// Copyright 2015 The Vanadium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.

package watchable

import (
	"v.io/x/ref/services/syncbase/server/interfaces"
)

// SyncgroupOp represents a change in the set of prefixes that should be tracked
// by sync, i.e. the union of prefix sets across all syncgroups. Note that an
// individual syncgroup's prefixes cannot be changed; this record type is used
// to track changes due to syncgroup create/join/leave/destroy.
type SyncgroupOp struct {
	SgId     interfaces.GroupId
	Prefixes []string
	Remove   bool
}

// SyncSnapshotOp represents a snapshot operation when creating and joining a
// syncgroup. The sync watcher needs to get a snapshot of the Database at the
// point of creating/joining a syncgroup. A SyncSnapshotOp entry is written to
// the log for each Database key that falls within the syncgroup prefixes. This
// allows sync to initialize its metadata at the correct versions of the objects
// when they become syncable. These log entries should be filtered by the
// client-facing Watch interface because the user data did not actually change.
type SyncSnapshotOp struct {
	Key         []byte
	Version     []byte
}

// StateChange represents the set of types of state change requests possible.
type StateChange enum {
	// PauseSync pauses sync for the db.
	PauseSync
	// ResumeSync resumes sync for the db.
	ResumeSync
}

// DbStateChangeRequestOp represents a database state change request.
// Specifically there are two events that create this op:
// PauseSync, indicating a client request to pause sync on this db.
// ResumeSync, indicating a client request to resume sync on this db.
// Client watcher will ignore this op.
type DbStateChangeRequestOp struct {
	RequestType StateChange
}