package com.lingyue.graph.service;

import com.lingyue.common.exception.ServiceException;
import com.lingyue.graph.entity.GraphNode;
import com.lingyue.graph.entity.GraphRelation;
import com.lingyue.graph.entity.TextStorage;
import com.lingyue.graph.repository.GraphNodeRepository;
import com.lingyue.graph.repository.GraphRelationRepository;
import com.lingyue.graph.repository.TextStorageRepository;
import lombok.RequiredArgsConstructor;
import lombok.extern.slf4j.Slf4j;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Transactional;

import java.nio.charset.StandardCharsets;
import java.nio.file.Files;
import java.nio.file.Path;
import java.util.*;

/**
 * 图数据库 NER 服务
 * 
 * 负责将 NER 提取结果保存到图数据库。
 * 此服务位于 graph-service 模块，可以直接访问图数据库相关的实体和仓库。
 *
 * @author lingyue
 * @since 2026-01-19
 */
@Slf4j
@Service
@RequiredArgsConstructor
public class GraphNerService {

    private final TextStorageRepository textStorageRepository;
    private final GraphNodeRepository graphNodeRepository;
    private final GraphRelationRepository graphRelationRepository;

    /**
     * 获取文档的文本内容
     *
     * @param documentId 文档ID
     * @return 文本内容
     */
    public String getDocumentText(String documentId) {
        TextStorage textStorage = textStorageRepository.findByDocumentId(documentId);
        if (textStorage == null) {
            throw new ServiceException("文档文本存储记录不存在: documentId=" + documentId);
        }
        
        String filePath = textStorage.getFilePath();
        try {
            return Files.readString(Path.of(filePath), StandardCharsets.UTF_8);
        } catch (Exception e) {
            throw new ServiceException("读取文档文本失败: " + e.getMessage(), e);
        }
    }

    /**
     * 检查文档是否存在文本存储
     *
     * @param documentId 文档ID
     * @return 是否存在
     */
    public boolean hasDocumentText(String documentId) {
        TextStorage textStorage = textStorageRepository.findByDocumentId(documentId);
        return textStorage != null;
    }

    /**
     * 批量保存 NER 实体到图数据库
     *
     * @param documentId 文档ID
     * @param userId     用户ID
     * @param entities   实体列表（包含 name, type, value, position, context, confidence, tempId）
     * @return tempId 到实际 nodeId 的映射
     */
    @Transactional
    public Map<String, String> saveEntitiesToGraph(String documentId, String userId, 
                                                    List<Map<String, Object>> entities) {
        Map<String, String> tempIdToNodeId = new HashMap<>();
        
        if (entities == null || entities.isEmpty()) {
            log.debug("无实体需要保存");
            return tempIdToNodeId;
        }
        
        log.info("开始保存实体到图数据库: documentId={}, count={}", documentId, entities.size());
        
        for (Map<String, Object> entity : entities) {
            GraphNode node = new GraphNode();
            node.setId(UUID.randomUUID().toString().replace("-", ""));
            node.setDocumentId(documentId);
            node.setUserId(userId);  // 可为 null，自动 NER 提取时没有用户上下文
            node.setName(getStringValue(entity, "name"));
            node.setType(getStringValue(entity, "type", "other").toLowerCase());
            node.setValue(getStringValue(entity, "value"));
            node.setLevel(0);
            node.setCreateTime(new Date());
            node.setUpdateTime(new Date());
            
            // 转换位置信息（直接使用字符偏移）
            Object positionObj = entity.get("position");
            if (positionObj instanceof Map) {
                @SuppressWarnings("unchecked")
                Map<String, Object> posMap = (Map<String, Object>) positionObj;
                log.debug("实体位置信息: name={}, position={}", node.getName(), posMap);
                node.setPosition(posMap);
            } else {
                log.debug("实体无位置信息: name={}, positionObj={}", node.getName(), positionObj);
            }
            
            // 保存元数据
            Map<String, Object> metadata = new HashMap<>();
            String context = getStringValue(entity, "context");
            if (context != null) {
                metadata.put("context", context);
            }
            Object confidence = entity.get("confidence");
            if (confidence != null) {
                metadata.put("confidence", confidence);
            }
            metadata.put("source", "ner");
            node.setMetadata(metadata);
            
            graphNodeRepository.insert(node);
            
            // 记录 tempId 到 nodeId 的映射
            String tempId = getStringValue(entity, "tempId");
            if (tempId != null) {
                tempIdToNodeId.put(tempId, node.getId());
            }
        }
        
        log.info("实体保存完成: documentId={}, savedCount={}", documentId, entities.size());
        return tempIdToNodeId;
    }

    /**
     * 批量保存 NER 关系到图数据库
     *
     * @param relations       关系列表
     * @param tempIdToNodeId  tempId 到 nodeId 的映射
     * @return 保存成功的数量
     */
    @Transactional
    public int saveRelationsToGraph(List<Map<String, Object>> relations, 
                                     Map<String, String> tempIdToNodeId) {
        if (relations == null || relations.isEmpty()) {
            log.debug("无关系需要保存");
            return 0;
        }
        
        log.info("开始保存关系到图数据库: count={}", relations.size());
        
        int savedCount = 0;
        for (Map<String, Object> relation : relations) {
            // 通过 tempId 获取实际的 nodeId
            String fromEntityId = getStringValue(relation, "fromEntityId");
            String toEntityId = getStringValue(relation, "toEntityId");
            
