refactor: move gateway package to app directory

app/gateway/handlers/index_handler.go

@@ -0,0 +1,49 @@
+package handlers
+
+import (
+	"github.com/labstack/echo/v4"
+	"github.com/onsonr/sonr/app/gateway/internal/pages/index"
+	"github.com/onsonr/sonr/app/gateway/internal/session"
+	"github.com/onsonr/sonr/pkg/common/response"
+)
+
+func HandleIndex(c echo.Context) error {
+	if isExpired(c) {
+		return response.TemplEcho(c, index.ReturningView())
+	}
+	return response.TemplEcho(c, index.InitialView())
+}
+
+// ╭─────────────────────────────────────────────────────────╮
+// │                    Utility Functions                    │
+// ╰─────────────────────────────────────────────────────────╯
+
+// Initial users have no authorization, user handle, or vault address
+func isInitial(c echo.Context) bool {
+	sess, err := session.Get(c)
+	if err != nil {
+		return false
+	}
+	data := sess.Session()
+	return data.UserHandle == "" && data.VaultAddress == ""
+}
+
+// Expired users have either a user handle or vault address
+func isExpired(c echo.Context) bool {
+	sess, err := session.Get(c)
+	if err != nil {
+		return false
+	}
+	data := sess.Session()
+	return data.UserHandle != "" || data.VaultAddress != ""
+}
+
+// Returning users have a valid authorization, and either a user handle or vault address
+func isReturning(c echo.Context) bool {
+	sess, err := session.Get(c)
+	if err != nil {
+		return false
+	}
+	data := sess.Session()
+	return data.UserHandle != "" && data.VaultAddress != ""
+}