/**
 * Standalone signaling server for the Nextcloud Spreed app.
 * Copyright (C) 2017 struktur AG
 *
 * @author Joachim Bauch <bauch@struktur.de>
 *
 * @license GNU AGPL version 3 or any later version
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */
package signaling

import (
	"context"
	"fmt"

	"github.com/dlintw/goconf"
)

const (
	McuTypeJanus = "janus"
	McuTypeProxy = "proxy"

	McuTypeDefault = McuTypeJanus
)

var (
	ErrNotConnected = fmt.Errorf("not connected")
)

type MediaType int

const (
	MediaTypeAudio  MediaType = 1 << 0
	MediaTypeVideo  MediaType = 1 << 1
	MediaTypeScreen MediaType = 1 << 2
)

type McuListener interface {
	PublicId() string

	OnUpdateOffer(client McuClient, offer map[string]interface{})

	OnIceCandidate(client McuClient, candidate interface{})
	OnIceCompleted(client McuClient)

	SubscriberSidUpdated(subscriber McuSubscriber)

	PublisherClosed(publisher McuPublisher)
	SubscriberClosed(subscriber McuSubscriber)
}

type McuInitiator interface {
	Country() string
}

type Mcu interface {
	Start() error
	Stop()
	Reload(config *goconf.ConfigFile)

	SetOnConnected(func())
	SetOnDisconnected(func())

	GetStats() interface{}

	NewPublisher(ctx context.Context, listener McuListener, id string, sid string, streamType StreamType, bitrate int, mediaTypes MediaType, initiator McuInitiator) (McuPublisher, error)
	NewSubscriber(ctx context.Context, listener McuListener, publisher string, streamType StreamType) (McuSubscriber, error)
}

type StreamType string

const (
	StreamTypeAudio  StreamType = "audio"
	StreamTypeVideo  StreamType = "video"
	StreamTypeScreen StreamType = "screen"
)

func IsValidStreamType(s string) bool {
	switch s {
	case string(StreamTypeAudio):
		fallthrough
	case string(StreamTypeVideo):
		fallthrough
	case string(StreamTypeScreen):
		return true
	default:
		return false
	}
}

type McuClient interface {
	Id() string
	Sid() string
	StreamType() StreamType
	MaxBitrate() int

	Close(ctx context.Context)

	SendMessage(ctx context.Context, message *MessageClientMessage, data *MessageClientMessageData, callback func(error, map[string]interface{}))
}

type McuPublisher interface {
	McuClient

	HasMedia(MediaType) bool
	SetMedia(MediaType)
}

type McuSubscriber interface {
	McuClient

	Publisher() string
}