Create app.py19

app.py19

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+import streamlit as st
+import requests
+import os
+from datetime import datetime, timedelta
+import re
+import hashlib
+import json
+import time
+
+# ===============================
+# SUPABASE CACHE CLASS - FIXED VERSION
+# ===============================
+class SupabaseCache:
+    def __init__(self, ttl_days=7):
+        """
+        Supabase-based cache for multi-user, persistent storage
+        """
+        self.ttl_days = ttl_days
+        
+        # Get Supabase credentials from environment
+        self.supabase_url = os.environ.get("SUPABASE_URL", "")
+        self.supabase_key = os.environ.get("SUPABASE_KEY", "")
+        
+        # Initialize Supabase client
+        self.supabase = None
+        self._init_supabase()
+        
+        # In-memory fallback cache
+        self.memory_cache = {}
+        self.max_memory_entries = 100
+        
+    def _init_supabase(self):
+        """Initialize Supabase client"""
+        if self.supabase_url and self.supabase_key:
+            try:
+                from supabase import create_client
+                self.supabase = create_client(self.supabase_url, self.supabase_key)
+                # Test connection
+                self.supabase.table("seba_cache").select("count", count="exact").limit(1).execute()
+            except ImportError:
+                # supabase-py not installed
+                self.supabase = None
+            except Exception as e:
+                # Connection failed
+                print(f"Supabase connection error: {e}")
+                self.supabase = None
+        else:
+            self.supabase = None
+    
+    def get(self, cache_key):
+        """Get cached answer - try Supabase first, then memory"""
+        # First check memory cache (fastest)
+        if cache_key in self.memory_cache:
+            entry = self.memory_cache[cache_key]
+            if self._is_valid(entry):
+                entry['access_count'] = entry.get('access_count', 0) + 1
+                entry['last_accessed'] = datetime.now().isoformat()
+                return entry
+        
+        # Try Supabase if available - FIXED: Removed TTL filter from query
+        if self.supabase:
+            try:
+                # Get entry without TTL filter - we'll check TTL in Python
+                response = self.supabase.table("seba_cache") \
+                    .select("*") \
+                    .eq("key_hash", cache_key) \
+                    .execute()
+                
+                if response.data and len(response.data) > 0:
+                    entry = response.data[0]
+                    
+                    # Check if entry is expired
+                    created_at_str = entry.get('created_at')
+                    is_expired = False
+                    
+                    if created_at_str:
+                        try:
+                            # Parse the timestamp
+                            if 'Z' in created_at_str:
+                                created_at = datetime.fromisoformat(created_at_str.replace('Z', '+00:00'))
+                            else:
+                                created_at = datetime.fromisoformat(created_at_str)
+                            
+                            # Check TTL
+                            if (datetime.now() - created_at).days >= self.ttl_days:
+                                # Entry expired, delete it
+                                is_expired = True
+                                try:
+                                    self.supabase.table("seba_cache") \
+                                        .delete() \
+                                        .eq("key_hash", cache_key) \
+                                        .execute()
+                                except:
+                                    pass
+                        except Exception:
+                            # If we can't parse date, assume not expired
+                            pass
+                    
+                    if not is_expired:
+                        # Convert to standard format
+                        cached_data = {
+                            'answer': entry['answer'],
+                            'tokens': entry.get('tokens', 0),
+                            'subject': entry.get('subject', ''),
+                            'chapter': entry.get('chapter', ''),
+                            'question': entry.get('question', ''),
+                            'access_count': entry.get('access_count', 0) + 1,
+                            'created_at': entry.get('created_at'),
+                            'last_accessed': datetime.now().isoformat()
+                        }
+                        
+                        # Update access count in Supabase
+                        try:
+                            self.supabase.table("seba_cache") \
+                                .update({
+                                    "last_accessed": datetime.now().isoformat(),
+                                    "access_count": entry.get('access_count', 0) + 1
+                                }) \
+                                .eq("key_hash", cache_key) \
+                                .execute()
+                        except:
+                            pass
+                        
+                        # Store in memory cache for faster access
+                        self.memory_cache[cache_key] = cached_data
+                        
+                        # Limit memory cache size
+                        if len(self.memory_cache) > self.max_memory_entries:
+                            oldest_key = min(self.memory_cache.keys(), 
+                                            key=lambda k: self.memory_cache[k].get('last_accessed', ''))
+                            del self.memory_cache[oldest_key]
+                        
+                        return cached_data
+            except Exception as e:
+                # Silently fail - fall back to memory cache
+                print(f"Supabase get error: {e}")
+                pass
+        
+        return None
+    
+    def set(self, cache_key, data):
+        """Store answer in both Supabase and memory cache"""
+        # Prepare data
+        cache_data = {
+            'answer': data['answer'],
+            'tokens': data.get('tokens', 0),
+            'subject': data.get('subject', ''),
+            'chapter': data.get('chapter', ''),
+            'question': data.get('question', '')[:200],
+            'access_count': 1,
+            'created_at': datetime.now().isoformat(),
+            'last_accessed': datetime.now().isoformat()
+        }
+        
+        # Store in memory cache
+        self.memory_cache[cache_key] = cache_data
+        
+        # Limit memory cache size
+        if len(self.memory_cache) > self.max_memory_entries:
+            oldest_key = min(self.memory_cache.keys(), 
+                            key=lambda k: self.memory_cache[k].get('last_accessed', ''))
+            del self.memory_cache[oldest_key]
+        
+        # Store in Supabase if available
+        if self.supabase:
+            try:
+                self.supabase.table("seba_cache").upsert({
+                    "key_hash": cache_key,
+                    "question": cache_data['question'],
+                    "answer": cache_data['answer'],
+                    "subject": cache_data['subject'],
+                    "chapter": cache_data['chapter'],
+                    "tokens": cache_data['tokens'],
+                    "created_at": cache_data['created_at'],
+                    "last_accessed": cache_data['last_accessed'],
+                    "access_count": cache_data['access_count']
+                }).execute()
+            except Exception as e:
+                # Silently fail - at least we have memory cache
+                print(f"Supabase set error: {e}")
+                pass
+    
+    def _is_valid(self, entry):
+        """Check if cache entry is not expired"""
+        created_at = entry.get('created_at')
+        if isinstance(created_at, str):
+            try:
+                if 'Z' in created_at:
+                    created_at = datetime.fromisoformat(created_at.replace('Z', '+00:00'))
+                else:
+                    created_at = datetime.fromisoformat(created_at)
+            except:
+                return True  # If we can't parse, assume valid
+        
+        if created_at and (datetime.now() - created_at).days < self.ttl_days:
+            return True
+        return False
+    
+    def clear_expired(self):
+        """Clear expired entries from memory cache"""
+        expired_keys = []
+        for key, entry in self.memory_cache.items():
+            if not self._is_valid(entry):
+                expired_keys.append(key)
+        
+        for key in expired_keys:
+            del self.memory_cache[key]
+        
+        return len(expired_keys)
+    
+    def clear_all(self):
+        """Clear all cache entries"""
+        self.memory_cache = {}
+        
+        # Also clear Supabase cache if available
+        if self.supabase:
+            try:
+                # Delete entries older than 1 day (safer than deleting all)
+                self.supabase.table("seba_cache") \
+                    .delete() \
+                    .lt("created_at", f"now() - interval '1 day'") \
+                    .execute()
+            except:
+                pass
+    
+    def get_stats(self):
+        """Get cache statistics"""
+        # Memory cache stats
+        memory_entries = len(self.memory_cache)
+        memory_tokens = sum(entry.get('tokens', 0) for entry in self.memory_cache.values())
+        
+        # Try to get Supabase stats
+        supabase_entries = 0
+        supabase_tokens = 0
+        
+        if self.supabase:
+            try:
+                # Get count from Supabase
+                response = self.supabase.table("seba_cache") \
+                    .select("count", count="exact") \
+                    .execute()
+                
+                supabase_entries = response.count or 0
+                
+                # Get total tokens (might be heavy, so approximate)
+                if supabase_entries > 0:
+                    response = self.supabase.table("seba_cache") \
+                        .select("tokens") \
+                        .limit(100) \
+                        .execute()
+                    
+                    supabase_tokens = sum(entry.get('tokens', 0) for entry in response.data)
+            except:
+                pass
+        
+        total_entries = memory_entries + supabase_entries
+        total_tokens = memory_tokens + supabase_tokens
+        
+        return {
+            'total_entries': total_entries,
+            'memory_entries': memory_entries,
+            'supabase_entries': supabase_entries,
+            'total_saved_tokens': total_tokens,
+            'ttl_days': self.ttl_days,
+            'storage_mode': 'Supabase + Memory' if self.supabase else 'Memory Only',
+            'supabase_connected': self.supabase is not None
+        }
+
+# ===============================
+# SUPABASE SUBSCRIPTION MANAGER
+# ===============================
+class SupabaseSubscriptionManager:
+    def __init__(self, supabase_client):
+        self.supabase = supabase_client
+    
+    def create_user(self, user_id, email=None, phone=None):
+        """Create a new user with free plan"""
+        try:
+            # Create user
+            user_data = {
+                "user_id": user_id,
+                "email": email,
+                "phone": phone,
+                "is_active": True
+            }
+            
+            # Remove None values
+            user_data = {k: v for k, v in user_data.items() if v is not None}
+            
+            # Upsert user (insert or update if exists)
+            response = self.supabase.table("seba_users").upsert(user_data).execute()
+            
+            # Create free subscription (30 questions lifetime)
+            subscription_data = {
+                "user_id": user_id,
+                "plan_type": "free",
+                "price_paid": 0.00,
+                "start_date": datetime.now().isoformat(),
+                "end_date": (datetime.now() + timedelta(days=3650)).isoformat(),  # 10 years
+                "total_questions": 30,
+                "questions_used": 0,
+                "daily_limit": 1,
+                "is_active": True
+            }
+            
+            response = self.supabase.table("seba_subscriptions").upsert(subscription_data).execute()
+            
+            return True
+        except Exception as e:
+            print(f"Error creating user: {e}")
+            return False
+    
+    def get_user_plan(self, user_id):
+        """Get user's current subscription plan"""
+        try:
+            response = self.supabase.table("seba_subscriptions") \
+                .select("*") \
+                .eq("user_id", user_id) \
+                .eq("is_active", True) \
+                .gte("end_date", datetime.now().isoformat()) \
+                .order("start_date", desc=True) \
+                .limit(1) \
+                .execute()
+            
+            if response.data and len(response.data) > 0:
+                plan = response.data[0]
+                return {
+                    'plan_type': plan['plan_type'],
+                    'total_questions': plan['total_questions'],
+                    'questions_used': plan['questions_used'],
+                    'daily_limit': plan['daily_limit'],
+                    'end_date': plan['end_date'],
+                    'questions_remaining': plan['total_questions'] - plan['questions_used'],
+                    'is_active': True,
+                    'plan_id': plan['id']
+                }
+            
+            # No active subscription found
+            return None
+            
+        except Exception as e:
+            print(f"Error getting user plan: {e}")
+            return None
+    
+    def get_or_create_user_plan(self, user_id, email=None, phone=None):
+        """Get user plan, create if doesn't exist"""
+        plan = self.get_user_plan(user_id)
+        
+        if plan is None:
+            # Create user with free plan
+            self.create_user(user_id, email, phone)
+            plan = self.get_user_plan(user_id)
+        
+        return plan
+    
+    def can_ask_question(self, user_id):
+        """Check if user can ask a new question"""
+        try:
+            # Get user's plan
+            plan = self.get_user_plan(user_id)
+            
+            if not plan:
+                return False, "No subscription found. Please sign up."
