fix ui

client/app.go

@@ -16,6 +16,7 @@ import (
 	"io"
 	"log"
 	"mime/multipart"
+	"net"
 	"net/http"
 	"net/url"
 	"os"
@@ -154,6 +155,7 @@ type App struct {
 	wifiRejected      bool
 	quitDialogShown   bool
 	monitoringTornDown bool
+	localBrowserActive bool // trình duyệt local — chỉ cho phép localhost
 	chatUnread        int
 	replyStaffID      uint
 	fetchAppsMu       sync.Mutex
@@ -276,6 +278,9 @@ func (a *App) startup(ctx context.Context) {
 
 	// Khởi chạy vòng lặp đọc local storage của trang Rikkei Portal khi chưa đăng nhập
 	go a.authStorageScanner()
+
+	// Chặn thoát localhost khi đang dùng trình duyệt local
+	go a.localBrowserGuardLoop()
 }
 
 func (a *App) handleGuardViolation(kind, reason string) {
@@ -296,7 +301,7 @@ func (a *App) HandleBeforeClose() (prevent bool) {
 	a.mu.Lock()
 	mode := a.dashboard.MonitorMode
 	a.mu.Unlock()
-	if mode == "" || mode == "not_configured" {
+	if !shouldRecordViolation(mode) {
 		a.clearRunLock()
 		return false
 	}
@@ -359,6 +364,16 @@ type pendingViolation struct {
 	StudentRkID int64  `json:"studentRkId"`
 }
 
+// shouldRecordViolation — chỉ lưu vi phạm khi đang thi hoặc đang học (trong giờ).
+func shouldRecordViolation(monitorMode string) bool {
+	switch strings.TrimSpace(monitorMode) {
+	case "exam", "learning":
+		return true
+	default:
+		return false
+	}
+}
+
 func (a *App) markRunLock() {
 	a.mu.Lock()
 	studentID := int64(0)
@@ -367,7 +382,7 @@ func (a *App) markRunLock() {
 		studentID = a.student.StudentID
 	}
 	a.mu.Unlock()
-	if studentID <= 0 || mode == "" || mode == "not_configured" {
+	if studentID <= 0 || !shouldRecordViolation(mode) {
 		return
 	}
 	payload, _ := json.Marshal(map[string]any{
@@ -402,7 +417,7 @@ func (a *App) detectUncleanShutdown() {
 		}
 		a.mu.Unlock()
 	}
-	if meta.StudentRkID <= 0 {
+	if meta.StudentRkID <= 0 || !shouldRecordViolation(meta.MonitorMode) {
 		return
 	}
 	reason := "Ứng dụng bị tắt đột ngột (Task Manager / kill process) khi đang giám sát"
@@ -457,8 +472,8 @@ func (a *App) flushPendingViolations() {
 }
 
 func (a *App) postViolation(v pendingViolation) bool {
-	if v.StudentRkID <= 0 {
+	if v.StudentRkID <= 0 || !shouldRecordViolation(v.MonitorMode) {
-		return true
+		return true // bỏ qua — không thi / không học thì không lưu
 	}
 	payload := map[string]any{
 		"studentRkId": v.StudentRkID,
@@ -492,7 +507,7 @@ func (a *App) reportViolation(kind, reason string) {
 		studentID = a.student.StudentID
 	}
 	a.mu.Unlock()
-	if studentID <= 0 {
+	if studentID <= 0 || !shouldRecordViolation(mode) {
 		return
 	}
 	v := pendingViolation{
@@ -578,6 +593,7 @@ func (a *App) startLocalServer() {
 			w.Header().Set("Access-Control-Allow-Methods", "GET, OPTIONS")
 			return
 		}
+		a.setLocalBrowserActive(false)
 		go func() {
 			guard.SuppressFor(5 * time.Second)
 			runtime.WindowReloadApp(a.ctx)
@@ -590,10 +606,50 @@ func (a *App) startLocalServer() {
 			w.Header().Set("Access-Control-Allow-Methods", "GET, POST, OPTIONS")
 			return
 		}
-		// Chỉ purge disk — JS trên trang exam-view tự clear storage + reload iframe.
+		// Chỉ xóa HTTP disk cache — không đụng cookie / localStorage (giữ phiên đăng nhập trang thi).
 		go a.purgeWebViewDiskCache()
 		w.Write([]byte("ok"))
 	})
+	mux.HandleFunc("/local-browser", func(w http.ResponseWriter, r *http.Request) {
+		blocked := strings.TrimSpace(r.URL.Query().Get("blocked"))
+		from := strings.TrimSpace(r.URL.Query().Get("from"))
+		w.Header().Set("Content-Type", "text/html; charset=utf-8")
+		notice := ""
+		if blocked == "1" {
+			notice = `<div class="notice">Đã chặn liên kết ngoài mạng. Trình duyệt này chỉ mở <strong>localhost</strong> / <strong>127.0.0.1</strong>.</div>`
+			if from != "" {
+				notice += `<div class="notice-sub">Đã chặn: ` + html.EscapeString(from) + `</div>`
+			}
+		}
+		_, _ = fmt.Fprintf(w, localBrowserHTML, notice)
+	})
+	mux.HandleFunc("/local-browser-go", func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Set("Access-Control-Allow-Origin", "*")
+		if r.Method == "OPTIONS" {
+			w.Header().Set("Access-Control-Allow-Methods", "GET, POST, OPTIONS")
+			return
+		}
+		raw := strings.TrimSpace(r.URL.Query().Get("url"))
+		if raw == "" {
+			http.Error(w, "missing url", http.StatusBadRequest)
+			return
+		}
+		if !strings.Contains(raw, "://") {
+			raw = "http://" + raw
+		}
+		if !isLoopbackURL(raw) {
+			http.Error(w, "only localhost allowed", http.StatusForbidden)
+			return
+		}
+		a.mu.Lock()
+		a.localBrowserActive = true
+		a.mu.Unlock()
+		go func() {
+			guard.SuppressFor(3 * time.Second)
+			runtime.WindowExecJS(a.ctx, fmt.Sprintf("window.location.href = %q", raw))
+		}()
+		w.Write([]byte("ok"))
+	})
 
