package main

import (
	"bytes"
	"context"
	"encoding/json"
	"fmt"
	"io"
	"math"
	"net/http"
	"os"
	"path/filepath"
	"regexp"
	"sort"
	"strings"
	"time"

	"qiweimanager/config"
)

const (
	retrievalModeKeywordOnly  = "keyword"
	retrievalModeHybridRerank = "hybrid_rerank"
	defaultRRFK               = 60.0
)

type EmbeddingEntry struct {
	ChunkID   string    `json:"chunkId"`
	Hash      string    `json:"hash"`
	Source    string    `json:"source"`
	Title     string    `json:"title"`
	Embedding []float64 `json:"embedding"`
	UpdatedAt int64     `json:"updatedAt"`
}

type EmbeddingIndex struct {
	Model         string                    `json:"model"`
	Dimensions    int                       `json:"dimensions"`
	Entries       map[string]EmbeddingEntry `json:"entries"`
	LastIndexedAt int64                     `json:"lastIndexedAt"`
}

type KnowledgeSearchResult struct {
	Hits                 []KnowledgeChunk
	KeywordScore         float64
	VectorScore          float64
	RerankScore          float64
	RetrievalMode        string
	UsedKnowledgeSources []string
	Timings              autoReplyTimings
}

var wikiLinkPattern = regexp.MustCompile(`\[\[([^\]|#]+)(?:[|#][^\]]*)?\]\]`)

type retrievalCandidate struct {
	Chunk        KnowledgeChunk
	KeywordScore float64
	VectorScore  float64
	FusionScore  float64
	RerankScore  float64
	KeywordRank  int
	VectorRank   int
}

func NewEmbeddingIndex(model string, dimensions int) *EmbeddingIndex {
	return &EmbeddingIndex{
		Model:      model,
		Dimensions: dimensions,
		Entries:    make(map[string]EmbeddingEntry),
	}
}

func (e *AutoReplyEngine) loadEmbeddingIndex() error {
	cfg := e.getConfig()
	path := resolveAutoReplyPath(cfg.Retrieval.EmbeddingIndexPath)
	data, err := os.ReadFile(path)
	if err != nil {
		if os.IsNotExist(err) {
			e.updateEmbeddingStatus(NewEmbeddingIndex(cfg.Retrieval.EmbeddingModel, cfg.Retrieval.EmbeddingDimensions))
			return nil
		}
		return err
	}
	var idx EmbeddingIndex
	if err := json.Unmarshal(data, &idx); err != nil {
		return err
	}
	if idx.Entries == nil {
		idx.Entries = make(map[string]EmbeddingEntry)
	}
	e.updateEmbeddingStatus(&idx)
	return nil
}

func (e *AutoReplyEngine) updateEmbeddingStatus(idx *EmbeddingIndex) {
	if idx == nil {
		idx = NewEmbeddingIndex("", 0)
	}
	e.mu.Lock()
	e.embeddingIndex = idx
	e.status.EmbeddingChunkCount = len(idx.Entries)
	e.status.EmbeddingModel = idx.Model
	e.status.EmbeddingDimensions = idx.Dimensions
	e.status.EmbeddingLastIndexedAt = idx.LastIndexedAt
	e.mu.Unlock()
}

func (e *AutoReplyEngine) rebuildEmbeddingIndex(idx *KnowledgeIndex) error {
	cfg := e.getConfig()
	if strings.TrimSpace(cfg.AI.APIKey) == "" || strings.TrimSpace(cfg.AI.BaseURL) == "" {
		e.updateEmbeddingStatus(NewEmbeddingIndex(cfg.Retrieval.EmbeddingModel, cfg.Retrieval.EmbeddingDimensions))
		return fmt.Errorf("Embedding索引跳过：AI Base URL 或 API Key 未配置")
	}
	if idx == nil {
		return nil
	}
	previous := e.embeddingIndex
	if previous == nil {
		previous = NewEmbeddingIndex(cfg.Retrieval.EmbeddingModel, cfg.Retrieval.EmbeddingDimensions)
	}
	next := NewEmbeddingIndex(cfg.Retrieval.EmbeddingModel, cfg.Retrieval.EmbeddingDimensions)
	next.LastIndexedAt = time.Now().Unix()

