feat: Implement core classroom functionality including video player, learning and quiz pages, course detail view, and i18n support.

Frontend-Learner/components/classroom/AnnouncementModal.vue

@@ -90,7 +90,7 @@ const getLocalizedText = (text: any) => {
               </div>
               <div v-else class="p-10 flex flex-col items-center justify-center text-slate-400">
                   <q-icon name="campaign" size="40px" class="mb-2 opacity-50" />
-                  <p>{{ $t('classroom.noAnnouncements', 'ไม่มีประกาศในขณะนี้') }}</p>
+                  <p>{{ $t('classroom.noAnnouncements') }}</p>
               </div>
           </q-card-section>
        </q-card>

Frontend-Learner/components/classroom/CurriculumSidebar.vue

@@ -61,7 +61,7 @@ const progressPercentage = computed(() => {
         <!-- Course Progress Header -->
         <div class="p-5 border-b border-gray-200 dark:border-white/10 bg-slate-50/50 dark:bg-slate-900/50">
           <div class="flex justify-between items-center mb-2">
-            <span class="text-xs font-black uppercase tracking-widest text-slate-500 dark:text-slate-400">{{ $t('course.progress', 'ความคืบหน้า') }}</span>
+            <span class="text-xs font-black uppercase tracking-widest text-slate-500 dark:text-slate-400">{{ $t('course.progress') }}</span>
             <span class="text-sm font-black text-blue-600 dark:text-blue-400">{{ progressPercentage }}%</span>
           </div>
           <div class="h-2 w-full bg-slate-200 dark:bg-slate-800 rounded-full overflow-hidden shadow-inner">

Frontend-Learner/components/classroom/VideoPlayer.vue

@@ -165,9 +165,21 @@ const togglePlay = () => {
         return;
     }
     if (!videoRef.value) return;
-    if (isPlaying.value) videoRef.value.pause();
-    else videoRef.value.play();
-    isPlaying.value = !isPlaying.value;
+    if (isPlaying.value) {
+        videoRef.value.pause();
+        isPlaying.value = false;
+    } else {
+        const playPromise = videoRef.value.play();
+        if (playPromise !== undefined) {
+            playPromise.then(() => {
+                isPlaying.value = true;
+            }).catch(error => {
+                // Auto-play was prevented or play was interrupted
+                // We can safely ignore this error
+                console.log("Video play request handled:", error.name);
+            });
+        }
+    }
 };
 
 const handleTimeUpdate = () => {
@@ -238,12 +250,12 @@ watch([volume, isMuted], () => {
         ></iframe>
 
         <!-- 2. Standard HTML5 Video Player -->
-        <div v-else class="w-full h-full relative">
+        <div v-else class="w-full h-full relative group/video cursor-pointer">
             <video
                 ref="videoRef"
                 :src="src"
                 :poster="poster"
-                class="w-full h-full object-contain"
+                class="w-full h-full object-contain bg-slate-900"
                 @click="togglePlay"
                 @timeupdate="handleTimeUpdate"
                 @loadedmetadata="handleLoadedMetadata"
@@ -251,26 +263,30 @@ watch([volume, isMuted], () => {
             />
         
             <!-- Custom Controls Overlay (Only for HTML5 Video) -->
-            <div class="absolute bottom-0 left-0 right-0 p-4 bg-gradient-to-t from-black/80 via-black/40 to-transparent transition-opacity opacity-0 group-hover:opacity-100">
+            <div class="absolute bottom-0 left-0 right-0 p-6 bg-gradient-to-t from-black/90 via-black/40 to-transparent transition-opacity opacity-0 group-hover/video:opacity-100 flex flex-col gap-3">
+                <!-- Progress Bar -->
+                <div class="relative flex-grow h-1.5 bg-white/20 rounded-full cursor-pointer group/progress overflow-hidden" @click="seek">
+                    <div class="absolute top-0 left-0 h-full bg-blue-500 rounded-full group-hover/progress:bg-blue-400 transition-all shadow-[0_0_12px_rgba(59,130,246,0.6)]" :style="{ width: videoProgress + '%' }"></div>
+                </div>
+
                 <div class="flex items-center gap-4 text-white">
-                    <q-btn flat round dense :icon="isPlaying ? 'pause' : 'play_arrow'" @click.stop="togglePlay" />
-                    <div class="relative flex-grow h-1.5 bg-white/20 rounded-full cursor-pointer group/progress overflow-hidden" @click="seek">
-                        <div class="absolute top-0 left-0 h-full bg-blue-500 rounded-full group-hover/progress:bg-blue-400 transition-all shadow-[0_0_10px_rgba(59,130,246,0.5)]" :style="{ width: videoProgress + '%' }"></div>
-                    </div>
-                    <span class="text-xs font-mono font-medium opacity-90">{{ currentTimeDisplay }} / {{ durationDisplay }}</span>
+                    <q-btn flat round dense :icon="isPlaying ? 'pause' : 'play_arrow'" @click.stop="togglePlay" class="hover:scale-110 active:scale-95 transition-transform" />
+                    <span class="text-xs font-mono font-bold opacity-80">{{ currentTimeDisplay }} / {{ durationDisplay }}</span>
                     
