server: implement getuser

server/api/user.go

@@ -1,9 +1,11 @@
 package api
 
 import (
+	"errors"
 	"log/slog"
 	"net/http"
 
+	"github.com/go-chi/chi/v5"
 	"github.com/go-chi/render"
 	"github.com/google/uuid"
 )
@@ -35,6 +37,34 @@ func ListUsers(w http.ResponseWriter, r *http.Request) {
 	}
 }
 
+func GetUser(w http.ResponseWriter, r *http.Request) {
+	slog.Debug("user: entering GetUser handler")
+
+	userID := chi.URLParam(r, "userID")
+	parsed, err := uuid.Parse(userID)
+	if err != nil {
+		render.Render(w, r, ErrInvalidRequest(err))
+		return
+	}
+
+	user, err := dbGetUser(parsed.String())
+	if err != nil {
+		if errors.Is(err, ErrUserNotFound) {
+			render.Render(w, r, ErrNotFound)
+		} else {
+			slog.Error("user: failed to fetch user", "userid", parsed.String(), "error", err)
+			render.Render(w, r, ErrRender(err))
+		}
+		return
+	}
+
+	slog.Debug("user: rendering user", "userid", user.ID, "username", user.Name)
+	if err := render.Render(w, r, NewUserPayloadResponse(user)); err != nil {
+		slog.Error("user: failed to render user", "userid", parsed.String(), "error", err)
+		render.Render(w, r, ErrRender(err))
+	}
+}
+
 func newUserID() uuid.UUID {
 	return uuid.New()
 }