from py2neo import Node, Relationship, Graph, NodeMatcher, RelationshipMatcher#导入我们需要的头文件

class Neo4jConn:
    head = None
    tail = None
    '''
        # 连接neo4j 数据库
    '''
    def initConnect(self, host, port, username, password):
        graph = Graph('http://'+host+':'+port, auth=(username,password), name='neo4j')
        return graph

    '''
        向图数据库插入三元组
    '''
    def inserTriple(self, graph, head_type, head_name, relation_name, tail_type, tail_name):
        matcher = NodeMatcher(graph)
        if matcher.match(head_type, name=head_name).first() == None:
            node = Node(head_type, name=head_name)
            graph.create(node)

            self.head = matcher.match(head_type, name=head_name).first()

        else:
            self.head = matcher.match(head_type, name=head_name).first()

        if matcher.match(tail_type, name=tail_name).first() == None:
            node = Node(tail_type, name=tail_name)
            graph.create(node)

            self.tail = matcher.match(tail_type, name=tail_name).first()

        else:
            self.tail = matcher.match(tail_type, name=tail_name).first()
        self.inserRelation(graph, self.head, relation_name, self.tail)

    '''
        向图数据库创建节点
    '''
    def inserNode(self, graph, Node_type, Node_name):
        node = Node(Node_type, name=Node_name)
        return graph.create(node)

    '''
        向图数据库创建已存在的头节点与尾节点之间的关系
    '''
    def inserRelation(self, graph, head, relation_name, tail):
        relation = Relationship(head, relation_name, tail)
        return graph.create(relation)

    '''
        查找符合条件的实体
    '''
    def findNode(self, graph, node_type, node_name):
        matcher = NodeMatcher(graph)
        result = matcher.match(node_type, node_name).first()
        return result

    '''
        删除所有已有结点
    '''
    def deleteAll(self, graph):
        return graph.delete_all()