import gradio as gr
import os
import csv
from datetime import datetime, timedelta
from huggingface_hub import Repository
import threading
import time
import json

# Configuration
DATA_STORAGE_REPO = "CIV3283/Data_Storage"
DATA_BRANCH_NAME = "data_branch"
LOCAL_DATA_DIR = "temp_data_storage"
MIN_IDLE_MINUTES = 20  # Minimum idle time required for space assignment
ALLOCATION_LOCK_DURATION = 10  # Lock duration in minutes

# 缓存配置 - 全部改为内存存储
CACHE_UPDATE_INTERVAL = 300  # 10分钟 = 600秒
DATA_SYNC_INTERVAL = 300    # 数据同步间隔，10分钟 = 600秒
CACHE_LOCK = threading.Lock()
ALLOCATION_LOCK = threading.Lock()

# 全局内存存储
class MemoryAllocationStore:
    """内存中的分配记录存储"""
    def __init__(self):
        self._allocations = {}  # {space_name: {'student_id': str, 'allocated_time': datetime, 'expires_at': datetime}}
        self._lock = threading.Lock()
        self._cleanup_interval = 60  # 每分钟清理一次过期记录
      
        # 启动后台清理线程
        self._start_cleanup_thread()
    
    def _start_cleanup_thread(self):
        """启动后台清理过期分配记录的线程"""
        def cleanup_worker():
            while True:
                time.sleep(self._cleanup_interval)
                self._cleanup_expired_allocations()
        
        cleanup_thread = threading.Thread(target=cleanup_worker, daemon=True)
        cleanup_thread.start()
        print("[MemoryAllocationStore] Background cleanup thread started")
    
    def _cleanup_expired_allocations(self):
        """清理过期的分配记录"""
        with self._lock:
            current_time = datetime.now()
            expired_spaces = []
            
            for space_name, alloc_info in self._allocations.items():
                if alloc_info['expires_at'] <= current_time:
                    expired_spaces.append(space_name)
            
            for space_name in expired_spaces:
                del self._allocations[space_name]
                if expired_spaces:  # 只在有过期记录时打印
                    print(f"[MemoryAllocationStore] Cleaned up expired allocation: {space_name}")
    
    def add_allocation(self, space_name, student_id):
        """添加新的分配记录"""
        with self._lock:
            current_time = datetime.now()
            expires_at = current_time + timedelta(minutes=ALLOCATION_LOCK_DURATION)
            
            self._allocations[space_name] = {
                'student_id': student_id,
                'allocated_time': current_time,
                'expires_at': expires_at
            }
            
            print(f"[MemoryAllocationStore] Added allocation: {space_name} -> {student_id} (expires at {expires_at.strftime('%H:%M:%S')})")
    
    def get_active_allocations(self):
        """��取所有有效的分配记录"""
        with self._lock:
            current_time = datetime.now()
            active_allocations = {}
            
            for space_name, alloc_info in self._allocations.items():
                if alloc_info['expires_at'] > current_time:
                    active_allocations[space_name] = alloc_info.copy()

            
            return active_allocations
    
    def is_allocated(self, space_name):
        """检查指定空间是否被分配"""
        with self._lock:
            if space_name not in self._allocations:
                return False, None
            
            alloc_info = self._allocations[space_name]
            current_time = datetime.now()
            
            if alloc_info['expires_at'] > current_time:
                return True, alloc_info['student_id']
            else:
                # 过期了，删除记录
                del self._allocations[space_name]
                return False, None
    
    def get_status_summary(self):
        """获取分配状态摘要"""
        with self._lock:
            current_time = datetime.now()
            active_count = 0
            summary = []
            
            for space_name, alloc_info in self._allocations.items():
                if alloc_info['expires_at'] > current_time:
                    active_count += 1
                    remaining_minutes = (alloc_info['expires_at'] - current_time).total_seconds() / 60
                    summary.append(f"{space_name} -> {alloc_info['student_id']} ({remaining_minutes:.1f}min left)")
            
            return {
                'active_count': active_count,
                'total_stored': len(self._allocations),
                'summary': summary
            }

# 全局数据管理器
class DataManager:
    def __init__(self):
        self.repo = None
        self.available_spaces = []
        self.last_data_sync = None
        self._sync_lock = threading.Lock()
        self._sync_thread = None
        self._stop_event = threading.Event()
        self.initialized = False
    
    def initialize(self):
        """初始化数据管理器 - 只在启动时调用一次"""
        if self.initialized:
            return True
        
        try:
            print("[DataManager] Initializing data manager...")
            
            # 初始化仓库连接
            self.repo = Repository(
                local_dir=LOCAL_DATA_DIR,
                clone_from=DATA_STORAGE_REPO,
                revision=DATA_BRANCH_NAME,
                repo_type="space",
                use_auth_token=os.environ.get("HF_HUB_TOKEN")
            )
            
            # 配置git用户
            self.repo.git_config_username_and_email("git_user", f"load_distributor")
            self.repo.git_config_username_and_email("git_email", f"loaddistributor@takeiteasy.space")
            
