturedConfig *audio.Config
-	newAudioProvider = func(config *audio.Config) (audio.Provider, error) {
-		copyConfig := *config
-		capturedConfig = &copyConfig
-		return fakeProvider, nil
-	}
 
 	tempDir := t.TempDir()
 	cardDir := filepath.Join(tempDir, "card")
@@ -306,6 +283,11 @@ func TestGenerateAudioUsesRandomGeminiVoiceAndAttribution(t *testing.T) {
 			GeminiVoice:    "",
 		},
 	}
+	app.newAudioProvider = func(config *audio.Config) (audio.Provider, error) {
+		copyConfig := *config
+		capturedConfig = &copyConfig
+		return fakeProvider, nil
+	}
 
 	outputPath, err := app.generateAudio(context.Background(), "ябълка", cardDir)
 	if err != nil {
@@ -367,11 +349,6 @@ func TestGenerateAudioUsesRandomGeminiVoiceAndAttribution(t *testing.T) {
 }
 
 func TestGenerateGeminiAudioWithFallbacksRetriesAlternateVoice(t *testing.T) {
-	originalFactory := newAudioProvider
-	t.Cleanup(func() {
-		newAudioProvider = originalFactory
-	})
-
 	originalVoices := append([]string(nil), audio.GeminiVoices...)
 	t.Cleanup(func() {
 		audio.GeminiVoices = originalVoices
@@ -379,17 +356,6 @@ func TestGenerateGeminiAudioWithFallbacksRetriesAlternateVoice(t *testing.T) {
 	audio.GeminiVoices = []string{"Charon", "Kore", "Leda"}
 
 	var attemptedVoices []string
-	newAudioProvider = func(config *audio.Config) (audio.Provider, error) {
-		attemptedVoices = append(attemptedVoices, config.GeminiVoice)
-		return &fakeAudioProvider{
-			generateFunc: func(_ string, _ string) error {
-				if config.GeminiVoice == "Charon" {
-					return audio.ErrGeminiNoAudioData
-				}
-				return nil
-			},
-		}, nil
-	}
 
 	tempDir := t.TempDir()
 	outputPath := filepath.Join(tempDir, "audio.wav")
@@ -405,6 +371,17 @@ func TestGenerateGeminiAudioWithFallbacksRetriesAlternateVoice(t *testing.T) {
 			GeminiTTSModel: "gemini-2.5-flash-preview-tts",
 		},
 	}
+	app.newAudioProvider = func(config *audio.Config) (audio.Provider, error) {
+		attemptedVoices = append(attemptedVoices, config.GeminiVoice)
+		return &fakeAudioProvider{
+			generateFunc: func(_ string, _ string) error {
+				if config.GeminiVoice == "Charon" {
+					return audio.ErrGeminiNoAudioData
+				}
+				return nil
+			},
+		}, nil
+	}
 
 	voice, err := audio.RunWithVoiceFallbacks("Charon", func(candidate string) error {
 		return app.generateAudioFile(context.Background(), "ябълка", outputPath, candidate, 1.0)
@@ -422,11 +399,6 @@ func TestGenerateGeminiAudioWithFallbacksRetriesAlternateVoice(t *testing.T) {
 }
 
 func TestGenerateAudioBgBgUsesSharedOpenAIVoices(t *testing.T) {
-	originalFactory := newAudioProvider
-	t.Cleanup(func() {
-		newAudioProvider = originalFactory
-	})
-
 	originalVoices := append([]string(nil), audio.OpenAIVoices...)
 	t.Cleanup(func() {
 		audio.OpenAIVoices = originalVoices
@@ -436,11 +408,6 @@ func TestGenerateAudioBgBgUsesSharedOpenAIVoices(t *testing.T) {
 
 	fakeProvider := &fakeAudioProvider{}
 	var capturedConfig *audio.Config
-	newAudioProvider = func(config *audio.Config) (audio.Provider, error) {
-		copyConfig := *config
-		capturedConfig = &copyConfig
-		return fakeProvider, nil
-	}
 
 	tempDir := t.TempDir()
 	cardDir := filepath.Join(tempDir, "card")
@@ -460,6 +427,11 @@ func TestGenerateAudioBgBgUsesSharedOpenAIVoices(t *testing.T) {
 			OpenAIInstruction: "Speak clearly.",
 		},
 	}
+	app.newAudioProvider = func(config *audio.Config) (audio.Provider, error) {
+		copyConfig := *config
+		capturedConfig = &copyConfig
+		return fakeProvider, nil
+	}
 
 	frontPath, backPath, err := app.generateAudioBgBg(context.Background(), "ябълка", "круша", cardDir)
 	if err != nil {
@@ -526,11 +498,6 @@ func TestGenerateAudioBgBgUsesSharedOpenAIVoices(t *testing.T) {
 }
 
 func TestGenerateAudioFrontUsesSharedOpenAIVoices(t *testing.T) {
-	originalFactory := newAudioProvider
-	t.Cleanup(func() {
-		newAudioProvider = originalFactory
-	})
-
 	originalVoices := append([]string(nil), audio.OpenAIVoices...)
 	t.Cleanup(func() {
 		audio.OpenAIVoices = originalVoices
@@ -540,11 +507,6 @@ func TestGenerateAudioFrontUsesSharedOpenAIVoices(t *testing.T) {
 