+            
+            # Check if subscription expired
+            try:
+                end_date_str = plan['end_date']
+                # Handle different timestamp formats
+                if 'Z' in end_date_str:
+                    end_date = datetime.fromisoformat(end_date_str.replace('Z', '+00:00'))
+                else:
+                    end_date = datetime.fromisoformat(end_date_str)
+                
+                if datetime.now() > end_date:
+                    return False, "Subscription expired. Please renew."
+            except Exception as date_error:
+                print(f"Date parsing error: {date_error}")
+                # Continue if date parsing fails
+            
+            # Check monthly/lifetime quota
+            if plan['questions_used'] >= plan['total_questions']:
+                if plan['plan_type'] == 'free':
+                    return False, "Free quota exhausted. Please upgrade to Pro."
+                else:
+                    return False, f"Monthly quota ({plan['total_questions']}) exhausted. Renew or upgrade."
+            
+            # For all plans, check daily limit
+            today_start = datetime.now().replace(hour=0, minute=0, second=0, microsecond=0)
+            today_end = datetime.now().replace(hour=23, minute=59, second=59, microsecond=999999)
+            
+            # Count today's non-cached questions
+            response = self.supabase.table("seba_usage_logs") \
+                .select("id", count="exact") \
+                .eq("user_id", user_id) \
+                .eq("cached", False) \
+                .gte("timestamp", today_start.isoformat()) \
+                .lt("timestamp", today_end.isoformat()) \
+                .execute()
+            
+            today_used = response.count or 0
+            
+            if today_used >= plan['daily_limit']:
+                return False, f"Daily limit ({plan['daily_limit']}) reached. Try again tomorrow."
+            
+            return True, "Can ask question"
+            
+        except Exception as e:
+            print(f"Error checking question allowance: {e}")
+            # For now, allow questions if check fails (fail-open)
+            return True, "Proceeding with question..."
+    
+    def log_question(self, user_id, question_hash, subject="", chapter="", tokens_used=0, cached=False):
+        """Log a question usage"""
+        try:
+            # Get current plan
+            plan = self.get_user_plan(user_id)
+            
+            if not plan:
+                plan_type = "free"
+            else:
+                plan_type = plan['plan_type']
+            
+            # Log usage
+            log_data = {
+                "user_id": user_id,
+                "question_hash": question_hash,
+                "subject": subject[:100] if subject else "",
+                "chapter": chapter[:100] if chapter else "",
+                "tokens_used": tokens_used,
+                "cached": cached,
+                "plan_type": plan_type
+            }
+            
+            response = self.supabase.table("seba_usage_logs").insert(log_data).execute()
+            
+            # Update subscription usage (only for non-cached questions)
+            if not cached and plan and plan.get('plan_id'):
+                # Increment questions_used
+                new_used = plan['questions_used'] + 1
+                self.supabase.table("seba_subscriptions") \
+                    .update({"questions_used": new_used}) \
+                    .eq("id", plan['plan_id']) \
+                    .execute()
+            
+            return True
+        except Exception as e:
+            print(f"Error logging question: {e}")
+            return False
+    
+    def upgrade_plan(self, user_id, plan_type, payment_id=None):
+        """Upgrade user's subscription plan"""
+        plans = {
+            'pro_monthly': {
+                'price': 50,
+                'questions': 450,
+                'daily_limit': 15,
+                'days': 30
+            },
+            'pro_plus': {
+                'price': 100,
+                'questions': 1200,
+                'daily_limit': 40,
+                'days': 30
+            }
+        }
+        
+        if plan_type not in plans:
+            return False, "Invalid plan type"
+        
+        plan = plans[plan_type]
+        
+        try:
+            # Deactivate current active subscription
+            self.supabase.table("seba_subscriptions") \
+                .update({"is_active": False}) \
+                .eq("user_id", user_id) \
+                .eq("is_active", True) \
+                .execute()
+            
+            # Create new subscription
+            subscription_data = {
+                "user_id": user_id,
+                "plan_type": plan_type,
+                "price_paid": plan['price'],
+                "start_date": datetime.now().isoformat(),
+                "end_date": (datetime.now() + timedelta(days=plan['days'])).isoformat(),
+                "total_questions": plan['questions'],
+                "questions_used": 0,
+                "daily_limit": plan['daily_limit'],
+                "is_active": True,
+                "payment_id": payment_id
+            }
+            
+            response = self.supabase.table("seba_subscriptions").insert(subscription_data).execute()
+            
+            return True, f"Upgraded to {plan_type.replace('_', ' ').title()} successfully!"
+            
+        except Exception as e:
+            return False, f"Error: {str(e)}"
+    
+    def get_user_stats(self, user_id):
+        """Get user statistics"""
+        try:
+            # Get today's usage
+            today_start = datetime.now().replace(hour=0, minute=0, second=0, microsecond=0)
+            today_end = datetime.now().replace(hour=23, minute=59, second=59, microsecond=999999)
+            
+            response = self.supabase.table("seba_usage_logs") \
+                .select("id", count="exact") \
+                .eq("user_id", user_id) \
+                .eq("cached", False) \
+                .gte("timestamp", today_start.isoformat()) \
+                .lt("timestamp", today_end.isoformat()) \
+                .execute()
+            
+            today_used = response.count or 0
+            
+            # Get total usage
+            response = self.supabase.table("seba_usage_logs") \
+                .select("id", count="exact") \
+                .eq("user_id", user_id) \
+                .eq("cached", False) \
+                .execute()
+            
+            total_used = response.count or 0
+            
+            # Get cached usage
+            response = self.supabase.table("seba_usage_logs") \
+                .select("id", count="exact") \
+                .eq("user_id", user_id) \
+                .eq("cached", True) \
+                .execute()
+            
+            cached_used = response.count or 0
+            
+            return {
+                'today_used': today_used,
+                'total_used': total_used,
+                'cached_used': cached_used
+            }
+            
+        except Exception as e:
+            print(f"Error getting user stats: {e}")
+            return {'today_used': 0, 'total_used': 0, 'cached_used': 0}
+
+# ===============================
+# API KEY HANDLING
+# ===============================
+# Get API key from environment variable
+api_key = os.environ.get("DEEPSEEK_API_KEY", "")
+
+# Page config - must be first Streamlit command
+st.set_page_config(
+    page_title="SEBA দশম শ্ৰেণীৰ AI টিউটাৰ",
+    page_icon="🎓",
+    layout="wide",
+    initial_sidebar_state="collapsed"
+)
+
+# Enhanced CSS with streaming and focus features - FIXED LATEX RENDERING
+st.markdown("""
+<style>
+    /* Assamese-friendly fonts */
+    @import url('https://fonts.googleapis.com/css2?family=Noto+Sans+Bengali:wght@400;500;600;700;800&family=Hind+Siliguri:wght@300;400;500;600;700&display=swap');
+    
+    * {
+        font-family: 'Noto Sans Bengali', 'Hind Siliguri', 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
+    }
+
+    /* Reduced spacing header */
+    .header-container {
+        background: linear-gradient(135deg, #0d47a1 0%, #1565c0 50%, #1976d2 100%);
+        padding: 1.25rem;
+        border-radius: 15px;
+        margin-bottom: 1rem;
+        color: white;
+        position: relative;
+        overflow: hidden;
+        border: 1px solid rgba(255,255,255,0.1);
+        box-shadow: 0 5px 15px rgba(13,71,161,0.2);
+    }
+
+    /* The top rainbow line */
+    .header-container::before {
+        content: '';
+        position: absolute;
+        top: 0;
+        left: 0;
+        right: 0;
+        height: 3px;
+        background: linear-gradient(90deg, #FF5722, #FF9800, #4CAF50);
+    }
+
+    /* Header text */
+    .header-container h1 {
+        color: #ffffff;
+        font-size: 1.5rem;
+        font-weight: 800;
+        text-shadow: 0px 1px 3px rgba(0,0,0,0.5);
+        margin: 0;
+        line-height: 1.2;
+    }
+
+    .header-container p {
+        color: #f6f9ff;
+        font-weight: 600;
+        font-size: 0.95rem;
+        opacity: 1 !important;
+        text-shadow: 0px 1px 2px rgba(0,0,0,0.4);
+        margin-top: .2rem;
+    }
+
+    .subject-card {
+        background: linear-gradient(145deg, #ffffff 0%, #f0f7ff 100%);
+        padding: 0.75rem;
+        border-radius: 10px;
+        box-shadow: 0 3px 8px rgba(0, 0, 0, 0.08);
+        border-left: 4px solid #2196F3;
+        margin: 0.5rem 0;
+        transition: all 0.3s ease;
+        border: 1px solid #e3f2fd;
+    }
+    
+    .subject-card:hover {
+        transform: translateY(-3px);
+        box-shadow: 0 5px 12px rgba(33, 150, 243, 0.15);
+    }
+    
+    .answer-box {
+        background: linear-gradient(145deg, #f8fdff 0%, #ffffff 100%);
+        padding: 1rem;
+        border-radius: 10px;
+        border: 1px solid #e1f5fe;
+        margin: 0.75rem 0;
+        box-shadow: 0 3px 8px rgba(0, 0, 0, 0.05);
+        position: relative;
+    }
+    
+    .stButton > button {
+        background: linear-gradient(135deg, #FF5722 0%, #FF9800 100%);
+        color: white;
+        border: none;
+        padding: 0.4rem 1rem;
+        border-radius: 8px;
+        font-weight: 600;
+        font-size: 0.9rem;
+        transition: all 0.3s;
+        box-shadow: 0 2px 6px rgba(255, 87, 34, 0.3);
+    }
+    
+    .stButton > button:hover {
+        transform: translateY(-1px);
+        box-shadow: 0 3px 9px rgba(255, 87, 34, 0.4);
+    }
+    
+    .sidebar-section {
+        background: linear-gradient(145deg, #f8f9fa 0%, #e3f2fd 100%);
+        padding: 0.75rem;
+        border-radius: 10px;
+        margin-bottom: 0.75rem;
+        border: 1px solid #bbdefb;
+        box-shadow: 0 2px 6px rgba(0, 0, 0, 0.05);
+    }
+    
+    .assamese-highlight {
+        background: linear-gradient(120deg, #FFF176 0%, #FFEB3B 100%);
+        background-repeat: no-repeat;
+        background-size: 100% 0.3em;
+        background-position: 0 90%;