            # 初始数据同步
            self._sync_data()


            
            # 启动后台同步线程
            self._start_background_sync()
            
            self.initialized = True
            print("[DataManager] Data manager initialized successfully")
            return True
            
        except Exception as e:
            print(f"[DataManager] Initialization failed: {e}")
            return False
    
    def _start_background_sync(self):
        """启动后台数据同步线程"""
        if self._sync_thread and self._sync_thread.is_alive():
            return
        
        self._stop_event.clear()
        self._sync_thread = threading.Thread(target=self._background_sync_worker, daemon=True)
        self._sync_thread.start()
        print("[DataManager] Background sync thread started")
    
    def _background_sync_worker(self):
        """后台同步工作线程"""
        while not self._stop_event.is_set():
            try:
                # 等待指定间隔或停止信号
                if self._stop_event.wait(timeout=DATA_SYNC_INTERVAL):
                    break
                
                print("[DataManager] Starting scheduled data sync...")
                self._sync_data()
                print("[DataManager] Scheduled data sync completed")
                
            except Exception as e:
                print(f"[DataManager] Error in background sync: {e}")
                if not self._stop_event.wait(timeout=60):  # 1分钟后重试
                    continue
    
    def _sync_data(self):
        """同步数据 - 拉取最新数据并更新可用空间列表"""
        with self._sync_lock:
            try:
                start_time = time.time()
                print("[DataManager] Syncing data from remote repository...")
                
                # 拉取最新数据
                self.repo.git_pull(rebase=True)
                
                # 更新可用空间列表
                self.available_spaces = self._get_available_spaces()
                self.last_data_sync = datetime.now()
                
                elapsed_time = time.time() - start_time
                print(f"[DataManager] Data sync completed in {elapsed_time:.2f}s, found {len(self.available_spaces)} spaces")

                
            except Exception as e:
                print(f"[DataManager] Error syncing data: {e}")
    
    def _get_available_spaces(self):
        """获取可用空间列表"""
        available_spaces = set()
        try:
            for filename in os.listdir(LOCAL_DATA_DIR):
                if filename.endswith('_query_log.csv') and '_Student_' in filename:
                    space_name = filename.replace('_query_log.csv', '')
                    available_spaces.add(space_name)
            return sorted(list(available_spaces))
        except Exception as e:
            print(f"[DataManager] Error getting available spaces: {e}")
            return []
    
    def get_available_spaces(self):
        """获取可用空间列表 - 不触发数据同步"""
        if not self.initialized:
            raise Exception("DataManager not initialized")
        return self.available_spaces.copy()
    
    def get_repo(self):
        """获取仓库对象"""
        if not self.initialized:
            raise Exception("DataManager not initialized")
        return self.repo
    
    def get_repo_dir(self):
        """获取仓库本地目录"""
        if not self.initialized:
            raise Exception("DataManager not initialized")
        return LOCAL_DATA_DIR
    
    def stop(self):
        """停止后台同步"""
        if self._sync_thread:
            self._stop_event.set()
            print("[DataManager] Background sync thread stopping...")

class SpaceActivityCache:
    """内存中的空间活动缓存"""
    def __init__(self, data_manager):
        self.data_manager = data_manager
        self._cache_data = {}
        self._last_update = None
        self._update_thread = None
        self._stop_event = threading.Event()
        
        # 启动时立即更新一次缓存
        self._update_cache()



















        
        # 启动后台更新线程
        self.start_background_updates()
    
    def start_background_updates(self):
        """启动后台缓存更新线程"""
        if self._update_thread and self._update_thread.is_alive():
            return
        
        self._stop_event.clear()
        self._update_thread = threading.Thread(target=self._background_update_worker, daemon=True)
        self._update_thread.start()
        print("[SpaceActivityCache] Background update thread started")







    
    def stop_background_updates(self):
        """停止后台更新线程"""
        if self._update_thread:
            self._stop_event.set()
            print("[SpaceActivityCache] Background update thread stopping...")
    
    def _background_update_worker(self):
        """后台更新工作线程"""
        while not self._stop_event.is_set():
            try:
                # 等待指定间隔或停止信号
                if self._stop_event.wait(timeout=CACHE_UPDATE_INTERVAL):
                    break
                
                print("[SpaceActivityCache] Starting scheduled cache update...")
                self._update_cache()
                print("[SpaceActivityCache] Scheduled cache update completed")
                
            except Exception as e:
                print(f"[SpaceActivityCache] Error in background update: {e}")
                if not self._stop_event.wait(timeout=60):  # 1分钟后重试
                    continue
    
    def _update_cache(self):
        """更新缓存数据"""
        try:
            print("[SpaceActivityCache] Updating activity cache...")
            start_time = time.time()
            
            # 从数据管理器获取可用空间（不触发数据同步）
            available_spaces = self.data_manager.get_available_spaces()
            repo_dir = self.data_manager.get_repo_dir()
            
            new_cache_data = {
                'last_updated': datetime.now().isoformat(),
                'update_interval_seconds': CACHE_UPDATE_INTERVAL,
                'spaces': {}
            }
            
            # 为每个空间读取最后活动时间
            for space_name in available_spaces:
                csv_file = os.path.join(repo_dir, f"{space_name}_query_log.csv")
                last_activity, status = self._get_last_activity_from_file(csv_file)
                
                new_cache_data['spaces'][space_name] = {
                    'last_activity': last_activity.isoformat() if last_activity != datetime.min else None,
                    'status': status,
                    'cache_update_time': datetime.now().isoformat()
                }
                
                print(f"[SpaceActivityCache] {space_name}: {status}")
            