	var batchChunks []KnowledgeChunk
	var batchTexts []string
	flush := func() error {
		if len(batchChunks) == 0 {
			return nil
		}
		vectors, err := callDashScopeEmbeddings(cfg.AI, cfg.Retrieval, batchTexts)
		if err != nil {
			return err
		}
		for i, vector := range vectors {
			if i >= len(batchChunks) {
				break
			}
			chunk := batchChunks[i]
			next.Entries[chunk.ID] = EmbeddingEntry{
				ChunkID:   chunk.ID,
				Hash:      chunk.Hash,
				Source:    chunk.Source,
				Title:     chunk.Title,
				Embedding: vector,
				UpdatedAt: chunk.UpdatedAt,
			}
		}
		batchChunks = nil
		batchTexts = nil
		return nil
	}

	for _, chunk := range idx.Chunks {
		if entry, ok := previous.Entries[chunk.ID]; ok &&
			entry.Hash == chunk.Hash &&
			len(entry.Embedding) > 0 &&
			previous.Model == cfg.Retrieval.EmbeddingModel &&
			previous.Dimensions == cfg.Retrieval.EmbeddingDimensions {
			next.Entries[chunk.ID] = entry
			continue
		}
		batchChunks = append(batchChunks, chunk)
		batchTexts = append(batchTexts, buildRetrievalDocumentText(chunk))
		if len(batchChunks) >= 10 {
			if err := flush(); err != nil {
				return err
			}
		}
	}
	if err := flush(); err != nil {
		return err
	}

	path := resolveAutoReplyPath(cfg.Retrieval.EmbeddingIndexPath)
	if err := os.MkdirAll(filepath.Dir(path), 0755); err != nil {
		return err
	}
	data, err := json.MarshalIndent(next, "", "  ")
	if err != nil {
		return err
	}
	if err := os.WriteFile(path, data, 0644); err != nil {
		return err
	}
	e.updateEmbeddingStatus(next)
	return nil
}

func (e *AutoReplyEngine) searchKnowledge(query string) []KnowledgeChunk {
	return e.searchKnowledgeDetailed(query).Hits
}

func (e *AutoReplyEngine) searchKnowledgeDetailed(query string) KnowledgeSearchResult {
	cfg := e.getConfig()
	mode := strings.TrimSpace(cfg.Retrieval.RetrievalMode)
	if mode == "" {
		mode = retrievalModeHybridRerank
	}
	result := KnowledgeSearchResult{RetrievalMode: mode}
	keywordStart := time.Now()
	keywordHits := e.searchKeywordKnowledge(query, maxInt(cfg.Retrieval.RecallTopK, cfg.Knowledge.TopK))
	if isGenericProductQuery(query) {
		keywordHits = e.expandProductKnowledgeHits(query, keywordHits)
	}
	result.Timings.KeywordDurationMS = time.Since(keywordStart).Milliseconds()
	result.KeywordScore = topChunkScore(keywordHits)

	if mode == retrievalModeKeywordOnly {
		result.Hits = e.expandKnowledgeNeighborHits(query, limitKnowledgeChunks(keywordHits, cfg.Retrieval.FinalTopK))
		result.UsedKnowledgeSources = knowledgeSources(result.Hits)
		result.Timings.KnowledgeDurationMS = result.Timings.KeywordDurationMS
		return result
	}

	vectorStart := time.Now()
	vectorHits, vectorErr := e.searchVectorKnowledge(query, cfg.Retrieval.RecallTopK)
	result.Timings.VectorDurationMS = time.Since(vectorStart).Milliseconds()
	result.VectorScore = topChunkScore(vectorHits)
	if vectorErr != nil {
		e.setLastErrorWithScope(autoReplyErrorScopeKnowledge, "向量召回失败，已降级关键词检索: "+vectorErr.Error())
		result.Hits = e.expandKnowledgeNeighborHits(query, limitKnowledgeChunks(keywordHits, cfg.Retrieval.FinalTopK))
		result.UsedKnowledgeSources = knowledgeSources(result.Hits)
		result.Timings.KnowledgeDurationMS = result.Timings.KeywordDurationMS + result.Timings.VectorDurationMS
		return result
	}

	candidates := fuseRetrievalCandidates(keywordHits, vectorHits, query)
	if len(candidates) == 0 {
		result.Hits = nil
		result.Timings.KnowledgeDurationMS = result.Timings.KeywordDurationMS + result.Timings.VectorDurationMS
		return result
	}
	candidates = limitCandidates(candidates, cfg.Retrieval.RerankTopK)