+                    <div class="flex-grow"></div>
+
                     <!-- Volume Control -->
-                    <div class="flex items-center gap-2 group/volume">
-                        <q-btn flat round dense :icon="volumeIcon" @click.stop="handleToggleMute" color="white" />
-                        <div class="w-0 group-hover/volume:w-20 overflow-hidden transition-all duration-300 flex items-center">
+                    <div class="flex items-center gap-2 group/volume relative">
+                        <q-btn flat round dense :icon="volumeIcon" @click.stop="handleToggleMute" color="white" class="hover:scale-110 transition-transform" />
+                        <div class="w-0 group-hover/volume:w-24 overflow-hidden transition-all duration-300 flex items-center bg-black/60 backdrop-blur-md rounded-full px-2">
                             <input 
                                 type="range" 
                                 min="0" 
                                 max="1" 
-                                step="0.1" 
+                                step="0.05" 
                                 :value="volume" 
                                 @input="handleVolumeChange"
-                                class="w-20 h-1 bg-white/30 rounded-lg appearance-none cursor-pointer accent-blue-500"
+                                class="w-20 h-1 bg-white/20 rounded-lg appearance-none cursor-pointer accent-blue-500 mx-2"
                             />
                         </div>
                     </div>

Frontend-Learner/components/discovery/CourseDetailView.vue

@@ -156,7 +156,7 @@ const handleEnroll = () => {
                            
                            <div class="relative">
                             <div v-if="course.price > 0" class="mb-4">
-                                <span class="text-xs font-black uppercase tracking-widest text-slate-400 mb-1 block">{{ $t('course.price', 'ราคาคอร์ส') }}</span>
+                                <span class="text-xs font-black uppercase tracking-widest text-slate-400 mb-1 block">{{ $t('course.price') }}</span>
                                 <div class="text-4xl font-black font-display">
                                     <span class="text-slate-900 dark:text-white">
                                         {{ formatPrice(course.price) }}
@@ -180,13 +180,13 @@ const handleEnroll = () => {
                             </q-btn>
                             
                             <div class="mt-6 space-y-4">
-                                <p class="text-[10px] font-black uppercase tracking-[0.2em] text-slate-400 mb-4">{{ $t('course.includes', 'คอร์สนี้รวมอะไรบ้าง') }}</p>
+                                <p class="text-[10px] font-black uppercase tracking-[0.2em] text-slate-400 mb-4">{{ $t('course.includes') }}</p>
                                 
                                 <div class="flex items-center gap-3 text-sm text-slate-600 dark:text-slate-300 font-bold">
                                     <div class="w-6 h-6 rounded-lg bg-blue-50 dark:bg-blue-500/10 flex items-center justify-center">
                                         <q-icon name="all_inclusive" size="14px" class="text-blue-600 dark:text-blue-400" />
                                     </div>
-                                    {{ $t('course.fullLifetimeAccess', 'เข้าเรียนได้ตลอดชีพ') }}
+                                    {{ $t('course.fullLifetimeAccess') }}
                                 </div>
 
                                 <div class="flex items-center gap-3 text-sm text-slate-600 dark:text-slate-300 font-bold">
@@ -200,7 +200,7 @@ const handleEnroll = () => {
                                     <div class="w-6 h-6 rounded-lg bg-purple-50 dark:bg-purple-500/10 flex items-center justify-center">
                                         <q-icon name="devices" size="14px" class="text-purple-600 dark:text-purple-400" />
                                     </div>
-                                    {{ $t('course.accessOnMobile', 'เข้าเรียนได้ทุกอุปกรณ์') }}
+                                    {{ $t('course.accessOnMobile') }}
                                 </div>
                             </div>
                            </div>

Frontend-Learner/i18n/locales/en.json

@@ -212,6 +212,15 @@
     "instructionTitle": "Instructions",
     "instruction1": "Pay attention to the questions to measure your learning progress.",
     "startBtn": "Start Quiz",
+    "warningTitle": "Warning",
+    "singleAttemptWarning": "This quiz can only be taken once. If you fail, you will not be able to try again. Do you want to continue?",
+    "continue": "Continue",
+    "alreadyPassed": "You have already passed",
+    "latestScore": "Latest Score",
+    "retryMaybe": "Try Again",
+    "passedStatus": "Passed",
+    "failedStatus": "Failed",
+    "passingScore": "Passing Score",
     "nextBtn": "Next Question",
     "prevBtn": "Previous Question",
     "submitBtn": "Submit Answers",

Frontend-Learner/i18n/locales/th.json

@@ -212,6 +212,15 @@
     "instructionTitle": "คำแนะนำ",
     "instruction1": "แบบทดสอบนี้มีไว้เพื่อวัดความรู้ความเข้าใจของคุณในบทเรียนนี้",
     "startBtn": "เริ่มทำแบบทดสอบ",
+    "warningTitle": "คำเตือน",
+    "singleAttemptWarning": "แบบทดสอบนี้สามารถทำได้เพียงครั้งเดียวเท่านั้น หากไม่ผ่านคุณจะไม่สามารถทำใหม่ได้อีก คุณต้องการดำเนินการต่อหรือไม่?",
+    "continue": "ดำเนินการต่อ",
+    "alreadyPassed": "คุณสอบผ่านเกณฑ์แล้ว",
+    "latestScore": "คะแนนล่าสุด",
+    "retryMaybe": "ลองใหม่อีกครั้ง",
+    "passedStatus": "ผ่านเกณฑ์",
+    "failedStatus": "ไม่ผ่านเกณฑ์",
+    "passingScore": "เกณฑ์การผ่าน",
     "exitTitle": "ออกจากแบบทดสอบ",
     "timeLeft": "เวลาที่เหลือ",
     "submitConfirm": "คุณต้องการส่งคำตอบหรือไม่?",