 	fakeProvider := &fakeAudioProvider{}
 	var capturedConfig *audio.Config
-	newAudioProvider = func(config *audio.Config) (audio.Provider, error) {
-		copyConfig := *config
-		capturedConfig = &copyConfig
-		return fakeProvider, nil
-	}
 
 	tempDir := t.TempDir()
 	cardDir := filepath.Join(tempDir, "card")
@@ -564,6 +526,11 @@ func TestGenerateAudioFrontUsesSharedOpenAIVoices(t *testing.T) {
 			OpenAIInstruction: "Speak clearly.",
 		},
 	}
+	app.newAudioProvider = func(config *audio.Config) (audio.Provider, error) {
+		copyConfig := *config
+		capturedConfig = &copyConfig
+		return fakeProvider, nil
+	}
 
 	outputPath, err := app.generateAudioFront(context.Background(), "ябълка", cardDir)
 	if err != nil {
@@ -604,11 +571,6 @@ func TestGenerateAudioFrontUsesSharedOpenAIVoices(t *testing.T) {
 }
 
 func TestGenerateAudioBackUsesSharedOpenAIVoices(t *testing.T) {
-	originalFactory := newAudioProvider
-	t.Cleanup(func() {
-		newAudioProvider = originalFactory
-	})
-
 	originalVoices := append([]string(nil), audio.OpenAIVoices...)
 	t.Cleanup(func() {
 		audio.OpenAIVoices = originalVoices
@@ -618,11 +580,6 @@ func TestGenerateAudioBackUsesSharedOpenAIVoices(t *testing.T) {
 
 	fakeProvider := &fakeAudioProvider{}
 	var capturedConfig *audio.Config
-	newAudioProvider = func(config *audio.Config) (audio.Provider, error) {
-		copyConfig := *config
-		capturedConfig = &copyConfig
-		return fakeProvider, nil
-	}
 
 	tempDir := t.TempDir()
 	cardDir := filepath.Join(tempDir, "card")
@@ -642,6 +599,11 @@ func TestGenerateAudioBackUsesSharedOpenAIVoices(t *testing.T) {
 			OpenAIInstruction: "Speak clearly.",
 		},
 	}
+	app.newAudioProvider = func(config *audio.Config) (audio.Provider, error) {
+		copyConfig := *config
+		capturedConfig = &copyConfig
+		return fakeProvider, nil
+	}
 
 	outputPath, err := app.generateAudioBack(context.Background(), "круша", cardDir)
 	if err != nil {
@@ -682,20 +644,12 @@ func TestGenerateAudioBackUsesSharedOpenAIVoices(t *testing.T) {
 }
 
 func TestGenerateAudioProviderFactoryError(t *testing.T) {
-	originalFactory := newAudioProvider
-	t.Cleanup(func() {
-		newAudioProvider = originalFactory
-	})
-
 	originalVoices := append([]string(nil), audio.OpenAIVoices...)
 	t.Cleanup(func() {
 		audio.OpenAIVoices = originalVoices
 	})
 
 	audio.OpenAIVoices = []string{"sentinel-error-voice"}
-	newAudioProvider = func(*audio.Config) (audio.Provider, error) {
-		return nil, errors.New("provider factory failed")
-	}
 
 	tempDir := t.TempDir()
 	cardDir := filepath.Join(tempDir, "card")
@@ -715,6 +669,9 @@ func TestGenerateAudioProviderFactoryError(t *testing.T) {
 			OpenAIInstruction: "Speak clearly.",
 		},
 	}
+	app.newAudioProvider = func(*audio.Config) (audio.Provider, error) {
+		return nil, errors.New("provider factory failed")
+	}
 
 	_, err := app.generateAudioFront(context.Background(), "ябълка", cardDir)
 	if err == nil {
diff --git a/internal/gui/navigation.go b/internal/gui/navigation.go
index 206da00..c7e9264 100644
--- a/internal/gui/navigation.go
+++ b/internal/gui/navigation.go
@@ -15,41 +15,11 @@ import (
 	"codeberg.org/snonux/totalrecall/internal/anki"
 )
 
-// findCardDirectory finds the directory for a given Bulgarian word
+// findCardDirectory finds the directory for a given Bulgarian word.
+// Delegates to the shared internal.FindCardDirectory which also handles the
+// legacy _word.txt fallback for backward compatibility.
 func (a *Application) findCardDirectory(word string) string {
-	entries, err := os.ReadDir(a.config.OutputDir)
-	if err != nil {
-		return ""
-	}
-
-	// Look through all directories to find one with matching _word.txt
-	for _, entry := range entries {
-		if !entry.IsDir() || strings.HasPrefix(entry.Name(), ".") {
-			continue
-		}
-
-		dirPath := filepath.Join(a.config.OutputDir, entry.Name())
-		wordFile := filepath.Join(dirPath, "word.txt")
-
-		// Read the word file to check if it matches
-		if data, err := os.ReadFile(wordFile); err == nil {
-			storedWord := strings.TrimSpace(string(data))
-			if storedWord == word {
-				return dirPath
-			}
-		} else {
-			// Try old format with underscore for backward compatibility
-			wordFile = filepath.Join(dirPath, "_word.txt")
-			if data, err := os.ReadFile(wordFile); err == nil {
-				storedWord := strings.TrimSpace(string(data))
-				if storedWord == word {
-					return dirPath
-				}
-			}
-		}
-	}
-
-	return ""
+	return internal.FindCardDirectory(a.config.OutputDir, word)
 }
 
 // scanExistingWords scans the output directory for existing words