+        padding: 0.1rem 0.2rem;
+        font-weight: 700;
+        color: #FF6F00;
+    }
+    
+    .assamese-text {
+        font-family: 'Noto Sans Bengali', sans-serif;
+        font-weight: 500;
+        color: #0d47a1;
+        line-height: 1.4;
+    }
+    
+    .assamese-title {
+        font-family: 'Noto Sans Bengali', sans-serif;
+        font-weight: 700;
+        color: #1565c0;
+    }
+    
+    /* Chat bubble styling */
+    .user-bubble {
+        background: linear-gradient(135deg, #2196F3 0%, #0d47a1 100%) !important;
+        color: white;
+        padding: 0.5rem 0.75rem;
+        border-radius: 12px 12px 0 12px;
+        max-width: 80%;
+        box-shadow: 0 2px 6px rgba(33, 150, 243, 0.2);
+        margin-left: auto;
+    }
+    
+    .ai-bubble {
+        background: linear-gradient(135deg, #f5f5f5 0%, #ffffff 100%) !important;
+        padding: 0.75rem;
+        border-radius: 12px 12px 12px 0;
+        border: 1px solid #e0e0e0;
+        box-shadow: 0 2px 6px rgba(0,0,0,0.05);
+    }
+    
+    /* Chat container */
+    .chat-container {
+        margin-bottom: 1rem;
+        scroll-margin-top: 20px;
+    }
+    
+    .chat-message {
+        margin-bottom: 0.75rem;
+        animation: fadeIn 0.3s ease-in;
+    }
+    
+    @keyframes fadeIn {
+        from { opacity: 0; transform: translateY(5px); }
+        to { opacity: 1; transform: translateY(0); }
+    }
+    
+    /* LaTeX equation styling - FIXED VERSION */
+    .katex {
+        font-size: 1.1em !important;
+        padding: 0.2rem 0.5rem !important;
+        background: rgba(33, 150, 243, 0.1) !important;
+        border-radius: 4px !important;
+        margin: 0.3rem 0.1rem !important;
+        display: inline-block !important;
+        vertical-align: middle !important;
+    }
+    
+    .katex-display {
+        margin: 1rem 0 !important;
+        padding: 1rem !important;
+        background: linear-gradient(145deg, #f0f7ff 0%, #e3f2fd 100%) !important;
+        border-radius: 8px !important;
+        border-left: 4px solid #2196F3 !important;
+        overflow-x: auto !important;
+        overflow-y: hidden !important;
+        text-align: center !important;
+    }
+    
+    .katex-display .katex {
+        background: transparent !important;
+        font-size: 1.2em !important;
+        padding: 0.5rem !important;
+    }
+    
+    /* Ensure LaTeX works inside streaming text */
+    .streaming-text .katex {
+        animation: none !important;
+        background: rgba(33, 150, 243, 0.05) !important;
+    }
+    
+    .streaming-text .katex-display {
+        margin: 0.5rem 0 !important;
+        padding: 0.8rem !important;
+    }
+    
+    /* Stop cursor animation on LaTeX elements */
+    .katex::after {
+        content: '' !important;
+        animation: none !important;
+    }
+    
+    /* Control panel styling */
+    .control-panel {
+        background: linear-gradient(145deg, #f8f9fa 0%, #e3f2fd 100%);
+        padding: 1rem;
+        border-radius: 15px;
+        margin: 1rem 0;
+        border: 1px solid #bbdefb;
+        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
+    }
+    
+    /* Enhanced streaming text animation */
+    .streaming-text {
+        display: inline-block;
+        overflow: hidden;
+        white-space: pre-wrap;
+    }
+    
+    .streaming-text::after {
+        content: '▋';
+        animation: cursor-blink 1s infinite;
+        font-weight: bold;
+        color: #2196F3;
+    }
+    
+    .streaming-character {
+        display: inline-block;
+        animation: charPop 0.1s ease-out;
+    }
+    
+    @keyframes charPop {
+        0% { opacity: 0; transform: translateY(2px); }
+        100% { opacity: 1; transform: translateY(0); }
+    }
+    
+    @keyframes cursor-blink {
+        0%, 100% { opacity: 1; }
+        50% { opacity: 0; }
+    }
+    
+    /* Enhanced progress indicator */
+    .progress-indicator {
+        display: flex;
+        align-items: center;
+        justify-content: center;
+        gap: 0.5rem;
+        color: #0d47a1;
+        font-weight: 600;
+        padding: 0.5rem;
+        min-height: 100px;
+    }
+    
+    .thinking-dots {
+        display: flex;
+        gap: 0.2rem;
+    }
+    
+    .thinking-dots span {
+        width: 0.4rem;
+        height: 0.4rem;
+        border-radius: 50%;
+        background: #2196F3;
+        animation: thinking 1.4s infinite ease-in-out;
+    }
+    
+    .thinking-dots span:nth-child(1) { animation-delay: -0.32s; }
+    .thinking-dots span:nth-child(2) { animation-delay: -0.16s; }
+    .thinking-dots span:nth-child(3) { animation-delay: 0s; }
+    
+    @keyframes thinking {
+        0%, 80%, 100% { transform: scale(0); }
+        40% { transform: scale(1); }
+    }
+    
+    /* Cache indicator styling */
+    .cache-badge {
+        background: linear-gradient(135deg, #4CAF50 0%, #2E7D32 100%);
+        color: white;
+        padding: 0.2rem 0.5rem;
+        border-radius: 12px;
+        font-size: 0.75rem;
+        font-weight: 600;
+        display: inline-flex;
+        align-items: center;
+        gap: 0.2rem;
+    }
+    
+    /* Enhanced answer container styling */
+    .answer-container {
+        background: linear-gradient(135deg, #f8fdff 0%, #ffffff 100%);
+        border-radius: 10px;
+        padding: 1rem;
+        margin: 1rem 0;
+        border: 1px solid #e1f5fe;
+        box-shadow: 0 3px 8px rgba(0, 0, 0, 0.05);
+        animation: slideIn 0.3s ease-out;
+    }
+    
+    @keyframes slideIn {
+        from { opacity: 0; transform: translateY(10px); }
+        to { opacity: 1; transform: translateY(0); }
+    }
+    
+    /* Highlight animation for new answers */
+    @keyframes highlightPulse {
+        0% { box-shadow: 0 0 0 0 rgba(33, 150, 243, 0.4); }
+        70% { box-shadow: 0 0 0 10px rgba(33, 150, 243, 0); }
+        100% { box-shadow: 0 0 0 0 rgba(33, 150, 243, 0); }
+    }
+    
+    .highlight-answer {
+        animation: highlightPulse 1.5s ease-in-out;
+    }
+    
+    /* Focus container for auto-scroll */
+    .focus-container {
+        scroll-margin-top: 100px;
+    }
+    
+    /* Responsive adjustments */
+    @media (max-width: 768px) {
+        .header-container {
+            padding: 0.75rem;
+        }
+        .subject-card {
+            padding: 0.5rem;
+        }
+        .user-bubble, .ai-bubble {
+            max-width: 90%;
+        }
+        .control-panel {
+            padding: 0.75rem;
+        }
+    }
+    
+    /* Subscription banner styling */
+    .subscription-banner {
+        padding: 0.75rem 1rem;
+        border-radius: 10px;
+        margin: 0.5rem 0 1.5rem 0;
+        border-left: 5px solid;
+        box-shadow: 0 3px 10px rgba(0,0,0,0.1);
+        color: white;
+    }
+    
+    .subscription-banner strong {
+        font-size: 1rem;
+    }
+    
+    .subscription-banner .usage-stats {
+        font-size: 0.85rem;
+        opacity: 0.9;
+    }
+    
+    .subscription-banner .upgrade-btn {
+        background: rgba(255,255,255,0.2);
+        padding: 0.3rem 0.8rem;
+        border-radius: 5px;
+        font-size: 0.85rem;
+        cursor: pointer;
+    }
+</style>
+""", unsafe_allow_html=True)
+
+# ===============================
+# HELPER FUNCTIONS - FIXED CACHE KEY
+# ===============================
+def create_cache_key(question, subject, chapter_name):
+    """Create a unique cache key for the question"""
+    # Normalize the question more aggressively for better cache matching
+    normalized_question = question.strip().lower()
+    
+    # Remove extra whitespace
+    normalized_question = re.sub(r'\s+', ' ', normalized_question)
+    
+    # Remove punctuation that might vary
+    normalized_question = re.sub(r'[^\w\s\u0980-\u09FF]', '', normalized_question)
+    
+    normalized_question = normalized_question[:200]
+    
+    # Normalize subject and chapter
+    # Take only the main subject name (before parentheses)
+    normalized_subject = subject.split('(')[0].strip() if '(' in subject else subject
+    # Take only chapter number/name before colon
+    normalized_chapter = chapter_name.split(':')[0].strip() if ':' in chapter_name else chapter_name
+    
+    key_string = f"{normalized_subject}|{normalized_chapter}|{normalized_question}"
+    cache_key = hashlib.md5(key_string.encode()).hexdigest()
+    
+    return cache_key
+
+def get_question_guidance(question, subject, chapter_name):
+    question_lower = question.lower()
+    
+    simple_keywords = [
+        "সংজ্ঞা", "কি", "কাক কয়", "মানে", "definition", "what is", 
+        "নাম", "কেইটা", "কিমান", "count", "number", "কি নাম", "কাক বোলে"
+    ]
+    
+    moderate_keywords = [
+        "কেনেকৈ", "কেনেকুৱা", "কিয়", "বুজাই দিয়ক", "explain", "how", 
+        "why", "difference", "পাৰ্থক্য", "উদাহৰণ", "example", "সমাধান", 
+        "solve", "কোনবোৰ", "তুলনা", "compare", "সাদৃশ্য", "similarity"
+    ]
+    
+    complex_keywords = [
+        "বিশ্লেষণ", "আলোচনা", "মূল্যায়ন", "বৰ্ণনা", "discuss", 
+        "analyze", "evaluate", "describe", "প্ৰমাণ", "prove", 
+        "সমাধান কৰি দেখুৱাওক", "solve and show", "step by step",
+        "ধাপে ধাপে", "সম্পূৰ্ণ", "সম্পূৰ্ণ বিৱৰণ", "full explanation",
+        "সবিশেষ", "in detail", "detailed", "সবিস্তাৰে"
+    ]
+    
+    guidance_text = ""
+    
+    if "📐 গণিত" in subject:
+        guidance_text = "গণিতৰ সমস্যাৰ বাবে ধাপে ধা��ে সমাধান দিব লাগে। "
+    elif "🔬 বিজ্ঞান" in subject:
+        guidance_text = "বিজ্ঞানৰ উত্তৰ বৈজ্ঞানিকভাৱে সঠিক হ'ব লাগে। "
+    elif "🌍 সমাজ বিজ্ঞান" in subject:
+        guidance_text = "তথ্য সঠিক আৰু বিশ্লেষণাত্মক হ'ব লাগে। "
+    
+    if any(keyword in question_lower for keyword in complex_keywords):
+        return f"{guidance_text} প্ৰশ্নটো জটিল, গতিকে বিশদ উত্তৰ দিবা।"
+    elif any(keyword in question_lower for keyword in moderate_keywords):
+        return f"{guidance_text} প্ৰশ্নটো মধ্যমীয়া, গতিকে সম্পূৰ্ণ উত্তৰ দিবা।"
+    elif any(keyword in question_lower for keyword in simple_keywords):
+        return f"{guidance_text} প্ৰশ্নটো সৰল, গতিকে সংক্ষিপ্ত উত্তৰ দিবা।"
+    else:
+        return f"{guidance_text} প্ৰশ্নৰ প্ৰকৃতি অনুসৰি উত্তৰ দিবা।"
+
+def get_subject_prompt(subject, chapter_name, question):
+    if subject not in SUBJECT_PROMPTS:
+        subject = "📐 গণিত (Mathematics)"
+    
+    prompt_template = SUBJECT_PROMPTS[subject]
+    base_prompt = prompt_template["base_prompt"].format(chapter_name=chapter_name)
+    guidance = prompt_template["guidance"]
+    
+    if subject == "📐 গণিত (Mathematics)" or subject == "🔬 বিজ্ঞান (Science)":
+        latex_instruction = "\n\n**গুৰুত্বপূৰ্ণ**: সকলো গাণিতিক সূত্ৰ, সমীকৰণ LaTeX ফৰ্মেটত দিবা ($ চিহ্নৰ মাজত)।"
+    else:
+        latex_instruction = ""
+    
+    question_guidance = get_question_guidance(question, subject, chapter_name)
+    
+    full_prompt = f"""{base_prompt}
+
+{guidance}{latex_instruction}
+
+**উত্তৰৰ নিৰ্দেশনা:**
+{question_guidance}
+**উত্তৰ যিমান দৰকাৰী সিমান দীঘল হ'ব লাগে।**
+**শুদ্ধ অসমীয়া ব্যৱহাৰ কৰিবা, বাংলা শব্দ বা বৰ্ণমালা ব্যৱহাৰ নকৰিবা**
+
+**ছাত্ৰক মাতি লওঁ:**
+"বন্ধু, এইটো এনেদৰে বুজিব লাগে..."
