package service

import (
	"fmt"
	"reflect"
	"sync"

	"git.loafle.net/commons/logging-go"

	cda "git.loafle.net/commons/di-go/annotation"
	cdr "git.loafle.net/commons/di-go/registry"
	ocmd "git.loafle.net/overflow/commons-go/model/discovery"
	ocscd "git.loafle.net/overflow/commons-go/service/container/discovery"
	ocs "git.loafle.net/overflow/container-go/service"
	"git.loafle.net/overflow/container_discovery/internal/discoverer"

	// For annotation
	_ "git.loafle.net/overflow/commons-go/core/annotation"
)

var DiscoveryServiceType = reflect.TypeOf((*DiscoveryService)(nil))

func init() {
	cdr.RegisterType(DiscoveryServiceType)
}

type DiscoveryService struct {
	ocscd.DiscoveryService
	cda.TypeAnnotation `annotation:"@overflow:RPCService()"`

	ProbeService *ocs.ProbeService `annotation:"@Inject()"`

	pendingDiscovery sync.Map
	discoverer       discoverer.Discoverer
}

func (s *DiscoveryService) InitService() error {
	s.discoverer = discoverer.GetDiscoverer()
	return nil
}

func (s *DiscoveryService) StartService() error {

	return nil
}

func (s *DiscoveryService) StopService() {

}

func (s *DiscoveryService) DestroyService() {

}

func (s *DiscoveryService) DiscoverZone(requesterID string, dz *ocmd.DiscoveryZone) error {
	go s.handleDiscovery(requesterID, func(dataChan chan *discoverer.DiscoveryData) {
		s.discoverer.DiscoverZone(dataChan, dz)
	})

	return nil
}

func (s *DiscoveryService) DiscoverHost(requesterID string, zone *ocmd.Zone, dh *ocmd.DiscoveryHost) error {
	go s.handleDiscovery(requesterID, func(dataChan chan *discoverer.DiscoveryData) {
		s.discoverer.DiscoverHost(dataChan, zone, dh)
	})

	return nil
}

func (s *DiscoveryService) DiscoverPort(requesterID string, host *ocmd.Host, dp *ocmd.DiscoveryPort) error {
	go s.handleDiscovery(requesterID, func(dataChan chan *discoverer.DiscoveryData) {
		s.discoverer.DiscoverPort(dataChan, host, dp)
	})

	return nil
}

func (s *DiscoveryService) DiscoverService(requesterID string, port *ocmd.Port, ds *ocmd.DiscoveryService) error {
	go s.handleDiscovery(requesterID, func(dataChan chan *discoverer.DiscoveryData) {
		s.discoverer.DiscoverSerice(dataChan, port, ds)
	})

	return nil
}

func (s *DiscoveryService) StopRequest(requesterID string) error {
	_stopChan, ok := s.pendingDiscovery.Load(requesterID)
	if !ok {
		return fmt.Errorf("discovery request for [%s] is not exist", requesterID)
	}
	stopChan := _stopChan.(chan struct{})

	close(stopChan)

	return nil
}

func (s *DiscoveryService) handleDiscovery(requesterID string, discoveryFunc func(dataChan chan *discoverer.DiscoveryData)) error {
	stopChan := make(chan struct{})
	s.pendingDiscovery.Store(requesterID, stopChan)
	defer func() {
		s.pendingDiscovery.Delete(requesterID)
	}()

	var dataChan chan *discoverer.DiscoveryData
	retainChan := make(chan struct{})

	go func() {
		dataChan = s.discoverer.Retain()
		close(retainChan)
	}()

	select {
	case <-stopChan:
		return nil
	case <-retainChan:
	}
	defer func() {
		s.discoverer.Release(dataChan)
	}()

	go discoveryFunc(dataChan)

	for {
		select {
		case data, ok := <-dataChan:
			if !ok {
				return nil
			}
			switch data.Type {
			case discoverer.DiscoveryDataTypeStart:
				logging.Logger().Debugf("DiscoveryService.DiscoveryStart")
				s.ProbeService.Send("DiscoveryService.DiscoveryStart", requesterID, data.Time)
			case discoverer.DiscoveryDataTypeStop:
				logging.Logger().Debugf("DiscoveryService.DiscoveryStop")
				s.ProbeService.Send("DiscoveryService.DiscoveryStop", requesterID, data.Time)
				data.Release()
				return nil
			case discoverer.DiscoveryDataTypeError:
				s.ProbeService.Send("DiscoveryService.DiscoveryError", requesterID, data.Error)
			case discoverer.DiscoveryDataTypeZone:
				s.ProbeService.Send("DiscoveryService.DiscoveredZone", requesterID, data.Result)
			case discoverer.DiscoveryDataTypeHost:
				s.ProbeService.Send("DiscoveryService.DiscoveredHost", requesterID, data.Result)
			case discoverer.DiscoveryDataTypePort:
				s.ProbeService.Send("DiscoveryService.DiscoveredPort", requesterID, data.Result)
			case discoverer.DiscoveryDataTypeService:
				s.ProbeService.Send("DiscoveryService.DiscoveredService", requesterID, data.Result)
			}
			data.Release()
		case <-stopChan:
			return nil
		}
	}
}