Frontend-Learner/pages/classroom/learning.vue

@@ -6,9 +6,8 @@
  * ออกแบบให้เหมือนระบบ LMS มาตรฐาน
  */
 
-
 definePageMeta({
-  layout: false, // Custom layout defined within this component
+  layout: false,
   middleware: 'auth'
 })
 
@@ -21,10 +20,9 @@ const router = useRouter()
 const { t } = useI18n()
 const { user } = useAuth()
 const { fetchCourseLearningInfo, fetchLessonContent, saveVideoProgress, checkLessonAccess, fetchVideoProgress, fetchCourseAnnouncements, markLessonComplete, getLocalizedText } = useCourse()
-// Media Prefs (Global Volume)
-const { volume, muted: isMuted, setVolume, setMuted, applyTo } = useMediaPrefs()
+const $q = useQuasar()
 
-// State
+// State management
 const sidebarOpen = ref(false)
 const courseId = computed(() => Number(route.query.course_id))
 
@@ -99,6 +97,83 @@ const toggleSidebar = () => {
   sidebarOpen.value = !sidebarOpen.value
 }
 
+// Logic Quiz Attempt Management
+const quizStatus = computed(() => {
+  if (!currentLesson.value || currentLesson.value.type !== 'QUIZ' || !currentLesson.value.quiz) return null
+  
+  const quiz = currentLesson.value.quiz
+  const latestAttempt = quiz.latest_attempt
+  const allowMultiple = quiz.allow_multiple_attempts
+
+  // If never attempted
+  if (!latestAttempt) {
+    return {
+      canStart: true,
+      label: t('quiz.startBtn'),
+      icon: 'play_arrow',
+      showScore: false
+    }
+  }
+
+  // If multiple attempts allowed
+  if (allowMultiple) {
+    return {
+      canStart: true,
+      label: t('quiz.retryBtn'),
+      icon: 'refresh',
+      showScore: true,
+      score: latestAttempt.score,
+      isPassed: latestAttempt.is_passed
+    }
+  }
+
+  // allowMultiple is false (Single attempt only)
+  // Lock the quiz regardless of pass/fail once attempted
+  return {
+    canStart: false,
+    label: latestAttempt.is_passed ? t('quiz.passedStatus') : t('quiz.failedStatus'),
+    icon: latestAttempt.is_passed ? 'check_circle' : 'cancel',
+    showScore: true,
+    score: latestAttempt.score,
+    isPassed: latestAttempt.is_passed
+  }
+})
+
+const handleStartQuiz = () => {
+    if (!currentLesson.value || !currentLesson.value.quiz) return
+
+    const quiz = currentLesson.value.quiz
+    
+    // If multiple attempts are disabled and it's the first time
+    if (!quiz.allow_multiple_attempts && !quiz.latest_attempt) {
+        $q.dialog({
+            title: `<div class="text-slate-900 dark:text-white font-black text-xl">${t('quiz.warningTitle')}</div>`,
+            message: `<div class="text-slate-600 dark:text-slate-300 text-base leading-relaxed mt-2">${t('quiz.singleAttemptWarning')}</div>`,
+            html: true,
+            persistent: true,
+            class: 'rounded-[24px]',
+            ok: {
+                label: t('quiz.continue'),
+                color: 'primary',
+                unelevated: true,
+                rounded: true,
+                class: 'px-8 font-black'
+            },
+            cancel: {
+                label: t('common.cancel'),
+                color: 'grey-7',
+                flat: true,
+                rounded: true,
+                class: 'font-bold'
+            }
+        }).onOk(() => {
+            router.push(`/classroom/quiz?course_id=${courseId.value}&lesson_id=${currentLesson.value.id}`)
+        })
+    } else {
+        router.push(`/classroom/quiz?course_id=${courseId.value}&lesson_id=${currentLesson.value.id}`)
+    }
+}
+
 // Helper สำหรับรีเซ็ตข้อมูลและย้ายหน้า (Hard Reload)
 const resetAndNavigate = (path: string) => {
   if (import.meta.client) {
@@ -117,18 +192,18 @@ const resetAndNavigate = (path: string) => {
         }
     }
     
-    // 2. ล้างข้อมูลใน localStorage ทั้งหมด
+    // 2. Clear all localStorage
     localStorage.clear()
     
-    // 3. นำข้อมูลที่ยกเว้นกลับมาใส่คืน
+    // 3. Restore whitelisted keys
     Object.entries(whitelist).forEach(([key, value]) => {
         localStorage.setItem(key, value)
     })
     
