Color price green/red based on direction, fix SSE middleware error

Show price in green when rising, red when falling. Use Tailwind
classes with a safelist comment so JIT includes them. Remove
middleware from SSE route to prevent "response already started" error.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

src/clj/pmagnus/btcprice/web/routes/ui.clj

@@ -12,8 +12,14 @@
    [io.undertow.server HttpServerExchange]
    [io.undertow.util HttpString]
    [java.io BufferedWriter OutputStreamWriter]
+   [java.time ZoneId]
+   [java.time.format DateTimeFormatter]
    [java.util.concurrent LinkedBlockingQueue TimeUnit]))
 
+(def ^:private time-fmt
+  (-> (DateTimeFormatter/ofPattern "dd-MM HH:mm:ss")
+      (.withZone (ZoneId/systemDefault))))
+
 (defn home-page [_req]
   (page {:title "BTC Price"}
     [:header.text-center.mb-8
@@ -25,15 +31,22 @@
       [:div.bg-white.rounded-2xl.shadow-sm.border.border-gray-200.p-6
        [:p.text-center.text-gray-400.text-sm "Connecting..."]]]]))
 
-(defn- render-price-html [{:keys [price recorded-at]}]
+;; Tailwind classes referenced for price color:
+;; text-green-600 text-red-600 text-gray-900
+(defn- render-price-html [{:keys [price prev-price recorded-at]}]
+  (let [color (cond
+                (nil? prev-price)      "text-gray-900"
+                (> price prev-price)   "text-green-600"
+                (< price prev-price)   "text-red-600"
+                :else                  "text-gray-900")]
     (str
      (h/html
       [:div.bg-white.rounded-2xl.shadow-sm.border.border-gray-200.p-6
        [:div.text-center
-      [:p.text-4xl.font-bold.text-gray-900
+        [:p {:class (str "text-4xl font-bold " color)}
          (str "$" (format "%,.2f" (double price)))]
         [:p.text-xs.text-gray-400.mt-2
-       (str "Updated " recorded-at)]]])))
+         (str "Updated " (.format time-fmt recorded-at))]]]))))
 
 (defn- format-sse [event data]
   (str "event: " event "\n"
@@ -76,7 +89,8 @@
   [["/"
     {:get home-page}]
    ["/price/stream"
-    {:get (fn [req] (price-stream-handler opts req))}]])
+    {:get        (fn [req] (price-stream-handler opts req))
+     :middleware []}]])
 
 (defn route-data [opts]
   (merge

src/clj/pmagnus/btcprice/ws/binance.clj

@@ -40,9 +40,11 @@
                                      (swap! state assoc :last-write now)
                                      (log/info "BTC price:" (str price))
                                      (save-price! query-fn price)
+                                     (let [prev-price (:price @latest-price)]
                                        (reset! latest-price
                                                {:price      price
-                                              :recorded-at (java.time.Instant/now)})))))
+                                                :prev-price prev-price
+                                                :recorded-at (java.time.Instant/now)}))))))
                              (catch Exception e
                                (log/error e "Failed to parse Binance message")))))
                        (let [^CompletionStage cf (CompletableFuture/completedFuture nil)]