package windowsv3

import (
	"context"
	"database/sql"
	"encoding/hex"
	"fmt"
	"sort"
	"strings"
	"time"

	"github.com/fsnotify/fsnotify"
	_ "github.com/mattn/go-sqlite3"
	"github.com/rs/zerolog/log"

	"github.com/sjzar/chatlog/internal/errors"
	"github.com/sjzar/chatlog/internal/model"
	"github.com/sjzar/chatlog/internal/wechatdb/datasource/dbm"
)

const (
	Message = "message"
	Contact = "contact"
	Image   = "image"
	Video   = "video"
	File    = "file"
	Voice   = "voice"
)

var Groups = []*dbm.Group{
	{
		Name:      Message,
		Pattern:   `^MSG([0-9]?[0-9])?\.db$`,
		BlackList: []string{},
	},
	{
		Name:      Contact,
		Pattern:   `^MicroMsg\.db$`,
		BlackList: []string{},
	},
	{
		Name:      Image,
		Pattern:   `^HardLinkImage\.db$`,
		BlackList: []string{},
	},
	{
		Name:      Video,
		Pattern:   `^HardLinkVideo\.db$`,
		BlackList: []string{},
	},
	{
		Name:      File,
		Pattern:   `^HardLinkFile\.db$`,
		BlackList: []string{},
	},
	{
		Name:      Voice,
		Pattern:   `^MediaMSG([0-9])?\.db$`,
		BlackList: []string{},
	},
}

// MessageDBInfo 保存消息数据库的信息
type MessageDBInfo struct {
	FilePath  string
	StartTime time.Time
	EndTime   time.Time
	TalkerMap map[string]int
}

// DataSource 实现了 DataSource 接口
type DataSource struct {
	path string
	dbm  *dbm.DBManager

	// 消息数据库信息
	messageInfos []MessageDBInfo
}

// New 创建一个新的 WindowsV3DataSource
func New(path string) (*DataSource, error) {
	ds := &DataSource{
		path:         path,
		dbm:          dbm.NewDBManager(path),
		messageInfos: make([]MessageDBInfo, 0),
	}

	for _, g := range Groups {
		ds.dbm.AddGroup(g)
	}

	if err := ds.dbm.Start(); err != nil {
		return nil, err
	}

	if err := ds.initMessageDbs(); err != nil {
		return nil, errors.DBInitFailed(err)
	}

	ds.dbm.AddCallback(Message, func(event fsnotify.Event) error {
		if !event.Op.Has(fsnotify.Create) {
			return nil
		}
		if err := ds.initMessageDbs(); err != nil {
			log.Err(err).Msgf("Failed to reinitialize message DBs: %s", event.Name)
		}
		return nil
	})

	return ds, nil
}

func (ds *DataSource) SetCallback(name string, callback func(event fsnotify.Event) error) error {
	if name == "chatroom" {
		name = Contact
	}
	return ds.dbm.AddCallback(name, callback)
}

// initMessageDbs 初始化消息数据库
func (ds *DataSource) initMessageDbs() error {
	// 获取所有消息数据库文件路径
	dbPaths, err := ds.dbm.GetDBPath(Message)
	if err != nil {
		if strings.Contains(err.Error(), "db file not found") {
			ds.messageInfos = make([]MessageDBInfo, 0)
			return nil
		}
		return err
	}

	// 处理每个数据库文件
	infos := make([]MessageDBInfo, 0)
	for _, filePath := range dbPaths {
		db, err := ds.dbm.OpenDB(filePath)
		if err != nil {
			log.Err(err).Msgf("获取数据库 %s 失败", filePath)
			continue
		}

		// 获取 DBInfo 表中的开始时间
		var startTime time.Time

		rows, err := db.Query("SELECT tableIndex, tableVersion, tableDesc FROM DBInfo")
		if err != nil {
			log.Err(err).Msgf("查询数据库 %s 的 DBInfo 表失败", filePath)
			continue
		}

		for rows.Next() {
			var tableIndex int
			var tableVersion int64
			var tableDesc string

			if err := rows.Scan(&tableIndex, &tableVersion, &tableDesc); err != nil {
				log.Err(err).Msg("扫描 DBInfo 行失败")
				continue
			}

			// 查找描述为 "Start Time" 的记录
			if strings.Contains(tableDesc, "Start Time") {
				startTime = time.Unix(tableVersion/1000, (tableVersion%1000)*1000000)
				break
			}
		}
		rows.Close()