+"চিন্তা নকৰিব, এইটো সহজ..."
+
+এতিয়া এই প্ৰশ্নটোৰ উত্তৰ দিয়া: {question}"""
+    
+    return full_prompt
+
+# ===============================
+# FIXED: STREAMING TEXT WITH LATEX SUPPORT
+# ===============================
+def stream_text_with_animation(text, placeholder, speed=10):
+    """
+    Display text with streaming animation (character by character)
+    WITH PROPER LATEX SUPPORT
+    """
+    display_text = ""
+    
+    # Split into characters for animation
+    for i, char in enumerate(text):
+        display_text += char
+        
+        # Update streaming display with better animation
+        placeholder.markdown(
+            f'<div class="streaming-text">{display_text}</div>',
+            unsafe_allow_html=True
+        )
+        
+        # Control speed (except for whitespace)
+        if char not in [' ', '\n']:
+            time.sleep(1/speed)
+    
+    # CRITICAL FIX: After completion, clear and re-render with proper LaTeX support
+    placeholder.empty()  # Clear the streaming placeholder
+    # Re-render the complete text with proper markdown/LaTeX support
+    placeholder.markdown(text)
+    
+    return True
+
+# ===============================
+# ENHANCED: STREAMLIT STREAMING RESPONSE FUNCTION
+# ===============================
+def stream_deepseek_response(prompt, question, subject, chapter_name):
+    headers = {
+        "Authorization": f"Bearer {api_key}",
+        "Content-Type": "application/json"
+    }
+    
+    payload = {
+        "model": "deepseek-chat",
+        "messages": [
+            {"role": "system", "content": "তুমি এজন বিশেষজ্ঞ SEBA দশম শ্ৰেণীৰ শিক্ষক।"},
+            {"role": "user", "content": prompt}
+        ],
+        "temperature": 0.3,
+        "stream": True
+    }
+    
+    try:
+        # Make streaming request
+        response = requests.post(
+            "https://api.deepseek.com/v1/chat/completions",
+            headers=headers,
+            json=payload,
+            stream=True,
+            timeout=180
+        )
+        
+        if response.status_code == 200:
+            full_response = ""
+            tokens_used = 0
+            
+            # Create a placeholder for streaming text
+            streaming_placeholder = st.empty()
+            
+            # Process streaming response
+            for line in response.iter_lines():
+                if line:
+                    line = line.decode('utf-8')
+                    if line.startswith('data: '):
+                        data = line[6:]  # Remove 'data: ' prefix
+                        if data == '[DONE]':
+                            break
+                        
+                        try:
+                            chunk = json.loads(data)
+                            if 'choices' in chunk and len(chunk['choices']) > 0:
+                                delta = chunk['choices'][0].get('delta', {})
+                                if 'content' in delta:
+                                    content = delta['content']
+                                    full_response += content
+                                    
+                                    # Update streaming display with better animation
+                                    streaming_placeholder.markdown(
+                                        f'<div class="streaming-text">{full_response}</div>',
+                                        unsafe_allow_html=True
+                                    )
+                                
+                                # Track tokens
+                                if 'usage' in chunk:
+                                    tokens_used = chunk['usage'].get('total_tokens', 0)
+                        except json.JSONDecodeError:
+                            continue
+            
+            # Clear streaming cursor after completion and re-render with LaTeX support
+            streaming_placeholder.empty()
+            
+            # Render the final answer with proper LaTeX support
+            st.markdown(full_response)
+            
+            # Store the complete response
+            st.session_state.last_answer = full_response
+            st.session_state.tokens_used = tokens_used
+            
+            # Save to cache using manager
+            cache_key = create_cache_key(question, subject, chapter_name)
+            st.session_state.cache_manager.set(cache_key, {
+                'answer': full_response,
+                'tokens': tokens_used,
+                'subject': subject,
+                'chapter': chapter_name,
+                'question': question[:200]
+            })
+            
+            # Add to history
+            history_entry = {
+                'subject': subject,
+                'chapter': chapter_name,
+                'question': question[:100],
+                'timestamp': datetime.now().strftime("%H:%M"),
+                'tokens': tokens_used,
+                'cached': False
+            }
+            st.session_state.history.append(history_entry)
+            
+            # Add JavaScript to scroll to answer and highlight it
+            st.markdown("""
+            <script>
+            // Scroll to answer container smoothly
+            setTimeout(function() {
+                const answerContainers = document.querySelectorAll('.chat-container');
+                if (answerContainers.length > 0) {
+                    const lastAnswer = answerContainers[answerContainers.length - 1];
+                    lastAnswer.scrollIntoView({ behavior: 'smooth', block: 'center' });
+                    
+                    // Add highlight animation
+                    lastAnswer.classList.add('highlight-answer');
+                    setTimeout(() => {
+                        lastAnswer.classList.remove('highlight-answer');
+                    }, 1500);
+                }
+            }, 100);
+            </script>
+            """, unsafe_allow_html=True)
+            
+        else:
+            st.error(f"API ত্ৰুটি {response.status_code}: {response.text}")
+            
+    except Exception as e:
+        st.error(f"সংযোগ ত্ৰুটি: {str(e)}")
+
+# ===============================
+# FIXED: CACHE ANSWER WITH THINKING ANIMATION
+# ===============================
+def display_cached_answer_with_animation(cached_data, question, subject, chapter_name, cache_source):
+    """
+    Display cached answer with thinking animation and streaming effect
+    """
+    # Display user question
+    st.markdown(f"""
+    <div class="chat-container">
+        <div style="display: flex; justify-content: flex-end; margin-bottom: 0.3rem;">
+            <div class="user-bubble">
+                <div style="font-weight: 600; margin-bottom: 0.2rem;">👤 আপুনি:</div>
+                <div>{question[:200]}{'...' if len(question) > 200 else ''}</div>
+            </div>
+        </div>
+    """, unsafe_allow_html=True)
+    
+    # AI answer header with thinking animation initially
+    st.markdown(f"""
+        <div style="display: flex; align-items: flex-start; margin-bottom: 0.3rem;">
+            <div style="margin-right: 0.5rem; font-size: 1.2rem;">🤖</div>
+            <div style="flex: 1;">
+                <div class="ai-bubble">
+                    <div style="display: flex; align-items: center; margin-bottom: 0.5rem; padding-bottom: 0.5rem; border-bottom: 2px solid #4CAF50;">
+                        <div style="display: flex; align-items: center;">
+                            <div style="background: #4CAF50; color: white; padding: 0.2rem 0.5rem; border-radius: 8px; 
+                                        font-weight: 600; font-size: 0.8rem; margin-right: 0.5rem;">
+                                <span style="margin-right: 0.3rem;">⚡</span> Cached Answer
+                            </div>
+                            <div style="font-weight: 600; color: #0d47a1; font-size: 0.9rem;">