 	go func() {
 		_ = server.ListenAndServe()
@@ -609,18 +665,18 @@ const examViewHTML = `<!DOCTYPE html>
 <title>%s</title>
 <style>
 *{box-sizing:border-box;margin:0;padding:0}
-body{font-family:Segoe UI,system-ui,sans-serif;background:#1e293b;color:#f8fafc;height:100vh;display:flex;flex-direction:column}
+body{font-family:Segoe UI,system-ui,sans-serif;background:#f5f7fa;color:#1a2332;height:100vh;display:flex;flex-direction:column}
-.bar{display:flex;align-items:center;gap:8px;padding:10px 14px;background:#0f172a;border-bottom:1px solid #334155;flex-shrink:0}
+.bar{display:flex;align-items:center;gap:8px;padding:10px 14px;background:#fff;border-bottom:1px solid #e4e9f0;flex-shrink:0}
-.bar-title{font-size:14px;font-weight:600;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;margin-right:auto;min-width:0}
+.bar-title{font-size:14px;font-weight:600;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;margin-right:auto;min-width:0;color:#1a2332}
-.bar button{border:none;border-radius:8px;padding:8px 12px;font-size:13px;cursor:pointer;font-weight:600;white-space:nowrap}
+.bar button{border-radius:8px;padding:8px 12px;font-size:13px;cursor:pointer;font-weight:600;white-space:nowrap}
-.btn-back{background:#7c3aed;color:#fff}
+.btn-back{background:#fff;color:#bb2126;border:1px solid #bb2126}
-.btn-back:hover{background:#6d28d9}
+.btn-back:hover{background:#fde8e9}
-.btn-refresh{background:#0ea5e9;color:#fff}
+.btn-refresh{background:#bb2126;color:#fff;border:1px solid #bb2126}
-.btn-refresh:hover{background:#0284c7}
+.btn-refresh:hover{background:#9e1c22;border-color:#9e1c22}
-.btn-cache{background:#f59e0b;color:#111}
+.btn-cache{background:#fff;color:#bb2126;border:1px solid #bb2126}
-.btn-cache:hover{background:#d97706}
+.btn-cache:hover{background:#fde8e9}
 .btn-cache:disabled,.btn-refresh:disabled{opacity:.65;cursor:wait}
-.hint{font-size:11px;color:#94a3b8;flex-shrink:0}
+.hint{font-size:11px;color:#8b99a8;flex-shrink:0}
 .frame-wrap{flex:1;min-height:0;background:#fff}
 iframe{width:100%%;height:100%%;border:0;display:block}
 </style>
@@ -629,7 +685,7 @@ iframe{width:100%%;height:100%%;border:0;display:block}
 <div class="bar">
 <button type="button" class="btn-back" onclick="goBack()">← Quay lại</button>
 <span class="bar-title">%s</span>
-<span class="hint">Nếu trang lỗi / trắng: F5 hoặc Xóa cache</span>
+<span class="hint">Trang trắng/lỗi: F5 hoặc Xóa cache (giữ đăng nhập)</span>
 <button type="button" class="btn-refresh" id="btn-refresh" onclick="refreshExam()">⟳ F5 Làm mới</button>
 <button type="button" class="btn-cache" id="btn-cache" onclick="clearExamCache()">🗑 Xóa cache</button>
 </div>
@@ -640,58 +696,35 @@ iframe{width:100%%;height:100%%;border:0;display:block}
 function goBack(){
   fetch('http://127.0.0.1:34115/exam-close').catch(function(){});
 }
-function refreshExam(){
+function reloadFrameSoft(){
   var f = document.getElementById('exam-frame');
   if (!f) return;
-  var btn = document.getElementById('btn-refresh');
-  if (btn) btn.disabled = true;
   try {
     f.contentWindow.location.reload();
   } catch (e) {
-    var src = f.src;
+    var src = f.getAttribute('src') || f.src;
     f.src = 'about:blank';
     setTimeout(function(){ f.src = src; }, 50);
   }
+}
+function refreshExam(){
+  var btn = document.getElementById('btn-refresh');
+  if (btn) btn.disabled = true;
+  reloadFrameSoft();
   setTimeout(function(){ if (btn) btn.disabled = false; }, 800);
 }
 async function clearExamCache(){
   var btn = document.getElementById('btn-cache');
   if (btn) btn.disabled = true;
-  try {
+  // Không xóa localStorage/sessionStorage/cookie — tránh văng đăng nhập trang thi.
-    if (window.caches) {
-      var keys = await caches.keys();
-      await Promise.all(keys.map(function(k){ return caches.delete(k); }));
-    }
-  } catch (e) {}
-  try { localStorage.clear(); } catch (e) {}
-  try { sessionStorage.clear(); } catch (e) {}
-  try {
-    var f = document.getElementById('exam-frame');
-    if (f && f.contentWindow) {
-      try { f.contentWindow.localStorage.clear(); } catch (e) {}
-      try { f.contentWindow.sessionStorage.clear(); } catch (e) {}
-      try {
-        if (f.contentWindow.caches) {
-          var ikeys = await f.contentWindow.caches.keys();
-          await Promise.all(ikeys.map(function(k){ return f.contentWindow.caches.delete(k); }));
-        }
-      } catch (e) {}
-    }
-  } catch (e) {}
   try {
     await fetch('http://127.0.0.1:34115/exam-clear-cache');
   } catch (e) {}
-  var f = document.getElementById('exam-frame');
+  // Chờ một nhịp để disk cache kịp xóa rồi reload cùng URL (không thêm query bust).
-  if (f) {
+  setTimeout(function(){
-    try {
+    reloadFrameSoft();
-      var u = new URL(f.src, window.location.href);
+    if (btn) btn.disabled = false;
-      u.searchParams.set('_sc_cb', String(Date.now()));
+  }, 400);
-      f.src = u.toString();
-    } catch (e) {
-      refreshExam();
-    }
-  }
-  setTimeout(function(){ if (btn) btn.disabled = false; }, 1200);
 }
 document.addEventListener('keydown', function(e){
   if (e.key === 'F5') {
@@ -703,6 +736,94 @@ document.addEventListener('keydown', function(e){
 </body>
 </html>`
 