		// 组织 TalkerMap
		talkerMap := make(map[string]int)
		rows, err = db.Query("SELECT UsrName FROM Name2ID")
		if err != nil {
			log.Err(err).Msgf("查询数据库 %s 的 Name2ID 表失败", filePath)
			continue
		}

		i := 1
		for rows.Next() {
			var userName string
			if err := rows.Scan(&userName); err != nil {
				log.Err(err).Msg("扫描 Name2ID 行失败")
				continue
			}
			talkerMap[userName] = i
			i++
		}
		rows.Close()

		// 保存数据库信息
		infos = append(infos, MessageDBInfo{
			FilePath:  filePath,
			StartTime: startTime,
			TalkerMap: talkerMap,
		})
	}

	// 按照 StartTime 排序数据库文件
	sort.Slice(infos, func(i, j int) bool {
		return infos[i].StartTime.Before(infos[j].StartTime)
	})

	// 设置结束时间
	for i := range infos {
		if i == len(infos)-1 {
			infos[i].EndTime = time.Now()
		} else {
			infos[i].EndTime = infos[i+1].StartTime
		}
	}
	ds.messageInfos = infos
	return nil
}

// getDBInfosForTimeRange 获取时间范围内的数据库信息
func (ds *DataSource) getDBInfosForTimeRange(startTime, endTime time.Time) []MessageDBInfo {
	var dbs []MessageDBInfo
	for _, info := range ds.messageInfos {
		if info.StartTime.Before(endTime) && info.EndTime.After(startTime) {
			dbs = append(dbs, info)
		}
	}
	return dbs
}

// GetMessages 实现 DataSource 接口的 GetMessages 方法
func (ds *DataSource) GetMessages(ctx context.Context, startTime, endTime time.Time, talker string, limit, offset int) ([]*model.Message, error) {
	// 找到时间范围内的数据库文件
	dbInfos := ds.getDBInfosForTimeRange(startTime, endTime)
	if len(dbInfos) == 0 {
		return nil, errors.TimeRangeNotFound(startTime, endTime)
	}

	if len(dbInfos) == 1 {
		// LIMIT 和 OFFSET 逻辑在单文件情况下可以直接在 SQL 里处理
		return ds.getMessagesSingleFile(ctx, dbInfos[0], startTime, endTime, talker, limit, offset)
	}

	// 从每个相关数据库中查询消息
	totalMessages := []*model.Message{}

	for _, dbInfo := range dbInfos {
		// 检查上下文是否已取消
		if err := ctx.Err(); err != nil {
			return nil, err
		}

		db, err := ds.dbm.OpenDB(dbInfo.FilePath)
		if err != nil {
			log.Error().Msgf("数据库 %s 未打开", dbInfo.FilePath)
			continue
		}

		messages, err := ds.getMessagesFromDB(ctx, db, dbInfo, startTime, endTime, talker)
		if err != nil {
			log.Err(err).Msgf("从数据库 %s 获取消息失败", dbInfo.FilePath)
			continue
		}

		totalMessages = append(totalMessages, messages...)

		if limit+offset > 0 && len(totalMessages) >= limit+offset {
			break
		}
	}

	// 对所有消息按时间排序
	sort.Slice(totalMessages, func(i, j int) bool {
		return totalMessages[i].Seq < totalMessages[j].Seq
	})

	// 处理分页
	if limit > 0 {
		if offset >= len(totalMessages) {
			return []*model.Message{}, nil
		}
		end := offset + limit
		if end > len(totalMessages) {
			end = len(totalMessages)
		}
		return totalMessages[offset:end], nil
	}

	return totalMessages, nil
}

// getMessagesSingleFile 从单个数据库文件获取消息
func (ds *DataSource) getMessagesSingleFile(ctx context.Context, dbInfo MessageDBInfo, startTime, endTime time.Time, talker string, limit, offset int) ([]*model.Message, error) {
	db, err := ds.dbm.OpenDB(dbInfo.FilePath)
	if err != nil {
		return nil, errors.DBConnectFailed(dbInfo.FilePath, nil)
	}