+                                {cached_data.get('subject', subject)} • {cached_data.get('chapter', chapter_name)}
+                            </div>
+                        </div>
+                        <div style="font-size: 0.75rem; color: #666; background: #f1f8e9; padding: 0.2rem 0.5rem; border-radius: 4px;">
+                            <span style="margin-right: 0.3rem;">💾</span> From {cache_source}
+                        </div>
+                    </div>
+                    <div id="cached-answer-content" style="color: #333; line-height: 1.5; font-size: 0.95rem;">
+                        <!-- Answer will be streamed here -->
+                    </div>
+                </div>
+            </div>
+        </div>
+    </div>
+    """, unsafe_allow_html=True)
+    
+    # Create a placeholder for the thinking animation
+    thinking_placeholder = st.empty()
+    
+    # Show thinking animation for 1 second
+    thinking_placeholder.markdown("""
+    <div class="progress-indicator">
+        <span>উত্তৰ প্ৰস্তুত কৰি আছো...</span>
+        <div class="thinking-dots">
+            <span></span>
+            <span></span>
+            <span></span>
+        </div>
+    </div>
+    """, unsafe_allow_html=True)
+    
+    # Wait for 1 second to simulate thinking
+    time.sleep(1)
+    
+    # Clear thinking animation
+    thinking_placeholder.empty()
+    
+    # Create a new placeholder for streaming answer
+    answer_placeholder = st.empty()
+    
+    # Stream the cached answer with animation (USING FIXED FUNCTION)
+    stream_text_with_animation(cached_data['answer'], answer_placeholder, speed=20)
+    
+    # Show token usage
+    if cached_data.get('tokens', 0) > 0:
+        st.caption(f"📊 Original token cost (saved): {cached_data['tokens']:,} tokens")
+    
+    # Add JavaScript to scroll to answer and highlight it
+    st.markdown("""
+    <script>
+    // Scroll to answer container smoothly
+    setTimeout(function() {
+        const answerContainers = document.querySelectorAll('.chat-container');
+        if (answerContainers.length > 0) {
+            const lastAnswer = answerContainers[answerContainers.length - 1];
+            lastAnswer.scrollIntoView({ behavior: 'smooth', block: 'center' });
+            
+            // Add highlight animation
+            lastAnswer.classList.add('highlight-answer');
+            setTimeout(() => {
+                lastAnswer.classList.remove('highlight-answer');
+            }, 1500);
+        }
+    }, 100);
+    </script>
+    """, unsafe_allow_html=True)
+    
+    # Add to history
+    history_entry = {
+        'subject': subject,
+        'chapter': chapter_name,
+        'question': question[:100],
+        'timestamp': datetime.now().strftime("%H:%M"),
+        'tokens': cached_data['tokens'],
+        'cached': True,
+        'cache_source': cache_source
+    }
+    st.session_state.history.append(history_entry)
+
+# ===============================
+# SEBA CURRICULUM DATA
+# ===============================
+SEBA_CURRICULUM = {
+    "📐 গণিত (Mathematics)": {
+        "অধ্যায় ১": "বাস্তৱ সংখ্যা (Real Numbers)",
+        "অধ্যায় ২": "বহুপদ (Polynomials)",
+        "অধ্যায় ৩": "দ্বিঘাত সমীকৰণ (Quadratic Equations)",
+        "অধ্যায় ৪": "সামান্তৰিক শ্রেণী (Arithmetic Progressions)",
+        "অধ্যায় ৫": "ত্ৰিভুজ (Triangles)",
+        "অধ্যায় ৬": "ত্রিকোণমিতি (Trigonometry)",
+        "অধ্যায় ৭": "বৃত্ত (Circles)",
+        "অধ্যায় ৮": "স্থানাঙ্ক জ্যামিতি (Coordinate Geometry)",
+        "অধ্যায় ৯": "ক্ষেত্রফল আৰু আয়তন (Areas and Volumes)",
+        "অধ্যায় ১০": "পৰিসংখ্যা (Statistics)",
+        "অধ্যায় ১১": "সম্ভাৱিতা (Probability)"
+    },
+    "🔬 বিজ্ঞান (Science)": {
+        "অধ্যায় ১": "ৰাসায়নিক বিক্রিয়া আৰু সমীকৰণ",
+        "অধ্যায় ২": "এছিড, ক্ষাৰক আৰু লৱণ",
+        "অধ্যায় ৩": "ধাতু আৰু অধাতু",
+        "অধ্যায় ৪": "কার্বন আৰু তা�� যৌগ",
+        "অধ্যায় ৫": "পৰ্যাবৃত্ত শ্রেণীবিভাজন",
+        "অধ্যায় ৬": "জীৱন প্ৰক্ৰিয়া",
+        "অধ্যায় ৭": "নিয়ন্ত্ৰণ আৰু সমন্বয়",
+        "অধ্যায় ৮": "জীৱই কেনেদৰে বংশবিস্তাৰ কৰে",
+        "অধ্যায় ৯": "আনুভূমিক আৰু ঊর্ধ্বমুখী বংশগতি",
+        "অধ্যায় ১০": "পোহৰ-প্ৰতিফলন আৰু প্ৰতিসৰণ",
+        "অধ্যায় ১১": "মানুহৰ চকু আৰু বৰ্ণিল পৃথিৱী",
+        "অধ্যায় ১২": "বিদ্যুৎ",
+        "অধ্যায় ১৩": "বিদ্যুৎ-চুম্বকীয় প্ৰভাৱ",
+        "অধ্যায় ১৪": "শক্তিৰ উৎসসমূহ",
+        "অধ্যায় ১৫": "আমাৰ পৰিৱেশ",
+        "অধ্যায় ১৬": "প্রাকৃতিক সম্পদৰ ব্যৱস্থাপনা"
+    },
+    "🌍 সমাজ বিজ্ঞান (Social Science)": {
+        "অধ্যায় ১": "ইউৰোপত ৰাষ্ট্ৰবাদৰ উত্থান",
+        "অধ্যায় ২": "ভাৰতীয় জাতীয়তাবাদৰ উত্থান",
+        "অধ্যায় ৩": "ভূগোল-প্রাকৃতিক আৰু মানৱ",
+        "অধ্যায় ৪": "অৰ্থনীতি-উন্নয়ন",
+        "অধ্যায় ৫": "লোকসাধাৰণৰ সংস্কৃতি আৰু জাতীয়তাবাদ",
+        "অধ্যায় ৬": "উদ্যোগ",
+        "অধ্যায় ৭": "অৰ্থনৈতিক অৱস্থা",
+        "অধ্যায় ৮": "ৰাজনৈতিক দল",
+        "অধ্যায় ৯": "ক্ষমতাৰ ভাগ-বতৰা",
+        "অধ্যায় ১০": "জনসম্পদ"
+    },
+    "📖 ইংৰাজী (English)": {
+        "পাঠ ১": "A Letter to God",
+        "পাঠ ২": "Nelson Mandela: Long Walk to Freedom",
+        "পাঠ ৩": "Two Stories about Flying",
+        "পাঠ ৪": "From the Diary of Anne Frank",
+        "পাঠ ৫": "The Hundred Dresses – I",
+        "পাঠ ৬": "The Hundred Dresses – II",
+        "পাঠ ৭": "Glimpses of India",
+        "পাঠ ৮": "Mijbil the Otter",
+        "পাঠ ৯": "Madam Rides the Bus",
+        "পাঠ ১০": "The Sermon at Benares",
+        "পাঠ ১১": "The Proposal"
+    },
+    "📜 অসমীয়া (Assamese)": {
+        "পাঠ ১": "বৰগীত",
+        "পাঠ ২": "জীৱন-সঙ্গীত",
+        "পাঠ ৩": "প্রশস্তি",
+        "পাঠ ৪": "মোৰ মৰমি জনমভূমি",
+        "পাঠ ৫": "অসমীয়া ভাষাৰ উন্নতি",
+        "পাঠ ৬": "অসমৰ লোক-সংস্কৃতি",
+        "পাঠ ৭": "আমাৰ ঋতু",
+        "পাঠ ৮": "বহাগ বিহু",
+        "পাঠ ৯": "মহাপুরুষীয়া ধৰ্ম",
+        "পাঠ ১০": "সাহিত্যৰ ৰূপ"
+    },
+    "📘 হিন্দী (Hindi)": {
+        "পাঠ ১": "साखी",
+        "পাঠ ২": "पद",
+        "পাঠ ৩": "दोहे",
+        "পাঠ ৪": "मनुष्यता",
+        "পাঠ ५": "पर्वत प्रदेश में पावस",
+        "পাঠ ६": "मधुर-मधुर मेरे दीपक जल",
+        "পাঠ ৭": "तोप",
+        "পাঠ ৮": "कर चले हम फ़िदा",
+        "পাঠ ৯": "आत्मत्राण",
+        "পাঠ ১০": "बड़े भाई साहब"
+    }
+}
+
+# Subject-wise prompt templates
+SUBJECT_PROMPTS = {
+    "📐 গণিত (Mathematics)": {
+        "base_prompt": """তুমি এজন বিশেষজ্ঞ গণিত শিক্ষক। SEBA দশম শ্ৰেণীৰ গণিতৰ পাঠ্যপুথিৰ {chapter_name} অধ্যায়ত থকা সকলো ধাৰণা, সূত্ৰ, আৰু উদাহৰণ তুমি ভালকৈ জানা।
+
+**গণিতৰ বিশেষ নিৰ্দেশনা:**
+১. **সকলো সূত্ৰ LaTeX ফৰ্মেটত দিবা**: $formula$ (দুয়োটা $ চিহ্নৰ মাজত)
+২. **ধাপে ধাপে সমাধান দেখুৱাবা**
+৩. **প্ৰতিটো ধাপৰ ব্যাখ্যা দিবা**
+৪. **সহজ পদ্ধতিৰ�� বুজাবা**
+৫. **পৰীক্ষাৰ বাবে গুৰুত্বপূৰ্ণ সূত্ৰবোৰ পৃথকৈ দেখুৱাবা**
+৬. **সকলো গাণিতিক সমীকৰণ আৰু সূতৰবোৰ `$` চিহ্নৰ মাজত লিখিবা, আলোচনাৰ বাহিৰত পৃথক লাইনত দেখুৱাবা।**
+
+**গণিতৰ সূত্ৰৰ উদাহৰণ (LaTeX ফৰ্মেটত):**
+- দ্বিঘাত সমীকৰণ: $ax^2 + bx + c = 0$
+- বৃত্তৰ কালি: $A = \\pi r^2$
+- সম্ভাৱিতা: $P(E) = \\frac{{n(E)}}{{n(S)}}$
+- পাইথাগোৰাছৰ উপপাদ্য: $a^2 + b^2 = c^2$
+
+**বক্তব্য শৈলী:**
+"চিন্তা নকৰিব, এই গণিতৰ সমস্যাটো সহজ।"
+"ধাপে ধাপে শিকো আহক..."
+"এই সূত্ৰটো মনত ৰাখিব - পৰীক্ষাত আহিব পাৰে!" """,
+        
+        "guidance": "সমীকৰণ, সূত্ৰ আৰু গাণিতিক প্ৰক্ৰিয়া LaTeX ফৰ্মেটত দেখুৱাব লাগে।"
+    },
+    
+    "🔬 বিজ্ঞান (Science)": {
+        "base_prompt": """তুমি এজন বিজ্ঞান শিক্ষক। SEBA দশম শ্ৰেণীৰ বিজ্ঞানৰ {chapter_name} অধ্যায়ৰ সকলো বৈজ্ঞানিক ধাৰণা, প্ৰক্ৰয়া, আৰু নীতি তুমি জানা।
+
+**বিজ্ঞানৰ বিশেষ নিৰ্দেশনা:**
+১. **বৈজ্ঞানিক প্ৰক্ৰয়া ধাপে ধাপে বুজাবা**
+২. **ৰাসায়নিক সমীকৰণ সঠিকভাৱে দিবা**
+৩. **জীৱবিজ্ঞানৰ চিত্ৰ/ৰেখাচিত্ৰৰ বৰ্ণনা দিবা**
+৪. **পদাৰ্থবিজ্ঞানৰ সূত্ৰ LaTeX ফৰ্মেটত দিবা**
+
+**ৰাসায়নিক উদাহৰণ:**
+$2H_2 + O_2 \\rightarrow 2H_2O$
+
+**পদাৰ্থবিজ্ঞান সূত্ৰ:**
+$F = ma$, $v = u + at$
+
+**বক্তব্য শৈলী:**
+"এই বৈজ্ঞানিক ধাৰণাটো বুজোৱাৰ বাবে এটা সাধাৰণ উদাহৰণ চাওঁ..."