	rerankStart := time.Now()
	reranked, rerankErr := callDashScopeRerank(cfg.AI, cfg.Retrieval, query, candidates)
	result.Timings.RerankDurationMS = time.Since(rerankStart).Milliseconds()
	if rerankErr == nil && len(reranked) > 0 {
		candidates = reranked
		result.RetrievalMode = retrievalModeHybridRerank
	} else if rerankErr != nil {
		e.setLastErrorWithScope(autoReplyErrorScopeKnowledge, "重排序失败，已使用混合召回结果: "+rerankErr.Error())
	}
	sort.Slice(candidates, func(i, j int) bool {
		return candidateScore(candidates[i]) > candidateScore(candidates[j])
	})
	candidates = limitCandidates(candidates, cfg.Retrieval.FinalTopK)
	result.Hits = e.expandKnowledgeNeighborHits(query, candidatesToKnowledgeChunks(candidates))
	if isGenericProductQuery(query) {
		result.Hits = e.expandProductKnowledgeHits(query, result.Hits)
	}
	result.RerankScore = topCandidateRerankScore(candidates)
	result.UsedKnowledgeSources = knowledgeSources(result.Hits)
	result.Timings.KnowledgeDurationMS = result.Timings.KeywordDurationMS + result.Timings.VectorDurationMS + result.Timings.RerankDurationMS
	return result
}

func isGenericProductQuery(query string) bool {
	query = strings.ToLower(strings.TrimSpace(query))
	if query == "" {
		return false
	}
	keywords := []string{
		"有什么产品", "有哪些产品", "具体有什么产品", "产品介绍", "产品线", "产品矩阵",
		"产品清单", "产品列表", "产品型号", "型号", "设备型号", "哪些型号",
		"全部产品", "所有产品", "全部产品介绍", "所有产品介绍", "产品大全", "完整产品线",
		"你们公司的全部产品", "你们公司全部产品", "你们所有产品", "公司的全部产品",
	}
	for _, keyword := range keywords {
		if strings.Contains(query, strings.ToLower(keyword)) {
			return true
		}
	}
	if strings.Contains(query, "产品") && (strings.Contains(query, "什么") || strings.Contains(query, "哪些") || strings.Contains(query, "介绍") || strings.Contains(query, "全部") || strings.Contains(query, "所有") || strings.Contains(query, "完整")) {
		return true
	}
	return false
}

func (e *AutoReplyEngine) expandProductKnowledgeHits(query string, hits []KnowledgeChunk) []KnowledgeChunk {
	e.mu.Lock()
	idx := e.index
	e.mu.Unlock()
	if idx == nil || len(idx.Chunks) == 0 {
		return hits
	}
	bySource := make(map[string][]KnowledgeChunk)
	for _, chunk := range idx.Chunks {
		if isLowValueKnowledgeBlock(chunk.Title, chunk.Content) {
			continue
		}
		sourceKey := normalizeKnowledgeSourceKey(chunk.Source)
		bySource[sourceKey] = append(bySource[sourceKey], chunk)
	}
	result := append([]KnowledgeChunk(nil), hits...)
	seen := make(map[string]bool)
	for _, hit := range result {
		seen[hit.ID] = true
	}
	linkedNames := make([]string, 0)
	for _, hit := range hits {
		if isProductHubChunk(hit) {
			linkedNames = append(linkedNames, extractWikiLinkNames(hit.Content)...)
		}
	}
	linkedNames = append(linkedNames, defaultProductKnowledgeNames()...)
	for _, name := range uniqueStrings(linkedNames) {
		if len(result) >= 10 {
			break
		}
		for _, chunk := range bySource[normalizeKnowledgeSourceKey(name+".md")] {
			if len(result) >= 10 {
				break
			}
			if seen[chunk.ID] || !isProductSummaryChunk(chunk, name) {
				continue
			}
			chunk.Score = productExpansionScore(query, chunk)
			result = append(result, chunk)
			seen[chunk.ID] = true
			break
		}
	}
	sort.SliceStable(result, func(i, j int) bool {
		return productHitRank(result[i]) < productHitRank(result[j])
	})
	return result
}

func isProductHubChunk(chunk KnowledgeChunk) bool {
	text := chunk.Source + " " + chunk.Title + " " + chunk.Content
	return strings.Contains(text, "产品矩阵") ||
		strings.Contains(text, "AgentBox") ||
		strings.Contains(text, "硬件载体") ||
		strings.Contains(text, "模型引擎") ||
		strings.Contains(text, "AI 应用")
}

