1 files changed, 41 insertions, 0 deletions
diff --git a/middleware/i18n.go b/middleware/i18n.go
new file mode 100644
index 0000000..5e33636
--- /dev/null
+++ b/middleware/i18n.go
@@ -0,0 +1,41 @@
+package middleware
+
+import (
+	"cmp"
+	"context"
+	"errors"
+	"log"
+	"net/http"
+	"strings"
+
+	"git.thomasvoss.com/euro-cash.eu/i18n"
+	"git.thomasvoss.com/euro-cash.eu/templates"
+)
+
+const PrinterKey = "printer"
+
+func I18n(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		var p, pZero i18n.Printer
+
+		if c, err := r.Cookie("lang"); errors.Is(err, http.ErrNoCookie) {
+			log.Println("Language cookie not set")
+		} else {
+			var ok bool
+			p, ok = i18n.Printers[strings.ToLower(c.Value)]
+			if !ok {
+				log.Printf("Language ‘%s’ is unsupported\n", c.Value)
+			}
+		}
+
+		used := cmp.Or(p, i18n.DefaultPrinter)
+		ctx := context.WithValue(r.Context(), PrinterKey, used)
+
+		if p == pZero {
+			templates.Root(nil, templates.SetLanguage()).Render(ctx, w)
+			/* TODO: Redirect the user back to where they came from */
+		} else {
+			next.ServeHTTP(w, r.WithContext(ctx))
+		}
+	})
+}