+"প্ৰকতিৰ এই ৰহস্যবোৰ মন কৰিছিল নেকি?" """,
+        
+        "guidance": "ৰাসায়নিক সমীকৰণ আৰু পদাৰ্থবিজ্ঞানৰ সূত্ৰ LaTeX ফৰ্মেটত দিব লাগে।"
+    },
+    
+    "🌍 সমাজ বিজ্ঞান (Social Science)": {
+        "base_prompt": """তুমি এজন সমাজ বিজ্ঞান শিক্ষক। SEBA দশম শ্ৰেণীৰ {chapter_name} অধ্যায়ৰ ঐতিহাসিক ঘটনা, ভৌগোলিক ধাৰণা, অৰ্থনৈতিক নীতি, আৰু ৰাজনৈতিক গঠন তুমি জানা।
+
+**সমাজ বিজ্ঞানৰ বিশেষ নিৰ্দেশনা:**
+১. **সহজ অসমীয়া ভাষা ব্যৱহাৰ কৰিবা**
+২. **প্ৰশ্ন অনুসৰি উত্তৰ দিবা**""",
+        
+        "guidance": "তথ্য আৰু বিশ্লেষণ স্পষ্টকৈ দিব লাগে।"
+    },
+    
+    "📖 ইংৰাজী (English)": {
+        "base_prompt": """তুমি এজন ইংৰাজী শিক্ষক। SEBA দশম শ্ৰেণীৰ {chapter_name} পাঠটোৰ সকলো সাহিত্যিক উপাদান, ব্যাকৰণ, আৰু ভাষা কৌশল তুমি জানা।
+
+**ইংৰাজীৰ বিশেষ নিৰ্দেশনা:**
+১. Answer in English with Assamese translation""",
+        
+        "guidance": "ইংৰাজী বাক্যৰ সৈতে অসমীয়া ব্যাখ্যা দিব লাগে।"
+    },
+    
+    "📜 অসমীয়া (Assamese)": {
+        "base_prompt": """তুমি এজন অসমীয়া সাহিত্য শিক্ষক। SEBA দশম শ্ৰেণীৰ {chapter_name} পাঠটোৰ সাহিত্যিক মুল্য, ভাষা বৈশিষ্ট্য, আৰু সাংস্কৃতিক প্ৰসংগ তুমি জানা।
+
+**অসমীয়াৰ বিশেষ নিৰ্দেশনা:**
+১. **সাহিত্যিক বিশ্লেষণ অসমীয়াত দিবা**
+২. **প্ৰশ্ন অনুসৰি উত্তৰ দিবা**""",
+        
+        "guidance": "অসমীয়া ভাষাৰ সৌন্দ��্য্য আৰু গভীৰতা দেখুৱাব লাগে।"
+    },
+    
+    "📘 হিন্দী (Hindi)": {
+        "base_prompt": """तुम एक हिंदी शिक्षक हो। SEBA दशम श्रेणी के {chapter_name} पाठ के सभी साहित्यिक तत्व, व्याकरण, और भाषा कौशल तुम जानते हो।
+
+**हिंदी के विशेष निर्देश:**
+१. **साहित्यिक विश्लेषण हिंदी में देना, साथ असमिया व्याख्या देना**
+२. **प्रश्न के अनुसार उत्तर देना**""",
+        
+        "guidance": "हिंदी वाक्य के साथ असमिया व्याख्या देना"
+    }
+}
+
+# ===============================
+# SIMPLE AUTHENTICATION UI
+# ===============================
+def show_simple_auth():
+    """Show simple login/signup for testing"""
+    st.markdown("""
+    <div style="text-align: center; padding: 2rem; background: linear-gradient(135deg, #0d47a1 0%, #1976d2 100%); 
+                border-radius: 15px; color: white; margin-bottom: 2rem;">
+        <h1 style="color: white;">🎓 SEBA AI Tutor</h1>
+        <p>Assam's Smart AI Tutor for Class 10 Students</p>
+    </div>
+    """, unsafe_allow_html=True)
+    
+    # Simple email-based authentication for testing
+    st.subheader("🔐 Quick Login for Testing")
+    
+    # Create two columns
+    col1, col2 = st.columns(2)
+    
+    with col1:
+        st.markdown("#### Test with Sample Account")
+        if st.button("Login as Test Student", use_container_width=True, type="primary"):
+            test_email = "student@example.com"
+            user_id = hashlib.md5(test_email.encode()).hexdigest()
+            
+            st.session_state.user_id = user_id
+            st.session_state.user_email = test_email
+            st.session_state.logged_in = True
+            
+            # Create user in database if subscription manager exists
+            if st.session_state.subscription_manager:
+                st.session_state.subscription_manager.create_user(user_id, email=test_email)
+                st.session_state.user_plan = st.session_state.subscription_manager.get_user_plan(user_id)
+            
+            st.success("✅ Logged in as test student!")
+            time.sleep(1)
+            st.rerun()
+    
+    with col2:
+        st.markdown("#### Use Your Email")
+        user_email = st.text_input("Enter your email")
+        
+        if st.button("Login / Sign Up", use_container_width=True, type="secondary"):
+            if user_email and "@" in user_email:
+                user_id = hashlib.md5(user_email.lower().strip().encode()).hexdigest()
+                
+                st.session_state.user_id = user_id
+                st.session_state.user_email = user_email
+                st.session_state.logged_in = True
+                
+                # Create user in database if subscription manager exists
+                if st.session_state.subscription_manager:
+                    st.session_state.subscription_manager.create_user(user_id, email=user_email)
+                    st.session_state.user_plan = st.session_state.subscription_manager.get_user_plan(user_id)
+                
+                st.success(f"✅ Welcome {user_email}!")
+                time.sleep(1)
+                st.rerun()
+            else:
+                st.error("Please enter a valid email address")
+    
+    # Show features
+    st.markdown("---")
+    st.markdown("### ✨ Features")
+    
+    features_col1, features_col2, features_col3 = st.columns(3)
+    
+    with features_col1:
+        st.markdown("""
+        <div style="text-align: center; padding: 1rem;">
+            <div style="font-size: 2.5rem;">📚</div>
+            <h4>All SEBA Subjects</h4>
+            <p>Mathematics, Science, Social Science, English, Assamese, Hindi</p>
+        </div>
+        """, unsafe_allow_html=True)
+    
+    with features_col2:
+        st.markdown("""
+        <div style="text-align: center; padding: 1rem;">
+            <div style="font-size: 2.5rem;">🤖</div>
+            <h4>AI Tutor</h4>
+            <p>Step-by-step explanations in Assamese & English</p>
+        </div>
+        """, unsafe_allow_html=True)
+    
+    with features_col3:
+        st.markdown("""
+        <div style="text-align: center; padding: 1rem;">
+            <div style="font-size: 2.5rem;">⚡</div>
+            <h4>Instant Answers</h4>
+            <p>Cached responses for faster learning</p>
+        </div>
+        """, unsafe_allow_html=True)
+    
+    # Pricing info
+    st.markdown("---")
+    st.markdown("### 💰 Pricing Plans")
+    
+    pricing_col1, pricing_col2, pricing_col3 = st.columns(3)
+    
+    with pricing_col1:
+        st.markdown("""
+        <div style="border: 2px solid #4CAF50; border-radius: 10px; padding: 1rem; text-align: center;">
+            <h3 style="color: #4CAF50;">🆓 Free</h3>
+            <h2>₹0</h2>
+            <p><strong>1 question/day</strong></p>
+            <p>30 lifetime questions</p>
+            <p>Perfect for trying out</p>
+        </div>
+        """, unsafe_allow_html=True)
+    
+    with pricing_col2:
+        st.markdown("""
+        <div style="border: 2px solid #FF9800; border-radius: 10px; padding: 1rem; text-align: center; background: #FFF8E1;">
+            <h3 style="color: #FF9800;">⭐ Pro</h3>
+            <h2>₹50/month</h2>
+            <p><strong>15 questions/day</strong></p>
+            <p>450 questions/month</p>
+            <p>Best for regular study</p>
+        </div>
+        """, unsafe_allow_html=True)
+    
+    with pricing_col3:
+        st.markdown("""
+        <div style="border: 2px solid #2196F3; border-radius: 10px; padding: 1rem; text-align: center; background: #E3F2FD;">
+            <h3 style="color: #2196F3;">✨ Pro Plus</h3>
+            <h2>₹100/month</h2>
+            <p><strong>40 questions/day</strong></p>
+            <p>1200 questions/month</p>
+            <p>For serious learners</p>
+        </div>
+        """, unsafe_allow_html=True)
+
+def show_user_dashboard():
+    """Show user dashboard in sidebar"""
+    if st.session_state.get('logged_in'):
+        st.sidebar.markdown("---")
+        st.sidebar.markdown("### 👤 Your Account")
+        
+        # Show user info
+        if st.session_state.get('user_email'):
+            st.sidebar.markdown(f"**Email:** {st.session_state.user_email}")
+        
+        # Show plan info
+        if st.session_state.get('user_plan'):
+            plan = st.session_state.user_plan
+            plan_name = plan['plan_type'].replace('_', ' ').title()
+            
+            st.sidebar.markdown(f"**Plan:** {plan_name}")
+            st.sidebar.markdown(f"**Used:** {plan['questions_used']}/{plan['total_questions']}")
+            
+            # Progress bar
+            progress = plan['questions_used'] / plan['total_questions']
+            st.sidebar.progress(min(progress, 1.0))
+            
+            # Daily usage stats
+            if st.session_state.subscription_manager:
+                stats = st.session_state.subscription_manager.get_user_stats(st.session_state.user_id)
+                st.sidebar.markdown(f"**Today:** {stats['today_used']}/{plan['daily_limit']}")
+            
+            # Upgrade button for free users
+            if plan['plan_type'] == 'free':
+                if st.sidebar.button("🚀 Upgrade Plan", use_container_width=True, type="primary"):
+                    st.session_state.show_subscription_plans = True
+                    st.rerun()
+        
+        # Logout button
+        if st.sidebar.button("🚪 Logout", use_container_width=True):
+            for key in ['user_id', 'user_email', 'user_phone', 'logged_in', 'user_plan', 'show_subscription_plans']:
+                if key in st.session_state:
+                    del st.session_state[key]
+            st.rerun()
+
+# ===============================
+# INITIALIZE SESSION STATE - FIXED
+# ===============================
+if 'history' not in st.session_state:
+    st.session_state.history = []
+if 'current_subject' not in st.session_state:
+    st.session_state.current_subject = "📐 গণিত (Mathematics)"
+if 'current_chapter' not in st.session_state:
+    st.session_state.current_chapter = "অধ্যায় ১"
+if 'processing' not in st.session_state:
+    st.session_state.processing = False
+if 'last_answer' not in st.session_state:
+    st.session_state.last_answer = None
+if 'question_text' not in st.session_state:
+    st.session_state.question_text = ""
+if 'streaming_answer' not in st.session_state:
+    st.session_state.streaming_answer = ""
+if 'tokens_used' not in st.session_state:
+    st.session_state.tokens_used = 0
+if 'cache_manager' not in st.session_state:
+    st.session_state.cache_manager = SupabaseCache(ttl_days=7)
+    # Pre-warm cache by checking Supabase connection on startup
+    cache_stats = st.session_state.cache_manager.get_stats()
+    if cache_stats['supabase_connected'] and cache_stats['supabase_entries'] > 0:
+        st.toast(f"📦 Cache loaded: {cache_stats['supabase_entries']} entries available", icon="✅")
+
+if 'show_cached_answer' not in st.session_state:
+    st.session_state.show_cached_answer = False
+if 'cached_answer_data' not in st.session_state:
+    st.session_state.cached_answer_data = None
+if 'current_cache_key' not in st.session_state:
+    st.session_state.current_cache_key = None
+if 'cache_debug' not in st.session_state:
+    st.session_state.cache_debug = False
+
+# ===============================
+# SUBSCRIPTION MANAGER INITIALIZATION
+# ===============================
+if 'subscription_manager' not in st.session_state:
+    if 'cache_manager' in st.session_state and st.session_state.cache_manager.supabase:
+        st.session_state.subscription_manager = SupabaseSubscriptionManager(
+            st.session_state.cache_manager.supabase
+        )
+    else:
+        st.session_state.subscription_manager = None
+
+# Initialize authentication state
+if 'logged_in' not in st.session_state:
+    st.session_state.logged_in = False
+if 'user_id' not in st.session_state:
+    st.session_state.user_id = None
+if 'user_email' not in st.session_state:
+    st.session_state.user_email = None
+if 'user_phone' not in st.session_state:
+    st.session_state.user_phone = None
+if 'show_subscription_plans' not in st.session_state:
+    st.session_state.show_subscription_plans = False
+if 'user_plan' not in st.session_state:
+    st.session_state.user_plan = None
+
+# ===============================
+# AUTHENTICATION CHECK
+# ===============================
+
+# Check if user needs to login
+if not st.session_state.get('logged_in'):
+    show_simple_auth()
+    st.stop()
+
+# Show subscription plans if requested
+if st.session_state.get('show_subscription_plans'):
