package sync

import (
	"context"
	"github.com/anytypeio/go-anytype-infrastructure-experiments/pkg/acl/aclchanges/aclpb"
	"github.com/anytypeio/go-anytype-infrastructure-experiments/pkg/acl/acltree"
	"github.com/anytypeio/go-anytype-infrastructure-experiments/service/sync/syncpb"
	"github.com/anytypeio/go-anytype-infrastructure-experiments/service/treecache"
	"github.com/anytypeio/go-anytype-infrastructure-experiments/util/slice"
)

type requestHander struct {
	treeCache treecache.Service
	client    SyncClient
}

func (r *requestHander) HandleHeadUpdate(ctx context.Context, senderId string, update *syncpb.SyncHeadUpdate) (err error) {
	var fullRequest *syncpb.SyncFullRequest
	var addedChanges []*aclpb.RawChange
	var headsWithPath []acltree.HeadWithPathToRoot
	defer func() {
		if err != nil || fullRequest != nil {
			return
		}
		newUpdate := syncpb.NewHeadsUpdate(update.TreeId, headsWithPath, addedChanges)
		err = r.client.NotifyHeadsChanged(newUpdate)
	}()
	err = r.treeCache.Do(ctx, update.TreeId, func(tree acltree.ACLTree) error {
		// TODO: check if we already have those changes
		res, err := tree.AddRawChanges(ctx, update.Changes...)
		if err != nil {
			return err
		}
		addedChanges = res.Added
		shouldFullSync := !r.compareHeads(update.Heads, tree.Heads())
		if shouldFullSync {
			fullRequest, err = r.prepareFullSyncRequest(tree)
			if err != nil {
				return err
			}
		}
		headsWithPath = tree.HeadsPathToRoot()
		return nil
	})
	if err != nil {
		return err
	}
	if fullRequest != nil {
		return r.client.RequestFullSync(senderId, fullRequest)
	}
	return
}

func (r *requestHander) HandleFullSync(ctx context.Context, senderId string, request *syncpb.SyncFullRequest) error {
	return nil
}

func (r *requestHander) compareHeads(syncHeads []*syncpb.SyncHead, heads []string) bool {
	for _, head := range syncHeads {
		if slice.FindPos(heads, head.Id) == -1 {
			return false
		}
	}
	return true
}

func (r *requestHander) prepareFullSyncRequest(tree acltree.ACLTree) (*syncpb.SyncFullRequest, error) {
	return nil, nil
}