            # 线程安全地更新缓存
            with CACHE_LOCK:
                self._cache_data = new_cache_data
                self._last_update = datetime.now()
            
            elapsed_time = time.time() - start_time
            print(f"[SpaceActivityCache] Cache updated in {elapsed_time:.2f}s, {len(available_spaces)} spaces processed")


            
        except Exception as e:
            print(f"[SpaceActivityCache] Error updating cache: {e}")
            import traceback
            print(f"[SpaceActivityCache] Traceback: {traceback.format_exc()}")
    
    def _get_last_activity_from_file(self, csv_file_path):
        """从文件读取最后活动时间"""
        try:
            if not os.path.exists(csv_file_path):
                return datetime.min, "file_not_found"
            
            # 检查文件大小
            file_size = os.path.getsize(csv_file_path)
            if file_size <= 100:
                return datetime.min, "empty_or_header_only"
            
            # 使用CSV reader读取最后一行
            with open(csv_file_path, 'r', encoding='utf-8') as f:
                csv_reader = csv.reader(f)
                
                # 跳过header
                try:
                    header = next(csv_reader)
                except StopIteration:
                    return datetime.min, "empty_file"
                
                # 读取所有行，获取最后一行
                rows = []
                try:
                    for row in csv_reader:
                        if row:  # 跳过空行
                            rows.append(row)
                except Exception as csv_error:
                    print(f"[SpaceActivityCache] CSV parsing error for {csv_file_path}: {csv_error}")
                    return datetime.min, "csv_parse_error"
            
            if not rows:
                return datetime.min, "no_data_rows"
            
            # 解析最后一行的时间戳
            last_row = rows[-1]
            if len(last_row) >= 3:
                timestamp_str = last_row[2].strip()  # timestamp column
                try:
                    parsed_time = datetime.strptime(timestamp_str, '%Y-%m-%d %H:%M:%S')
                    return parsed_time, f"active_last_at_{parsed_time.strftime('%Y-%m-%d_%H:%M:%S')}"
                except ValueError as ve:
                    print(f"[SpaceActivityCache] Date parsing error for '{timestamp_str}': {ve}")
                    return datetime.min, "date_parse_error"
            else:
                return datetime.min, "invalid_row_format"
                
        except Exception as e:
            print(f"[SpaceActivityCache] Error reading {csv_file_path}: {e}")
            return datetime.min, "read_error"
    
    def get_space_activity(self, space_name):
        """获取指定空间的活动信息"""
        with CACHE_LOCK:
            if not self._cache_data or 'spaces' not in self._cache_data:
                print("[SpaceActivityCache] No cache available, updating immediately...")
                self._update_cache()
            
            spaces_data = self._cache_data.get('spaces', {})
            space_info = spaces_data.get(space_name, {})

            
            if not space_info:
                return datetime.min, "not_in_cache"

            
            # 解析时间戳
            last_activity_str = space_info.get('last_activity')
            if last_activity_str:
                try:
                    last_activity = datetime.fromisoformat(last_activity_str)
                except:
                    last_activity = datetime.min
            else:
                last_activity = datetime.min
            
            status = space_info.get('status', 'unknown')
            return last_activity, status
    
    def get_all_spaces_activity(self):
        """获取所有空间的活动信息"""
        with CACHE_LOCK:
            if not self._cache_data or 'spaces' not in self._cache_data:
                print("[SpaceActivityCache] No cache available, updating immediately...")
                self._update_cache()
            
            result = {}
            spaces_data = self._cache_data.get('spaces', {})

            
            for space_name, space_info in spaces_data.items():
                last_activity_str = space_info.get('last_activity')
                if last_activity_str:




                    try:
                        last_activity = datetime.fromisoformat(last_activity_str)
                    except:
                        last_activity = datetime.min





















                else:
                    last_activity = datetime.min
                
                result[space_name] = {
                    'last_activity': last_activity,
                    'status': space_info.get('status', 'unknown')
                }
            
            return result
    
    def get_cache_info(self):
        """获取缓存状态信息"""
        with CACHE_LOCK:
            if self._cache_data and 'last_updated' in self._cache_data:
                last_updated_str = self._cache_data['last_updated']
                try:
                    last_updated = datetime.fromisoformat(last_updated_str)
                    age_minutes = (datetime.now() - last_updated).total_seconds() / 60
                    return {
                        'last_updated': last_updated,
                        'age_minutes': age_minutes,
                        'spaces_count': len(self._cache_data.get('spaces', {})),
                        'is_fresh': age_minutes < (CACHE_UPDATE_INTERVAL / 60) * 1.5
                    }
                except:
                    pass
            
            return {
                'last_updated': None,
                'age_minutes': float('inf'),
                'spaces_count': 0,
                'is_fresh': False
            }
    
    def force_update(self):
        """强制立即更新缓存"""
        print("[SpaceActivityCache] Force updating cache...")
        self._update_cache()

# 新增：本地防撞车机制
class LocalAllocationTracker:
    def __init__(self):
        self._recent_allocations = {}  # {space_name: {'student_id': str, 'timestamp': datetime}}
        self._lock = threading.Lock()
        self._cleanup_interval = 600  # 清理间隔（秒）
        self._allocation_ttl = 60   # 本地分配记录的生存时间（秒）
        