+    st.title("📊 Upgrade Your Plan")
+    
+    # Simple plans display
+    col1, col2, col3 = st.columns(3)
+    
+    with col1:
+        st.markdown("""
+        <div style="border: 2px solid #e0e0e0; border-radius: 10px; padding: 1.5rem; text-align: center; height: 100%;">
+            <h3 style="color: #0d47a1;">🆓 Free</h3>
+            <h1 style="color: #4CAF50;">₹0</h1>
+            <p><strong>1 question/day</strong></p>
+            <p>30 lifetime questions</p>
+            <hr>
+            <p>✓ Basic access</p>
+            <p>✓ Cached answers</p>
+        </div>
+        """, unsafe_allow_html=True)
+        
+        if st.session_state.get('user_plan', {}).get('plan_type') == 'free':
+            st.success("✓ Current Plan")
+        else:
+            st.button("Select", disabled=True, use_container_width=True)
+    
+    with col2:
+        st.markdown("""
+        <div style="border: 2px solid #FF9800; border-radius: 10px; padding: 1.5rem; text-align: center; height: 100%; background: #FFF8E1;">
+            <h3 style="color: #FF9800;">⭐ Pro Monthly</h3>
+            <h1 style="color: #FF9800;">₹50</h1>
+            <p><strong>450 questions/month</strong></p>
+            <p>≈ 15 questions/day</p>
+            <hr>
+            <p>✓ All Free features</p>
+            <p>✓ Priority access</p>
+            <p>✓ 30-day validity</p>
+        </div>
+        """, unsafe_allow_html=True)
+        
+        if st.session_state.get('user_plan', {}).get('plan_type') == 'pro_monthly':
+            st.success("✓ Current Plan")
+        else:
+            if st.button("Upgrade to Pro", type="primary", use_container_width=True):
+                if st.session_state.subscription_manager:
+                    success, message = st.session_state.subscription_manager.upgrade_plan(
+                        st.session_state.user_id, 'pro_monthly'
+                    )
+                    if success:
+                        st.success(message)
+                        st.session_state.user_plan = st.session_state.subscription_manager.get_user_plan(st.session_state.user_id)
+                        time.sleep(2)
+                        st.session_state.show_subscription_plans = False
+                        st.rerun()
+                    else:
+                        st.error(message)
+    
+    with col3:
+        st.markdown("""
+        <div style="border: 2px solid #2196F3; border-radius: 10px; padding: 1.5rem; text-align: center; height: 100%; background: #E3F2FD;">
+            <h3 style="color: #2196F3;">✨ Pro Plus</h3>
+            <h1 style="color: #2196F3;">₹100</h1>
+            <p><strong>1200 questions/month</strong></p>
+            <p>≈ 40 questions/day</p>
+            <hr>
+            <p>✓ All Pro features</p>
+            <p>✓ Highest priority</p>
+            <p>✓ 30-day validity</p>
+        </div>
+        """, unsafe_allow_html=True)
+        
+        if st.session_state.get('user_plan', {}).get('plan_type') == 'pro_plus':
+            st.success("✓ Current Plan")
+        else:
+            if st.button("Upgrade to Pro Plus", type="primary", use_container_width=True):
+                if st.session_state.subscription_manager:
+                    success, message = st.session_state.subscription_manager.upgrade_plan(
+                        st.session_state.user_id, 'pro_plus'
+                    )
+                    if success:
+                        st.success(message)
+                        st.session_state.user_plan = st.session_state.subscription_manager.get_user_plan(st.session_state.user_id)
+                        time.sleep(2)
+                        st.session_state.show_subscription_plans = False
+                        st.rerun()
+                    else:
+                        st.error(message)
+    
+    st.markdown("---")
+    st.info("💡 **Note:** For now, this is a simulation. Real payment integration will be added soon.")
+    
+    if st.button("← Back to Tutor", use_container_width=True):
+        st.session_state.show_subscription_plans = False
+        st.rerun()
+    
+    st.stop()
+
+# User is logged in - show main app
+# Load user plan if not loaded
+if st.session_state.logged_in and not st.session_state.get('user_plan'):
+    if st.session_state.subscription_manager and st.session_state.user_id:
+        st.session_state.user_plan = st.session_state.subscription_manager.get_user_plan(st.session_state.user_id)
+        if not st.session_state.user_plan:
+            # Create user if doesn't exist
+            st.session_state.subscription_manager.create_user(
+                st.session_state.user_id, 
+                email=st.session_state.get('user_email')
+            )
+            st.session_state.user_plan = st.session_state.subscription_manager.get_user_plan(st.session_state.user_id)
+
+# Show user dashboard in sidebar
+show_user_dashboard()
+
+# ===============================
+# HEADER SECTION
+# ===============================
+st.markdown("""
+<div class="header-container">
+    <div style="display: flex; align-items: center; gap: 1rem; margin-bottom: 0.5rem;">
+        <div style="font-size: 2rem;">🎓</div>
+        <div>
+            <h1 class="assamese-title">
+                নমস্কাৰ! মই আপোনাৰ দশম শ্ৰেণীৰ AI শিক্ষক
+            </h1>
+            <p class="assamese-text">
+                <span class="assamese-highlight">SEBAৰ সকলো বিষয় মই জানো</span> – গণিত, বিজ্ঞান, সমাজ বিজ্ঞান, ইংৰাজী, অসমীয়া, হিন্দী ইত্যাদি।
+            </p>
+        </div>
+    </div>
+</div>
+""", unsafe_allow_html=True)
+
+# ===============================
+# USAGE BANNER
+# ===============================
+if st.session_state.get('logged_in') and st.session_state.get('user_plan'):
+    user_plan = st.session_state.user_plan
+    remaining = user_plan['questions_remaining']
+    plan_name = user_plan['plan_type'].replace('_', ' ').title()
+    
+    # Get today's usage
+    today_used = 0
+    if st.session_state.subscription_manager:
+        stats = st.session_state.subscription_manager.get_user_stats(st.session_state.user_id)
+        today_used = stats['today_used']
+    
+    # Determine banner color based on usage
+    if remaining <= 5 or today_used >= user_plan['daily_limit']:
+        # Warning banner
+        banner_color = "linear-gradient(135deg, #FF5722 0%, #FF9800 100%)"
+        border_color = "#D32F2F"
+    elif user_plan['plan_type'] == 'free':
+        # Info banner for free users
+        banner_color = "linear-gradient(135deg, #2196F3 0%, #1976D2 100%)"
+        border_color = "#0D47A1"
+    else:
+        # Success banner for paid users
+        banner_color = "linear-gradient(135deg, #4CAF50 0%, #2E7D32 100%)"
+        border_color = "#1B5E20"
+    
+    st.markdown(f"""
+    <div style="background: {banner_color};
+                color: white;
+                padding: 0.75rem 1rem;
+                border-radius: 10px;
+                margin: 0.5rem 0 1.5rem 0;
+                border-left: 5px solid {border_color};
+                box-shadow: 0 3px 10px rgba(0,0,0,0.1);">
+        <div style="display: flex; justify-content: space-between; align-items: center;">
+            <div>
+                <strong style="font-size: 1rem;">📊 {plan_name} Plan</strong>
+                <div style="font-size: 0.85rem; opacity: 0.9;">
+                    Today: {today_used}/{user_plan['daily_limit']} • Remaining: {remaining}/{user_plan['total_questions']}
+                </div>
+            </div>
+            <div>
+                <span style="background: rgba(255,255,255,0.2); 
+                             padding: 0.3rem 0.8rem; 
+                             border-radius: 5px;
+                             font-size: 0.85rem;
+                             cursor: pointer;"
+                      onclick="window.location.href='?show_plans=true'">
+                    { 'Upgrade' if user_plan['plan_type'] == 'free' else 'Manage' } →
+                </span>
+            </div>
+        </div>
+    </div>
+    """, unsafe_allow_html=True)
+
+# ===============================
+# CONTROL PANEL SECTION
+# ===============================
+st.markdown('<div class="control-panel">', unsafe_allow_html=True)
+
+control_col1, control_col2 = st.columns(2)
+with control_col1:
+    st.markdown("#### 📚 বিষয় বাছনি কৰক")
+    subject_list = list(SEBA_CURRICULUM.keys())
+    current_subject = st.session_state.current_subject
+    current_index = subject_list.index(current_subject) if current_subject in subject_list else 0
+    
+    selected_subject = st.selectbox(
+        "আপুনি কোনটো বিষয় শিকিব বিচাৰে?",
+        subject_list,
+        index=current_index,
+        key="subject_selector",
+        label_visibility="collapsed"
+    )
+    
+    if selected_subject != st.session_state.current_subject:
+        st.session_state.current_subject = selected_subject
+        chapters = SEBA_CURRICULUM[selected_subject]
+        st.session_state.current_chapter = list(chapters.keys())[0]
+
+with control_col2:
+    st.markdown("#### 📖 অধ্যায় বাছনি কৰক")
+    chapters = SEBA_CURRICULUM[selected_subject]
+    
+    chapter_options = []
+    chapter_display_map = {}
+    for chap_num, chap_name in chapters.items():
+        display_text = f"{chap_num}: {chap_name}"
+        chapter_options.append(display_text)
+        chapter_display_map[display_text] = chap_num
+    
+    current_chapter = st.session_state.current_chapter
+    current_chap_display = next((disp for disp, num in chapter_display_map.items() if num == current_chapter), chapter_options[0])
+    current_chap_index = chapter_options.index(current_chap_display) if current_chap_display in chapter_options else 0
+    
+    selected_chapter_display = st.selectbox(
+        "কোন অধ্যায়ৰ পৰা প্ৰশ্ন সুধিব?",
+        chapter_options,
+        index=current_chap_index,
+        key="chapter_selector",
+        label_visibility="collapsed"
+    )
+    
+    selected_chapter_key = chapter_display_map[selected_chapter_display]
+    if selected_chapter_key != st.session_state.current_chapter:
+        st.session_state.current_chapter = selected_chapter_key
+
+st.markdown('</div>', unsafe_allow_html=True)
+
+# ===============================
+# CURRENT SELECTION INFO
+# ===============================
+current_chapter_name = chapters[selected_chapter_key]
+st.info(f"""
+**📚 বৰ্তমানৰ বিষয়:** {selected_subject}
+**📖 বৰ্তমানৰ অধ্যায়:** {current_chapter_name}
+""")
+
+# ===============================
+# QUESTION INPUT AREA
+# ===============================
+st.markdown("---")
+st.markdown("#### ✍️ আপোনাৰ প্ৰশ্নটো ইয়াত লিখক")
+
+question = st.text_area(
+    "আপোনাৰ প্ৰশ্নটো ইয়াত লিখক:",
+    value=st.session_state.question_text,
+    height=100,
+    placeholder=f"উদাহৰণ: '{current_chapter_name}' অধ্যায়টো মোৰ বাবে বুজাই দিয়ক...",
+    key="question_input",
+    label_visibility="collapsed"
+)
+
+if question != st.session_state.question_text:
+    st.session_state.question_text = question
+
+# Show API key status
+if not api_key:
+    st.error("""
+    ⚠️ **API কি ছেট আপ কৰক:**
+    
+    **Hugging Face Spaces:**
+    ১. Space Settings → Repository secrets
+    ২. `DEEPSEEK_API_KEY` যোগ কৰক
+    ৩. আপোনাৰ DeepSeek API কি দিয়ক
+    
+    **স্থানীয়ভাবে:**
+    ```bash
+    export DEEPSEEK_API_KEY="your-api-key-here"
+    ```
+    """)
+
+# ===============================
+# CACHE CHECK AND SUBMIT BUTTON - WITH SUBSCRIPTION CHECK
+# ===============================
+submit_disabled = not (question.strip() and api_key)
+col1, col2, col3 = st.columns([1, 2, 1])
+
+with col2:
+    if st.button(
+        "🚀 উত্তৰ দিবলৈ দিয়ক!", 
+        type="primary", 
+        use_container_width=True,
+        disabled=submit_disabled
+    ):
+        if not question.strip():
+            st.error("❌ অনুগ্ৰহ কৰি প্ৰশ্নটো লিখক!")