func extractWikiLinkNames(text string) []string {
	matches := wikiLinkPattern.FindAllStringSubmatch(text, -1)
	names := make([]string, 0, len(matches))
	for _, match := range matches {
		if len(match) < 2 {
			continue
		}
		name := strings.TrimSpace(match[1])
		if name != "" {
			names = append(names, name)
		}
	}
	return names
}

func defaultProductKnowledgeNames() []string {
	return []string{
		"产品矩阵", "AgentBox", "VISION-S01", "PRO-S01", "PRO-Y01", "SUPER-S01",
		"AWIN25", "数字员工", "万川智媒", "智雕工坊",
	}
}

func isProductSummaryChunk(chunk KnowledgeChunk, name string) bool {
	title := strings.TrimSpace(chunk.Title)
	content := strings.TrimSpace(chunk.Content)
	if title == name || strings.EqualFold(title, name) {
		return true
	}
	if strings.HasPrefix(content, ">") {
		return true
	}
	if strings.Contains(title, "核心定位") || strings.Contains(title, "定义") || strings.Contains(title, "关键能力") {
		return true
	}
	return false
}

func productExpansionScore(query string, chunk KnowledgeChunk) float64 {
	score := 0.82 + exactMatchBoost(query, chunk)
	if strings.Contains(chunk.Source, "产品矩阵") {
		score += 0.12
	}
	return score
}

func productHitRank(chunk KnowledgeChunk) int {
	source := normalizeKnowledgeSourceKey(chunk.Source)
	order := defaultProductKnowledgeNames()
	for i, name := range order {
		if source == normalizeKnowledgeSourceKey(name+".md") {
			return i
		}
	}
	return len(order) + 1
}

func normalizeKnowledgeSourceKey(source string) string {
	source = strings.ToLower(strings.TrimSpace(filepath.ToSlash(source)))
	source = strings.TrimSuffix(source, ".md")
	source = strings.TrimSuffix(source, ".txt")
	source = strings.TrimSuffix(source, ".csv")
	source = strings.TrimSuffix(source, ".xlsx")
	source = strings.TrimSuffix(source, ".docx")
	source = strings.TrimSuffix(source, ".pdf")
	return filepath.Base(source)
}

func uniqueStrings(values []string) []string {
	seen := make(map[string]bool)
	result := make([]string, 0, len(values))
	for _, value := range values {
		value = strings.TrimSpace(value)
		key := normalizeKnowledgeSourceKey(value)
		if value == "" || seen[key] {
			continue
		}
		seen[key] = true
		result = append(result, value)
	}
	return result
}

func (e *AutoReplyEngine) searchKeywordKnowledge(query string, limit int) []KnowledgeChunk {
	e.mu.Lock()
	idx := e.index
	e.mu.Unlock()
	if idx == nil || len(idx.Chunks) == 0 {
		return nil
	}
	queryTokens := tokenizeKnowledgeText(query)
	if len(queryTokens) == 0 {
		return nil
	}
	results := make([]KnowledgeChunk, 0, limit)
	for _, chunk := range idx.Chunks {
		score := scoreKnowledgeChunk(queryTokens, chunk)
		score += exactMatchBoost(query, chunk)
		if score <= 0 {
			continue
		}
		c := chunk
		c.Score = score
		results = append(results, c)
	}
	sort.Slice(results, func(i, j int) bool {
		return results[i].Score > results[j].Score
	})
	return limitKnowledgeChunks(results, limit)
}