+const localBrowserHTML = `<!DOCTYPE html>
+<html lang="vi">
+<head>
+<meta charset="utf-8">
+<meta name="viewport" content="width=device-width, initial-scale=1">
+<title>Trình duyệt Local — Simple Care</title>
+<style>
+*{box-sizing:border-box;margin:0;padding:0}
+body{font-family:Segoe UI,system-ui,sans-serif;background:#f5f7fa;color:#1a2332;min-height:100vh;display:flex;flex-direction:column}
+.bar{display:flex;align-items:center;gap:8px;padding:10px 14px;background:#fff;border-bottom:1px solid #e4e9f0;flex-wrap:wrap}
+.bar button{border-radius:8px;padding:8px 12px;font-size:13px;cursor:pointer;font-weight:600;white-space:nowrap}
+.btn-back{background:#fff;color:#bb2126;border:1px solid #bb2126}
+.btn-back:hover{background:#fde8e9}
+.btn-go{background:#bb2126;color:#fff;border:1px solid #bb2126}
+.btn-go:hover{background:#9e1c22}
+.addr{flex:1;min-width:220px;padding:8px 12px;border:1px solid #e4e9f0;border-radius:8px;font-size:13px}
+.addr:focus{outline:2px solid rgba(187,33,38,.25);border-color:#bb2126}
+.main{flex:1;padding:28px 20px;max-width:720px;margin:0 auto;width:100%%}
+h1{font-size:1.35rem;margin-bottom:8px;color:#bb2126}
+.lead{color:#5a6a7e;font-size:0.95rem;margin-bottom:18px;line-height:1.5}
+.notice{background:#fde8e9;color:#9e1c22;border:1px solid #f5c2c4;border-radius:10px;padding:12px 14px;margin-bottom:10px;font-size:0.9rem}
+.notice-sub{font-size:0.8rem;color:#8b99a8;margin-bottom:14px;word-break:break-all}
+.chips{display:flex;flex-wrap:wrap;gap:8px;margin-top:16px}
+.chip{background:#fff;border:1px solid #e4e9f0;border-radius:999px;padding:6px 12px;font-size:12px;cursor:pointer;color:#bb2126;font-weight:600}
+.chip:hover{background:#fde8e9;border-color:#bb2126}
+.hint{margin-top:22px;font-size:12px;color:#8b99a8;line-height:1.5}
+</style>
+</head>
+<body>
+<div class="bar">
+<button type="button" class="btn-back" onclick="goHome()">← Về trang chính</button>
+<input class="addr" id="addr" type="url" placeholder="http://localhost:3000" spellcheck="false" />
+<button type="button" class="btn-go" onclick="goLocal()">Mở</button>
+</div>
+<div class="main">
+%s
+<h1>Trình duyệt Local</h1>
+<p class="lead">Chỉ dùng để xem bài làm chạy trên máy bạn (<strong>localhost</strong> / <strong>127.0.0.1</strong>). Mọi link online (GitHub, Google, …) đều bị chặn tại đây.</p>
+<div class="chips">
+<button type="button" class="chip" onclick="fill('http://localhost:3000')">localhost:3000</button>
+<button type="button" class="chip" onclick="fill('http://localhost:5173')">localhost:5173</button>
+<button type="button" class="chip" onclick="fill('http://127.0.0.1:8080')">127.0.0.1:8080</button>
+<button type="button" class="chip" onclick="fill('http://localhost:5500')">localhost:5500</button>
+</div>
+<p class="hint">Mẹo: chạy dự án (npm run dev / Live Server), dán URL vào ô trên rồi bấm Mở. Về trang chính: nút ← hoặc menu Simple Care → Ctrl+H.</p>
+</div>
+<script>
+function fill(u){ document.getElementById('addr').value = u; }
+function goHome(){
+  fetch('http://127.0.0.1:34115/exam-close').catch(function(){});
+}
+function isLoopback(raw){
+  try {
+    if (!raw) return false;
+    if (raw.indexOf('://') < 0) raw = 'http://' + raw;
+    var u = new URL(raw);
+    if (u.protocol !== 'http:' && u.protocol !== 'https:') return false;
+    var h = (u.hostname || '').toLowerCase();
+    if (h === 'localhost' || h === '127.0.0.1' || h === '::1' || h === '[::1]') return true;
+    if (/^127\.\d{1,3}\.\d{1,3}\.\d{1,3}$/.test(h)) return true;
+    return false;
+  } catch (e) { return false; }
+}
+async function goLocal(){
+  var raw = (document.getElementById('addr').value || '').trim();
+  if (!raw) { alert('Nhập URL localhost'); return; }
+  if (!isLoopback(raw)) {
+    alert('Chỉ được mở localhost / 127.0.0.1');
+    return;
+  }
+  if (raw.indexOf('://') < 0) raw = 'http://' + raw;
+  try {
+    var res = await fetch('http://127.0.0.1:34115/local-browser-go?url=' + encodeURIComponent(raw));
+    if (!res.ok) {
+      alert('Không mở được — chỉ localhost');
+      return;
+    }
+  } catch (e) {
+    location.href = raw;
+  }
+}
+document.getElementById('addr').addEventListener('keydown', function(e){
+  if (e.key === 'Enter') { e.preventDefault(); goLocal(); }
+});
+</script>
+</body>
+</html>`
+
 // loadSession nạp session từ file cục bộ
 func (a *App) loadSession() {
 	a.mu.Lock()
@@ -821,6 +942,7 @@ func (a *App) GetStudentInfo() map[string]any {
 
 // NavigateToLogin chuyển WebView đến trang đăng nhập Rikkei Portal
 func (a *App) NavigateToLogin() {
+	a.setLocalBrowserActive(false)
 	a.mu.Lock()
 	a.expectingLogin = true
 	a.mu.Unlock()
@@ -1857,10 +1979,88 @@ func (a *App) examStudentContext() (int64, *StudentExamSnapshot, error) {
 
 // ReturnToDashboard quay lại giao diện chính của app (giữ cookie WebView2).
 func (a *App) ReturnToDashboard() {
+	a.setLocalBrowserActive(false)
 	guard.SuppressFor(5 * time.Second)
 	runtime.WindowReloadApp(a.ctx)
 }
 
+func (a *App) setLocalBrowserActive(on bool) {
+	a.mu.Lock()
+	a.localBrowserActive = on
+	a.mu.Unlock()
+}
+
+func isLoopbackURL(raw string) bool {
+	raw = strings.TrimSpace(raw)
+	if raw == "" {
+		return false
+	}
+	if !strings.Contains(raw, "://") {
+		raw = "http://" + raw
+	}
+	u, err := url.Parse(raw)
+	if err != nil || u.Host == "" {
+		return false
+	}
+	scheme := strings.ToLower(u.Scheme)
+	if scheme != "http" && scheme != "https" {
+		return false
+	}
+	host := strings.ToLower(u.Hostname())
+	if host == "localhost" {
+		return true
+	}
+	ip := net.ParseIP(host)
+	return ip != nil && ip.IsLoopback()
+}
+
+func (a *App) localBrowserGuardLoop() {
+	ticker := time.NewTicker(500 * time.Millisecond)
+	defer ticker.Stop()
+	for range ticker.C {
+		a.mu.Lock()
+		active := a.localBrowserActive && a.ctx != nil && !a.monitoringTornDown
+		ctx := a.ctx
+		a.mu.Unlock()
+		if !active {
+			continue
+		}
+		// Nếu hostname không phải loopback → đá về trang local-browser
+		runtime.WindowExecJS(ctx, `
+			(function(){
+				try {
+					var h = (location.hostname || '').toLowerCase();
+					var ok = h === 'localhost' || h === '127.0.0.1' || h === '::1' || h === '[::1]' || /^127\.\d+\.\d+\.\d+$/.test(h);
+					if (!ok) {
+						location.href = 'http://127.0.0.1:34115/local-browser?blocked=1&from=' + encodeURIComponent(location.href);
+					}
+				} catch (e) {}
+			})();
+		`)
+	}
+}
+
+// OpenGitHub mở github.com trong WebView (về trang chính: Ctrl+H).
+func (a *App) OpenGitHub() {
+	a.setLocalBrowserActive(false)
+	guard.SuppressFor(5 * time.Second)
+	runtime.WindowExecJS(a.ctx, `window.location.href = 'https://github.com'`)
+}
+
+// OpenGoogleTranslate mở Google Dịch trong WebView.
+func (a *App) OpenGoogleTranslate() {
+	a.setLocalBrowserActive(false)
+	guard.SuppressFor(5 * time.Second)
+	runtime.WindowExecJS(a.ctx, `window.location.href = 'https://translate.google.com/?sl=auto&tl=vi'`)
+}
+
+// OpenLocalBrowser mở trình duyệt chỉ cho phép localhost (test bài làm local).
+func (a *App) OpenLocalBrowser() {
+	a.setLocalBrowserActive(true)
+	guard.SuppressFor(5 * time.Second)
+	runtime.WindowExecJS(a.ctx, `window.location.href = 'http://127.0.0.1:34115/local-browser'`)
+}
+
 // ReloadExamPage — F5: làm mới trang / iframe đang mở (trắc nghiệm).
 func (a *App) ReloadExamPage() {
 	guard.SuppressFor(3 * time.Second)
@@ -1880,36 +2080,26 @@ func (a *App) ReloadExamPage() {
 	`)
 }
 