        # 启动后台清理线程
        self._start_cleanup_thread()
    
    def _start_cleanup_thread(self):
        """启动后台线程定期清理过期的本地分配记录"""
        def cleanup_worker():
            while True:
                time.sleep(self._cleanup_interval)
                self._cleanup_expired_allocations()
        
        cleanup_thread = threading.Thread(target=cleanup_worker, daemon=True)
        cleanup_thread.start()
        print("[LocalAllocationTracker] Background cleanup thread started")
    
    def _cleanup_expired_allocations(self):
        """清理过期的本地分配记录"""
        with self._lock:
            current_time = datetime.now()
            expired_spaces = []
            
            for space_name, alloc_info in self._recent_allocations.items():
                if (current_time - alloc_info['timestamp']).total_seconds() > self._allocation_ttl:
                    expired_spaces.append(space_name)
            
            for space_name in expired_spaces:
                del self._recent_allocations[space_name]
                if expired_spaces:  # 只在有过期记录时打印
                    print(f"[LocalAllocationTracker] Cleaned up expired allocation: {space_name}")
    
    def is_recently_allocated_locally(self, space_name):
        """检查空间是否在本地被最近分配过"""
        with self._lock:
            if space_name not in self._recent_allocations:
                return False, None
            
            alloc_info = self._recent_allocations[space_name]
            current_time = datetime.now()
            elapsed_seconds = (current_time - alloc_info['timestamp']).total_seconds()
            
            if elapsed_seconds > self._allocation_ttl:
                # 过期了，删除记录
                del self._recent_allocations[space_name]
                print(f"[LocalAllocationTracker] Expired local allocation removed: {space_name}")
                return False, None
            
            print(f"[LocalAllocationTracker] Space {space_name} recently allocated locally to {alloc_info['student_id']} ({elapsed_seconds:.1f}s ago)")
            return True, alloc_info['student_id']
    
    def record_local_allocation(self, space_name, student_id):
        """记录本地分配"""
        with self._lock:
            self._recent_allocations[space_name] = {
                'student_id': student_id,
                'timestamp': datetime.now()
            }
            print(f"[LocalAllocationTracker] Locally recorded allocation: {space_name} -> {student_id}")
    
    def get_recent_allocations_summary(self):
        """获取最近本地分配的摘要（用于调试）"""
        with self._lock:
            current_time = datetime.now()
            summary = []
            for space_name, alloc_info in self._recent_allocations.items():
                elapsed = (current_time - alloc_info['timestamp']).total_seconds()
                summary.append(f"{space_name} -> {alloc_info['student_id']} ({elapsed:.1f}s ago)")
            return summary

# 全局实例
data_manager = DataManager()
activity_cache = None
local_tracker = LocalAllocationTracker()
memory_allocation_store = MemoryAllocationStore()

def init_system():
    """初始化整个系统 - 只在启动时调用一次"""
    global activity_cache
    
    print("[init_system] Initializing load distributor system...")
    
    # 初始化数据管理器
    if not data_manager.initialize():
        raise Exception("Failed to initialize data manager")
    
    # 初始化活动缓存
    activity_cache = SpaceActivityCache(data_manager)
    
    print("[init_system] System initialization completed")

def analyze_space_activity_cached():
    """使用缓存的空间活动分析 - 完全使用内存数据"""
    global activity_cache
    
    if activity_cache is None:
        raise Exception("Activity cache not initialized")
    
    # 从数据管理器获取可用空间列表（不触发数据同步）
    available_spaces = data_manager.get_available_spaces()
    
    space_activity = []
    current_time = datetime.now()
    
    # 获取缓存信息
    cache_info = activity_cache.get_cache_info()
    print(f"[analyze_space_activity_cached] Using cache (age: {cache_info['age_minutes']:.1f} min, fresh: {cache_info['is_fresh']})")
    
    # 获取所有空间的缓存活动数据
    all_spaces_activity = activity_cache.get_all_spaces_activity()
    
    # 从内存获取分配记录 - 不再读取文件
    active_allocations = memory_allocation_store.get_active_allocations()
    
    print(f"[analyze_space_activity_cached] Analyzing {len(available_spaces)} spaces using cached data...")
    print(f"[analyze_space_activity_cached] Memory allocations: {len(active_allocations)} active")
    
    for space_name in available_spaces:
        # 从缓存获取活动信息
        cached_info = all_spaces_activity.get(space_name)
        
        if cached_info:
            last_activity = cached_info['last_activity']
            cached_status = cached_info['status']
        else:
            # 缓存中没有这个空间，可能是新空间
            last_activity = datetime.min
            cached_status = "not_in_cache"
        
        # Calculate idle time in minutes
        if last_activity == datetime.min or 'empty' in cached_status or 'not_found' in cached_status:
            idle_minutes = float('inf')  # Never used
            status = "Never used"
            last_activity_str = "Never"
        else:
            idle_minutes = (current_time - last_activity).total_seconds() / 60
            status = f"Idle for {idle_minutes:.1f} minutes (cached)"
            last_activity_str = last_activity.strftime('%Y-%m-%d %H:%M:%S')
        
        # 检查内存中的分配记录
        is_recently_allocated_memory = space_name in active_allocations
        if is_recently_allocated_memory:
            alloc_info = active_allocations[space_name]
            minutes_until_free = (alloc_info['expires_at'] - current_time).total_seconds() / 60
            status += f" (Allocated in memory to {alloc_info['student_id']}, free in {minutes_until_free:.1f} min)"
        