func (e *AutoReplyEngine) searchVectorKnowledge(query string, limit int) ([]KnowledgeChunk, error) {
	cfg := e.getConfig()
	e.mu.Lock()
	idx := e.index
	embeddingIndex := e.embeddingIndex
	e.mu.Unlock()
	if idx == nil || embeddingIndex == nil || len(embeddingIndex.Entries) == 0 {
		return nil, fmt.Errorf("向量索引为空，请先重建知识库索引")
	}
	if strings.TrimSpace(cfg.AI.APIKey) == "" || strings.TrimSpace(cfg.AI.BaseURL) == "" {
		return nil, fmt.Errorf("AI Base URL 或 API Key 未配置")
	}
	vectors, err := callDashScopeEmbeddings(cfg.AI, cfg.Retrieval, []string{query})
	if err != nil {
		return nil, err
	}
	if len(vectors) == 0 {
		return nil, fmt.Errorf("Embedding返回空向量")
	}
	chunksByID := make(map[string]KnowledgeChunk, len(idx.Chunks))
	for _, chunk := range idx.Chunks {
		chunksByID[chunk.ID] = chunk
	}
	results := make([]KnowledgeChunk, 0, limit)
	for chunkID, entry := range embeddingIndex.Entries {
		chunk, ok := chunksByID[chunkID]
		if !ok || len(entry.Embedding) == 0 {
			continue
		}
		score := cosineSimilarity(vectors[0], entry.Embedding)
		if score <= 0 {
			continue
		}
		chunk.Score = (score + 1) / 2
		results = append(results, chunk)
	}
	sort.Slice(results, func(i, j int) bool {
		return results[i].Score > results[j].Score
	})
	return limitKnowledgeChunks(results, limit), nil
}

func callDashScopeEmbeddings(aiCfg config.AIConfig, retrievalCfg config.RetrievalConfig, inputs []string) ([][]float64, error) {
	if len(inputs) == 0 {
		return nil, nil
	}
	url := strings.TrimRight(aiCfg.BaseURL, "/")
	if !strings.HasSuffix(url, "/embeddings") {
		url += "/embeddings"
	}
	payload := map[string]interface{}{
		"model":           retrievalCfg.EmbeddingModel,
		"input":           inputs,
		"encoding_format": "float",
	}
	if retrievalCfg.EmbeddingDimensions > 0 {
		payload["dimensions"] = retrievalCfg.EmbeddingDimensions
	}
	var response struct {
		Data []struct {
			Embedding []float64 `json:"embedding"`
			Index     int       `json:"index"`
		} `json:"data"`
		Error interface{} `json:"error"`
	}
	if err := doRetrievalJSONRequest(aiCfg, url, payload, &response); err != nil {
		// 检测是否是模型配置错误
		errMsg := err.Error()
		if strings.Contains(strings.ToLower(errMsg), "unsupported model") &&
			strings.Contains(strings.ToLower(errMsg), "rerank") {
			return nil, fmt.Errorf("Embedding模型配置错误：'%s' 是一个Rerank模型，不是Embedding模型。请使用 text-embedding-v4 或 text-embedding-v3 等Embedding模型", retrievalCfg.EmbeddingModel)
		}
		return nil, err
	}
	if response.Error != nil {
		return nil, fmt.Errorf("Embedding返回错误: %v", response.Error)
	}
	vectors := make([][]float64, len(response.Data))
	for i, item := range response.Data {
		target := i
		if item.Index >= 0 && item.Index < len(response.Data) {
			target = item.Index
		}
		vectors[target] = item.Embedding
	}
	return vectors, nil
}

func callDashScopeRerank(aiCfg config.AIConfig, retrievalCfg config.RetrievalConfig, query string, candidates []retrievalCandidate) ([]retrievalCandidate, error) {
	if len(candidates) == 0 {
		return nil, nil
	}
	documents := make([]string, 0, len(candidates))
	for _, candidate := range candidates {
		documents = append(documents, truncateTextForPrompt(buildRetrievalDocumentText(candidate.Chunk), 1200))
	}
	topN := retrievalCfg.FinalTopK
	if topN <= 0 || topN > len(documents) {
		topN = len(documents)
	}
	payload := map[string]interface{}{
		"model":     retrievalCfg.RerankModel,
		"query":     query,
		"documents": documents,
		"top_n":     topN,
		"instruct":  "Given a customer support query, retrieve passages that directly answer the query about Lingze Wanchuan products, services, or after-sales support.",
	}
	var response struct {
		Results []struct {
			Index          int     `json:"index"`
			RelevanceScore float64 `json:"relevance_score"`
			Score          float64 `json:"score"`
		} `json:"results"`
		Error interface{} `json:"error"`
	}
	var lastErr error
	for _, url := range dashScopeRerankURLs(aiCfg) {
		if err := doRetrievalJSONRequest(aiCfg, url, payload, &response); err != nil {
			lastErr = err
			continue
		}
		lastErr = nil
		break
	}
	if lastErr != nil {
		return nil, lastErr
	}
	if response.Error != nil {
		return nil, fmt.Errorf("Rerank返回错误: %v", response.Error)
	}
	if len(response.Results) == 0 {
		return nil, fmt.Errorf("Rerank返回空结果")
	}
	reranked := make([]retrievalCandidate, 0, len(response.Results))
	for _, item := range response.Results {
		if item.Index < 0 || item.Index >= len(candidates) {
			continue
		}
		candidate := candidates[item.Index]
		candidate.RerankScore = item.RelevanceScore
		if candidate.RerankScore <= 0 {
			candidate.RerankScore = item.Score
		}
		reranked = append(reranked, candidate)
	}
	return reranked, nil
}