	// 构建查询条件
	conditions := []string{"Sequence >= ? AND Sequence <= ?"}
	args := []interface{}{startTime.Unix() * 1000, endTime.Unix() * 1000}
	if len(talker) > 0 {
		// TalkerId 有索引，优先使用
		talkerID, ok := dbInfo.TalkerMap[talker]
		if ok {
			conditions = append(conditions, "TalkerId = ?")
			args = append(args, talkerID)
		} else {
			conditions = append(conditions, "StrTalker = ?")
			args = append(args, talker)
		}
	}
	query := fmt.Sprintf(`
        SELECT MsgSvrID, Sequence, CreateTime, StrTalker, IsSender, 
            Type, SubType, StrContent, CompressContent, BytesExtra
        FROM MSG 
        WHERE %s 
        ORDER BY Sequence ASC
    `, strings.Join(conditions, " AND "))

	if limit > 0 {
		query += fmt.Sprintf(" LIMIT %d", limit)

		if offset > 0 {
			query += fmt.Sprintf(" OFFSET %d", offset)
		}
	}

	// 执行查询
	rows, err := db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, errors.QueryFailed(query, err)
	}
	defer rows.Close()

	// 处理查询结果
	totalMessages := []*model.Message{}
	for rows.Next() {
		var msg model.MessageV3
		var compressContent []byte
		var bytesExtra []byte
		err := rows.Scan(
			&msg.MsgSvrID,
			&msg.Sequence,
			&msg.CreateTime,
			&msg.StrTalker,
			&msg.IsSender,
			&msg.Type,
			&msg.SubType,
			&msg.StrContent,
			&compressContent,
			&bytesExtra,
		)
		if err != nil {
			return nil, errors.ScanRowFailed(err)
		}
		msg.CompressContent = compressContent
		msg.BytesExtra = bytesExtra
		totalMessages = append(totalMessages, msg.Wrap())
	}
	return totalMessages, nil
}

// getMessagesFromDB 从数据库获取消息
func (ds *DataSource) getMessagesFromDB(ctx context.Context, db *sql.DB, dbInfo MessageDBInfo, startTime, endTime time.Time, talker string) ([]*model.Message, error) {
	// 构建查询条件
	conditions := []string{"Sequence >= ? AND Sequence <= ?"}
	args := []interface{}{startTime.Unix() * 1000, endTime.Unix() * 1000}

	if len(talker) > 0 {
		talkerID, ok := dbInfo.TalkerMap[talker]
		if ok {
			conditions = append(conditions, "TalkerId = ?")
			args = append(args, talkerID)
		} else {
			conditions = append(conditions, "StrTalker = ?")
			args = append(args, talker)
		}
	}

	query := fmt.Sprintf(`
		SELECT MsgSvrID, Sequence, CreateTime, StrTalker, IsSender, 
			Type, SubType, StrContent, CompressContent, BytesExtra
		FROM MSG 
		WHERE %s 
		ORDER BY Sequence ASC
	`, strings.Join(conditions, " AND "))

	// 执行查询
	rows, err := db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, errors.QueryFailed(query, err)
	}
	defer rows.Close()

	// 处理查询结果
	messages := []*model.Message{}
	for rows.Next() {
		var msg model.MessageV3
		var compressContent []byte
		var bytesExtra []byte

		err := rows.Scan(
			&msg.MsgSvrID,
			&msg.Sequence,
			&msg.CreateTime,
			&msg.StrTalker,
			&msg.IsSender,
			&msg.Type,
			&msg.SubType,
			&msg.StrContent,
			&compressContent,
			&bytesExtra,
		)
		if err != nil {
			return nil, errors.ScanRowFailed(err)
		}
		msg.CompressContent = compressContent
		msg.BytesExtra = bytesExtra

		messages = append(messages, msg.Wrap())
	}

	return messages, nil
}

// GetContacts 实现获取联系人信息的方法
func (ds *DataSource) GetContacts(ctx context.Context, key string, limit, offset int) ([]*model.Contact, error) {
	var query string
	var args []interface{}

	if key != "" {
		// 按照关键字查询
		query = `SELECT UserName, Alias, Remark, NickName, Reserved1 FROM Contact 
                WHERE UserName = ? OR Alias = ? OR Remark = ? OR NickName = ?`
		args = []interface{}{key, key, key, key}
	} else {
		// 查询所有联系人
		query = `SELECT UserName, Alias, Remark, NickName, Reserved1 FROM Contact`
	}

	// 添加排序、分页
	query += ` ORDER BY UserName`
	if limit > 0 {
		query += fmt.Sprintf(" LIMIT %d", limit)
		if offset > 0 {
			query += fmt.Sprintf(" OFFSET %d", offset)
		}
	}

