package deliver

import (
	"context"
	"errors"
	"fmt"
	"google.golang.org/protobuf/proto"
	"sonet/api/gen/postal"
	"sonet/pkg/plugins/mq"
	"sonet/pkg/protocol/event"
	"sonet/pkg/utils/collect"
	"sonet/pkg/utils/logger"
)

type GroupLoader interface {
	Load(uid string) (groupIds []string, err error)
}

type GroupDeliver struct {
	svcName      string
	groupLoader  GroupLoader
	consumer     mq.Consumer
	postalPicker *PostalPicker
}

func NewGroupDeliver(
	msgInServiceName string,
	postalPicker *PostalPicker,
	groupLoader GroupLoader,
	consumer mq.Consumer,
) *GroupDeliver {
	return &GroupDeliver{
		svcName:      msgInServiceName,
		postalPicker: postalPicker,
		groupLoader:  groupLoader,
		consumer:     consumer,
	}
}

func (d *GroupDeliver) Init(ctx context.Context) (err error) {
	if d.consumer != nil {
		err = d.subscribe()
	}
	return
}

// toPostalGid 加上 svc name 前缀避免和其他服务群组冲突
func (d *GroupDeliver) toPostalGid(gid string) string {
	return d.svcName + "." + gid
}

// subscribe postal online events
func (d *GroupDeliver) subscribe() error {
	consumerChannel := fmt.Sprintf("%s:%s", "deliver", d.svcName)
	return d.consumer.Subscribe(event.TopicOnline, consumerChannel, func(message *mq.Message) (err error) {
		online := &event.Online{}
		if e := online.UnmarshalBinary(message.Body); e != nil {
			logger.Error("deliver unmarshal online event payload error: ", e)
			return
		}
		// load uid groups join to postal
		groupIds, err := d.groupLoader.Load(online.Uid)
		if err != nil {
			logger.Error("deliver load groups error:", err)
			return
		}
		if err = d.GroupJoin(context.Background(), online.Uid, groupIds); err != nil {
			logger.Errorf("deliver uid %s group join error: %v", online.Uid, err)
			return
		}
		return
	})
}

// DeliverGroup 群组消息广播投递到所有 postal 节点
func (d *GroupDeliver) DeliverGroup(ctx context.Context, gid string, msg proto.Message, options ...Option) (err error) {
	message, err := Proto2DeliverMessage(d.svcName, msg)
	if err != nil {
		return
	}
	clients := d.postalPicker.PickAll()

	var errs []error
	req := postal.ReqDeliverGroup{Gid: d.toPostalGid(gid), Msg: message}
	for _, client := range clients {
		_, err := client.DeliverGroup(ctx, &req)
		if err != nil {
			errs = append(errs, err)
		}
	}
	if len(errs) > 0 {
		err = errors.Join(errs...)
		return
	}
	return
}

// GroupDissolve 群组消息广播投递到所有 postal 节点
func (d *GroupDeliver) GroupDissolve(ctx context.Context, gid string) (err error) {
	clients := d.postalPicker.PickAll()

	var errs []error
	req := postal.ReqGroupDissolve{Gid: d.toPostalGid(gid)}
	for _, client := range clients {
		_, err := client.GroupDissolve(ctx, &req)
		if err != nil {
			errs = append(errs, err)
		}
	}
	if len(errs) > 0 {
		err = errors.Join(errs...)
		return
	}
	return
}

func (d *GroupDeliver) GroupJoin(ctx context.Context, uid string, gids []string) (err error) {
	if len(gids) == 0 {
		return
	}
	gids = collect.Mapping(gids, d.toPostalGid)

	client, err := d.postalPicker.Pick(uid)
	if err != nil {
		return
	}
	_, err = client.GroupJoin(ctx, &postal.ReqGroupJoin{Uid: uid, Gids: gids})
	return
}

func (d *GroupDeliver) GroupLeave(ctx context.Context, uid string, gids []string) (err error) {
	if len(gids) == 0 {
		return
	}
	gids = collect.Mapping(gids, d.toPostalGid)

	client, err := d.postalPicker.Pick(uid)
	if err != nil {
		return
	}
	req := &postal.ReqGroupLeave{Uid: uid, Gids: gids}
	_, err = client.GroupLeave(ctx, req)
	return
}