package gfdb

import (
	"context"
	"database/sql"
	"encoding/json"
	"fmt"
	"regexp"
	"strings"
	"time"

	"gitea.com/red-future/common/beans"
	"gitea.com/red-future/common/utils"
	"github.com/bwmarrin/snowflake"
	"github.com/gogf/gf/v2/crypto/gmd5"
	"github.com/gogf/gf/v2/database/gdb"
	"github.com/gogf/gf/v2/database/gredis"
	"github.com/gogf/gf/v2/frame/g"
	"github.com/gogf/gf/v2/os/gcache"
	"github.com/gogf/gf/v2/os/glog"
	"github.com/gogf/gf/v2/text/gstr"
	"github.com/gogf/gf/v2/util/gconv"
	"go.opentelemetry.io/otel/trace"
)

// ==================== 缓存管理器（单例） ====================

var (
	localCache *gcache.Cache
)

// getLocalCache 获取本地缓存实例
func getLocalCache() *gcache.Cache {
	if localCache == nil {
		localCache = gcache.New()
	}
	return localCache
}

// getFromCache 从缓存获取数据（本地缓存 -> Redis）
func getFromCache(ctx context.Context, key string) ([]byte, bool) {

	// 1. 先查本地缓存
	if val, err := getLocalCache().Get(ctx, key); err == nil && val != nil {
		if data := val.Bytes(); len(data) > 0 {
			return data, true
		}
	}

	// 2. 再查Redis缓存
	if g.Redis() != nil {
		result, err := g.Redis().Get(ctx, key)
		if err == nil && !result.IsEmpty() {
			data := result.Bytes()
			// 写入本地缓存
			err = getLocalCache().Set(ctx, key, data, time.Duration(g.Cfg().MustGet(ctx, "cache.localTTL", 60).Int64())*time.Second)
			if err != nil {
				return nil, false
			}
			return data, true
		}
	}

	return nil, false
}

// setToCache 写入缓存（本地缓存 + Redis）
func setToCache(ctx context.Context, key string, data []byte) (err error) {
	if len(data) == 0 {
		return
	}

	// 1. 写入本地缓存
	if err = getLocalCache().Set(ctx, key, data, time.Duration(g.Cfg().MustGet(ctx, "cache.localTTL", 60).Int64())*time.Second); err != nil {
		return
	}

	// 2. 写入Redis缓存
	if g.Redis() != nil {
		_, err = g.Redis().Set(ctx, key, data, gredis.SetOption{
			TTLOption: gredis.TTLOption{
				EX: gconv.PtrInt64(g.Cfg().MustGet(ctx, "cache.redisTTL", 300)),
			},
		})
		if err != nil {
			return
		}
	}
	return
}

// deleteCacheByPattern 根据模式删除缓存
func deleteCacheByPattern(ctx context.Context, pattern string) (err error) {
	// 1. 删除匹配模式的本地缓存
	localCache := getLocalCache()
	keys := localCache.MustKeyStrings(ctx)
	if len(keys) > 0 {
		for _, key := range keys {
			if matchPattern(key, pattern) {
				_, err = localCache.Remove(ctx, key)
				if err != nil {
					return err
				}
			}
		}
	}

	// 2. 删除Redis缓存（使用SCAN+DEL）
	if g.Redis() != nil {

		keys, err := g.Redis().Keys(ctx, pattern)
		if err != nil {
			return err
		}
		for _, key := range keys {
			_, err = g.Redis().Del(ctx, key)
			if err != nil {
				return err
			}
		}

	}
	return nil
}

// matchPattern 检查 key 是否匹配 Redis SCAN 的 MATCH 模式（支持 * 通配符）
func matchPattern(key string, pattern string) bool {
	// 将 Redis 的 MATCH 模式转换为正则表达式
	// 转义正则特殊字符（除了 *）
	regexPattern := regexp.QuoteMeta(pattern)
	// 将转义后的 \* 替换回 .*
	regexPattern = strings.ReplaceAll(regexPattern, `\*`, ".*")
	// 添加开始和结束锚点
	regexPattern = "^" + regexPattern + "$"

