from flask import Blueprint, request, jsonify
from app.services.recommendation_service import RecommendationService
from app.functions.FAuth import FAuth
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from config import Config
from functools import wraps

recommend_bp = Blueprint('recommend', __name__, url_prefix='/api/recommend')

def token_required(f):
    """装饰器：需要令牌验证"""
    @wraps(f)
    def decorated(*args, **kwargs):
        token = request.headers.get('Authorization')
        if not token:
            return jsonify({'success': False, 'message': '缺少访问令牌'}), 401
        
        session = None
        try:
            # 移除Bearer前缀
            if token.startswith('Bearer '):
                token = token[7:]
            
            engine = create_engine(Config.SQLURL)
            SessionLocal = sessionmaker(bind=engine)
            session = SessionLocal()
            f_auth = FAuth(session)
            
            user = f_auth.get_user_by_token(token)
            if not user:
                return jsonify({'success': False, 'message': '无效的访问令牌'}), 401
            
            # 将用户信息传递给路由函数
            return f(user, *args, **kwargs)
        except Exception as e:
            if session:
                session.rollback()
            return jsonify({'success': False, 'message': '令牌验证失败'}), 401
        finally:
            if session:
                session.close()
    
    return decorated

# 初始化推荐服务
recommendation_service = RecommendationService()

@recommend_bp.route('/get_recommendations', methods=['POST'])
@token_required
def get_recommendations(current_user):
    """获取个性化推荐"""
    try:
        data = request.get_json()
        user_id = data.get('user_id') or current_user.user_id
        topk = data.get('topk', 2)
        
        recommendations = recommendation_service.get_recommendations(user_id, topk)
        
        return jsonify({
            'success': True,
            'data': {
                'user_id': user_id,
                'recommendations': recommendations,
                'count': len(recommendations)
            },
            'message': '推荐获取成功'
        })
    except Exception as e:
        return jsonify({
            'success': False, 
            'message': f'推荐获取失败: {str(e)}'
        }), 500

@recommend_bp.route('/cold_start', methods=['GET'])
def cold_start_recommendations():
    """冷启动推荐（无需登录）"""
    try:
        topk = request.args.get('topk', 2, type=int)
        
        recommendations = recommendation_service.user_cold_start(topk)
        
        return jsonify({
            'success': True,
            'data': {
                'recommendations': recommendations,
                'count': len(recommendations),
                'type': 'cold_start'
            },
            'message': '热门推荐获取成功'
        })
    except Exception as e:
        return jsonify({
            'success': False, 
            'message': f'推荐获取失败: {str(e)}'
        }), 500

@recommend_bp.route('/health', methods=['GET'])
def health_check():
    """推荐系统健康检查"""
    try:
        # 简单的健康检查
        import torch
        cuda_available = torch.cuda.is_available()
        
        return jsonify({
            'success': True,
            'data': {
                'status': 'healthy',
                'cuda_available': cuda_available,
                'device': 'cuda' if cuda_available else 'cpu'
            },
            'message': '推荐系统运行正常'
        })
    except Exception as e:
        return jsonify({
            'success': False,
            'message': f'推荐系统异常: {str(e)}'
        }), 500

@recommend_bp.route('/multi_recall', methods=['POST'])
@token_required
def multi_recall_recommendations(current_user):
    """多路召回推荐"""
    try:
        data = request.get_json()
        user_id = data.get('user_id') or current_user.user_id
        topk = data.get('topk', 2)
        
        # 强制使用多路召回
        result = recommendation_service.run_inference(user_id, topk, use_multi_recall=True)
        
        # 如果是冷启动直接返回详细信息，否则查详情
        if isinstance(result, list) and result and isinstance(result[0], dict):
            recommendations = result
        else:
            # result 是 (topk_post_ids, topk_scores) 的元组
            if isinstance(result, tuple) and len(result) == 2:
                topk_post_ids, topk_scores = result
                recommendations = recommendation_service.get_post_info(topk_post_ids, topk_scores)
            else:
                recommendations = recommendation_service.get_post_info(result)
        
        return jsonify({
            'success': True,
            'data': {
                'user_id': user_id,
                'recommendations': recommendations,
                'count': len(recommendations),
                'type': 'multi_recall'
            },
            'message': '多路召回推荐获取成功'
        })
    except Exception as e:
        return jsonify({
            'success': False, 
            'message': f'多路召回推荐获取失败: {str(e)}'
        }), 500

