package etcd

import (
	clientv3 "go.etcd.io/etcd/client/v3"
	"leit.com/leit_seat_aps/common"
	conf "leit.com/leit_seat_aps/config"
	"context"
	"fmt"
)


/******************************************************************************
 *
 * @Struct Name              : ETCDServiceImplement
 *-----------------------------------------------------------------------------
 *
 * @Description              : 的数据访问对象实现
 *
 * @Author                   : zhangxin
 *
 * @Date                     : 2021-06-17
 *
 ******************************************************************************/
type ETCDServiceImplement struct {
	Client        *clientv3.Client
	Lease         clientv3.Lease
	LeaseResp     *clientv3.LeaseGrantResponse
	CancelFunc    func()
	KeepAliveChan <-chan *clientv3.LeaseKeepAliveResponse
	Addr          string
	CTX           context.Context
}

/******************************************************************************
*
* @Function Name            : NewETCDLockClientDAOImplement
*-----------------------------------------------------------------------------
*
* @Description              : 创建一个NewETCDLockClientDAOImplement实例
*
* @Function Parameters      : etcd客户端连接
*

* @Return Value             : ETCDLockClientImplement实例
*
* @Author                   : zhangxin
*
* @Date                     : 2021-06-16
*
******************************************************************************/
func NewETCDServiceImplement(client *clientv3.Client, addr string) *ETCDServiceImplement {
	lease := clientv3.NewLease(client)
	ctx, cancelFunc := context.WithCancel(context.TODO())
	return &ETCDServiceImplement{
		Client:     client,
		Lease:      lease,
		Addr:       addr,
		CTX:        ctx,
		CancelFunc: cancelFunc,
	}
}

/******************************************************************************
 *
 * @Reference LAPP_ETL/dao/etl/ETCDServiceImplement.RegisterService
 *
 ******************************************************************************/
func (impl *ETCDServiceImplement) RegisterService(name string) (err error) {
	err = impl.SetLease()
	if err != nil {
		return err
	}
	go impl.ListenLeaseRespChan()
	kv := clientv3.NewKV(impl.Client)
	serviceKey := fmt.Sprintf("/services/%s/%s", conf.AppConfig.LocalAddr, name)
	_, err = kv.Put(impl.CTX, serviceKey, common.SERVICE_STATUS_RUNNING, clientv3.WithLease(impl.LeaseResp.ID))
	return err
}

/******************************************************************************
 *
 * @Reference LAPP_ETL/dao/etl/ETCDServiceImplement.RegisterTask
 *
 ******************************************************************************/
func (impl *ETCDServiceImplement) RegisterTask(taskId int, stage string) (err error) {
	err = impl.SetLease()
	if err != nil {
		return err
	}
	go impl.ListenLeaseRespChan()
	kv := clientv3.NewKV(impl.Client)
	serviceKey := fmt.Sprintf("/task/%s/%d/%s", conf.AppConfig.LocalAddr, taskId, stage)
	_, err = kv.Put(impl.CTX, serviceKey, common.SERVICE_STATUS_RUNNING, clientv3.WithLease(impl.LeaseResp.ID))
	return err
}

/******************************************************************************
 *
 * @Reference LAPP_ETL/dao/etl/ETCDServiceImplement.SetLease
 *
 ******************************************************************************/
func (impl *ETCDServiceImplement) SetLease() error {
	//设置租约时间
	leaseResp, err := impl.Lease.Grant(impl.CTX, conf.AppConfig.ServiceLease)
	if err != nil {
		return err
	}

	//设置续租
	leaseRespChan, err := impl.Lease.KeepAlive(impl.CTX, leaseResp.ID)
	if err != nil {
		impl.CancelFunc()
		return err
	}
	impl.LeaseResp = leaseResp
	impl.KeepAliveChan = leaseRespChan
	return nil
}

/******************************************************************************
 *
 * @Reference LAPP_ETL/dao/etl/ETCDServiceImplement.ListenLeaseRespChan
 *
 ******************************************************************************/
func (impl *ETCDServiceImplement) ListenLeaseRespChan() {
	for {
		select {
		case <-impl.CTX.Done():
			fmt.Println("context 结束运行")
			return
		case leaseKeepResp := <-impl.KeepAliveChan:
			if leaseKeepResp == nil {
				return
			}
		}
	}
}

/******************************************************************************
 *
 * @Reference LAPP_ETL/dao/etl/ETCDServiceImplement.RevokeLease
 *
 ******************************************************************************/
func (impl *ETCDServiceImplement) RevokeLease() error {
	var err error
	if impl.LeaseResp != nil {
		_, err = impl.Lease.Revoke(impl.CTX, impl.LeaseResp.ID)
		err = impl.Lease.Close()
	}

	impl.CancelFunc()
	return err
}