// Copyright 2022 The Matrix.org Foundation C.I.C.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

package caching

import (
	"github.com/matrix-org/dendrite/roomserver/types"
	"github.com/matrix-org/gomatrixserverlib"
	"github.com/matrix-org/gomatrixserverlib/fclient"
)

// Caches contains a set of references to caches. They may be
// different implementations as long as they satisfy the Cache
// interface.
type Caches struct {
	RoomVersions            Cache[string, gomatrixserverlib.RoomVersion]           // room ID -> room version
	ServerKeys              Cache[string, gomatrixserverlib.PublicKeyLookupResult] // server name -> server keys
	RoomServerRoomNIDs      Cache[string, types.RoomNID]                           // room ID -> room NID
	RoomServerRoomIDs       Cache[types.RoomNID, string]                           // room NID -> room ID
	RoomServerEvents        Cache[int64, *gomatrixserverlib.Event]                 // event NID -> event
	RoomServerStateKeys     Cache[types.EventStateKeyNID, string]                  // eventStateKey NID -> event state key
	RoomServerStateKeyNIDs  Cache[string, types.EventStateKeyNID]                  // event state key -> eventStateKey NID
	RoomServerEventTypeNIDs Cache[string, types.EventTypeNID]                      // eventType -> eventType NID
	RoomServerEventTypes    Cache[types.EventTypeNID, string]                      // eventType NID -> eventType
	FederationPDUs          Cache[int64, *types.HeaderedEvent]                     // queue NID -> PDU
	FederationEDUs          Cache[int64, *gomatrixserverlib.EDU]                   // queue NID -> EDU
	SpaceSummaryRooms       Cache[string, fclient.MSC2946SpacesResponse]           // room ID -> space response
	LazyLoading             Cache[lazyLoadingCacheKey, string]                     // composite key -> event ID
}

// Cache is the interface that an implementation must satisfy.
type Cache[K keyable, T any] interface {
	Get(key K) (value T, ok bool)
	Set(key K, value T)
	Unset(key K)
}

type keyable interface {
	// from https://github.com/dgraph-io/ristretto/blob/8e850b710d6df0383c375ec6a7beae4ce48fc8d5/z/z.go#L34
	~uint64 | ~string | []byte | byte | ~int | ~int32 | ~uint32 | ~int64 | lazyLoadingCacheKey
}

type costable interface {
	CacheCost() int
}