package common_db

import (
	"context"
	_ "database/sql"
	"reflect"
	"sync/atomic"
	"time"

	"git.shuncheng.lu/bigthing/gocommon/pkg/trace"

	"git.shuncheng.lu/bigthing/gocommon/pkg/conf"
	"git.shuncheng.lu/bigthing/gocommon/pkg/internal/constant"
	. "git.shuncheng.lu/bigthing/gocommon/pkg/internal/util"
	_ "github.com/go-sql-driver/mysql"
	"xorm.io/xorm"
)

type DbConn interface {
	Close() error
	DbName() string
	NewSlaveEngine() *xorm.Engine
	NewMasterEngine() *xorm.Engine
	NewSlaveSession() *xorm.Session
	NewMasterSession() *xorm.Session
	NewSlaveCtxSession(ctx context.Context) *xorm.Session
	NewMasterCtxSession(ctx context.Context) *xorm.Session
}

const (
	defaultPingConnection    = 30
	defaultRefreshConfigTime = 30
)

type dbConn struct {
	dbName     string
	realDbName string

	config map[string]string
	/**
	// 原子包的速度
	BenchmarkName-8   	1000000000	         0.817 ns/op
	// 速写锁的速度
	BenchmarkName-8   	28494505	        39.3 ns/op
	// 完全不是一个量级
	*/
	engineGroup atomic.Value
}

func (d *dbConn) getConfig(key string) string {
	return d.config[key]
}

func (d *dbConn) setConfig(conf map[string]string) {
	d.config = conf
}

func (d *dbConn) getEngineGroup() *xorm.EngineGroup {
	group := d.engineGroup.Load()
	if group == nil {
		return nil
	}
	return group.(*xorm.EngineGroup)
}

func (d *dbConn) setEngineGroup(group *xorm.EngineGroup) {
	d.engineGroup.Store(group)
}

//主库从库engine group
func NewDbConn(dbName string) (DbConn, error) {
	conn := &dbConn{
		dbName: dbName,
	}
	err := conn.reloadEngine()
	if err != nil {
		return nil, err
	}

	// 热加载
	GoWithRecover(func() {
		conn.checkRefreshConfig()
	}, func(error interface{}) {
		Errorf("[database.checkConn] run panic find err, err=%v", err)
	})

	// 健康检测 v1.0.2.3 取消，go std driver的feature支持 自动处理断开的连接， https://github.com/go-sql-driver/mysql#features
	//go func() {
	//	conn.checkConn()
	//}()

	return conn, nil
}

func (d *dbConn) NewSlaveEngine() *xorm.Engine {
	return d.getEngineGroup().Slave()
}

func (d *dbConn) NewMasterEngine() *xorm.Engine {
	return d.getEngineGroup().Master()
}

func (d *dbConn) NewSlaveSession() *xorm.Session {
	return d.NewSlaveEngine().NewSession()
}

func (d *dbConn) NewMasterSession() *xorm.Session {
	return d.NewMasterEngine().NewSession()
}

func (d *dbConn) NewSlaveCtxSession(ctx context.Context) *xorm.Session {
	ctx = d.withContext(ctx)
	return d.NewSlaveEngine().Context(ctx)
}

func (d *dbConn) NewMasterCtxSession(ctx context.Context) *xorm.Session {
	ctx = d.withContext(ctx)
	return d.NewMasterEngine().Context(ctx)
}

func (d *dbConn) withContext(ctx context.Context) context.Context {
	if ctx == nil {
		ctx = context.Background()
	}
	ctx = context.WithValue(ctx, constant.DbName, d.dbName)
	span, err := trace.NewMysqlExitSpan(ctx, d.dbName)
	if span != nil && err == nil {
		ctx = trace.SetMySqlExitSpan(ctx, span)
	}
	return ctx
}

func (d *dbConn) DbName() string {
	return d.realDbName
}

func (d *dbConn) Close() error {
	return closeEngine(d.getEngineGroup())
}

/**
定期检测！健康！！
*/
//func (d *dbConn) checkConn() {
//	getRefreshTime := func() time.Duration {
//		return time.Second * time.Duration(String2Int64(d.getConfig("ping_connection"), defaultPingConnection))
//	}
//	timer := time.NewTimer(getRefreshTime())
//	for {
//		<-timer.C
//		func() {
//			defer func() {
//				if err := recover(); err != nil {
//					Errorf("[database.checkConn] find panic,err=%v", err)
//				}
//			}()
//			serr := d.NewSlaveSession().Ping()
//			merr := d.NewMasterSession().Ping()
//			if serr != nil || merr != nil {
//				Errorf("[database.checkConn] ping err,err=%v", serr, merr)
//				oldEngine := d.getEngineGroup()
//				err := d.reloadEngine()
//				if err != nil {
//					Errorf("[database.checkConn] reload err,err=%v", err)
//					return
//				}
//				go func() {
//					err := closeEngine(oldEngine) // 异步关闭
//					if err != nil {
//						Errorf("[database.checkConn] close err,err=%v", err)
//					}
//					return
//				}()
//			}
//		}()
//		timer.Reset(getRefreshTime())
//	}
//}

/**
定期刷新配置，查看db是否变更！！
*/
func (d *dbConn) checkRefreshConfig() {
	getRefreshTime := func() time.Duration {
		return time.Second * time.Duration(String2Int64(d.getConfig("refresh_config_time"), defaultRefreshConfigTime))
	}
	timer := time.NewTimer(getRefreshTime())
	for {
		<-timer.C
		func() {
			defer func() {
				if err := recover(); err != nil {
					Errorf("[database.checkRefreshConfig] panic,err=%v", err)
				}
			}()
			newConf, err := getMysqlConfig(d.dbName, conf.SetAndAssertNil)
			if err != nil {
				Errorf("[database.checkRefreshConfig] getMysqlConfig err,err=%v", err)
				return
			}
			isSame := reflect.DeepEqual(d.config, newConf)
			if !isSame {
				oldEngine := d.getEngineGroup()
				if err := d.reloadEngine(); err != nil {
					Errorf("[database.checkRefreshConfig] reload err,err=%v", err)
					return
				}
				go func(oldEngine *xorm.EngineGroup) {
					defer func() {
						if err := recover(); err != nil {
							Errorf("[database.checkRefreshConfig] close engine panic, err=%v", err)
						}
					}()
					err := closeEngine(oldEngine) // 异步关闭
					if err != nil {
						Errorf("[database.checkConn] close err, err=%v", err)
					}
				}(oldEngine)
			}
		}()
		timer.Reset(getRefreshTime())
	}
}

func (d *dbConn) reloadEngine() error {
	group, config, err := newEngine(d.dbName)
	if err != nil {
		return err
	}
	if err := testConn(group); err != nil {
		return err
	}
	d.realDbName = If(config["dbname"] == "", d.dbName, config["dbname"]).(string)
	d.setConfig(config)
	d.setEngineGroup(group)
	return nil
}

/**
测试 engine 连接, 创建 Engine时候需要测试连接
*/
func testConn(engine *xorm.EngineGroup) error {
	if engine == nil {
		return NewError("the engine group is nil can not test")
	}
	if engine.Slave() == nil {
		return NewError("the slave engine is nil can not test")
	}
	if err := engine.Slave().Ping(); err != nil {
		return NewError("slave engine ping find err, err: %s", err)
	}
	if engine.Master() == nil {
		return NewError("the master engine is nil can not test")
	}
	if err := engine.Master().Ping(); err != nil {
		return NewError("master engine ping find err, err: %s", err)
	}
	return nil
}