	matched, _ := regexp.MatchString(regexPattern, key)
	return matched
}

// ==================== 统一Hook入口 ====================

// CatchSQLHook 返回统一的 HookHandler（包含租户自动赋值和缓存）
// 使用示例：
//
//	// 基础使用（自动租户赋值，无缓存）
//	g.DB().Model("user").Hook(base.CatchSQLHook()).Ctx(ctx).Insert(data)
//
//	// 启用缓存（用户无感知，自动处理缓存key）
//	ctx = base.WithCacheEnabled(ctx, "asset")
//	Asset.CtxWithCache(ctx).Where("id", 123).Scan(&result)
func catchSQLHook() gdb.HookHandler {
	return gdb.HookHandler{
		Insert: insertHook,
		Update: updateHook,
		Delete: deleteHook,
		Select: selectHook,
	}
}

// ==================== Insert钩子 ====================

func insertHook(ctx context.Context, in *gdb.HookInsertInput) (result sql.Result, err error) {

	userInfo, err := utils.GetUserInfo(ctx)
	if err != nil {
		return nil, err
	}

	node, err := snowflake.NewNode(g.Cfg().MustGet(ctx, "server.workerId").Int64())
	if err != nil {
		return nil, err
	}
	for i := range in.Data {
		if _, ok := in.Data[i]["id"]; ok {
			in.Data[i]["id"] = node.Generate().Int64()
		}
		if _, ok := in.Data[i]["tenant_id"]; ok {
			if !g.IsEmpty(userInfo.TenantId) {
				in.Data[i]["tenant_id"] = userInfo.TenantId
			} else {
				return nil, fmt.Errorf("tenantId cannot be empty")
			}
		}
		if _, ok := in.Data[i]["creator"]; ok {
			if !g.IsEmpty(userInfo.UserName) {
				in.Data[i]["creator"] = userInfo.UserName
			} else {
				return nil, fmt.Errorf("user info cannot be empty")
			}
		}
		if _, ok := in.Data[i]["updater"]; ok {
			if !g.IsEmpty(userInfo.UserName) {
				in.Data[i]["updater"] = userInfo.UserName
			} else {
				return nil, fmt.Errorf("user info cannot be empty")
			}
		}
	}

	// 2. 执行插入
	result, err = in.Next(ctx)
	if err != nil {
		return nil, err
	}

	// 3. 清除相关缓存
	if userInfo != nil && userInfo.TenantId != 0 {
		if err = deleteCacheByPattern(ctx, getCacheKey(userInfo.TenantId, in.Table, true)); err != nil {
			return nil, err
		}
	}

	return result, nil
}

// ==================== Update钩子 ====================

func updateHook(ctx context.Context, in *gdb.HookUpdateInput) (result sql.Result, err error) {
	// 1. 自动赋值修改人
	userInfo, _ := utils.GetUserInfo(ctx)

	switch data := in.Data.(type) {
	case gdb.Map:
		if _, ok := data["updater"]; ok {
			if !g.IsEmpty(userInfo.UserName) {
				data["updater"] = userInfo.UserName
			} else {
				return nil, fmt.Errorf("user info cannot be empty")
			}
		}
	case gdb.List:
		for i := range data {
			if !g.IsEmpty(userInfo.UserName) {
				if _, ok := data[i]["updater"]; ok {
					if !g.IsEmpty(userInfo.UserName) {
						data[i]["updater"] = userInfo.UserName
					} else {
						return nil, fmt.Errorf("user info cannot be empty")
					}
				}
			}
		}
	}

	// 2. 执行更新
	result, err = in.Next(ctx)
	if err != nil {
		return nil, err
	}

	// 3. 清除相关缓存
	if userInfo != nil && userInfo.TenantId != 0 {
		if err = deleteCacheByPattern(ctx, getCacheKey(userInfo.TenantId, in.Table, true)); err != nil {
			return nil, err
		}
	}

	return result, nil
}

// ==================== Delete钩子 ====================

func deleteHook(ctx context.Context, in *gdb.HookDeleteInput) (result sql.Result, err error) {
	// 1. 执行删除
	result, err = in.Next(ctx)
	if err != nil {
		return nil, err
	}