func doRetrievalJSONRequest(aiCfg config.AIConfig, url string, payload interface{}, out interface{}) error {
	timeout := time.Duration(aiCfg.TimeoutSeconds) * time.Second
	if timeout <= 0 {
		timeout = 20 * time.Second
	}
	body, err := json.Marshal(payload)
	if err != nil {
		return err
	}
	ctx, cancel := context.WithTimeout(context.Background(), timeout)
	defer cancel()
	req, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewBuffer(body))
	if err != nil {
		return err
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Set("Authorization", "Bearer "+strings.TrimSpace(aiCfg.APIKey))
	resp, err := http.DefaultClient.Do(req)
	if err != nil {
		return err
	}
	defer resp.Body.Close()
	respBody, err := io.ReadAll(resp.Body)
	if err != nil {
		return err
	}
	if resp.StatusCode < 200 || resp.StatusCode >= 300 {
		return fmt.Errorf("HTTP状态码错误: %d, body=%s", resp.StatusCode, truncateText(string(respBody), 240))
	}
	if err := json.Unmarshal(respBody, out); err != nil {
		return fmt.Errorf("解析响应失败: %v, body=%s", err, truncateText(string(respBody), 240))
	}
	return nil
}

func dashScopeRerankURLs(aiCfg config.AIConfig) []string {
	baseURL := strings.TrimRight(aiCfg.BaseURL, "/")
	if strings.Contains(baseURL, "dashscope.aliyuncs.com") {
		return []string{
			"https://dashscope.aliyuncs.com/compatible-api/v1/reranks",
			"https://dashscope.aliyuncs.com/compatible-api/v1/rerank",
		}
	}
	if strings.HasSuffix(baseURL, "/v1") {
		prefix := strings.TrimSuffix(baseURL, "/v1") + "/v1"
		return []string{prefix + "/reranks", prefix + "/rerank"}
	}
	return []string{baseURL + "/reranks", baseURL + "/rerank"}
}

func fuseRetrievalCandidates(keywordHits []KnowledgeChunk, vectorHits []KnowledgeChunk, query string) []retrievalCandidate {
	candidates := make(map[string]*retrievalCandidate)
	maxKeyword := topChunkScore(keywordHits)
	maxVector := topChunkScore(vectorHits)
	add := func(hit KnowledgeChunk) *retrievalCandidate {
		candidate, ok := candidates[hit.ID]
		if !ok {
			candidate = &retrievalCandidate{Chunk: hit}
			candidates[hit.ID] = candidate
		}
		return candidate
	}
	for i, hit := range keywordHits {
		candidate := add(hit)
		candidate.KeywordScore = hit.Score
		candidate.KeywordRank = i + 1
	}
	for i, hit := range vectorHits {
		candidate := add(hit)
		candidate.VectorScore = hit.Score
		candidate.VectorRank = i + 1
	}
	result := make([]retrievalCandidate, 0, len(candidates))
	for _, candidate := range candidates {
		keywordScore := normalizedScore(candidate.KeywordScore, maxKeyword)
		vectorScore := normalizedScore(candidate.VectorScore, maxVector)
		boost := exactMatchBoost(query, candidate.Chunk)
		rrfScore := 0.0
		if candidate.KeywordRank > 0 {
			rrfScore += 1 / (defaultRRFK + float64(candidate.KeywordRank))
		}
		if candidate.VectorRank > 0 {
			rrfScore += 1 / (defaultRRFK + float64(candidate.VectorRank))
		}
		candidate.FusionScore = keywordScore*0.45 + vectorScore*0.45 + math.Min(boost, 0.10) + rrfScore
		result = append(result, *candidate)
	}
	sort.Slice(result, func(i, j int) bool {
		return result[i].FusionScore > result[j].FusionScore
	})
	return result
}