-// ClearExamBrowserCache — xóa cache WebView (storage + disk cache) rồi làm mới trang thi.
+// ClearExamBrowserCache — chỉ xóa HTTP disk cache, giữ cookie/localStorage (không văng đăng nhập trang thi).
 func (a *App) ClearExamBrowserCache() {
 	guard.SuppressFor(8 * time.Second)
 	a.purgeWebViewDiskCache()
 	runtime.WindowExecJS(a.ctx, `
-		(async function(){
+		(function(){
 			try {
-				if (window.caches) {
+				if (typeof window.reloadFrameSoft === 'function') {
-					var keys = await caches.keys();
+					window.reloadFrameSoft();
-					await Promise.all(keys.map(function(k){ return caches.delete(k); }));
+					return;
 				}
-			} catch (e) {}
-			try { localStorage.clear(); } catch (e) {}
-			try { sessionStorage.clear(); } catch (e) {}
-			try {
 				var f = document.getElementById('exam-frame');
 				if (f) {
-					try { f.contentWindow.localStorage.clear(); } catch (e) {}
+					try { f.contentWindow.location.reload(); }
-					try { f.contentWindow.sessionStorage.clear(); } catch (e) {}
+					catch (e) {
-					try {
+						var s = f.getAttribute('src') || f.src;
-						var u = new URL(f.src, window.location.href);
+						f.src = 'about:blank';
-						u.searchParams.set('_sc_cb', String(Date.now()));
+						setTimeout(function(){ f.src = s; }, 50);
-						f.src = u.toString();
-						return;
-					} catch (e) {
-						try { f.contentWindow.location.reload(); } catch (e2) {
-							var s = f.src; f.src = 'about:blank'; setTimeout(function(){ f.src = s; }, 50);
-						}
-						return;
 					}
+					return;
 				}
 			} catch (e) {}
 			location.reload();
@@ -1921,12 +2111,11 @@ func (a *App) purgeWebViewDiskCache() {
 	if a.webviewDataPath == "" {
 		return
 	}
+	// Chỉ Cache tải tài nguyên — KHÔNG xóa Cookies / Local Storage / Service Worker (giữ phiên đăng nhập).
 	subs := []string{
 		filepath.Join("EBWebView", "Default", "Cache"),
 		filepath.Join("EBWebView", "Default", "Code Cache"),
 		filepath.Join("EBWebView", "Default", "GPUCache"),
-		filepath.Join("EBWebView", "Default", "Service Worker", "CacheStorage"),
-		filepath.Join("EBWebView", "Default", "Service Worker", "ScriptCache"),
 	}
 	for _, sub := range subs {
 		path := filepath.Join(a.webviewDataPath, sub)
@@ -1948,17 +2137,13 @@ func isLocalExamURL(raw string) bool {
 }
 
 func (a *App) openExamWebView(targetURL, title string) error {
-	return a.openExamWebViewOpts(targetURL, title, false)
-}
-
-// openExamWebViewOpts mở nội dung trong WebView.
-// forceWrap=true luôn dùng khung exam-view (có nút F5 / xóa cache) — dùng cho trắc nghiệm.
-func (a *App) openExamWebViewOpts(targetURL, title string, forceWrap bool) error {
 	targetURL = strings.TrimSpace(targetURL)
 	if targetURL == "" {
 		return errors.New("không có nội dung để mở")
 	}
-	if forceWrap || isLocalExamURL(targetURL) {
+	a.setLocalBrowserActive(false)
+	// URL local (PDF/resource): khung exam-view. URL ngoài (quiz): mở top-level giữ first-party cookies/session.
+	if isLocalExamURL(targetURL) {
 		wrapper := fmt.Sprintf(
 			"http://127.0.0.1:34115/exam-view?url=%s&title=%s",
 			url.QueryEscape(targetURL),
@@ -1968,7 +2153,6 @@ func (a *App) openExamWebViewOpts(targetURL, title string, forceWrap bool) error
 		runtime.WindowExecJS(a.ctx, fmt.Sprintf("window.location.href = %q", wrapper))
 		return nil
 	}
-	// Trang thi bên ngoài (đề/tài nguyên): mở trực tiếp để giữ first-party cookies.
 	guard.SuppressFor(5 * time.Second)
 	runtime.WindowExecJS(a.ctx, fmt.Sprintf("window.location.href = %q", targetURL))
 	return nil
@@ -2060,8 +2244,9 @@ func (a *App) OpenExamQuiz() error {
 	if err != nil {
 		return err
 	}
-	// Luôn mở trong khung có nút F5 / Xóa cache để SV tự xử lý khi trang lỗi.
+	// Mở trực tiếp (không iframe) để cookie/localStorage đăng nhập web quiz là first-party.
-	return a.openExamWebViewOpts(viewURL, "Làm trắc nghiệm", true)
+	// F5 / Xóa cache / Về trang chính: menu Simple Care.
+	return a.openExamWebView(viewURL, "Làm trắc nghiệm")
 }
 
 func (a *App) OpenExamResource(fileID uint) error {

client/frontend/src/app.css

@@ -18,10 +18,12 @@
   --offline-light: #fdeaea;
   --shadow-sm: 0 1px 3px rgba(26, 35, 50, 0.05);
   --shadow-md: 0 4px 16px rgba(26, 35, 50, 0.07);
-  --radius-sm: 8px;
+  --radius-sm: 7px;
-  --radius-md: 12px;
+  --radius-md: 10px;
-  --radius-lg: 16px;
+  --radius-lg: 12px;
   --transition: 0.2s ease;
+  --page-pad: 0.75rem 0.9rem;
+  --card-pad: 0.95rem 1rem;
 }
 
 * {
@@ -32,7 +34,8 @@
 
 html {
   height: 100%;
-  overflow: hidden;
+  overflow-x: hidden;
+  overflow-y: auto;
 }
 
 body {
@@ -40,18 +43,22 @@ body {
   background-color: var(--bg-main);
   color: var(--text-primary);
   font-family: 'Be Vietnam Pro', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
-  overflow: hidden;
+  font-size: 14px;
-  height: 100%;
+  overflow-x: hidden;
+  overflow-y: auto;
+  min-height: 100%;
+  height: auto;
   width: 100%;
   -webkit-font-smoothing: antialiased;
 }
 