	// 2. 清除相关缓存
	userInfo, _ := utils.GetUserInfo(ctx)
	if userInfo != nil && userInfo.TenantId != 0 {
		if err = deleteCacheByPattern(ctx, getCacheKey(userInfo.TenantId, in.Table, true)); err != nil {
			return nil, err
		}
	}

	return result, nil
}

// ==================== Select钩子（缓存读取） ====================

func selectHook(ctx context.Context, in *gdb.HookSelectInput) (result gdb.Result, err error) {
	var tenantId uint64
	// ===================== 最终版：安全追加租户ID =====================
	tenantEnabled, err := gcache.Get(ctx, getTraceID(ctx, noTenantIdKeyPrefix))
	if err != nil {
		return
	}
	if !gconv.Bool(tenantEnabled) {
		user, err := utils.GetUserInfo(ctx)
		if err != nil {
			return nil, err
		}
		tenantId = user.TenantId
		// 【关键修复】找到 SQL 中第一个出现的 ORDER BY / GROUP BY / LIMIT 等关键字位置
		sql := in.Sql
		insertPos := len(sql)
		keywords := []string{" ORDER BY ", " GROUP BY ", " HAVING ", " LIMIT ", " FOR UPDATE"}
		for _, kw := range keywords {
			if idx := gstr.PosI(sql, kw); idx != -1 {
				insertPos = idx
				break
			}
		}

		// 【正确拼接】把条件插入到关键字之前，而不是直接拼在最后
		condition := " " + beans.DefSQLBaseCol.TenantId + " = ?"
		if gstr.Contains(gstr.ToUpper(sql), " WHERE ") {
			// 有 WHERE → 加 AND
			in.Sql = sql[:insertPos] + " AND" + condition + sql[insertPos:]
		} else {
			// 无 WHERE → 加 WHERE
			in.Sql = sql[:insertPos] + " WHERE" + condition + sql[insertPos:]
		}
		in.Args = append(in.Args, tenantId)
	}
	// ==================================================================

	cacheEnabled, err := gcache.Get(ctx, getTraceID(ctx, cacheKeyPrefix))
	if err != nil {
		return
	}
	// 未启用缓存，直接执行查询
	if !gconv.Bool(cacheEnabled) {
		return in.Next(ctx)
	}

	// 从 SQL 字符串中提取 WHERE 条件部分
	whereCondition := ""
	// 查找 WHERE 关键字（不区分大小写）
	whereIndex := gstr.PosI(in.Sql, " WHERE ")
	if whereIndex != -1 {
		// 提取 WHERE 之后的内容
		whereCondition = in.Sql[whereIndex+7:]
		// 移除 ORDER BY, GROUP BY, HAVING, LIMIT 等后续子句
		for _, keyword := range []string{" ORDER BY ", " GROUP BY ", " HAVING ", " LIMIT ", " FOR UPDATE"} {
			if idx := gstr.PosI(whereCondition, keyword); idx != -1 {
				whereCondition = whereCondition[:idx]
			}
		}
	}

	encrypt, err := gmd5.Encrypt(fmt.Sprintf("%s:%s", whereCondition, in.Args))
	if err != nil {
		return nil, err
	}

	// 构建缓存key：sql:tenantId:table:where条件:args
	cacheKey := fmt.Sprintf("%s:%s:%s", getCacheKey(tenantId, in.Table, false), getSelectTypeString(in.SelectType), encrypt)

	// 1. 先查缓存
	if data, ok := getFromCache(ctx, cacheKey); ok {
		var records gdb.Result
		if err := json.Unmarshal(data, &records); err == nil && len(records) > 0 {
			return records, nil
		}
	}

	// 2. 执行数据库查询
	result, err = in.Next(ctx)
	if err != nil {
		return nil, err
	}

	// 3. 写入缓存
	if len(result) > 0 {
		if data, err := json.Marshal(result); err == nil {
			if err = setToCache(ctx, cacheKey, data); err != nil {
				return nil, err
			}
		}
	}

	return result, nil
}

func getCacheKey(tenantId uint64, table string, isBlur bool) string {
	var cacheKey string
	if g.IsEmpty(tenantId) {
		cacheKey = fmt.Sprintf("sql:%s", table)
	} else {
		cacheKey = fmt.Sprintf("sql:tenantId-%v:%s", tenantId, table)
	}
	if isBlur {
		cacheKey = fmt.Sprintf("%s:*", cacheKey)
	}
	return cacheKey
}