        # Check if space is recently allocated (local)
        is_recently_allocated_local, local_student = local_tracker.is_recently_allocated_locally(space_name)
        if is_recently_allocated_local:
            status += f" (Recently allocated locally to {local_student})"
        
        space_activity.append({
            'space_name': space_name,
            'last_activity': last_activity,
            'last_activity_str': last_activity_str,
            'idle_minutes': idle_minutes,
            'status': status,
            'is_recently_allocated_memory': is_recently_allocated_memory,
            'is_recently_allocated_local': is_recently_allocated_local,
            'cached_status': cached_status
        })
        
        print(f"[analyze_space_activity_cached] {space_name}: {status}")
    
    # Sort by idle time (most idle first)
    space_activity.sort(key=lambda x: x['idle_minutes'], reverse=True)
    
    return space_activity

def create_status_display(space_activity):
    """Create formatted status display for all spaces with proper line breaks"""
    status_display = "📊 **Current Space Status (sorted by availability):**<br><br>"
    
    # 显示内存分配记录摘要
    memory_summary = memory_allocation_store.get_status_summary()
    if memory_summary['active_count'] > 0:
        status_display += f"🧠 **Memory Allocations ({memory_summary['active_count']} active):**<br>"
        for alloc in memory_summary['summary']:
            status_display += f"&nbsp;&nbsp;&nbsp;• {alloc}<br>"
        status_display += "<br>"
    
    # 显示本地分配记录摘要
    local_summary = local_tracker.get_recent_allocations_summary()
    if local_summary:
        status_display += "🔒 **Recent Local Allocations:**<br>"
        for alloc in local_summary:
            status_display += f"&nbsp;&nbsp;&nbsp;• {alloc}<br>"
        status_display += "<br>"
    
    for i, space in enumerate(space_activity, 1):
        status_display += f"{i}. **{space['space_name']}**<br>"
        status_display += f"&nbsp;&nbsp;&nbsp;• Status: {space['status']}<br>"
        status_display += f"&nbsp;&nbsp;&nbsp;• Last activity: {space['last_activity_str']}<br><br>"
    
    return status_display

def select_space_with_enhanced_collision_avoidance_cached(space_activity, student_id):
    """使用缓存的增强防撞空间选择函数 - 完全使用内存存储"""
    
    print(f"[select_space_with_enhanced_collision_avoidance_cached] Starting selection for student: {student_id}")
    
    # 第一步：过滤掉不符合基本条件的空间
    basic_available_spaces = []
    for space in space_activity:
        # 检查基本条件 - 使用内存分配记录
        if (space['idle_minutes'] >= MIN_IDLE_MINUTES and 
            not space['is_recently_allocated_memory'] and 
            not space['is_recently_allocated_local']):
            basic_available_spaces.append(space)
    
    print(f"[select_space_with_enhanced_collision_avoidance_cached] Basic available spaces: {len(basic_available_spaces)}")
    
    if not basic_available_spaces:
        # 生成详细的错误信息
        idle_spaces = [s for s in space_activity if s['idle_minutes'] >= MIN_IDLE_MINUTES]
        memory_allocated = [s for s in space_activity if s['is_recently_allocated_memory']]
        local_allocated = [s for s in space_activity if s['is_recently_allocated_local']]
        
        error_parts = []
        if not idle_spaces:
            error_parts.append(f"all spaces used within {MIN_IDLE_MINUTES} minutes")
        if memory_allocated:
            error_parts.append(f"{len(memory_allocated)} spaces allocated in memory")
        if local_allocated:
            error_parts.append(f"{len(local_allocated)} spaces locally allocated")
        
        error_msg = (
            f"🚫 **All learning assistants are currently busy**\n\n"
            f"Blocking conditions: {', '.join(error_parts)}\n\n"
            f"**Please try again in 1-2 minutes.**"
        )
        
        print(f"[select_space_with_enhanced_collision_avoidance_cached] No available spaces: {error_msg}")
        raise gr.Error(error_msg, duration=10)
    
    # 第二步：选择最优空间并进行最终验证
    selected_space = basic_available_spaces[0]  # 已经按idle_time排序
    space_name = selected_space['space_name']
    
    print(f"[select_space_with_enhanced_collision_avoidance_cached] Preliminary selection: {space_name}")
    
    # 第三步：最终防撞车检查 - 再次验证本地分配状态
    is_local_conflict, conflicting_student = local_tracker.is_recently_allocated_locally(space_name)
    if is_local_conflict:
        print(f"[select_space_with_enhanced_collision_avoidance_cached] COLLISION DETECTED! {space_name} recently allocated to {conflicting_student}")
        
        # 寻找替代空间
        alternative_spaces = [s for s in basic_available_spaces[1:] 
                            if not local_tracker.is_recently_allocated_locally(s['space_name'])[0]]

        if alternative_spaces:
            selected_space = alternative_spaces[0]
            space_name = selected_space['space_name']
            print(f"[select_space_with_enhanced_collision_avoidance_cached] Using alternative space: {space_name}")
        else:
            error_msg = (
                f"🚫 **Collision detected and no alternatives available**\n\n"
                f"The system detected a potential conflict with another student's allocation.\n\n"
                f"**Please try again in 10-15 seconds.**"
            )
            print(f"[select_space_with_enhanced_collision_avoidance_cached] No alternatives available")
            raise gr.Error(error_msg, duration=8)
    
    # 第四步：立即记录本地分配（在写入内存之前）
    local_tracker.record_local_allocation(space_name, student_id)
    print(f"[select_space_with_enhanced_collision_avoidance_cached] Local allocation recorded BEFORE memory write")
    
    # 第五步：记录到内存存储 - 不再写入文件或推送到远程
    memory_allocation_store.add_allocation(space_name, student_id)
    print(f"[select_space_with_enhanced_collision_avoidance_cached] Allocation recorded in memory only")
    