 #app {
   width: 100%;
-  height: 100%;
+  min-height: 100%;
-  max-height: 100vh;
+  height: auto;
-  display: flex;
+  max-height: none;
-  overflow: hidden;
+  display: block;
+  overflow: visible;
 }
 
 /* ── Cards ── */
@@ -60,7 +67,7 @@ body {
   border: 1px solid var(--border-color);
   border-radius: var(--radius-lg);
   box-shadow: var(--shadow-sm);
-  padding: 1.75rem;
+  padding: var(--card-pad);
   transition: var(--transition);
 }
 
@@ -70,10 +77,10 @@ body {
   align-items: center;
   justify-content: center;
   width: 100%;
-  height: 100%;
+  min-height: 100%;
-  padding: 1.5rem;
+  padding: 1rem;
   background: var(--bg-main);
-  overflow: hidden;
+  overflow: visible;
 }
 
 .login-prompt-container .card {
@@ -94,8 +101,8 @@ body {
 }
 
 .brand-logo-img {
-  width: 42px;
+  width: 34px;
-  height: 42px;
+  height: 34px;
   border-radius: var(--radius-sm);
   object-fit: cover;
   flex-shrink: 0;
@@ -103,8 +110,8 @@ body {
 }
 
 .login-brand-row .brand-logo-img {
-  width: 48px;
+  width: 40px;
-  height: 48px;
+  height: 40px;
 }
 
 .login-logo {
@@ -159,11 +166,13 @@ body {
   display: flex;
   flex-direction: column;
   width: 100%;
-  height: 100%;
+  min-height: 100%;
-  max-height: 100vh;
+  height: auto;
-  padding: 1.25rem 1.5rem;
+  max-height: none;
+  padding: var(--page-pad);
+  padding-bottom: 1.25rem;
   box-sizing: border-box;
-  overflow: hidden;
+  overflow: visible;
   animation: fadeIn 0.35s ease-out;
 }
 
@@ -171,10 +180,14 @@ body {
   display: flex;
   justify-content: space-between;
   align-items: center;
-  margin-bottom: 1rem;
+  margin-bottom: 0.65rem;
-  padding-bottom: 0.85rem;
+  padding-bottom: 0.55rem;
   border-bottom: 1px solid var(--border-color);
   flex-shrink: 0;
+  position: sticky;
+  top: 0;
+  z-index: 20;
+  background: var(--bg-main);
 }
 
 .brand {
@@ -184,15 +197,15 @@ body {
 }
 
 .brand-logo {
-  width: 38px;
+  width: 32px;
-  height: 38px;
+  height: 32px;
   background: var(--accent);
   border-radius: var(--radius-sm);
   display: flex;
   align-items: center;
   justify-content: center;
   font-weight: 800;
-  font-size: 0.85rem;
+  font-size: 0.75rem;
   color: white;
   flex-shrink: 0;
 }
@@ -205,25 +218,27 @@ body {
 
 .brand-name {
   font-weight: 800;
-  font-size: 1.05rem;
+  font-size: 0.95rem;
   letter-spacing: -0.3px;
   color: var(--text-primary);
   line-height: 1.2;
 }
 
 .brand-sub {
-  font-size: 0.7rem;
+  font-size: 0.62rem;
   font-weight: 500;
   color: var(--accent);
 }
 
 .main-grid {
   display: grid;
-  grid-template-columns: minmax(220px, 260px) 1fr;
+  grid-template-columns: minmax(180px, 220px) 1fr;
-  gap: 1rem;
+  gap: 0.75rem;
-  flex: 1;
+  flex: none;
   min-height: 0;
-  overflow: hidden;
+  height: auto;
+  overflow: visible;
+  align-items: start;
 }
 
 /* ── Profile Card ── */
@@ -232,25 +247,25 @@ body {
   flex-direction: column;
   align-items: center;
   text-align: center;
-  height: 100%;
+  height: auto;
   min-height: 0;
-  overflow-y: auto;
+  overflow: visible;
   justify-content: flex-start;
-  padding-top: 1rem;
+  padding-top: 0.75rem;
 }
 
 .avatar-container {
   position: relative;
-  margin-bottom: 1.25rem;
+  margin-bottom: 0.75rem;
 }
 
 .avatar {
-  width: 84px;
+  width: 68px;
-  height: 84px;
+  height: 68px;
   border-radius: 50%;
   object-fit: cover;
-  border: 3px solid var(--accent-light);
+  border: 2px solid var(--accent-light);
-  padding: 3px;
+  padding: 2px;
   background: var(--bg-subtle);
 }
 
@@ -276,7 +291,7 @@ body {
 
 .student-name {
   margin: 0;
-  font-size: 1.2rem;
+  font-size: 1.05rem;
   font-weight: 700;
   color: var(--text-primary);
   letter-spacing: -0.3px;
@@ -285,12 +300,12 @@ body {
 .student-code {
   background: var(--accent-light);
   color: var(--accent);
-  padding: 3px 10px;
+  padding: 2px 8px;
   border-radius: 6px;
-  font-size: 0.8rem;
+  font-size: 0.72rem;
   font-weight: 700;
-  margin-top: 0.4rem;
+  margin-top: 0.3rem;
-  margin-bottom: 0.5rem;
+  margin-bottom: 0.35rem;
   border: 1px solid rgba(187, 33, 38, 0.15);
   letter-spacing: 0.3px;
   display: inline-block;
@@ -299,22 +314,22 @@ body {
 .student-email {
   margin: 0;
   color: var(--text-muted);
-  font-size: 0.82rem;
+  font-size: 0.75rem;
 }
 
 .divider {
   width: 100%;
   height: 1px;
   background: var(--border-color);
-  margin: 1.25rem 0;
+  margin: 0.75rem 0;
 }
 
 .profile-info-row {
   display: flex;
   justify-content: space-between;
   width: 100%;
-  font-size: 0.82rem;
+  font-size: 0.75rem;
-  margin-bottom: 0.6rem;
+  margin-bottom: 0.4rem;
 }
 
 .profile-info-row span {
@@ -330,17 +345,17 @@ body {
 .right-column {
   display: flex;
   flex-direction: column;
-  gap: 0.85rem;
+  gap: 0.65rem;
-  overflow: hidden;
+  overflow: visible;
-  height: 100%;
+  height: auto;
   min-height: 0;
 }
 
 .status-banner {
-  padding: 0.75rem 1rem;
+  padding: 0.55rem 0.75rem;
   display: flex;
   align-items: flex-start;
-  gap: 0.75rem;
+  gap: 0.55rem;
   border-left: 3px solid var(--accent);
   flex-shrink: 0;
 }
@@ -393,13 +408,13 @@ body {
 .exam-panel {
   border: 1px solid #c4b5fd;
   background: linear-gradient(135deg, #faf5ff 0%, #fff 100%);
-  padding: 1rem 1.15rem;
+  padding: 0.75rem 0.9rem;
-  margin-bottom: 0.75rem;
+  margin-bottom: 0;
 }
 