// getSelectTypeString 将 SelectType 枚举转换为可读字符串
func getSelectTypeString(selectType gdb.SelectType) string {
	switch selectType {
	case gdb.SelectTypeDefault:
		return "default"
	case gdb.SelectTypeCount:
		return "count"
	case gdb.SelectTypeValue:
		return "value"
	case gdb.SelectTypeArray:
		return "array"
	default:
		return "unknown"
	}
}

// ==================== 调用方法 ====================
var TablePrefix string
var (
	schemaPrefix        = "tenant-"
	cacheKeyPrefix      = "cache-"
	noTenantIdKeyPrefix = "tenantId-"
)

type Gfdb interface {
	Exec(ctx context.Context, sql string, args ...any) (sql.Result, error)
	GetAll(ctx context.Context, sql string, args ...any) (gdb.Result, error)
	Model(ctx context.Context, tableNameOrStruct ...any) *model
	Transaction(ctx context.Context, f func(ctx context.Context, tx gdb.TX) error) error
}

type cache interface {
	Cache(ctx context.Context) *gdb.Model
}

type noTenantId interface {
	NoTenantId(ctx context.Context) *modelCache
}

type dataBase struct {
	gdb.DB
}

type model struct {
	*gdb.Model
}

type modelCache struct {
	*model
}

func checkSchemaConfig(ctx context.Context) (uint64, bool) {
	user, err := utils.GetUserInfo(ctx)
	if err != nil {
		return 0, false
	}
	var schema = fmt.Sprintf("%s%v", schemaPrefix, user.TenantId)
	sprintf := fmt.Sprintf("database.%s", schema)
	if !g.Cfg().MustGet(ctx, sprintf).IsEmpty() {
		return user.TenantId, true
	}
	return user.TenantId, false
}

func DB(ctx context.Context, name ...string) Gfdb {
	var groupName = gdb.DefaultGroupName
	if len(name) > 0 && name[0] != "" {
		groupName = name[0]
	} else {
		tenantId, config := checkSchemaConfig(ctx)
		if config {
			groupName = fmt.Sprintf("%s%v", schemaPrefix, tenantId)
		}
	}
	db := g.DB(groupName)
	TablePrefix = db.GetConfig().Prefix
	return &dataBase{
		DB: db,
	}
}

func (d *dataBase) Model(ctx context.Context, tableNameOrStruct ...any) *model {
	return &model{
		Model: d.DB.Model(tableNameOrStruct...).Ctx(ctx).OmitNil().Hook(catchSQLHook()),
	}
}

func (d *dataBase) Transaction(ctx context.Context, f func(ctx context.Context, tx gdb.TX) error) error {
	return d.DB.Transaction(ctx, f)
}

func (d *model) Cache(ctx context.Context) *gdb.Model {
	traceID := getTraceID(ctx, cacheKeyPrefix)
	if traceID == "" {
		glog.Errorf(ctx, "[DB] GetTraceID error: traceID is empty")
		return nil
	}
	if err := gcache.Set(ctx, traceID, true, time.Second); err != nil {
		glog.Errorf(ctx, "[DB] Cache error: %v", err)
		return nil
	}
	return d.Model
}

func (d *model) NoTenantId(ctx context.Context) *modelCache {
	traceID := getTraceID(ctx, noTenantIdKeyPrefix)
	if traceID == "" {
		glog.Errorf(ctx, "[DB] GetTraceID error: traceID is empty")
		return nil
	}
	if err := gcache.Set(ctx, traceID, true, time.Second); err != nil {
		glog.Errorf(ctx, "[DB] Cache error: %v", err)
		return nil
	}
	return &modelCache{
		&model{
			Model: d.Model,
		},
	}
}

// getTraceID 从 context 中获取链路追踪 ID
func getTraceID(ctx context.Context, prefix string) string {
	span := trace.SpanFromContext(ctx)
	if span != nil && span.SpanContext().HasTraceID() {
		return fmt.Sprintf("%s%v", prefix, span.SpanContext().TraceID().String())
	}
	return ""
}