from models import db, User, APIKey
from datetime import datetime

class APIKeyService:
    @staticmethod
    def list_api_keys(user_id):
        """获取用户的所有 API Key"""
        user = User.query.get(user_id)
        
        if not user:
            return {'error': '用户不存在'}, 404
        
        keys = APIKey.query.filter_by(user_id=user_id).all()
        
        return {
            'total': len(keys),
            'keys': [key.to_dict() for key in keys]
        }, 200

    @staticmethod
    def create_api_key(user_id, data):
        """创建新的 API Key"""
        user = User.query.get(user_id)
        
        if not user:
            return {'error': '用户不存在'}, 404
        
        name = data.get('name', '').strip()
        
        if not name:
            return {'error': 'API Key 名称不能为空'}, 400
        
        if len(name) > 100:
            return {'error': 'API Key 名称长度不能超过100个字符'}, 400
        
        # 生成 API Key
        api_key = APIKey.generate_key()
        
        # 创建数据库记录
        new_key = APIKey(
            user_id=user_id,
            name=name,
            api_key=api_key
        )
        
        try:
            db.session.add(new_key)
            db.session.commit()
            
            return {
                'message': 'API Key 创建成功',
                'key': new_key.to_dict()
            }, 201
        except Exception as e:
            db.session.rollback()
            return {'error': '创建失败，请稍后重试'}, 500

    @staticmethod
    def get_api_key(user_id, key_id):
        """获取单个 API Key 详情"""
        key = APIKey.query.filter_by(id=key_id, user_id=user_id).first()
        
        if not key:
            return {'error': 'API Key 不存在'}, 404
        
        return key.to_dict(), 200

    @staticmethod
    def update_api_key(user_id, key_id, data):
        """更新 API Key 名称或状态"""
        key = APIKey.query.filter_by(id=key_id, user_id=user_id).first()
        
        if not key:
            return {'error': 'API Key 不存在'}, 404
        
        if 'name' in data:
            name = data.get('name', '').strip()
            if not name or len(name) > 100:
                return {'error': 'API Key 名称无效'}, 400
            key.name = name
        
        if 'is_active' in data:
            key.is_active = bool(data.get('is_active'))
        
        try:
            db.session.commit()
            return {
                'message': 'API Key 更新成功',
                'key': key.to_dict()
            }, 200
        except Exception as e:
            db.session.rollback()
            return {'error': '更新失败，请稍后重试'}, 500

    @staticmethod
    def delete_api_key(user_id, key_id):
        """删除 API Key"""
        key = APIKey.query.filter_by(id=key_id, user_id=user_id).first()
        
        if not key:
            return {'error': 'API Key 不存在'}, 404
        
        try:
            db.session.delete(key)
            db.session.commit()
            return {'message': 'API Key 已删除'}, 200
        except Exception as e:
            db.session.rollback()
            return {'error': '删除失败，请稍后重试'}, 500

    @staticmethod
    def regenerate_api_key(user_id, key_id):
        """重置/轮换 API Key"""
        key = APIKey.query.filter_by(id=key_id, user_id=user_id).first()
        
        if not key:
            return {'error': 'API Key 不存在'}, 404
        
        # 生成新的 API Key
        new_api_key = APIKey.generate_key()
        key.api_key = new_api_key
        
        try:
            db.session.commit()
            return {
                'message': 'API Key 已重置',
                'key': key.to_dict()
            }, 200
        except Exception as e:
            db.session.rollback()
            return {'error': '重置失败，请稍后重试'}, 500

    @staticmethod
    def authenticate_api_key(auth_header):
        """验证 API Key 并返回用户"""
        if not auth_header:
            return None, "缺少 Authorization 头"
        
        parts = auth_header.split()
        if parts[0].lower() != "bearer":
            return None, "Authorization 头格式错误"
        
        if len(parts) == 1:
            return None, "无效的 Token"
            
        api_key_str = parts[1]
        
        # 查找 API Key
        api_key = APIKey.query.filter_by(api_key=api_key_str).first()
        
        if not api_key:
            return None, "无效的 API Key"
            
        if not api_key.is_active:
            return None, "API Key 已被禁用"
            
        # 更新最后使用时间
        api_key.last_used_at = datetime.utcnow()
        db.session.commit()
        
        user = User.query.get(api_key.user_id)
        if not user or not user.is_active:
            return None, "账户不存在或已被禁用"
            
        return user, None