+        elif not api_key:
+            st.error("❌ API কি ছেট আপ কৰক!")
+        else:
+            # Check subscription if available
+            if st.session_state.subscription_manager and st.session_state.get('user_id'):
+                can_ask, message = st.session_state.subscription_manager.can_ask_question(
+                    st.session_state.user_id
+                )
+                
+                if not can_ask:
+                    st.error(f"❌ {message}")
+                    
+                    # Show upgrade option for free users
+                    user_plan = st.session_state.get('user_plan')
+                    if user_plan and user_plan.get('plan_type') == 'free':
+                        st.info("💡 Upgrade to Pro for more questions!")
+                        if st.button("View Upgrade Plans", key="upgrade_from_error"):
+                            st.session_state.show_subscription_plans = True
+                            st.rerun()
+                    
+                    st.stop()
+            
+            # Check cache first
+            cache_key = create_cache_key(question, selected_subject, current_chapter_name)
+            
+            # Get cache stats for debugging
+            cache_stats = st.session_state.cache_manager.get_stats()
+            
+            cached_entry = st.session_state.cache_manager.get(cache_key)
+            
+            if cached_entry:
+                # Determine cache source
+                cache_source = "Memory" if cache_key in st.session_state.cache_manager.memory_cache else "Supabase"
+                
+                # Log the cached question usage
+                if st.session_state.subscription_manager and st.session_state.get('user_id'):
+                    st.session_state.subscription_manager.log_question(
+                        user_id=st.session_state.user_id,
+                        question_hash=cache_key,
+                        subject=selected_subject,
+                        chapter=current_chapter_name,
+                        tokens_used=cached_entry.get('tokens', 0),
+                        cached=True
+                    )
+                
+                # Show cached answer
+                st.session_state.show_cached_answer = True
+                st.session_state.cached_answer_data = cached_entry
+                st.session_state.current_cache_key = cache_key
+                st.session_state.processing = False
+                st.session_state.cache_source = cache_source
+            else:
+                # Not in cache, proceed with API call
+                # Log the new question usage
+                if st.session_state.subscription_manager and st.session_state.get('user_id'):
+                    st.session_state.subscription_manager.log_question(
+                        user_id=st.session_state.user_id,
+                        question_hash=cache_key,
+                        subject=selected_subject,
+                        chapter=current_chapter_name,
+                        cached=False
+                    )
+                
+                st.session_state.processing = True
+                st.session_state.current_cache_key = cache_key
+
+# ===============================
+# DISPLAY CACHED ANSWER WITH THINKING ANIMATION
+# ===============================
+if st.session_state.get('show_cached_answer') and st.session_state.get('cached_answer_data'):
+    cached_data = st.session_state.cached_answer_data
+    cache_source = st.session_state.get('cache_source', 'Cache')
+    
+    # Display cached answer with animation
+    display_cached_answer_with_animation(
+        cached_data, 
+        question, 
+        selected_subject, 
+        current_chapter_name, 
+        cache_source
+    )
+    
+    # Reset flag
+    st.session_state.show_cached_answer = False
+    if 'cached_answer_data' in st.session_state:
+        del st.session_state.cached_answer_data
+    if 'current_cache_key' in st.session_state:
+        del st.session_state.current_cache_key
+
+# ===============================
+# PROCESS QUESTION WITH STREAMING AND THINKING ANIMATION
+# ===============================
+if st.session_state.get('processing') and question and api_key:
+    # Display user question
+    st.markdown(f"""
+    <div class="chat-container">
+        <div style="display: flex; justify-content: flex-end; margin-bottom: 0.3rem;">
+            <div class="user-bubble">
+                <div style="font-weight: 600; margin-bottom: 0.2rem;">👤 আপুনি:</div>
+                <div>{question[:200]}{'...' if len(question) > 200 else ''}</div>
+            </div>
+        </div>
+    """, unsafe_allow_html=True)
+    
+    # AI answer header with thinking animation initially
+    st.markdown(f"""
+        <div style="display: flex; align-items: flex-start; margin-bottom: 0.3rem;">
+            <div style="margin-right: 0.5rem; font-size: 1.2rem;">🤖</div>
+            <div style="flex: 1;">
+                <div class="ai-bubble">
+                    <div style="display: flex; align-items: center; margin-bottom: 0.5rem; padding-bottom: 0.5rem; border-bottom: 2px solid #2196F3;">
+                        <div style="display: flex; align-items: center;">
+                            <div style="background: #2196F3; color: white; padding: 0.2rem 0.5rem; border-radius: 8px; 
+                                        font-weight: 600; font-size: 0.8rem; margin-right: 0.5rem;">
+                                AI টিউটাৰ
+                            </div>
+                            <div style="font-weight: 600; color: #0d47a1; font-size: 0.9rem;">
+                                {selected_subject} • {current_chapter_name}
+                            </div>
+                        </div>
+                        <div style="font-size: 0.75rem; color: #666; background: #e3f2fd; padding: 0.2rem 0.5rem; border-radius: 4px;">
+                            <span style="margin-right: 0.3rem;">⚡</span> Generating...
+                        </div>
+                    </div>
+                    <div id="ai-answer-content" style="color: #333; line-height: 1.5; font-size: 0.95rem;">
+                        <!-- Answer will be streamed here -->
+                    </div>
+                </div>
+            </div>
+        </div>
+    </div>
+    """, unsafe_allow_html=True)
+    
+    # Create a placeholder for the thinking animation
+    thinking_placeholder = st.empty()
+    
+    # Show thinking animation
+    thinking_placeholder.markdown("""
+    <div class="progress-indicator">
+        <span>উত্তৰ প্ৰস্তুত কৰি আছো...</span>
+        <div class="thinking-dots">
+            <span></span>
+            <span></span>
+            <span></span>
+        </div>
+    </div>
+    """, unsafe_allow_html=True)
+    
+    # Get the prompt and stream the response
+    system_prompt = get_subject_prompt(selected_subject, current_chapter_name, question)
+    
+    # Stream the response
+    stream_deepseek_response(system_prompt, question, selected_subject, current_chapter_name)
+    
+    st.session_state.processing = False
+
+# ===============================
+# HISTORY
+# ===============================
+if st.session_state.history:
+    st.markdown("---")
+    st.markdown("#### 📜 আজিৰ প্ৰশ্নাৱলী")
+    
+    for i, item in enumerate(reversed(st.session_state.history[-5:]), 1):
+        cache_indicator = " ⚡" if item.get('cached') else " 🤖"
+        cache_source = f" ({item.get('cache_source', 'API')})" if item.get('cached') else ""
+        
+        with st.expander(f"প্ৰশ্ন {i}: {item['question']} ({item['timestamp']}{cache_indicator}{cache_source})"):
+            st.write(f"**বিষয়:** {item['subject']}")
+            st.write(f"**অধ্যায়:** {item['chapter']}")
+            st.write(f"**ট'কেন:** {item.get('tokens', 0):,}")
+            if item.get('cached'):
+                st.caption(f"⚡ This answer was served from {item.get('cache_source', 'cache')}")
+
+# ===============================
+# FOOTER
+# ===============================
+st.markdown("---")
+st.markdown("""
+<div style="text-align: center; padding: 0.5rem;">
+    <h3 style="color: #0d47a1; margin-bottom: 0.5rem;">
+        🎓 আপোনাৰ সফলতাৰ বাবে মই সদায় আছো!
+    </h3>
+</div>
+""", unsafe_allow_html=True)
+
+st.markdown("""
+<div style="text-align: center; padding: 0.5rem; margin-top: 1rem; color: #1976D2; font-size: 0.8rem;">
+    <p style="margin: 0;">© 2025 Jajabor AI. All rights reserved.</p>
+</div>
+""", unsafe_allow_html=True)