	// 执行查询
	db, err := ds.dbm.GetDB(Contact)
	if err != nil {
		return nil, err
	}
	rows, err := db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, errors.QueryFailed(query, err)
	}
	defer rows.Close()

	contacts := []*model.Contact{}
	for rows.Next() {
		var contactV3 model.ContactV3
		err := rows.Scan(
			&contactV3.UserName,
			&contactV3.Alias,
			&contactV3.Remark,
			&contactV3.NickName,
			&contactV3.Reserved1,
		)

		if err != nil {
			return nil, errors.ScanRowFailed(err)
		}

		contacts = append(contacts, contactV3.Wrap())
	}

	return contacts, nil
}

// GetChatRooms 实现获取群聊信息的方法
func (ds *DataSource) GetChatRooms(ctx context.Context, key string, limit, offset int) ([]*model.ChatRoom, error) {
	var query string
	var args []interface{}

	if key != "" {
		// 按照关键字查询
		query = `SELECT ChatRoomName, Reserved2, RoomData FROM ChatRoom WHERE ChatRoomName = ?`
		args = []interface{}{key}

		// 执行查询
		db, err := ds.dbm.GetDB(Contact)
		if err != nil {
			return nil, err
		}
		rows, err := db.QueryContext(ctx, query, args...)
		if err != nil {
			return nil, errors.QueryFailed(query, err)
		}
		defer rows.Close()

		chatRooms := []*model.ChatRoom{}
		for rows.Next() {
			var chatRoomV3 model.ChatRoomV3
			err := rows.Scan(
				&chatRoomV3.ChatRoomName,
				&chatRoomV3.Reserved2,
				&chatRoomV3.RoomData,
			)

			if err != nil {
				return nil, errors.ScanRowFailed(err)
			}

			chatRooms = append(chatRooms, chatRoomV3.Wrap())
		}

		// 如果没有找到群聊，尝试通过联系人查找
		if len(chatRooms) == 0 {
			contacts, err := ds.GetContacts(ctx, key, 1, 0)
			if err == nil && len(contacts) > 0 && strings.HasSuffix(contacts[0].UserName, "@chatroom") {
				// 再次尝试通过用户名查找群聊
				rows, err := db.QueryContext(ctx,
					`SELECT ChatRoomName, Reserved2, RoomData FROM ChatRoom WHERE ChatRoomName = ?`,
					contacts[0].UserName)

				if err != nil {
					return nil, errors.QueryFailed(query, err)
				}
				defer rows.Close()

				for rows.Next() {
					var chatRoomV3 model.ChatRoomV3
					err := rows.Scan(
						&chatRoomV3.ChatRoomName,
						&chatRoomV3.Reserved2,
						&chatRoomV3.RoomData,
					)

					if err != nil {
						return nil, errors.ScanRowFailed(err)
					}

					chatRooms = append(chatRooms, chatRoomV3.Wrap())
				}

				// 如果群聊记录不存在，但联系人记录存在，创建一个模拟的群聊对象
				if len(chatRooms) == 0 {
					chatRooms = append(chatRooms, &model.ChatRoom{
						Name:             contacts[0].UserName,
						Users:            make([]model.ChatRoomUser, 0),
						User2DisplayName: make(map[string]string),
					})
				}
			}
		}

		return chatRooms, nil
	} else {
		// 查询所有群聊
		query = `SELECT ChatRoomName, Reserved2, RoomData FROM ChatRoom`

		// 添加排序、分页
		query += ` ORDER BY ChatRoomName`
		if limit > 0 {
			query += fmt.Sprintf(" LIMIT %d", limit)
			if offset > 0 {
				query += fmt.Sprintf(" OFFSET %d", offset)
			}
		}

		// 执行查询
		db, err := ds.dbm.GetDB(Contact)
		if err != nil {
			return nil, err
		}
		rows, err := db.QueryContext(ctx, query, args...)
		if err != nil {
			return nil, errors.QueryFailed(query, err)
		}
		defer rows.Close()

		chatRooms := []*model.ChatRoom{}
		for rows.Next() {
			var chatRoomV3 model.ChatRoomV3
			err := rows.Scan(
				&chatRoomV3.ChatRoomName,
				&chatRoomV3.Reserved2,
				&chatRoomV3.RoomData,
			)

			if err != nil {
				return nil, errors.ScanRowFailed(err)
			}

			chatRooms = append(chatRooms, chatRoomV3.Wrap())
		}

		return chatRooms, nil
	}
}

// GetSessions 实现获取会话信息的方法
func (ds *DataSource) GetSessions(ctx context.Context, key string, limit, offset int) ([]*model.Session, error) {
	var query string
	var args []interface{}

	if key != "" {
		// 按照关键字查询
		query = `SELECT strUsrName, nOrder, strNickName, strContent, nTime 
                FROM Session 
                WHERE strUsrName = ? OR strNickName = ?
                ORDER BY nOrder DESC`
		args = []interface{}{key, key}
	} else {
		// 查询所有会话
		query = `SELECT strUsrName, nOrder, strNickName, strContent, nTime 
                FROM Session 
                ORDER BY nOrder DESC`
	}

