package logic

import (
	"context"
	"go.etcd.io/etcd/api/v3/mvccpb"
	clientv3 "go.etcd.io/etcd/client/v3"
	"sonet/api/gen/postal"
	"sonet/pkg/grpc/discovery"
	"sonet/pkg/utils/logger"
)

type PostalMonitor struct {
	client    *clientv3.Client
	keyPrefix string
}

func NewPostalMonitor(client *clientv3.Client) *PostalMonitor {
	return &PostalMonitor{
		client: client,
	}
}

func (m *PostalMonitor) Init(ctx context.Context) (err error) {
	m.keyPrefix = discovery.BuildPrefix(discovery.Server{Name: postal.Postal_ServiceDesc.ServiceName})
	go m.watch(ctx)
	m.build(ctx)
	return
}

func (m *PostalMonitor) Next() {

}

func (m *PostalMonitor) build(ctx context.Context) {
	res, err := m.client.Get(ctx, m.keyPrefix, clientv3.WithPrefix())
	if err != nil {
		return
	}
	//for _, kv := range res.Kvs {
	//
	//}
	m.update(res.Kvs)

}

func (m *PostalMonitor) watch(ctx context.Context) {
	w := m.client.Watch(ctx, m.keyPrefix, clientv3.WithPrefix())
	cancelCh := ctx.Done()

	for {
		select {
		case <-cancelCh:
			return
		case res := <-w:
			if err := res.Err(); err != nil {
				logger.Errorf("watch etcd instance error: %v\n", err)
				continue
			}
			rebuild := false
		eLoop:
			for _, event := range res.Events {
				switch event.Type {
				case clientv3.EventTypePut:
					fallthrough
				case clientv3.EventTypeDelete:
					rebuild = true
					break eLoop
				}
			}
			if rebuild {
				go m.build(ctx)
			}
		}
	}

}

func (m *PostalMonitor) update(value []*mvccpb.KeyValue) {

}