Improve themes handling

- Store user theme in session
- Logged out users will keep their theme
- Add theme background color to web manifest and meta tag

2 files changed, 15 insertions, 2 deletions

diff --git a/model/session.go b/model/app_session.go
index 763f709..e9ee06e 100644
--- a/model/session.go
+++ b/model/app_session.go
@@ -18,12 +18,13 @@ type SessionData struct {
 	FlashMessage       string `json:"flash_message"`
 	FlashErrorMessage  string `json:"flash_error_message"`
 	Language           string `json:"language"`
+	Theme              string `json:"Theme"`
 	PocketRequestToken string `json:"pocket_request_token"`
 }
 
 func (s SessionData) String() string {
-	return fmt.Sprintf(`CSRF="%s", "OAuth2State="%s", FlashMessage="%s", FlashErrorMessage="%s", Lang="%s"`,
-		s.CSRF, s.OAuth2State, s.FlashMessage, s.FlashErrorMessage, s.Language)
+	return fmt.Sprintf(`CSRF=%q, "OAuth2State=%q, FlashMsg=%q, FlashErrorMsg=%q, Lang=%q, Theme=%q`,
+		s.CSRF, s.OAuth2State, s.FlashMessage, s.FlashErrorMessage, s.Language, s.Theme)
 }
 
 // Value converts the session data to JSON.
diff --git a/model/theme.go b/model/theme.go
index 5d32df4..f58f91c 100644
--- a/model/theme.go
+++ b/model/theme.go
@@ -15,6 +15,18 @@ func Themes() map[string]string {
 	}
 }
 
+// ThemeColor returns the color for the address bar or/and the browser color.
+// https://developer.mozilla.org/en-US/docs/Web/Manifest#theme_color
+// https://developers.google.com/web/tools/lighthouse/audits/address-bar
+func ThemeColor(theme string) string {
+	switch theme {
+	case "black":
+		return "#222"
+	default:
+		return "#fff"
+	}
+}
+
 // ValidateTheme validates theme value.
 func ValidateTheme(theme string) error {
 	for key := range Themes() {