	// 添加分页
	if limit > 0 {
		query += fmt.Sprintf(" LIMIT %d", limit)
		if offset > 0 {
			query += fmt.Sprintf(" OFFSET %d", offset)
		}
	}

	// 执行查询
	db, err := ds.dbm.GetDB(Contact)
	if err != nil {
		return nil, err
	}
	rows, err := db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, errors.QueryFailed(query, err)
	}
	defer rows.Close()

	sessions := []*model.Session{}
	for rows.Next() {
		var sessionV3 model.SessionV3
		err := rows.Scan(
			&sessionV3.StrUsrName,
			&sessionV3.NOrder,
			&sessionV3.StrNickName,
			&sessionV3.StrContent,
			&sessionV3.NTime,
		)

		if err != nil {
			return nil, errors.ScanRowFailed(err)
		}

		sessions = append(sessions, sessionV3.Wrap())
	}

	return sessions, nil
}

func (ds *DataSource) GetMedia(ctx context.Context, _type string, key string) (*model.Media, error) {
	if key == "" {
		return nil, errors.ErrKeyEmpty
	}

	if _type == "voice" {
		return ds.GetVoice(ctx, key)
	}

	md5key, err := hex.DecodeString(key)
	if err != nil {
		return nil, errors.DecodeKeyFailed(err)
	}

	var dbType string
	var table1, table2 string

	switch _type {
	case "image":
		dbType = Image
		table1 = "HardLinkImageAttribute"
		table2 = "HardLinkImageID"
	case "video":
		dbType = Video
		table1 = "HardLinkVideoAttribute"
		table2 = "HardLinkVideoID"
	case "file":
		dbType = File
		table1 = "HardLinkFileAttribute"
		table2 = "HardLinkFileID"
	default:
		return nil, errors.MediaTypeUnsupported(_type)
	}

	db, err := ds.dbm.GetDB(dbType)
	if err != nil {
		return nil, err
	}

	query := fmt.Sprintf(`
        SELECT 
            a.FileName,
            a.ModifyTime,
            IFNULL(d1.Dir,"") AS Dir1,
            IFNULL(d2.Dir,"") AS Dir2
        FROM 
            %s a
        LEFT JOIN 
            %s d1 ON a.DirID1 = d1.DirId
        LEFT JOIN 
            %s d2 ON a.DirID2 = d2.DirId
        WHERE 
            a.Md5 = ?
    `, table1, table2, table2)
	args := []interface{}{md5key}

	rows, err := db.QueryContext(ctx, query, args...)
	if err != nil {
		return nil, errors.QueryFailed(query, err)
	}
	defer rows.Close()

	var media *model.Media
	for rows.Next() {
		var mediaV3 model.MediaV3
		err := rows.Scan(
			&mediaV3.Name,
			&mediaV3.ModifyTime,
			&mediaV3.Dir1,
			&mediaV3.Dir2,
		)
		if err != nil {
			return nil, errors.ScanRowFailed(err)
		}
		mediaV3.Type = _type
		mediaV3.Key = key
		media = mediaV3.Wrap()
	}

	if media == nil {
		return nil, errors.ErrMediaNotFound
	}

	return media, nil
}

func (ds *DataSource) GetVoice(ctx context.Context, key string) (*model.Media, error) {
	if key == "" {
		return nil, errors.ErrKeyEmpty
	}

	query := `
	SELECT Buf
	FROM Media
	WHERE Reserved0 = ? 
	`
	args := []interface{}{key}

	dbs, err := ds.dbm.GetDBs(Voice)
	if err != nil {
		return nil, errors.DBConnectFailed("", err)
	}

	for _, db := range dbs {
		rows, err := db.QueryContext(ctx, query, args...)
		if err != nil {
			return nil, errors.QueryFailed(query, err)
		}
		defer rows.Close()

		for rows.Next() {
			var voiceData []byte
			err := rows.Scan(
				&voiceData,
			)
			if err != nil {
				return nil, errors.ScanRowFailed(err)
			}
			if len(voiceData) > 0 {
				return &model.Media{
					Type: "voice",
					Key:  key,
					Data: voiceData,
				}, nil
			}
		}
	}

	return nil, errors.ErrMediaNotFound
}

// Close 实现 DataSource 接口的 Close 方法
func (ds *DataSource) Close() error {
	return ds.dbm.Close()
}