package memory

import (
	"fmt"
	"os"
	"path/filepath"
	"strings"
	"time"

	"github.com/hxclaw/hxclaw/cmd/hxclaw/internal"
)

var lastContext string

var ErrNeedNewSession = fmt.Errorf("需要创建新会话")

func GetContextPrompt(userInput string) string {
	db := GetDB()
	if db == nil {
		return ""
	}

	memoryCfg := internal.GetProjectConfig().Memory
	if !memoryCfg.Enabled {
		return ""
	}

	session := currentSession
	if session == nil {
		return "" // 没有 session，不提供上下文
	}

	var context string

	// 读取 picoclaw 的长期记忆
	picoMemory := readPicoClawMemory()
	if picoMemory != "" {
		context += "=== 长期记忆 ===\n" + picoMemory + "\n============\n"
	}

	// 添加会话摘要
	if session.Summary != "" {
		context += "=== 当前会话摘要 ===\n" + session.Summary + "\n============\n"
	}

	if shouldRecall(userInput) {
		recallResult := detectAndRecall(userInput)
		if recallResult != "" {
			context += recallResult
		}
	}

	lastContext = context
	return context
}

func readPicoClawMemory() string {
	memoryPath := filepath.Join(getPicoclawWorkspace(), "memory", "MEMORY.md")
	data, err := os.ReadFile(memoryPath)
	if err != nil {
		return ""
	}

	content := strings.TrimSpace(string(data))

	lines := strings.Split(content, "\n")
	var sb strings.Builder
	inSection := false

	for _, line := range lines {
		trimmed := strings.TrimSpace(line)
		if trimmed == "" {
			continue
		}
		if strings.HasPrefix(trimmed, "#") {
			inSection = true
			continue
		}
		if inSection {
			sb.WriteString(trimmed)
			sb.WriteString("\n")
		}
	}

	return strings.TrimSpace(sb.String())
}

func getPicoclawWorkspace() string {
	home, err := os.UserHomeDir()
	if err != nil {
		return ""
	}
	return filepath.Join(home, ".picoclaw", "workspace")
}

func shouldRecall(input string) bool {
	memoryCfg := internal.GetProjectConfig().Memory

	for _, cmd := range []string{"/recall", "/memory"} {
		if strings.HasPrefix(input, cmd) {
			return true
		}
	}

	recallCfg := memoryCfg.Recall
	for _, keyword := range recallCfg.Keywords {
		if strings.Contains(input, keyword) {
			return true
		}
	}

	if recallCfg.AutoRecall {
		return shouldAutoRecall(input)
	}

	return false
}

func shouldAutoRecall(input string) bool {
	vs := GetVectorService()
	if vs == nil {
		return false
	}

	memoryCfg := internal.GetProjectConfig().Memory
	threshold := memoryCfg.Recall.SimilarityThreshold
	if threshold <= 0 {
		threshold = 0.7
	}

	session := currentSession
	if session == nil {
		return false
	}

	if session.Summary == "" || len(session.SummaryEmbedding) == 0 {
		return false
	}

	inputEmb, err := vs.Generate(input)
	if err != nil {
		return false
	}

	similarity := vs.CosineSimilarity(inputEmb, session.SummaryEmbedding)
	return similarity > threshold
}

func detectAndRecall(input string) string {
	input = strings.TrimSpace(input)

	if strings.HasPrefix(input, "/recall") {
		input = strings.TrimPrefix(input, "/recall")
		input = strings.TrimSpace(input)
		if input == "" {
			result, _ := RecallHistory()
			return FormatRecallResults(result)
		}
	}

	for _, keyword := range []string{"之前", "聊过", "记得", "曾经", "谈论过", "提过"} {
		if strings.Contains(input, keyword) {
			return recallByKeyword(input, keyword)
		}
	}

	return ""
}

func recallByKeyword(input, keyword string) string {
	db := GetDB()
	if db == nil {
		return ""
	}

	if keyword == "之前" || keyword == "聊过" || keyword == "曾经" {
		if strings.Contains(input, "什么") || input == "之前" || strings.Contains(input, "都聊") {
			result, _ := RecallHistory()
			return FormatRecallResults(result)
		}

		topic := extractTopic(input)
		if topic != "" {
			result, _ := RecallTopic(topic, 5)
			return FormatRecallResults(result)
		}
	}

	if strings.Contains(input, "那次") || strings.Contains(input, "那次") {
		result, _ := RecallHistory()
		return FormatRecallResults(result)
	}

	topic := extractTopic(input)
	if topic != "" {
		result, _ := RecallTopic(topic, 5)
		return FormatRecallResults(result)
	}

	return ""
}

func extractTopic(input string) string {
	topic := input
	removePrefixes := []string{"之前", "聊过", "谈论过", "提过", "记得", "曾经", "关于", "我问过"}
	for _, prefix := range removePrefixes {
		topic = strings.Replace(topic, prefix, "", -1)
	}
	topic = strings.Trim(topic, " ，,。.？?！!：:")
	return topic
}

func ShouldSkipSummaryUpdate(input string) bool {
	return shouldRecall(input)
}

func SaveChat(userInput, aiReply string, useSessionSummary bool) (int, error) {
	db := GetDB()
	if db == nil {
		return 0, fmt.Errorf("数据库未初始化")
	}

	memoryCfg := internal.GetProjectConfig().Memory
	if !memoryCfg.Enabled {
		return 0, nil
	}

	// 获取或创建 Session
	session := currentSession
	if session == nil {
		// 如果没有 session，返回错误让用户创建
		return 0, ErrNeedNewSession
	}