            String fromNodeId = fromEntityId != null ? tempIdToNodeId.get(fromEntityId) : null;
            String toNodeId = toEntityId != null ? tempIdToNodeId.get(toEntityId) : null;
            
            // 如果无法找到对应的节点，跳过
            if (fromNodeId == null || toNodeId == null) {
                log.debug("跳过关系保存（节点不存在）: from={}, to={}", 
                        getStringValue(relation, "fromEntity"), 
                        getStringValue(relation, "toEntity"));
                continue;
            }
            
            GraphRelation graphRelation = new GraphRelation();
            graphRelation.setId(UUID.randomUUID().toString().replace("-", ""));
            graphRelation.setFromNodeId(fromNodeId);
            graphRelation.setToNodeId(toNodeId);
            graphRelation.setRelationType(mapRelationType(getStringValue(relation, "relationType")));
            graphRelation.setOrderIndex(0);
            graphRelation.setCreateTime(new Date());
            graphRelation.setUpdateTime(new Date());
            
            // 保存元数据
            Map<String, Object> metadata = new HashMap<>();
            Object confidence = relation.get("confidence");
            if (confidence != null) {
                metadata.put("confidence", confidence);
            }
            metadata.put("originalType", getStringValue(relation, "relationType"));
            metadata.put("source", "ner");
            graphRelation.setMetadata(metadata);
            
            graphRelationRepository.insert(graphRelation);
            savedCount++;
        }
        
        log.info("关系保存完成: savedCount={}", savedCount);
        return savedCount;
    }

    /**
     * 删除文档的所有 NER 生成的节点和关系
     *
     * @param documentId 文档ID
     * @return 删除的节点数量
     */
    @Transactional
    public int deleteNerResultsByDocumentId(String documentId) {
        log.info("删除文档 NER 结果: documentId={}", documentId);
        
        // 获取文档的所有节点
        List<GraphNode> nodes = graphNodeRepository.findByDocumentId(documentId);
        
        int deletedCount = 0;
        for (GraphNode node : nodes) {
            // 检查是否是 NER 生成的节点
            if (node.getMetadata() instanceof Map) {
                Map<?, ?> metadata = (Map<?, ?>) node.getMetadata();
                if ("ner".equals(metadata.get("source"))) {
                    // 先删除相关的关系
                    List<GraphRelation> relations = graphRelationRepository.findByNodeId(node.getId());
                    for (GraphRelation relation : relations) {
                        graphRelationRepository.deleteById(relation.getId());
                    }
                    // 再删除节点
                    graphNodeRepository.deleteById(node.getId());
                    deletedCount++;
                }
            }
        }
        
        log.info("NER 结果删除完成: documentId={}, deletedCount={}", documentId, deletedCount);
        return deletedCount;
    }

    /**
     * 获取文档的 NER 统计信息
     *
     * @param documentId 文档ID
     * @return 统计信息
     */
    public Map<String, Object> getNerStatsByDocumentId(String documentId) {
        List<GraphNode> nodes = graphNodeRepository.findByDocumentId(documentId);
        
        int nerNodeCount = 0;
        Map<String, Integer> typeStats = new HashMap<>();
        
        for (GraphNode node : nodes) {
            if (node.getMetadata() instanceof Map) {
                Map<?, ?> metadata = (Map<?, ?>) node.getMetadata();
                if ("ner".equals(metadata.get("source"))) {
                    nerNodeCount++;
                    String type = node.getType();
                    typeStats.put(type, typeStats.getOrDefault(type, 0) + 1);
                }
            }
        }
        
        Map<String, Object> stats = new HashMap<>();
        stats.put("documentId", documentId);
        stats.put("totalNerNodes", nerNodeCount);
        stats.put("typeStats", typeStats);
        
        return stats;
    }

    /**
     * 映射关系类型到系统定义的类型
     */
    private String mapRelationType(String originalType) {
        if (originalType == null) {
            return "DEP";
        }
        
        // 映射常见关系类型
        switch (originalType) {
            case "负责":
            case "管理":
            case "承担":
            case "属于":
            case "隶属":
            case "包含":
            case "包括":
            case "位于":
            case "在":
            case "使用":
            case "采用":
                return "DEP";  // 依赖关系
            default:
                return "DEP";  // 默认为依赖关系
        }
    }

    /**
     * 从 Map 中获取字符串值
     */
    private String getStringValue(Map<String, Object> map, String key) {
        return getStringValue(map, key, null);
    }

    /**
     * 从 Map 中获取字符串值，带默认值
     */
    private String getStringValue(Map<String, Object> map, String key, String defaultValue) {
        Object value = map.get(key);
        if (value == null) {
            return defaultValue;
        }
        return value.toString();
    }
}