-    // 4. บังคับโหลดหน้าใหม่ทั้งหมด (Hard Reload) ไปที่ path ใหม่
+    // 4. Force hard reload to the new path
     window.location.href = path
   } else {
-    // Fallback สำหรับ SSR
+    // SSR Fallback
     router.push(path)
   }
 }
@@ -137,13 +212,13 @@ const resetAndNavigate = (path: string) => {
 const handleLessonSelect = (lessonId: number) => {
   if (currentLesson.value?.id === lessonId) return
   
-  // 1. เปลี่ยน URL แบบนุ่มนวล
+  // 1. Update URL query params
   router.push({ query: { ...route.query, lesson_id: lessonId.toString() } })
   
-  // 2. โหลดเนื้อหาใหม่โดยไม่ Refresh หน้า
+  // 2. Load content without refresh
   loadLesson(lessonId)
   
-  // ปิด Sidebar บนมือถือเมื่อเลือกบทเรียน
+  // Close sidebar on mobile
   if (sidebarOpen.value) {
     sidebarOpen.value = false
   }
@@ -169,14 +244,12 @@ const loadCourseData = async () => {
     if (res.success) {
       courseData.value = res.data
       
-      // Auto-load logic: เช็คจาก URL ก่อน ถ้าไม่มีค่อยหาบทแรก
+      // Auto-load logic: Check URL first, fallback to first available lesson
       const urlLessonId = route.query.lesson_id ? Number(route.query.lesson_id) : null
       
       if (urlLessonId) {
-          // ถ้ามีใน URL ให้โหลดบทนั้นเลย
           loadLesson(urlLessonId)
       } else if (!currentLesson.value) {
-          // ถ้าไม่มีใน URL ให้หาบทแรกที่ไม่ล็อค
           const firstChapter = res.data.chapters[0]
           if (firstChapter && firstChapter.lessons.length > 0) {
               const availableLesson = firstChapter.lessons.find((l: any) => !l.is_locked) || firstChapter.lessons[0]
@@ -184,7 +257,7 @@ const loadCourseData = async () => {
           }
       }
 
-      // Fetch Announcements
+      // Fetch Course Announcements
       const annRes = await fetchCourseAnnouncements(courseId.value)
       if (annRes.success) {
           announcements.value = annRes.data || []
@@ -192,7 +265,7 @@ const loadCourseData = async () => {
       }
     }
   } catch (error) {
-    console.error('Error loading course:', error)
+    console.error('Error loading course data:', error)
   } finally {
     isLoading.value = false
   }
@@ -483,14 +556,13 @@ const videoSrc = computed(() => {
 
 // เมื่อวิดีโอจบ ให้บันทึกว่าเรียนจบ (Complete)
 const onVideoEnded = async () => {
-    // Safety check BEFORE trying to save
+    // Safety check before saving
     const lesson = currentLesson.value
     if (!lesson || !lesson.progress || lesson.progress.is_completed || isCompleting.value) return
 
     isCompleting.value = true
     try {
-        // 1. Force save progress at 100%
-        // This will trigger the backend's auto-complete logic
+        // Force save progress at 100% to trigger backend completion
         await performSaveProgress(true, false)
     } catch (err) {
         console.error('Failed to save progress on end:', err)
@@ -539,7 +611,7 @@ onBeforeUnmount(() => {
           @click="toggleSidebar"
         >
            <q-icon name="format_list_bulleted" size="18px" class="mr-1.5" />
-           <span class="hidden md:inline">{{ $t('classroom.curriculum', 'เนื้อหาหลักสูตร') }}</span>
+           <span class="hidden md:inline">{{ $t('classroom.curriculum') }}</span>
         </q-btn>
         
