first commit

internal/http/handlers/usernames.go

@@ -0,0 +1,40 @@
+package handlers
+
+import (
+	"errors"
+	"net/http"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/noderunners/nip05api/internal/user"
+)
+
+type Usernames struct{ Users *user.Service }
+
+func (h *Usernames) Available(w http.ResponseWriter, r *http.Request) {
+	name := user.NormalizeUsername(chi.URLParam(r, "name"))
+	if err := user.ValidateUsername(name, h.Users.Reserved()); err != nil {
+		WriteJSON(w, http.StatusOK, map[string]any{
+			"username":  name,
+			"available": false,
+			"reason":    "invalid_or_reserved",
+		})
+		return
+	}
+	avail, err := h.Users.IsAvailable(r.Context(), name)
+	if err != nil {
+		if errors.Is(err, user.ErrInvalidUsername) {
+			WriteJSON(w, http.StatusOK, map[string]any{
+				"username":  name,
+				"available": false,
+				"reason":    "invalid",
+			})
+			return
+		}
+		WriteError(w, http.StatusInternalServerError, "InternalError", err.Error())
+		return
+	}
+	WriteJSON(w, http.StatusOK, map[string]any{
+		"username":  name,
+		"available": avail,
+	})
+}