    # 第六步：生成结果（使用带缓存信息的状态显示）
    status_display = create_status_display_with_cache_info(space_activity)
    redirect_url = f"https://huggingface.co/spaces/CIV3283/{space_name}/?check={student_id}"
    
    print(f"[select_space_with_enhanced_collision_avoidance_cached] Final allocation: {space_name} -> {student_id}")
    
    return redirect_to_space(redirect_url, selected_space, status_display)

def redirect_to_space(redirect_url, selected_space, status_display):
    """Display redirect information with manual click option"""
    
    if selected_space['idle_minutes'] == float('inf'):
        idle_info = "Never used (completely fresh)"
    else:
        idle_info = f"{selected_space['idle_minutes']:.1f} minutes"
    
    # Modified HTML structure - Only Access section, removed analysis section
    redirect_html = f"""
    <div style="max-width: 900px; margin: 0 auto; padding: 20px; font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;">
        <div style="text-align: center; margin-bottom: 30px; padding: 25px; background: linear-gradient(135deg, #28a745, #20c997); color: white; border-radius: 12px; box-shadow: 0 4px 6px rgba(0,0,0,0.1);">
            <h1 style="margin: 0 0 15px 0; font-size: 28px;">🎯 Learning Assistant Assigned</h1>
            <h2 style="margin: 0 0 10px 0; font-weight: normal; font-size: 24px;">{selected_space['space_name']}</h2>
            <p style="margin: 0; font-size: 18px; opacity: 0.9;">
                ✨ This space was idle for: <strong>{idle_info}</strong>
            </p>
        </div>
        
        <div style="text-align: center; margin-bottom: 30px; padding: 25px; background: linear-gradient(135deg, #2196f3, #1976d2); color: white; border-radius: 12px; box-shadow: 0 4px 6px rgba(33,150,243,0.3);">
            <h2 style="margin-top: 0; color: white;">🚀 Access Your Learning Assistant</h2>
            <p style="color: rgba(255,255,255,0.9); font-size: 16px; margin-bottom: 25px;">
                Click the button below to access your assigned learning assistant.
            </p>
            
            <a href="{redirect_url}" 
               target="_blank"
               style="display: inline-block; background: rgba(255,255,255,0.15); color: white; 
                      padding: 15px 30px; font-size: 18px; font-weight: bold; text-decoration: none; 
                      border-radius: 25px; border: 2px solid rgba(255,255,255,0.3);
                      transition: all 0.3s ease; margin-bottom: 20px;"
               onmouseover="this.style.background='rgba(255,255,255,0.25)'; this.style.transform='translateY(-2px)'"
               onmouseout="this.style.background='rgba(255,255,255,0.15)'; this.style.transform='translateY(0px)'">
                ➤ Open Learning Assistant
            </a>
            
            <p style="margin: 15px 0 0 0; color: rgba(255,255,255,0.8); font-size: 14px;">
                💡 Left-click the button above or right-click it and select "Open in new tab"
            </p>
        </div>
        
        <div style="text-align: center; padding: 20px; background: #f1f3f4; border-radius: 8px; margin-top: 20px;">
            <p style="margin: 0; color: #5f6368; font-size: 14px;">
                🔄 Need a different assistant? <a href="javascript:location.reload()" style="color: #1976d2; text-decoration: none;">Refresh this page</a> to get reassigned.
            </p>
        </div>
    </div>
    """
    
    return gr.HTML(redirect_html)

def load_balance_user_cached(student_id):
    """使用缓存的负载均衡函数 - 完全使用内存存储"""
    print(f"[load_balance_user_cached] Starting cached load balancing for student ID: {student_id}")
    
    # 检查系统是否已初始化
    if not data_manager.initialized:
        raise gr.Error("🚫 System not properly initialized. Please contact administrator.", duration=8)
    
    # 使用缓存版本的分析函数（不触发数据同步）
    space_activity = analyze_space_activity_cached()
    
    # Select space with enhanced collision avoidance
    return select_space_with_enhanced_collision_avoidance_cached(space_activity, student_id)

def get_url_params(request: gr.Request):
    """Extract URL parameters from request"""
    query_params = dict(request.query_params)
    check_id = query_params.get('check', None)
    if check_id:
        return f"Load Distributor", check_id
    else:
        return "Load Distributor", None


def create_status_display_with_cache_info(space_activity):
    """创建包含缓存信息的状态显示"""
    global activity_cache

    
    # 获取缓存状态
    cache_info = activity_cache.get_cache_info() if activity_cache else None
    
    status_display = "📊 **Current Space Status (sorted by availability):**<br><br>"


    # 显示缓存信息
    if cache_info:
        if cache_info['is_fresh']:
            cache_status = f"✅ Fresh (updated {cache_info['age_minutes']:.1f} min ago)"

        else:
            cache_status = f"⚠️ Stale (updated {cache_info['age_minutes']:.1f} min ago)"
        
        status_display += f"🔄 **Cache Status:** {cache_status}<br>"
        status_display += f"📋 **Cached Spaces:** {cache_info['spaces_count']}<br><br>"
    
    # 显示内存分配记录摘要
    memory_summary = memory_allocation_store.get_status_summary()
    if memory_summary['active_count'] > 0:
        status_display += f"🧠 **Memory Allocations ({memory_summary['active_count']} active):**<br>"
        for alloc in memory_summary['summary']:
            status_display += f"&nbsp;&nbsp;&nbsp;• {alloc}<br>"
        status_display += "<br>"
    