         <q-toolbar-title class="text-base font-bold text-left truncate text-slate-900 dark:text-white">
@@ -557,7 +629,7 @@ onBeforeUnmount(() => {
              class="text-slate-600 dark:text-slate-300 hover:text-blue-600 transition-colors"
            >
              <q-badge v-if="hasUnreadAnnouncements" color="red" floating rounded />
-             <q-tooltip>{{ $t('classroom.announcements', 'ประกาศในคอร์ส') }}</q-tooltip>
+             <q-tooltip>{{ $t('classroom.announcements') }}</q-tooltip>
            </q-btn>
         </div>
       </q-toolbar>
@@ -580,39 +652,46 @@ onBeforeUnmount(() => {
       <q-page class="flex flex-col h-full bg-slate-50 dark:bg-[#0B0F1A]">
          <!-- Video Player & Content Area -->
          <div class="w-full max-w-7xl mx-auto p-4 md:p-6 flex-grow">
-            <!-- Video Player -->
-            <VideoPlayer
-               v-if="currentLesson && videoSrc && !isLessonLoading"
-               ref="videoPlayerComp"
-               :src="videoSrc"
-               :poster="courseData?.course?.thumbnail_url"
-               :initialSeekTime="initialSeekTime"
-               @timeupdate="handleVideoTimeUpdate"
-               @ended="onVideoEnded"
-               @loadedmetadata="(d: number) => onVideoMetadataLoaded(d)"
-            />
-            
-            <!-- Skeleton Loader for Video/Content -->
-            <div v-if="isLessonLoading" class="aspect-video bg-slate-200 dark:bg-slate-800 rounded-2xl animate-pulse flex items-center justify-center mb-6 overflow-hidden relative shadow-xl">
-                <!-- Course Thumbnail as a background during loading -->
-                <img 
-                    v-if="courseData?.course?.thumbnail_url"
-                    :src="courseData.course.thumbnail_url" 
-                    class="absolute inset-0 w-full h-full object-cover opacity-20 blur-md"
-                />
-                <div class="absolute inset-0 bg-gradient-to-br from-slate-200/50 to-slate-300/50 dark:from-slate-900/80 dark:to-slate-800/80"></div>
-                
-                <div class="z-10 flex flex-col items-center">
-                    <div class="relative">
-                        <q-spinner size="4rem" color="primary" :thickness="4" />
-                        <q-icon name="play_circle" size="2rem" color="primary" class="absolute inset-0 m-auto opacity-50" />
+            <!-- 1. LOADING STATE (Comprehensive Skeleton) -->
+            <div v-if="isLessonLoading" class="animate-fade-in">
+                <!-- Video Skeleton -->
+                <div class="aspect-video bg-slate-200 dark:bg-slate-800 rounded-3xl animate-pulse flex items-center justify-center mb-10 overflow-hidden relative shadow-xl focus:outline-none">
+                    <img 
+                        v-if="courseData?.course?.thumbnail_url"
+                        :src="courseData.course.thumbnail_url" 
+                        class="absolute inset-0 w-full h-full object-cover opacity-20 blur-md"
+                    />
+                    <div class="absolute inset-0 bg-gradient-to-br from-slate-200/50 to-slate-300/50 dark:from-slate-900/80 dark:to-slate-800/80"></div>
+                    <div class="z-10 flex flex-col items-center">
+                        <q-spinner size="3.5rem" color="primary" :thickness="2" />
+                        <p class="mt-4 text-slate-500 font-bold text-xs uppercase tracking-[0.2em]">{{ $t('common.loading') }}</p>
                     </div>
-                    <p class="mt-4 text-slate-600 dark:text-slate-300 font-black text-xs uppercase tracking-[0.2em] animate-pulse">{{ $t('common.loading') }}</p>
+                </div>
+                
+                <!-- Info Skeleton -->
+                <div class="bg-white dark:bg-slate-800/50 p-8 rounded-3xl border border-slate-100 dark:border-white/5 shadow-sm">
+                    <div class="h-10 bg-slate-200 dark:bg-slate-800 rounded-xl w-3/4 mb-4 animate-pulse"></div>
+                    <div class="h-4 bg-slate-100 dark:bg-slate-800 rounded-lg w-full mb-2 animate-pulse"></div>
+                    <div class="h-4 bg-slate-100 dark:bg-slate-800 rounded-lg w-2/3 animate-pulse"></div>
                 </div>
             </div>
             
-             <!-- Lesson Info -->
-             <div v-if="currentLesson" class="bg-[var(--bg-surface)] p-6 md:p-8 rounded-3xl shadow-sm border border-[var(--border-color)]">
+            <!-- 2. READY STATE (Real Lesson Content) -->
+            <div v-else-if="currentLesson" class="animate-fade-in">
+                <!-- Video Player -->
+                <VideoPlayer
+                   v-if="videoSrc"
+                   ref="videoPlayerComp"
+                   :src="videoSrc"
+                   :poster="courseData?.course?.thumbnail_url"
+                   :initialSeekTime="initialSeekTime"
+                   @timeupdate="handleVideoTimeUpdate"
+                   @ended="onVideoEnded"
+                   @loadedmetadata="(d: number) => onVideoMetadataLoaded(d)"
+                />
+            
+              <!-- Lesson Info -->
+              <div class="bg-[var(--bg-surface)] p-6 md:p-8 rounded-3xl shadow-sm border border-[var(--border-color)]">
                 <!-- ใช้สีจากตัวแปรกลาง: จะแยกโหมดให้อัตโนมัติ (สว่าง=ดำ / มืด=ขาว) -->
                 <div class="flex items-start justify-between gap-4 mb-4">
                     <h1 class="text-3xl md:text-5xl font-black text-slate-900 dark:text-white leading-tight tracking-tight font-display">{{ getLocalizedText(currentLesson.title) }}</h1>
@@ -625,27 +704,51 @@ onBeforeUnmount(() => {
                     <div class="bg-white dark:bg-slate-800 w-20 h-20 rounded-full flex items-center justify-center mx-auto mb-4 shadow-sm text-blue-500 dark:text-blue-400 border dark:border-white/10">
                         <q-icon name="quiz" size="40px" />
                     </div>
-                    <h2 class="text-xl font-bold mb-2 text-slate-900 dark:text-white">{{ $t('quiz.startTitle', 'แบบทดสอบท้ายบทเรียน') }}</h2>
+                    <h2 class="text-xl font-bold mb-2 text-slate-900 dark:text-white">{{ $t('quiz.startTitle') }}</h2>
                     <p class="text-slate-500 dark:text-slate-400 mb-6 max-w-md mx-auto">{{ getLocalizedText(currentLesson.quiz?.description || currentLesson.description) }}</p>
                     