 .exam-panel-desc {
-  margin: 0 0 0.85rem;
+  margin: 0 0 0.65rem;
-  font-size: 0.85rem;
+  font-size: 0.78rem;
   color: var(--text-secondary);
 }
 
@@ -410,6 +425,38 @@ body {
   align-items: center;
 }
 
+.tools-panel {
+  margin-bottom: 0;
+  padding: 0.75rem 0.9rem;
+  border: 1px solid #f5c2c4;
+  background: linear-gradient(135deg, #fff8f8 0%, #fff 100%);
+}
+
+.tools-panel-desc {
+  margin: 0 0 0.65rem;
+  font-size: 0.78rem;
+  color: var(--text-secondary);
+}
+
+.tools-panel-actions {
+  display: flex;
+  flex-wrap: wrap;
+  gap: 0.5rem;
+  align-items: center;
+}
+
+.btn-tool {
+  background: #fff;
+  color: var(--accent);
+  border: 1px solid var(--accent);
+  padding: 0.4rem 0.75rem;
+  font-size: 0.78rem;
+}
+
+.btn-tool:hover {
+  background: var(--accent-light);
+}
+
 .exam-wait, .exam-done {
   font-size: 0.82rem;
   color: var(--text-muted);
@@ -608,7 +655,7 @@ body {
 .stats-grid {
   display: grid;
   grid-template-columns: repeat(3, 1fr);
-  gap: 0.65rem;
+  gap: 0.5rem;
 }
 
 .stats-grid--two {
@@ -957,9 +1004,10 @@ body {
 }
 
 .shifts-wrap {
-  flex: 1;
+  flex: none;
   min-height: 0;
-  overflow: auto;
+  max-height: none;
+  overflow: visible;
 }
 
 .shifts-table {
@@ -1028,14 +1076,14 @@ body {
 }
 
 .status-banner-icon {
-  width: 36px;
+  width: 30px;
-  height: 36px;
+  height: 30px;
   background: var(--accent-light);
   border-radius: var(--radius-sm);
   display: flex;
   align-items: center;
   justify-content: center;
-  font-size: 1.1rem;
+  font-size: 0.95rem;
   flex-shrink: 0;
 }
 
@@ -1048,7 +1096,7 @@ body {
 }
 
 .status-banner-value {
-  font-size: 0.9rem;
+  font-size: 0.82rem;
   font-weight: 600;
   color: var(--text-primary);
 }
@@ -1056,19 +1104,19 @@ body {
 .stat-card {
   display: flex;
   align-items: center;
-  gap: 0.85rem;
+  gap: 0.65rem;
-  padding: 0.9rem 1rem;
+  padding: 0.65rem 0.75rem;
 }
 
 .stat-icon-wrap {
-  width: 40px;
+  width: 34px;
-  height: 40px;
+  height: 34px;
   background: var(--bg-subtle);
   border-radius: var(--radius-sm);
   display: flex;
   align-items: center;
   justify-content: center;
-  font-size: 1.2rem;
+  font-size: 1rem;
   flex-shrink: 0;
 }
 
@@ -1088,7 +1136,7 @@ body {
 }
 
 .stat-value {
-  font-size: 0.95rem;
+  font-size: 0.85rem;
   font-weight: 700;
   color: var(--text-primary);
   white-space: nowrap;
@@ -1100,11 +1148,11 @@ body {
 .clocks-card {
   display: flex;
   flex-direction: column;
-  gap: 0.3rem;
+  gap: 0.25rem;
-  flex: 1;
+  flex: none;
   min-height: 0;
-  overflow: hidden;
+  overflow: visible;
-  padding: 0.5rem 0.65rem;
+  padding: 0.45rem 0.55rem;
 }
 
 .card-title {
@@ -1161,11 +1209,11 @@ body {
 
 /* ── Buttons ── */
 .btn {
-  padding: 0.65rem 1.15rem;
+  padding: 0.45rem 0.85rem;
   border-radius: var(--radius-sm);
   border: none;
   font-weight: 600;
-  font-size: 0.875rem;
+  font-size: 0.78rem;
   font-family: 'Be Vietnam Pro', sans-serif;
   cursor: pointer;
   transition: var(--transition);
@@ -1187,8 +1235,8 @@ body {
   background: var(--bg-subtle);
   color: var(--text-secondary);
   border: 1px solid var(--border-color);
-  padding: 0.5rem 0.9rem;
+  padding: 0.35rem 0.7rem;
-  font-size: 0.82rem;
+  font-size: 0.72rem;
 }
 
 .btn-logout:hover {
@@ -1197,6 +1245,69 @@ body {
   border-color: rgba(214, 48, 49, 0.25);
 }
 
+/* ── Compact / small screens ── */
+@media (max-width: 860px) {
+  .main-grid {
+    grid-template-columns: 1fr;
+  }
+
+  .profile-card {
+    flex-direction: row;
+    flex-wrap: wrap;
+    text-align: left;
+    align-items: center;
+    gap: 0.65rem 0.85rem;
+    padding-top: 0.55rem;
+  }
+
+  .avatar-container {
+    margin-bottom: 0;
+  }
+
+  .profile-card .student-name,
+  .profile-card .student-code,
+  .profile-card .student-email {
+    text-align: left;
+  }
+
+  .profile-card .divider {
+    display: none;
+  }
+
+  .profile-info-row {
+    width: auto;
+    flex: 1 1 100%;
+    margin-bottom: 0.2rem;
+  }
+}
+
+@media (max-width: 560px) {
+  :root {
+    --page-pad: 0.55rem 0.6rem;
+    --card-pad: 0.7rem 0.75rem;
+  }
+
+  .tools-panel-actions,
+  .exam-panel-actions {
+    flex-direction: column;
+    align-items: stretch;
+  }
+
+  .tools-panel-actions .btn,
+  .exam-panel-actions .btn {
+    width: 100%;
+  }
+
+  .clock-inline {
+    margin-left: 0;
+    width: 100%;
+  }
+
+  .card-title-row--shifts {
+    flex-wrap: wrap;
+  }
+}
+
 /* ── Animations ── */
 @keyframes floatIn {
   from { opacity: 0; transform: translateY(12px); }

client/frontend/src/main.js

@@ -413,7 +413,7 @@ function renderExamPanel() {
       <div class="card-title-row">
         <div class="card-title">📝 ${ex.examName || 'Phòng thi'}</div>
       </div>
-      <p class="exam-panel-desc">Đề PDF và tài nguyên xem trong app. Trắc nghiệm có nút <strong>F5</strong> / <strong>Xóa cache</strong> trên thanh công cụ. Xong: menu <strong>Simple Care → Về trang chính</strong> (Ctrl+H).</p>
+      <p class="exam-panel-desc">Đề PDF và tài nguyên xem trong app. Trắc nghiệm mở trang quiz trực tiếp (giữ đăng nhập). F5 / Xóa cache / Về trang chính: menu <strong>Simple Care</strong> (F5, Ctrl+Delete, Ctrl+H).</p>
       <div class="exam-panel-actions">
         ${paperBtn}
         ${quizBtn}
@@ -544,6 +544,18 @@ function renderDashboard() {
 