@recommend_bp.route('/lightgcn', methods=['POST'])
@token_required
def lightgcn_recommendations(current_user):
    """LightGCN推荐"""
    try:
        data = request.get_json()
        user_id = data.get('user_id') or current_user.user_id
        topk = data.get('topk', 2)
        
        # 强制使用LightGCN
        result = recommendation_service.run_inference(user_id, topk, use_multi_recall=False)
        
        # 如果是冷启动直接返回详细信息，否则查详情
        if isinstance(result, list) and result and isinstance(result[0], dict):
            recommendations = result
        else:
            # result 是 (topk_post_ids, topk_scores) 的元组
            if isinstance(result, tuple) and len(result) == 2:
                topk_post_ids, topk_scores = result
                recommendations = recommendation_service.get_post_info(topk_post_ids, topk_scores)
            else:
                recommendations = recommendation_service.get_post_info(result)
        
        return jsonify({
            'success': True,
            'data': {
                'user_id': user_id,
                'recommendations': recommendations,
                'count': len(recommendations),
                'type': 'lightgcn'
            },
            'message': 'LightGCN推荐获取成功'
        })
    except Exception as e:
        return jsonify({
            'success': False, 
            'message': f'LightGCN推荐获取失败: {str(e)}'
        }), 500

@recommend_bp.route('/train_multi_recall', methods=['POST'])
@token_required  
def train_multi_recall(current_user):
    """训练多路召回模型"""
    try:
        # 只有管理员才能训练模型
        if not hasattr(current_user, 'is_admin') or not current_user.is_admin:
            return jsonify({
                'success': False,
                'message': '需要管理员权限'
            }), 403
        
        recommendation_service.train_multi_recall()
        
        return jsonify({
            'success': True,
            'message': '多路召回模型训练完成'
        })
    except Exception as e:
        return jsonify({
            'success': False,
            'message': f'模型训练失败: {str(e)}'
        }), 500

@recommend_bp.route('/recall_config', methods=['GET'])
@token_required
def get_recall_config(current_user):
    """获取多路召回配置"""
    try:
        config = recommendation_service.recall_config
        return jsonify({
            'success': True,
            'data': {
                'config': config,
                'multi_recall_enabled': recommendation_service.multi_recall_enabled
            },
            'message': '配置获取成功'
        })
    except Exception as e:
        return jsonify({
            'success': False,
            'message': f'配置获取失败: {str(e)}'
        }), 500

@recommend_bp.route('/recall_config', methods=['POST'])
@token_required
def update_recall_config(current_user):
    """更新多路召回配置"""
    try:
        # 只有管理员才能更新配置
        if not hasattr(current_user, 'is_admin') or not current_user.is_admin:
            return jsonify({
                'success': False,
                'message': '需要管理员权限'
            }), 403
        
        data = request.get_json()
        new_config = data.get('config', {})
        
        # 更新多路召回启用状态
        if 'multi_recall_enabled' in data:
            recommendation_service.multi_recall_enabled = data['multi_recall_enabled']
        
        # 更新具体配置
        if new_config:
            recommendation_service.update_recall_config(new_config)
        
        return jsonify({
            'success': True,
            'data': {
                'config': recommendation_service.recall_config,
                'multi_recall_enabled': recommendation_service.multi_recall_enabled
            },
            'message': '配置更新成功'
        })
    except Exception as e:
        return jsonify({
            'success': False,
            'message': f'配置更新失败: {str(e)}'
        }), 500

@recommend_bp.route('/recall_stats/<int:user_id>', methods=['GET'])
@token_required
def get_recall_stats(current_user, user_id):
    """获取用户的召回统计信息"""
    try:
        # 只允许查看自己的统计或管理员查看
        if current_user.user_id != user_id and (not hasattr(current_user, 'is_admin') or not current_user.is_admin):
            return jsonify({
                'success': False,
                'message': '权限不足'
            }), 403
        
        stats = recommendation_service.get_multi_recall_stats(user_id)
        
        return jsonify({
            'success': True,
            'data': stats,
            'message': '统计信息获取成功'
        })
    except Exception as e:
        return jsonify({
            'success': False,
            'message': f'统计信息获取失败: {str(e)}'
        }), 500