refactor: unexport internal identifiers and fix naming nits

internal/deezer/blowfish_test.go

@@ -51,6 +51,6 @@ func TestDecryptBlowfishRoundTrip(t *testing.T) {
 
 func TestDecryptBlowfishInvalidKey(t *testing.T) {
 	if _, err := DecryptBlowfish(make([]byte, 8), nil); err == nil {
-		t.Error("expected error for empty key")
+		t.Error("expected error for nil key")
 	}
 }

internal/deezer/client.go

@@ -78,7 +78,7 @@ func (c *Client) FetchResource(ctx context.Context, kind Kind, id string) (Resou
 		return nil, err
 	}
 
-	url := fmt.Sprintf("https://www.deezer.com/ajax/gw-light.php?method=deezer.page%s&input=3&api_version=1.0&api_token=%s", kind.pageMethod(), c.Session.APIToken)
+	url := fmt.Sprintf("https://www.deezer.com/ajax/gw-light.php?method=deezer.page%s&input=3&api_version=1.0&api_token=%s", kind.pageMethod(), c.Session.apiToken)
 	req, err := http.NewRequestWithContext(ctx, http.MethodPost, url, bytes.NewBuffer(jsonData))
 	if err != nil {
 		return nil, err
@@ -132,7 +132,7 @@ func (c *Client) FetchMedia(ctx context.Context, track *Track, quality string) (
 		"flac":    `[{"cipher":"BF_CBC_STRIPE","format":"FLAC"},{"cipher":"BF_CBC_STRIPE","format":"MP3_320"},{"cipher":"BF_CBC_STRIPE","format":"MP3_128"}]`,
 	}
 
-	reqBody := fmt.Sprintf(`{"license_token":"%s","media":[{"type":"FULL","formats":%s}],"track_tokens":["%s"]}`, c.Session.LicenseToken, qualityFormats[quality], track.TrackToken)
+	reqBody := fmt.Sprintf(`{"license_token":"%s","media":[{"type":"FULL","formats":%s}],"track_tokens":["%s"]}`, c.Session.licenseToken, qualityFormats[quality], track.TrackToken)
 	req, err := http.NewRequestWithContext(ctx, http.MethodPost, "https://media.deezer.com/v1/get_url", bytes.NewBuffer([]byte(reqBody)))
 	if err != nil {
 		return nil, err

internal/deezer/credentials.go

@@ -19,7 +19,7 @@ type Credentials struct {
 	ARL      string `json:"arl,omitempty"`
 }
 
-func LoadCredentials() (*Credentials, error) {
+func loadCredentials() (*Credentials, error) {
 	secret, err := keyring.Get(keyringService, keyringUser)
 	if err != nil {
 		if errors.Is(err, keyring.ErrNotFound) {
@@ -36,7 +36,7 @@ func LoadCredentials() (*Credentials, error) {
 	return &creds, nil
 }
 
-func SaveCredentials(creds *Credentials) error {
+func saveCredentials(creds *Credentials) error {
 	data, err := json.Marshal(creds)
 	if err != nil {
 		return err

internal/deezer/login.go

@@ -7,7 +7,7 @@ import (
 )
 
 func resolveARL(ctx context.Context, validate func(ctx context.Context, arl string) error) (string, error) {
-	creds, err := LoadCredentials()
+	creds, err := loadCredentials()
 	if err != nil {
 		return "", err
 	}
@@ -46,7 +46,7 @@ func Login(ctx context.Context, email, password string) (string, string, error)
 		return "", "", err
 	}
 
-	if err := SaveCredentials(creds); err != nil {
+	if err := saveCredentials(creds); err != nil {
 		return "", "", err
 	}
 

internal/deezer/session.go

@@ -14,8 +14,8 @@ import (
 var ErrInvalidARL = errors.New("invalid or expired ARL cookie")
 
 type Session struct {
-	APIToken     string
-	LicenseToken string
+	apiToken     string
+	licenseToken string
 	HTTPClient   *http.Client
 	Premium      bool
 }
@@ -79,8 +79,8 @@ func authenticate(ctx context.Context, arlCookie string) (*Session, error) {
 
 	opts := res.Results.User.Options
 	return &Session{
-		APIToken:     res.Results.APIToken,
-		LicenseToken: opts.LicenseToken,
+		apiToken:     res.Results.APIToken,
+		licenseToken: opts.LicenseToken,
 		HTTPClient:   client,
 		Premium:      opts.MobileOffline || opts.WebOffline,
 	}, nil

internal/deezer/track.go

@@ -69,17 +69,17 @@ func (t *Track) Filename(kind Kind, mediaFormat string) string {
 	return base + "." + ext
 }
 
-func truncateBytes(s string, max int) string {
-	if max <= 0 {
+func truncateBytes(s string, maxLen int) string {
+	if maxLen <= 0 {
 		return ""
 	}
-	if len(s) <= max {
+	if len(s) <= maxLen {
 		return s
 	}
 
 	last := 0
 	for i := range s {
-		if i > max {
+		if i > maxLen {
 			return s[:last]
 		}
 		last = i