                     <div class="flex justify-center flex-wrap gap-3 text-sm mb-8">
-                         <span v-if="currentLesson.quiz?.questions?.length" class="px-3 py-1 bg-white dark:bg-white rounded-full border border-gray-200 dark:border-white/10 shadow-sm flex items-center gap-1.5 text-slate-900 font-bold">
-                            <q-icon name="format_list_numbered" size="14px" class="text-blue-600" /> {{ currentLesson.quiz.questions.length }} {{ $t('quiz.questions') }}
+                         <span v-if="currentLesson.quiz?.questions?.length" class="px-4 py-1.5 bg-white dark:bg-slate-800 rounded-full border border-gray-100 dark:border-white/5 shadow-sm flex items-center gap-2 text-slate-700 dark:text-slate-300 font-bold">
+                            <q-icon name="format_list_numbered" size="14px" class="text-blue-500" /> {{ currentLesson.quiz.questions.length }} {{ $t('quiz.questions') }}
                          </span>
-                         <span v-if="currentLesson.quiz?.time_limit" class="px-3 py-1 bg-white dark:bg-white rounded-full border border-gray-200 dark:border-white/10 shadow-sm flex items-center gap-1.5 text-slate-900 font-bold">
-                            <q-icon name="schedule" size="14px" class="text-orange-600" /> {{ currentLesson.quiz.time_limit }} {{ $t('quiz.minutes') }}
+                         <span v-if="currentLesson.quiz?.time_limit" class="px-4 py-1.5 bg-white dark:bg-slate-800 rounded-full border border-gray-100 dark:border-white/5 shadow-sm flex items-center gap-2 text-slate-700 dark:text-slate-300 font-bold">
+                            <q-icon name="schedule" size="14px" class="text-orange-500" /> {{ currentLesson.quiz.time_limit }} {{ $t('quiz.minutes') }}
                          </span>
                     </div>
 
+                    <div v-if="quizStatus?.showScore" class="mb-8 p-6 bg-white dark:!bg-slate-800/80 rounded-[32px] border border-blue-50 dark:border-white/5 shadow-xl max-w-sm mx-auto backdrop-blur-md">
+                        <div class="text-[10px] uppercase font-black tracking-[0.2em] text-slate-400 dark:text-slate-500 mb-4">{{ $t('quiz.latestScore') }}</div>
+                        <div class="flex items-center justify-center gap-6">
+                            <div class="text-5xl font-black" :class="quizStatus.isPassed ? 'text-emerald-500' : 'text-rose-500'">
+                                {{ quizStatus.score }}
+                            </div>
+                            <div class="h-12 w-px bg-slate-100 dark:bg-white/10"></div>
+                            <div class="flex flex-col items-start gap-1">
+                                <span class="text-[10px] font-black px-2.5 py-1 rounded-lg uppercase tracking-wider" :class="quizStatus.isPassed ? 'bg-emerald-500/10 text-emerald-500' : 'bg-rose-500/10 text-rose-500'">
+                                    {{ quizStatus.isPassed ? $t('quiz.passedStatus') : $t('quiz.failedStatus') }}
+                                </span>
+                                <span class="text-[10px] text-slate-400 dark:text-slate-500 font-bold">{{ $t('quiz.passingScore') }} {{ currentLesson.quiz.passing_score }}%</span>
+                            </div>
+                        </div>
+                    </div>
+
                     <q-btn 
+                        v-if="quizStatus?.canStart"
                         class="bg-blue-600 text-white shadow-lg shadow-blue-600/30 hover:shadow-blue-600/50 transition-all font-bold px-8"
                         size="lg" 
                         rounded 
                         no-caps
-                        :label="$t('quiz.startBtn')" 
-                        icon="play_arrow"
-                        @click="$router.push(`/classroom/quiz?course_id=${courseId}&lesson_id=${currentLesson.id}`)"
+                        :label="quizStatus.label" 
+                        :icon="quizStatus.icon"
+                        @click="handleStartQuiz"
                     />
+                    <div v-else-if="quizStatus" 
+                         class="inline-flex items-center gap-2 px-6 py-3 rounded-full font-bold"
+                         :class="quizStatus.isPassed ? 'bg-emerald-50 dark:bg-emerald-500/10 text-emerald-600 dark:text-emerald-400' : 'bg-rose-50 dark:bg-rose-500/10 text-rose-600 dark:text-rose-400'"
+                    >
+                        <q-icon :name="quizStatus.icon" size="20px" />
+                        {{ quizStatus.label }}
+                    </div>
                 </div>
                 <div v-else-if="currentLesson.content" class="prose prose-lg dark:prose-invert max-w-none p-6 md:p-8 bg-gray-50 dark:bg-slate-800/50 rounded-2xl border border-gray-100 dark:border-white/5">
                     <div v-html="getLocalizedText(currentLesson.content)" class="leading-relaxed text-slate-800 dark:text-slate-200"></div>
@@ -682,9 +785,10 @@ onBeforeUnmount(() => {
                             <q-icon name="download" class="text-slate-300 group-hover:text-blue-500 z-10" />
                         </a>
                     </div>
-                </div>
-            </div>
-         </div>
+                </div> <!-- End Attachments -->
+              </div> <!-- End Lesson Info -->
+            </div> <!-- End Ready State Wrapper -->
+         </div> <!-- End Main Content Wrapper -->
       </q-page>
     </q-page-container>
 

