package consul

import (
	"context"
	"gitee.com/h79/goutils/common/system"
	"gitee.com/h79/goutils/discovery/service"
	discoveryWatch "gitee.com/h79/goutils/discovery/watch"
	consul2 "github.com/hashicorp/consul/api"
	"github.com/hashicorp/consul/api/watch"
)

type Watcher struct {
	client *consul2.Client
	wc     discoveryWatch.Chan
	wp     *watch.Plan
	ctx    context.Context
	cancel context.CancelFunc
}

func NewWatcher(client *consul2.Client, sizeChan int) (*Watcher, error) {
	ctx, cancel := context.WithCancel(context.Background())
	watcher := &Watcher{
		client: client,
		wc:     make(discoveryWatch.Chan, sizeChan),
		wp:     nil,
		ctx:    ctx,
		cancel: cancel,
	}
	return watcher, nil
}

func (watcher *Watcher) Watch(key discoveryWatch.Key) (discoveryWatch.Chan, error) {
	wp, err := watch.Parse(key.ToMap())
	if err != nil {
		return nil, err
	}
	watcher.wp = wp
	wp.Handler = func(idx uint64, data interface{}) {
		if data == nil {
			return
		}
		sulkv, ok := data.(consul2.KVPairs)
		if !ok {
			return
		}
		for _, pairs := range sulkv {
			da := service.Data{Key: service.NewKey(pairs.Key), Value: string(pairs.Value)}
			watcher.wc <- discoveryWatch.Changed{
				D:   da,
				Cmd: discoveryWatch.Put,
			}
		}
	}
	//is a blocking
	system.ChildRunning(func() {
		_ = wp.RunWithClientAndHclog(watcher.client, nil)
	})
	return watcher.wc, nil
}

func (watcher *Watcher) Changed(cmd discoveryWatch.Changed) {
	watcher.wc <- cmd
}

func (watcher *Watcher) Stop() error {
	if watcher.wp != nil {
		watcher.wp.Stop()
		watcher.wp = nil
	}
	watcher.cancel()
	return nil
}