func buildRetrievalDocumentText(chunk KnowledgeChunk) string {
	var b strings.Builder
	if strings.TrimSpace(chunk.Source) != "" {
		b.WriteString("文件：")
		b.WriteString(chunk.Source)
		b.WriteString("\n")
	}
	if strings.TrimSpace(chunk.Title) != "" {
		b.WriteString("标题：")
		b.WriteString(chunk.Title)
		b.WriteString("\n")
	}
	b.WriteString("内容：")
	b.WriteString(chunk.Content)
	return b.String()
}

func (e *AutoReplyEngine) expandKnowledgeNeighborHits(query string, hits []KnowledgeChunk) []KnowledgeChunk {
	e.mu.Lock()
	idx := e.index
	e.mu.Unlock()
	if idx == nil || len(idx.Chunks) == 0 || len(hits) == 0 {
		return hits
	}
	bySource := make(map[string][]KnowledgeChunk)
	for _, chunk := range idx.Chunks {
		if isLowValueKnowledgeBlock(chunk.Title, chunk.Content) {
			continue
		}
		sourceKey := normalizeKnowledgeSourceKey(chunk.Source)
		bySource[sourceKey] = append(bySource[sourceKey], chunk)
	}
	seen := make(map[string]bool, len(hits))
	result := make([]KnowledgeChunk, 0, len(hits)+4)
	for _, hit := range hits {
		if seen[hit.ID] {
			continue
		}
		seen[hit.ID] = true
		result = append(result, hit)
	}
	for _, hit := range hits {
		sourceChunks := bySource[normalizeKnowledgeSourceKey(hit.Source)]
		if len(sourceChunks) == 0 {
			continue
		}
		for i, chunk := range sourceChunks {
			if chunk.ID != hit.ID {
				continue
			}
			for _, offset := range []int{-1, 1} {
				pos := i + offset
				if pos < 0 || pos >= len(sourceChunks) {
					continue
				}
				neighbor := sourceChunks[pos]
				if neighbor.ID == "" || seen[neighbor.ID] {
					continue
				}
				neighbor.Score = hit.Score * 0.95
				seen[neighbor.ID] = true
				result = append(result, neighbor)
			}
			break
		}
	}
	sort.SliceStable(result, func(i, j int) bool {
		return result[i].Score > result[j].Score
	})
	if len(result) > 12 {
		result = result[:12]
	}
	return result
}

func exactMatchBoost(query string, chunk KnowledgeChunk) float64 {
	query = strings.ToLower(strings.TrimSpace(query))
	if query == "" {
		return 0
	}
	haystack := strings.ToLower(chunk.Source + " " + chunk.Title + " " + chunk.Content)
	boost := 0.0
	for _, token := range append(extractExactBoostTokens(query), extractKnowledgeReferenceTokens(query)...) {
		if token == "" {
			continue
		}
		if strings.Contains(strings.ToLower(chunk.Source+" "+chunk.Title), token) {
			boost += 0.18
			continue
		}
		if strings.Contains(haystack, token) {
			boost += 0.08
		}
	}
	for _, phrase := range extractChineseBoostPhrases(query) {
		if phrase == "" {
			continue
		}
		if strings.Contains(strings.ToLower(chunk.Source+" "+chunk.Title), phrase) {
			boost += 0.22
			continue
		}
		if strings.Contains(haystack, phrase) {
			boost += 0.12
		}
	}
	return boost
}

func extractExactBoostTokens(query string) []string {
	parts := strings.FieldsFunc(query, func(r rune) bool {
		return !(r == '-' || r == '_' || (r >= '0' && r <= '9') || (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z'))
	})
	tokens := make([]string, 0, len(parts))
	for _, part := range parts {
		part = strings.ToLower(strings.Trim(part, ".,;:!?，。！？；：、"))
		if len([]rune(part)) >= 3 || strings.Contains(part, "-") {
			tokens = append(tokens, part)
		}
	}
	for _, keyword := range []string{"产品", "产品线", "设备", "工作站", "模型", "数字员工", "agentbox", "awin25", "pro-s01", "pro-y01", "super-s01", "vision-s01"} {
		if strings.Contains(query, keyword) {
			tokens = append(tokens, keyword)
		}
	}
	return tokens
}