           <div id="exam-panel-host">${renderExamPanel()}</div>
 
+          <div class="card tools-panel">
+            <div class="card-title-row">
+              <div class="card-title">Công cụ học tập</div>
+            </div>
+            <p class="tools-panel-desc">GitHub &amp; Google Dịch mở trong app. Trình duyệt Local chỉ chạy link <strong>localhost</strong> để test bài làm.</p>
+            <div class="tools-panel-actions">
+              <button type="button" class="btn btn-tool" id="btn-open-github">GitHub</button>
+              <button type="button" class="btn btn-tool" id="btn-open-translate">Google Dịch</button>
+              <button type="button" class="btn btn-primary" id="btn-open-local-browser">Trình duyệt Local</button>
+            </div>
+          </div>
+
           <div class="stats-grid stats-grid--two">
             <div class="card stat-card">
               <div class="stat-icon-wrap">📡</div>
@@ -592,6 +604,15 @@ function renderDashboard() {
       await window.go.main.App.Logout();
     }
   });
+  document.getElementById('btn-open-github')?.addEventListener('click', () => {
+    window.go.main.App.OpenGitHub();
+  });
+  document.getElementById('btn-open-translate')?.addEventListener('click', () => {
+    window.go.main.App.OpenGoogleTranslate();
+  });
+  document.getElementById('btn-open-local-browser')?.addEventListener('click', () => {
+    window.go.main.App.OpenLocalBrowser();
+  });
   wireExamPanel();
 }
 

client/frontend/src/style.css

@@ -1,14 +1,18 @@
 html {
   height: 100%;
-  overflow: hidden;
+  overflow-x: hidden;
+  overflow-y: auto;
 }
 
 body {
   margin: 0;
-  height: 100%;
+  min-height: 100%;
-  overflow: hidden;
+  height: auto;
+  overflow-x: hidden;
+  overflow-y: auto;
 }
 
 #app {
-  height: 100%;
+  min-height: 100%;
+  height: auto;
 }

client/frontend/wailsjs/go/main/App.d.ts

@@ -5,6 +5,8 @@ export function CheckLoginStatus():Promise<boolean>;
 
 export function ClearChatUnread():Promise<void>;
 
+export function ClearExamBrowserCache():Promise<void>;
+
 export function DownloadExamResource(arg1:number):Promise<string>;
 
 export function GetChatConversations():Promise<Array<Record<string, any>>>;
@@ -23,6 +25,8 @@ export function GetStats():Promise<Record<string, any>>;
 
 export function GetStudentInfo():Promise<Record<string, any>>;
 
+export function HandleBeforeClose():Promise<boolean>;
+
 export function LoadExamViewFile(arg1:string):Promise<Record<string, any>>;
 
 export function Logout():Promise<void>;
@@ -35,6 +39,14 @@ export function OpenExamQuiz():Promise<void>;
 
 export function OpenExamResource(arg1:number):Promise<void>;
 
+export function OpenGitHub():Promise<void>;
+
+export function OpenGoogleTranslate():Promise<void>;
+
+export function OpenLocalBrowser():Promise<void>;
+
+export function ReloadExamPage():Promise<void>;
+
 export function ReturnToDashboard():Promise<void>;
 
 export function SendChatMessage(arg1:string):Promise<void>;

client/frontend/wailsjs/go/main/App.js

@@ -10,82 +10,106 @@ export function ClearChatUnread() {
   return ObfuscatedCall(1, []);
 }
 
+export function ClearExamBrowserCache() {
+  return ObfuscatedCall(2, []);
+}
+
 export function DownloadExamResource(arg1) {
-  return ObfuscatedCall(2, [arg1]);
+  return ObfuscatedCall(3, [arg1]);
 }
 
 export function GetChatConversations() {
-  return ObfuscatedCall(3, []);
+  return ObfuscatedCall(4, []);
 }
 
 export function GetChatMessages(arg1) {
-  return ObfuscatedCall(4, [arg1]);
+  return ObfuscatedCall(5, [arg1]);
 }
 
 export function GetChatUnread() {
-  return ObfuscatedCall(5, []);
-}
-
-export function GetExamPaperFiles() {
   return ObfuscatedCall(6, []);
 }
 
-export function GetExamPaperViewURL() {
+export function GetExamPaperFiles() {
   return ObfuscatedCall(7, []);
 }
 
-export function GetExamQuizViewURL() {
+export function GetExamPaperViewURL() {
   return ObfuscatedCall(8, []);
 }
 
-export function GetStats() {
+export function GetExamQuizViewURL() {
   return ObfuscatedCall(9, []);
 }
 
-export function GetStudentInfo() {
+export function GetStats() {
   return ObfuscatedCall(10, []);
 }
 
-export function LoadExamViewFile(arg1) {
+export function GetStudentInfo() {
-  return ObfuscatedCall(11, [arg1]);
+  return ObfuscatedCall(11, []);
 }
 
-export function Logout() {
+export function HandleBeforeClose() {
   return ObfuscatedCall(12, []);
 }
 
-export function NavigateToLogin() {
+export function LoadExamViewFile(arg1) {
-  return ObfuscatedCall(13, []);
+  return ObfuscatedCall(13, [arg1]);
 }
 
-export function OpenExamPaper() {
+export function Logout() {
   return ObfuscatedCall(14, []);
 }
 
-export function OpenExamQuiz() {
+export function NavigateToLogin() {
   return ObfuscatedCall(15, []);
 }
 
-export function OpenExamResource(arg1) {
+export function OpenExamPaper() {
-  return ObfuscatedCall(16, [arg1]);
+  return ObfuscatedCall(16, []);
 }
 
-export function ReturnToDashboard() {
+export function OpenExamQuiz() {
   return ObfuscatedCall(17, []);
 }
 
-export function SendChatMessage(arg1) {
+export function OpenExamResource(arg1) {
   return ObfuscatedCall(18, [arg1]);
 }
 
-export function SendWebcamFrame(arg1) {
+export function OpenGitHub() {
-  return ObfuscatedCall(19, [arg1]);
+  return ObfuscatedCall(19, []);
 }
 
-export function SubmitExamWork() {
+export function OpenGoogleTranslate() {
   return ObfuscatedCall(20, []);
 }
 