	// 保存原始 session summary（用于恢复）
	originalSummary := session.Summary

	// 创建聊天记录
	chat, err := db.CreateChat(session.ID, userInput)
	if err != nil {
		return 0, fmt.Errorf("创建聊天记录失败: %v", err)
	}

	// 添加 AI 回复
	chat.AddAIReply(aiReply)
	chat.Summary = GenerateSummary(userInput, aiReply)
	chat.UpdatedAt = time.Now().Unix()

	// 生成并保存向量
	vs := GetVectorService()
	if vs != nil && memoryCfg.Vector.APIKey != "" {
		generateEmbedding(chat)
	}

	if err := db.UpdateChat(chat); err != nil {
		return 0, fmt.Errorf("更新聊天记录失败: %v", err)
	}

	// 更新 Session
	session.AddChatID(chat.ID)

	// 只有普通对话才更新 session summary，recall 查询保持原 summary
	if useSessionSummary {
		session.Summary = GenerateSummary("", session.Summary+"\n"+aiReply)
	}
	session.UpdatedAt = time.Now().Unix()

	// Session 也要生成向量
	if vs != nil && memoryCfg.Vector.APIKey != "" && useSessionSummary {
		generateSessionEmbedding(session)
	}

	if err := db.UpdateSession(session); err != nil {
		return 0, fmt.Errorf("更新会话失败: %v", err)
	}

	// 恢复原始 session summary（避免 recall 结果污染）
	session.Summary = originalSummary
	currentSession = session

	return len(session.ChatIDs), nil
}

func generateEmbedding(chat *Chat) {
	vs := GetVectorService()
	if vs == nil {
		return
	}

	text := chat.UserInput
	if len(chat.AIReplies) > 0 {
		text = text + "\n" + chat.AIReplies[len(chat.AIReplies)-1]
	}

	embedding, err := vs.Generate(text)
	if err != nil {
		fmt.Printf("[memory] 向量生成失败: %v\n", err)
		return
	}

	chat.SummaryEmbedding = embedding
	chat.UpdatedAt = time.Now().Unix()

	if err := GetDB().UpdateChat(chat); err != nil {
		fmt.Printf("[memory] 向量保存失败: %v\n", err)
	}
}

func generateSessionEmbedding(session *Session) {
	vs := GetVectorService()
	if vs == nil {
		return
	}

	embedding, err := vs.Generate(session.Summary)
	if err != nil {
		fmt.Printf("[memory] Session 向量生成失败: %v\n", err)
		return
	}

	session.SummaryEmbedding = embedding
	session.UpdatedAt = time.Now().Unix()

	if err := GetDB().UpdateSession(session); err != nil {
		fmt.Printf("[memory] Session 向量保存失败: %v\n", err)
	}
}

func createSession() (*Session, error) {
	return CreateNewSession()
}

type SearchResult struct {
	Chat      *Chat
	Similarity float64
}

func SearchSimilar(query string, topK int) ([]SearchResult, error) {
	db := GetDB()
	if db == nil {
		return nil, fmt.Errorf("数据库未初始化")
	}

	vs := GetVectorService()
	if vs == nil {
		return nil, fmt.Errorf("向量服务未初始化")
	}

	// 获取配置的最大检索数
	maxResults := internal.GetProjectConfig().Memory.Vector.MaxSearchResults
	if maxResults <= 0 {
		maxResults = 10
	}
	if topK > maxResults {
		topK = maxResults
	}

	// 生成查询向量
	queryEmbedding, err := vs.Generate(query)
	if err != nil {
		return nil, fmt.Errorf("查询向量生成失败: %w", err)
	}

	// 获取所有有向量的 chat
	chats, err := db.GetAllChats()
	if err != nil {
		return nil, fmt.Errorf("获取聊天记录失败: %w", err)
	}

	// 计算相似度并排序
	type scoredChat struct {
		chat       *Chat
		similarity float64
	}

	var scored []scoredChat
	for _, chat := range chats {
		if len(chat.SummaryEmbedding) == 0 {
			continue
		}
		sim := vs.CosineSimilarity(queryEmbedding, chat.SummaryEmbedding)
		scored = append(scored, scoredChat{chat: chat, similarity: sim})
	}

	// 按相似度排序
	for i := 0; i < len(scored); i++ {
		for j := i + 1; j < len(scored); j++ {
			if scored[j].similarity > scored[i].similarity {
				scored[i], scored[j] = scored[j], scored[i]
			}
		}
	}

	// 取前 K 个
	if topK > len(scored) {
		topK = len(scored)
	}

	results := make([]SearchResult, topK)
	for i := 0; i < topK; i++ {
		results[i] = SearchResult{
			Chat:      scored[i].chat,
			Similarity: scored[i].similarity,
		}
	}

	return results, nil
}

func (db *DB) GetAllChats() ([]*Chat, error) {
	rows, err := db.db.Query(
		`SELECT id, session_id, user_input, ai_replies, summary, summary_embedding, created_at, updated_at FROM chats WHERE summary_embedding IS NOT NULL AND length(summary_embedding) > 0 ORDER BY id DESC`,
	)
	if err != nil {
		return nil, err
	}
	defer rows.Close()

	var chats []*Chat
	for rows.Next() {
		var c Chat
		var aiRepliesJSON string
		var summaryEmbedding []byte
		if err := rows.Scan(&c.ID, &c.SessionID, &c.UserInput, &aiRepliesJSON, &c.Summary, &summaryEmbedding, &c.CreatedAt, &c.UpdatedAt); err != nil {
			continue
		}
		c.SummaryEmbedding = summaryEmbedding
		c.SetAIRepliesFromJSON(aiRepliesJSON)
		chats = append(chats, &c)
	}

	return chats, nil
}