Frontend-Learner/pages/classroom/quiz.vue

@@ -83,7 +83,7 @@ const jumpToQuestion = (targetIndex: number) => {
          if (!isAnswered && !isSkippable) {
             $q.notify({
                 type: 'warning',
-                message: t('quiz.pleaseSelectAnswer', 'กรุณาเลือกคำตอบ'),
+                message: t('quiz.pleaseSelectAnswer'),
                 position: 'top',
                 timeout: 2000
             })
@@ -106,6 +106,8 @@ const totalQuestions = computed(() => {
     return quizData.value?.questions?.length || 0
 })
 
+const hasQuestions = computed(() => totalQuestions.value > 0)
+
 const showQuestionMap = computed(() => $q.screen.gt.sm)
 
 const timerDisplay = computed(() => {
@@ -252,12 +254,37 @@ const submitQuiz = async (auto = false) => {
         return
      }
 
-     // Confirmation before submission
-     if (!confirm(t('quiz.submitConfirm', 'ยืนยันการส่งคำตอบ?'))) {
-         return
-     }
+     // Premium Confirmation before submission
+     $q.dialog({
+         title: `<div class="text-slate-900 dark:text-white font-black text-xl">${t('quiz.warningTitle')}</div>`,
+         message: `<div class="text-slate-600 dark:text-slate-300 text-base leading-relaxed mt-2">${t('quiz.submitConfirm')}</div>`,
+         html: true,
+         persistent: true,
+         class: 'rounded-[24px]',
+         ok: {
+             label: t('common.ok'),
+             color: 'primary',
+             unelevated: true,
+             rounded: true,
+             class: 'px-8 font-black'
+         },
+         cancel: {
+             label: t('common.cancel'),
+             color: 'grey-7',
+             flat: true,
+             rounded: true,
+             class: 'font-bold'
+         }
+     }).onOk(() => {
+         processSubmitQuiz(auto)
+     })
+     return
   }
 
+  processSubmitQuiz(auto)
+}
+
+const processSubmitQuiz = async (auto = false) => {
   // 2. Start Submission Process
   if (timerInterval) clearInterval(timerInterval)
   
@@ -285,12 +312,13 @@ const submitQuiz = async (auto = false) => {
           }
       } else {
           // Fallback error handling
-          alert(res.error || 'Failed to submit quiz')
-          // Maybe go back to taking?
+          $q.notify({
+              type: 'negative',
+              message: res.error || 'Failed to submit quiz'
+          })
       }
   } catch (err) {
       console.error('Submit quiz error:', err)
-      alert('An unexpected error occurred.')
   } finally {
       isSubmitting.value = false
   }
@@ -349,7 +377,7 @@ const getCorrectChoiceId = (questionId: number) => {
             </button>
             <div class="w-[1px] h-4 bg-slate-300 dark:bg-white/10 mx-4"/>
             <h1 class="text-base font-bold text-slate-900 dark:text-white truncate max-w-[200px] md:max-w-md hidden md:block">
-                {{ currentScreen === 'review' ? $t('quiz.reviewAnswers', 'เฉลยคำตอบ') : (quizData ? getLocalizedText(quizData.title) : (courseData ? getLocalizedText(courseData.course.title) : $t('quiz.startTitle'))) }}
+                {{ currentScreen === 'review' ? $t('quiz.reviewAnswers') : (quizData ? getLocalizedText(quizData.title) : (courseData ? getLocalizedText(courseData.course.title) : $t('quiz.startTitle'))) }}
             </h1>
         </div>
         
@@ -370,6 +398,22 @@ const getCorrectChoiceId = (questionId: number) => {
           <p class="text-sm font-medium text-slate-500">{{ $t('classroom.loadingTitle') }}</p>
       </div>
 
+      <div v-else-if="!quizData || !hasQuestions" class="w-full max-w-[640px] animate-fade-in py-12">
+          <div class="bg-white dark:!bg-[#1e293b] border border-slate-200 dark:border-white/5 rounded-[32px] p-8 md:p-14 shadow-lg text-center">
+              <div class="w-20 h-20 rounded-3xl bg-amber-50 dark:bg-amber-500/10 border border-amber-100 dark:border-amber-500/20 flex items-center justify-center mx-auto mb-6">
+                  <q-icon name="warning" size="2.5rem" color="warning" />
+              </div>
+              <h2 class="text-2xl font-black text-slate-900 dark:text-white mb-2">{{ $t('quiz.noQuizData') }}</h2>
+              <p class="text-slate-500 dark:text-slate-400 mb-8">{{ $t('quiz.noQuizDesc') }}</p>
+              <button 
+                class="px-8 py-3 bg-blue-600 text-white rounded-xl hover:bg-blue-500 transition-all font-black"
+                @click="confirmExit"
+              >
+                {{ $t('quiz.backToLesson') }}
+              </button>
+          </div>
+      </div>
+
       <template v-else>
           <!-- 1. START SCREEN -->
           <div v-if="currentScreen === 'start'" class="w-full max-w-[640px] animate-fade-in py-12">
@@ -476,7 +520,7 @@ const getCorrectChoiceId = (questionId: number) => {
                          :disabled="currentQuestionIndex === 0"
                          class="px-6 py-3 rounded-xl font-bold text-slate-600 dark:text-slate-300 bg-slate-100 dark:bg-white/5 hover:bg-slate-200 dark:hover:bg-white/10 disabled:opacity-30 disabled:cursor-not-allowed transition-all flex items-center gap-2"
                      >
-                         <q-icon name="arrow_back" /> {{ $t('common.back', 'ย้อนกลับ') }}
+                         <q-icon name="arrow_back" /> {{ $t('common.back') }}
                      </button>
 