func extractChineseBoostPhrases(query string) []string {
	query = strings.TrimSpace(query)
	if query == "" {
		return nil
	}
	for _, suffix := range []string{"有哪些", "有啥", "是什么", "怎么", "如何", "哪些", "问题", "内容"} {
		query = strings.TrimSpace(strings.ReplaceAll(query, suffix, ""))
	}
	runes := []rune(query)
	if len(runes) < 2 {
		return nil
	}
	phrases := make([]string, 0, 4)
	phrases = append(phrases, query)
	if len(runes) >= 3 {
		phrases = append(phrases, string(runes[:2]))
		phrases = append(phrases, string(runes[:3]))
	}
	return dedupeNonEmptyStrings(phrases)
}

func extractKnowledgeReferenceTokens(query string) []string {
	query = strings.TrimSpace(query)
	if query == "" {
		return nil
	}
	candidates := make([]string, 0)
	for _, match := range regexp.MustCompile(`[《<"“]?([^《》<>"“”\s]+?\.(?:xlsx|xls|docx|doc|pdf|md|txt|csv))[》>"”]?`).FindAllStringSubmatch(query, -1) {
		if len(match) > 1 {
			candidates = append(candidates, match[1])
		}
	}
	for _, wrapped := range regexp.MustCompile(`[《"“]([^》"”]+)[》"”]`).FindAllStringSubmatch(query, -1) {
		if len(wrapped) > 1 {
			candidates = append(candidates, wrapped[1])
		}
	}
	result := make([]string, 0, len(candidates)*2)
	seen := make(map[string]bool)
	for _, candidate := range candidates {
		candidate = strings.ToLower(strings.TrimSpace(filepath.ToSlash(candidate)))
		if candidate == "" {
			continue
		}
		for _, token := range []string{candidate, normalizeKnowledgeSourceKey(candidate)} {
			token = strings.TrimSpace(token)
			if token != "" && !seen[token] {
				seen[token] = true
				result = append(result, token)
			}
		}
	}
	return result
}

func cosineSimilarity(a []float64, b []float64) float64 {
	if len(a) == 0 || len(b) == 0 {
		return 0
	}
	n := len(a)
	if len(b) < n {
		n = len(b)
	}
	var dot, normA, normB float64
	for i := 0; i < n; i++ {
		dot += a[i] * b[i]
		normA += a[i] * a[i]
		normB += b[i] * b[i]
	}
	if normA == 0 || normB == 0 {
		return 0
	}
	return dot / (math.Sqrt(normA) * math.Sqrt(normB))
}

func candidatesToKnowledgeChunks(candidates []retrievalCandidate) []KnowledgeChunk {
	chunks := make([]KnowledgeChunk, 0, len(candidates))
	for _, candidate := range candidates {
		chunk := candidate.Chunk
		chunk.Score = candidateScore(candidate)
		chunks = append(chunks, chunk)
	}
	return chunks
}

func candidateScore(candidate retrievalCandidate) float64 {
	if candidate.RerankScore > 0 {
		return candidate.RerankScore
	}
	if candidate.FusionScore > 0 {
		return candidate.FusionScore
	}
	if candidate.KeywordScore > candidate.VectorScore {
		return candidate.KeywordScore
	}
	return candidate.VectorScore
}

func topCandidateRerankScore(candidates []retrievalCandidate) float64 {
	for _, candidate := range candidates {
		if candidate.RerankScore > 0 {
			return candidate.RerankScore
		}
	}
	return 0
}

func topChunkScore(chunks []KnowledgeChunk) float64 {
	if len(chunks) == 0 {
		return 0
	}
	return chunks[0].Score
}

func normalizedScore(score float64, maxScore float64) float64 {
	if score <= 0 || maxScore <= 0 {
		return 0
	}
	return score / maxScore
}

func limitCandidates(candidates []retrievalCandidate, limit int) []retrievalCandidate {
	if limit <= 0 || len(candidates) <= limit {
		return candidates
	}
	return candidates[:limit]
}

func limitKnowledgeChunks(chunks []KnowledgeChunk, limit int) []KnowledgeChunk {
	if limit <= 0 || len(chunks) <= limit {
		return chunks
	}
	return chunks[:limit]
}

func knowledgeSources(chunks []KnowledgeChunk) []string {
	seen := make(map[string]bool)
	sources := make([]string, 0, len(chunks))
	for _, chunk := range chunks {
		source := strings.TrimSpace(chunk.Source)
		if source == "" || seen[source] {
			continue
		}
		seen[source] = true
		sources = append(sources, source)
	}
	return sources
}

func maxInt(a int, b int) int {
	if a > b {
		return a
	}
	return b
}