knowledge-graph-agent/backend/internal/service/graph_queries.go

package service

import (
	"context"
	"fmt"

	"github.com/neo4j/neo4j-go-driver/v5/neo4j"

	"knowledge-graph-backend/internal/model"
)

func (s *Neo4jService) GetGraphData() model.GraphData {
	ctx := context.Background()
	var nodes []model.Node
	var edges []model.Edge

	nodeResult, err := neo4j.ExecuteQuery(ctx, s.driver,
		"MATCH (n) RETURN n",
		map[string]any{},
		neo4j.EagerResultTransformer,
	)
	if err != nil {
		fmt.Printf("Error querying nodes: %v\n", err)
		return model.GraphData{}
	}
	for _, record := range nodeResult.Records {
		if v, ok := record.Get("n"); ok {
			if n, ok := v.(neo4j.Node); ok {
				nodes = append(nodes, neo4jNodeToModel(n))
			}
		}
	}

	edgeResult, err := neo4j.ExecuteQuery(ctx, s.driver,
		"MATCH (a)-[r]->(b) RETURN a.id AS source, b.id AS target, r",
		map[string]any{},
		neo4j.EagerResultTransformer,
	)
	if err != nil {
		fmt.Printf("Error querying edges: %v\n", err)
		return model.GraphData{Nodes: nodes}
	}
	for _, record := range edgeResult.Records {
		source, _ := record.Get("source")
		target, _ := record.Get("target")
		v, _ := record.Get("r")
		if rel, ok := v.(neo4j.Relationship); ok {
			edge := neo4jRelToModel(rel)
			if s, ok := source.(string); ok {
				edge.Source = s
			}
			if t, ok := target.(string); ok {
				edge.Target = t
			}
			edges = append(edges, edge)
		}
	}

	return model.GraphData{Nodes: nodes, Edges: edges}
}

func (s *Neo4jService) GetNodeByID(id string) (model.Node, bool) {
	node, found, err := s.fetchNodeByID(id)
	if err != nil || !found {
		return model.Node{}, false
	}
	return node, true
}

func (s *Neo4jService) SearchNodes(query string) []model.Node {
	if query == "" {
		return []model.Node{}
	}
	ctx := context.Background()
	result, err := neo4j.ExecuteQuery(ctx, s.driver,
		`MATCH (n)
		 WHERE toLower(n.label) CONTAINS toLower($query)
		    OR toLower(n.id) CONTAINS toLower($query)
		    OR (n.type IS NOT NULL AND toLower(n.type) CONTAINS toLower($query))
		 RETURN n`,
		map[string]any{"query": query},
		neo4j.EagerResultTransformer,
	)
	if err != nil {
		return []model.Node{}
	}
	var nodes []model.Node
	for _, record := range result.Records {
		v, _ := record.Get("n")
		if n, ok := v.(neo4j.Node); ok {
			nodes = append(nodes, neo4jNodeToModel(n))
		}
	}
	return nodes
}

func (s *Neo4jService) GetNeighbors(nodeID string) (model.NeighborResponse, bool) {
	ctx := context.Background()

	if _, exists := s.GetNodeByID(nodeID); !exists {
		return model.NeighborResponse{}, false
	}

	result, err := neo4j.ExecuteQuery(ctx, s.driver,
		`MATCH ({id: $id})-[r]-(m)
		 RETURN m, r, startNode(r).id AS source, endNode(r).id AS target`,
		map[string]any{"id": nodeID},
		neo4j.EagerResultTransformer,
	)
	if err != nil {
		return model.NeighborResponse{Nodes: []model.Node{}, Edges: []model.Edge{}}, true
	}

	neighborMap := make(map[string]model.Node)
	edgeMap := make(map[string]model.Edge)

	for _, record := range result.Records {
		if v, ok := record.Get("m"); ok {
			if n, ok := v.(neo4j.Node); ok {
				modelNode := neo4jNodeToModel(n)
				neighborMap[modelNode.ID] = modelNode
			}
		}

		if v, ok := record.Get("r"); ok {
			if rel, ok := v.(neo4j.Relationship); ok {
				edge := neo4jRelToModel(rel)
				if source, ok := record.Get("source"); ok {
					if s, ok := source.(string); ok {
						edge.Source = s
					}
				}
				if target, ok := record.Get("target"); ok {
					if t, ok := target.(string); ok {
						edge.Target = t
					}
				}
				edgeMap[edge.ID] = edge
			}
		}
	}

	var neighborNodes []model.Node
	for _, n := range neighborMap {
		neighborNodes = append(neighborNodes, n)
	}

	var relatedEdges []model.Edge
	for _, e := range edgeMap {
		relatedEdges = append(relatedEdges, e)
	}

	return model.NeighborResponse{Nodes: neighborNodes, Edges: relatedEdges}, true
}

func (s *Neo4jService) GetStats() map[string]int {
	ctx := context.Background()
	result, err := neo4j.ExecuteQuery(ctx, s.driver,
		`MATCH (n)
		 RETURN count(n) AS totalNodes,
		        sum(CASE WHEN n.type = '概念' THEN 1 ELSE 0 END) AS conceptNodes,
		        sum(CASE WHEN n.type = '工具' THEN 1 ELSE 0 END) AS toolNodes,
		        sum(CASE WHEN n.type = '应用' THEN 1 ELSE 0 END) AS applicationNodes`,
		map[string]any{},
		neo4j.EagerResultTransformer,
	)
	if err != nil || len(result.Records) == 0 {
		return map[string]int{}
	}

	record := result.Records[0]
	totalNodes := getInt(record, "totalNodes")
	conceptNodes := getInt(record, "conceptNodes")
	toolNodes := getInt(record, "toolNodes")
	applicationNodes := getInt(record, "applicationNodes")

	totalEdges := 0
	edgeResult, err := neo4j.ExecuteQuery(ctx, s.driver,
		"MATCH ()-[r]->() RETURN count(r) AS totalEdges",
		map[string]any{},
		neo4j.EagerResultTransformer,
	)
	if err == nil && len(edgeResult.Records) > 0 {
		totalEdges = getInt(edgeResult.Records[0], "totalEdges")
	}

	return map[string]int{
		"totalNodes":       totalNodes,
		"totalEdges":       totalEdges,
		"conceptNodes":     conceptNodes,
		"toolNodes":        toolNodes,
		"applicationNodes": applicationNodes,
	}
}