    # 显示本地分配记录摘要
    local_summary = local_tracker.get_recent_allocations_summary()
    if local_summary:
        status_display += "🔒 **Recent Local Allocations:**<br>"
        for alloc in local_summary:
            status_display += f"&nbsp;&nbsp;&nbsp;• {alloc}<br>"
        status_display += "<br>"
    
    for i, space in enumerate(space_activity, 1):
        status_display += f"{i}. **{space['space_name']}**<br>"
        status_display += f"&nbsp;&nbsp;&nbsp;• Status: {space['status']}<br>"
        status_display += f"&nbsp;&nbsp;&nbsp;• Last activity: {space['last_activity_str']}<br>"
        
        # 显示缓存状态（可选）
        if 'cached_status' in space:
            status_display += f"&nbsp;&nbsp;&nbsp;• Cache: {space['cached_status']}<br>"
        
        status_display += "<br>"
    
    return status_display

def handle_user_access_cached(request: gr.Request):
    """使用缓存的用户访问处理"""
    title, check_id = get_url_params(request)
    
    if not check_id:
        # No student ID provided
        error_html = """
        <div style="max-width: 600px; margin: 50px auto; padding: 30px; text-align: center; 
                    background: #fff3cd; border: 1px solid #ffeaa7; border-radius: 12px;">
            <h2 style="color: #856404;">⚠️ Invalid Access</h2>
            <p style="color: #856404; font-size: 16px; line-height: 1.6;">
                This load distributor requires a valid student ID parameter.<br><br>
                <strong>Please access this system through the official link provided in Moodle.</strong>
            </p>
        </div>
        """
        return title, gr.HTML(error_html)
    
    # Valid student ID - perform cached load balancing
    try:
        result = load_balance_user_cached(check_id)
        return title, result
    except Exception as e:
        # Handle any errors during load balancing
        error_html = f"""
        <div style="max-width: 600px; margin: 50px auto; padding: 30px; text-align: center; 
                    background: #f8d7da; border: 1px solid #f5c6cb; border-radius: 12px;">
            <h2 style="color: #721c24;">🚫 Load Balancing Error</h2>
            <p style="color: #721c24; font-size: 16px; line-height: 1.6;">
                {str(e)}<br><br>
                Please try again in a few moments or contact your instructor if the problem persists.
            </p>
        </div>
        """
        return title, gr.HTML(error_html)

# 管理功能
def get_cache_status():
    """获取缓存状态（用于调试或管理）"""
    global activity_cache
    if activity_cache:
        return activity_cache.get_cache_info()
    return {"error": "Cache not initialized"}

def force_cache_update():
    """强制更新缓存（用于调试或管理）"""
    global activity_cache
    if activity_cache:
        activity_cache.force_update()
        return {"status": "Cache updated"}
    return {"error": "Cache not initialized"}

def get_data_manager_status():
    """获取数据管理器状态"""
    return {
        "initialized": data_manager.initialized,
        "last_sync": data_manager.last_data_sync.isoformat() if data_manager.last_data_sync else None,
        "spaces_count": len(data_manager.available_spaces),
        "repo_connected": data_manager.repo is not None
    }

def force_data_sync():
    """强制数据同步"""
    try:
        data_manager._sync_data()
        return {"status": "Data sync completed"}










    except Exception as e:
        return {"error": str(e)}



def get_memory_allocation_status():
    """获取内存分配状态"""
    return memory_allocation_store.get_status_summary()

def clear_memory_allocations():
    """清除所有内存分配记录（管理功能）"""
    try:
        with memory_allocation_store._lock:
            cleared_count = len(memory_allocation_store._allocations)
            memory_allocation_store._allocations.clear()
        return {"status": f"Cleared {cleared_count} memory allocations"}
    except Exception as e:
        return {"error": str(e)}

# 添加可选的管理界面（用于调试）
def create_admin_interface():
    """创建管理界面（可选）- 增强版本"""
    with gr.Blocks(title="CIV3283 Load Distributor - Admin") as admin_interface:
        gr.Markdown("# 🔧 CIV3283 Load Distributor - Admin Panel")
        
        with gr.Tab("Cache Management"):
            with gr.Row():
                cache_status_btn = gr.Button("📊 Check Cache Status", variant="secondary")
                force_cache_update_btn = gr.Button("🔄 Force Cache Update", variant="primary")
            
            cache_info_display = gr.JSON(label="Cache Information")
            cache_status_message = gr.Markdown("")
            
        with gr.Tab("Data Management"):
            with gr.Row():
                data_status_btn = gr.Button("📊 Check Data Manager Status", variant="secondary")
                force_data_sync_btn = gr.Button("🔄 Force Data Sync", variant="primary")
            
            data_info_display = gr.JSON(label="Data Manager Information")
            data_status_message = gr.Markdown("")
        
        with gr.Tab("Memory Allocation"):
            with gr.Row():
                memory_status_btn = gr.Button("🧠 Check Memory Allocations", variant="secondary")
                clear_memory_btn = gr.Button("🗑️ Clear All Memory Allocations", variant="stop")
            
            memory_info_display = gr.JSON(label="Memory Allocation Information")
            memory_status_message = gr.Markdown("")
        