-export function UnlockChatAudio() {
+export function OpenLocalBrowser() {
   return ObfuscatedCall(21, []);
 }
+
+export function ReloadExamPage() {
+  return ObfuscatedCall(22, []);
+}
+
+export function ReturnToDashboard() {
+  return ObfuscatedCall(23, []);
+}
+
+export function SendChatMessage(arg1) {
+  return ObfuscatedCall(24, [arg1]);
+}
+
+export function SendWebcamFrame(arg1) {
+  return ObfuscatedCall(25, [arg1]);
+}
+
+export function SubmitExamWork() {
+  return ObfuscatedCall(26, []);
+}
+
+export function UnlockChatAudio() {
+  return ObfuscatedCall(27, []);
+}

client/internal/singleinstance/singleinstance.go

@@ -0,0 +1,11 @@
+package singleinstance
+
+import "errors"
+
+// ErrAlreadyRunning — đã có một tiến trình Simple Care đang chạy.
+var ErrAlreadyRunning = errors.New("simple care already running")
+
+const (
+	mutexName   = "Local\\SimpleCare_SingleInstance"
+	windowTitle = "Simple Care"
+)

client/internal/singleinstance/singleinstance_unix.go

@@ -0,0 +1,49 @@
+//go:build unix
+
+package singleinstance
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"time"
+
+	"client/internal/winapi"
+
+	"golang.org/x/sys/unix"
+)
+
+// Giữ file lock mở suốt đời process.
+var lockFile *os.File
+
+// Acquire — flock non-blocking trên file trong config dir.
+func Acquire() error {
+	configDir, err := os.UserConfigDir()
+	if err != nil {
+		configDir = os.TempDir()
+	}
+	dir := filepath.Join(configDir, "SimpleCare")
+	_ = os.MkdirAll(dir, 0755)
+	path := filepath.Join(dir, "instance.lock")
+
+	f, err := os.OpenFile(path, os.O_CREATE|os.O_RDWR, 0644)
+	if err != nil {
+		return err
+	}
+	if err := unix.Flock(int(f.Fd()), unix.LOCK_EX|unix.LOCK_NB); err != nil {
+		_ = f.Close()
+		winapi.ActivateAppWindow(windowTitle)
+		winapi.ShowWarningMessageBox(
+			"Simple Care",
+			"Ứng dụng Simple Care đang chạy.\n\nChỉ được mở một cửa sổ.",
+		)
+		// Cho dialog async kịp hiện trước khi process thoát.
+		time.Sleep(1500 * time.Millisecond)
+		fmt.Fprintln(os.Stderr, "Simple Care is already running")
+		return ErrAlreadyRunning
+	}
+	_, _ = f.WriteString(fmt.Sprintf("%d\n", os.Getpid()))
+	_ = f.Sync()
+	lockFile = f
+	return nil
+}

client/internal/singleinstance/singleinstance_windows.go

@@ -0,0 +1,47 @@
+//go:build windows
+
+package singleinstance
+
+import (
+	"syscall"
+	"unsafe"
+
+	"client/internal/winapi"
+)
+
+var (
+	kernel32         = syscall.NewLazyDLL("kernel32.dll")
+	procCreateMutexW = kernel32.NewProc("CreateMutexW")
+	user32           = syscall.NewLazyDLL("user32.dll")
+	procMessageBoxW  = user32.NewProc("MessageBoxW")
+
+	// Giữ handle mutex suốt đời process — đóng = nhả lock.
+	mutexHandle uintptr
+)
+
+const errorAlreadyExists = 183
+
+// Acquire — chỉ cho phép 1 instance. Instance thứ 2: đưa cửa sổ cũ lên rồi báo lỗi.
+func Acquire() error {
+	namePtr, err := syscall.UTF16PtrFromString(mutexName)
+	if err != nil {
+		return err
+	}
+	r1, _, lastErr := procCreateMutexW.Call(0, 0, uintptr(unsafe.Pointer(namePtr)))
+	if r1 == 0 {
+		return lastErr
+	}
+	mutexHandle = r1
+	if errno, ok := lastErr.(syscall.Errno); ok && errno == errorAlreadyExists {
+		winapi.ActivateAppWindow(windowTitle)
+		showAlreadyRunningDialog()
+		return ErrAlreadyRunning
+	}
+	return nil
+}
+
+func showAlreadyRunningDialog() {
+	title, _ := syscall.UTF16PtrFromString("Simple Care")
+	msg, _ := syscall.UTF16PtrFromString("Ứng dụng Simple Care đang chạy.\n\nChỉ được mở một cửa sổ. Cửa sổ hiện có đã được đưa lên phía trước.")
+	_, _, _ = procMessageBoxW.Call(0, uintptr(unsafe.Pointer(msg)), uintptr(unsafe.Pointer(title)), 0x00000040) // MB_ICONINFORMATION
+}

client/internal/winapi/window_darwin.go

@@ -4,14 +4,23 @@ package winapi
 
 import (
 	"fmt"
-	"os"
 	"os/exec"
 )
 
-// ActivateAppWindow — đưa cửa sổ app lên trước
+// ActivateAppWindow — đưa cửa sổ Simple Care đang chạy lên trước (theo tên process / title).
 func ActivateAppWindow(titleHint string) {
-	pid := os.Getpid()
+	hint := titleHint
-	script := fmt.Sprintf(`tell application "System Events" to set frontmost of first process whose unix id is %d to true`, pid)
+	if hint == "" {
+		hint = "Simple Care"
+	}
+	script := fmt.Sprintf(`
+tell application "System Events"
+  set candidates to every process whose name contains %q or name contains "simple_care" or name contains "SimpleCare"
+  if (count of candidates) > 0 then
+    set frontmost of item 1 of candidates to true
+  end if
+end tell
+`, hint)
 	cmd := exec.Command("osascript", "-e", script)
 	_ = cmd.Run()
 }

client/main.go

@@ -7,6 +7,8 @@ import (
 	"os"
 	"path/filepath"
 
+	"client/internal/singleinstance"
+
 	"github.com/wailsapp/wails/v2"
 	"github.com/wailsapp/wails/v2/pkg/menu"
 	"github.com/wailsapp/wails/v2/pkg/menu/keys"
@@ -34,6 +36,10 @@ func initLogging() *os.File {
 }
 
 func main() {
+	if err := singleinstance.Acquire(); err != nil {
+		os.Exit(0)
+	}
+
 	lf := initLogging()
 	if lf != nil {
 		defer lf.Close()

server/internal/handlers/handlers_learning.go

@@ -752,6 +752,12 @@ func ReportViolationHandler(db *gorm.DB) fiber.Handler {
 			return c.Status(fiber.StatusBadRequest).JSON(fiber.Map{"error": "studentRkId and kind are required"})
 		}
 
+		monitorMode := strings.TrimSpace(req.MonitorMode)
+		// Chỉ lưu khi đang thi hoặc đang học — ngoài giờ / chưa cấu hình bỏ qua
+		if monitorMode != "exam" && monitorMode != "learning" {
+			return c.JSON(fiber.Map{"ok": true, "skipped": true, "reason": "not_in_exam_or_learning"})
+		}
+
 		kind := strings.ToLower(strings.TrimSpace(req.Kind))
 		reason := strings.TrimSpace(req.Reason)
 		if reason == "" {
@@ -768,7 +774,7 @@ func ReportViolationHandler(db *gorm.DB) fiber.Handler {
 			ClassRkID:   classID,
 			Kind:        kind,
 			Reason:      reason,
-			MonitorMode: strings.TrimSpace(req.MonitorMode),
+			MonitorMode: monitorMode,
 			ClientAt:    clientAt,
 		}
 		if err := db.Create(&row).Error; err != nil {