                      <button 
@@ -484,7 +528,7 @@ const getCorrectChoiceId = (questionId: number) => {
                          @click="nextQuestion"
                          class="px-8 py-3 bg-blue-600 hover:bg-blue-500 text-white rounded-xl font-bold transition-all shadow-lg shadow-blue-500/20 flex items-center gap-2"
                      >
-                         {{ $t('common.next', 'ถัดไป') }} <q-icon name="arrow_forward" />
+                         {{ $t('common.next') }} <q-icon name="arrow_forward" />
                      </button>
                      <button 
                          v-else
@@ -556,7 +600,7 @@ const getCorrectChoiceId = (questionId: number) => {
                       @click="reviewQuiz"
                       class="w-full py-2 text-blue-500 hover:text-blue-700 dark:hover:text-blue-400 font-bold text-sm transition-colors mt-2"
                     >
-                       {{ $t('quiz.reviewAnswers', 'ดูเฉลยคำตอบ') }}
+                       {{ $t('quiz.reviewAnswers') }}
                     </button>
                  </div>
              </div>

Frontend-Learner/pages/verify-email.vue

@@ -24,7 +24,7 @@ onMounted(async () => {
     if (!token) {
         isLoading.value = false
         isSuccess.value = false
-        errorMessage.value = t('auth.invalidToken') || 'Token ไม่ถูกต้อง'
+        errorMessage.value = t('auth.invalidToken')
         return
     }
 
@@ -38,15 +38,13 @@ onMounted(async () => {
     } else {
         isSuccess.value = false
         if (result.code === 400) {
-             errorMessage.value = t('profile.emailAlreadyVerified') || 'อีเมลได้รับการยืนยันแล้ว'
-             // Treat as success visually or show specific message? 
-             // Requirement says "check mark" for done. 
-             // If already verified, maybe show success-like state with "Already Verified" message.
-             isSuccess.value = true // Let's show checkmark but with specific message
+             errorMessage.value = t('profile.emailAlreadyVerified')
+             // If already verified, show success state with specific message
+             isSuccess.value = true 
         } else if (result.code === 401) {
-            errorMessage.value = t('auth.tokenExpired') || 'Token หมดอายุหรือล้มเหลว'
+            errorMessage.value = t('auth.tokenExpired')
         } else {
-            errorMessage.value = result.error || 'ยืนยันอีเมลไม่สำเร็จ'
+            errorMessage.value = result.error || t('common.error')
         }
     }
 })
@@ -64,7 +62,7 @@ const navigateToHome = () => {
       <div v-if="isLoading" class="flex flex-col items-center justify-center py-8">
         <q-spinner-dots size="4rem" color="primary" />
         <h2 class="mt-6 text-xl font-bold text-slate-900 dark:text-white animate-pulse">
-          {{ $t('auth.verifyingEmail') || 'กำลังยืนยันอีเมล...' }}
+          {{ $t('auth.verifyingEmail') }}
         </h2>
       </div>
 
@@ -75,10 +73,10 @@ const navigateToHome = () => {
         </div>
         
         <h2 class="text-3xl font-black text-slate-900 dark:text-white mb-2">
-            {{ errorMessage && errorMessage !== '' ? (errorMessage) : ($t('auth.emailVerified') || 'ยืนยันอีเมลสำเร็จ!') }}
+            {{ errorMessage && errorMessage !== '' ? (errorMessage) : ($t('auth.emailVerified')) }}
         </h2>
         <p class="text-slate-500 dark:text-slate-400 mb-8">
-          {{ $t('auth.emailVerifiedDesc') || 'บัญชีของคุณได้รับการยืนยันเรียบร้อยแล้ว' }}
+          {{ $t('auth.emailVerifiedDesc') }}
         </p>
 
         <q-btn
@@ -86,7 +84,7 @@ const navigateToHome = () => {
           rounded
           color="primary"
           class="w-full py-3 font-bold text-lg shadow-lg shadow-blue-500/30"
-          :label="$t('common.backToHome') || 'กลับสู่หน้าหลัก'"
+          :label="$t('common.backToHome')"
           @click="navigateToHome"
         />
       </div>
@@ -109,7 +107,7 @@ const navigateToHome = () => {
           rounded
           color="slate-700"
           class="w-full py-3 font-bold text-lg"
-          label="ลองใหม่อีกครั้ง"
+          :label="$t('common.tryAgain')"
           @click="router.push('/')"
         />
       </div>