        def check_cache_status():
            try:
                status = get_cache_status()
                if 'error' in status:
                    return status, "❌ Cache not available"
                else:
                    age_min = status.get('age_minutes', 0)
                    spaces_count = status.get('spaces_count', 0)
                    is_fresh = status.get('is_fresh', False)
                    
                    if is_fresh:
                        message = f"✅ Cache is fresh ({age_min:.1f} min old, {spaces_count} spaces)"
                    else:
                        message = f"⚠️ Cache is stale ({age_min:.1f} min old, {spaces_count} spaces)"
                    
                    return status, message
            except Exception as e:
                return {"error": str(e)}, f"❌ Error checking cache: {str(e)}"
        
        def force_update():
            try:
                result = force_cache_update()
                if 'error' in result:
                    return result, "❌ Failed to update cache"
                else:
                    # 获取更新后的状态
                    status = get_cache_status()
                    return status, "✅ Cache updated successfully"
            except Exception as e:
                return {"error": str(e)}, f"❌ Error updating cache: {str(e)}"
        
        def check_data_status():
            try:
                status = get_data_manager_status()
                if status['initialized']:
                    last_sync = status['last_sync']
                    if last_sync:
                        sync_time = datetime.fromisoformat(last_sync)
                        age_minutes = (datetime.now() - sync_time).total_seconds() / 60
                        message = f"✅ Data manager active (last sync: {age_minutes:.1f} min ago, {status['spaces_count']} spaces)"
                    else:
                        message = "⚠️ Data manager initialized but no sync recorded"
                else:
                    message = "❌ Data manager not initialized"
                return status, message
            except Exception as e:
                return {"error": str(e)}, f"❌ Error checking data manager: {str(e)}"
        
        def force_sync():
            try:
                result = force_data_sync()
                if 'error' in result:
                    return result, "❌ Failed to sync data"
                else:
                    # 获取更新后的状态
                    status = get_data_manager_status()
                    return status, "✅ Data sync completed successfully"
            except Exception as e:
                return {"error": str(e)}, f"❌ Error syncing data: {str(e)}"
        
        def check_memory_status():
            try:
                status = get_memory_allocation_status()
                active_count = status['active_count']
                total_stored = status['total_stored']
                
                if active_count > 0:
                    message = f"🧠 {active_count} active allocations ({total_stored} total in memory)"
                else:
                    message = "✅ No active memory allocations"
                
                return status, message
            except Exception as e:
                return {"error": str(e)}, f"❌ Error checking memory allocations: {str(e)}"
        
        def clear_memory():
            try:
                result = clear_memory_allocations()
                if 'error' in result:
                    return result, "❌ Failed to clear memory allocations"
                else:
                    # 获取更新后的状态
                    status = get_memory_allocation_status()
                    return status, f"✅ {result['status']}"
            except Exception as e:
                return {"error": str(e)}, f"❌ Error clearing memory: {str(e)}"
        
        # Cache tab event handlers
        cache_status_btn.click(
            fn=check_cache_status,
            outputs=[cache_info_display, cache_status_message]
        )
        
        force_cache_update_btn.click(
            fn=force_update,
            outputs=[cache_info_display, cache_status_message]
        )
        
        # Data tab event handlers
        data_status_btn.click(
            fn=check_data_status,
            outputs=[data_info_display, data_status_message]
        )
        
        force_data_sync_btn.click(
            fn=force_sync,
            outputs=[data_info_display, data_status_message]
        )
        
        # Memory tab event handlers
        memory_status_btn.click(
            fn=check_memory_status,
            outputs=[memory_info_display, memory_status_message]
        )
        
        clear_memory_btn.click(
            fn=clear_memory,
            outputs=[memory_info_display, memory_status_message]
        )
    
    return admin_interface

# 修改后的主Gradio界面
def create_main_interface():
    """创建主要的用户界面"""
    with gr.Blocks(title="CIV3283 Load Distributor") as interface:
        title_display = gr.Markdown("# 🔄 CIV3283 Learning Assistant Load Distributor", elem_id="title")
        content_display = gr.HTML("")
        
        # 主要的负载均衡逻辑 - 页面加载时执行
        interface.load(
            fn=handle_user_access_cached,
            outputs=[title_display, content_display]
        )
    
    return interface

# 修改后的main函数
if __name__ == "__main__":
    import sys
    
    try:
        # 系统初始化 - 只在启动时执行一次
        print("🚀 Initializing CIV3283 Load Distributor System...")
        init_system()
        print("✅ System initialization completed successfully")
        print("🧠 Using pure memory storage for allocations (no file I/O during user access)")
        
        # 检查是否需要管理界面
        enable_admin = "--admin" in sys.argv or os.environ.get("ENABLE_ADMIN", "false").lower() == "true"
        
        if enable_admin:
            print("🔧 Starting with admin interface enabled")
            # 创建带管理界面的组合界面
            main_interface = create_main_interface()
            admin_interface = create_admin_interface()
            
            # 使用TabbedInterface组合两个界面
            combined_interface = gr.TabbedInterface(
                [main_interface, admin_interface],
                ["🎯 Load Distributor", "🔧 Admin Panel"],
                title="CIV3283 Load Distributor System"
            )
            combined_interface.launch()
        else:
            print("🎯 Starting main interface only")
            # 只启动主界面
            main_interface = create_main_interface()
            main_interface.launch()
            
    except Exception as e:
        print(f"❌ System initialization failed: {e}")
        import traceback
        print(f"Traceback: {traceback.format_exc()}")
        raise