package boot

import (
	"encoding/json"
	"g365sfu/bytebuffer"
	"g365sfu/logger"
	"g365sfu/network"
	"g365sfu/sfu"
	"g365sfu/socket"
	connection "g365sfu/socket/struct"
	"g365sfu/turn"
	"g365sfu/utils"
	"net/http"
	"os"

	"github.com/joho/godotenv"
	"github.com/pion/webrtc/v4"
)

func Bootstrap() {
	godotenv.Load()
	sfu.InitWebRTCEngines()
	if os.Getenv("SECRET") == "" {
		logger.LogErrorMessage("server failed to start because not set secret key in .env variables")
		return
	}
	http.HandleFunc("/", socket.HandleWebSocket)
	port := os.Getenv("PORT")
	if port == "" {
		port = "1001"
	}
	sfu.OnLocalICECandidate = OnLocalICECandidate
	sfu.OnServerOffer = OnServerOffer
	sfu.OnRoomDelete = OnRoomDelete
	sfu.OnPeerDisconnected = OnPeerDisconnected
	if os.Getenv("TURN_ALLOW") == "true" {
		turnServer, err := turn.Start(turn.Config{
			ListenAddr:   "0.0.0.0:3478",
			PublicIP:     os.Getenv("TURN_PUBLIC_IP"),
			Realm:        "g365sfu",
			Username:     os.Getenv("TURN_USER"),
			Password:     os.Getenv("TURN_PASS"),
			MinRelayPort: uint16(utils.AtoiOrDefault(os.Getenv("TURN_PORT_RANGE_FROM"), 40000)),
			MaxRelayPort: uint16(utils.AtoiOrDefault(os.Getenv("TURN_PORT_RANGE_TO"), 50000)),
		})
		if err != nil {
			logger.LogWarnMessage("error while starting TURN server: " + err.Error())
			logger.LogInfoMessage("starting without TURN server, peer connections may fail if clients are behind symmetric NATs")
		} else {
			logger.LogInfoMessage("server TURN started at 0.0.0.0:3478")
			// Заполняем глобальные переменные для TURN провайдера, чтобы их могли использовать другие части приложения
			// Обратите внимание, заполняем их только в случе успешного старта Turn сервера
			turn.TURN_PASS = os.Getenv("TURN_PASS")
			turn.TURN_USER = os.Getenv("TURN_USER")
			turn.TURN_PUBLIC_IP = os.Getenv("TURN_PUBLIC_IP")
			defer turnServer.Close()
		}
	} else {
		// TURN сервер выключен в конфиге, что может влиять на соединение некоторых пользователей
		logger.LogInfoMessage("starting without TURN server, peer connections may fail if clients are behind symmetric NATs")
	}
	logger.LogInfoMessage("server SFU started at x.x.x.x:" + port)
	http.ListenAndServe(":"+port, nil)
}

// Коллбек для обработки новых ICE кандидатов от сервера к пиру
func OnLocalICECandidate(roomID string, peerID string, candidate webrtc.ICECandidateInit) {
	room, exists := sfu.GetRoom(roomID)
	if !exists {
		logger.LogWarnMessage("tried to send local ICE candidate to non existing room " + roomID)
		return
	}
	jsonCandidate, _ := json.Marshal(candidate)
	buffer := bytebuffer.Allocate(
		1 + 4 + len([]byte(roomID)) + 4 + len([]byte(peerID)) + 4 + len(jsonCandidate),
	)
	buffer.Put(byte(network.ON_LOCAL_ICE_CANDIDATE))
	buffer.PutUint32(uint32(len([]byte(roomID))))
	buffer.PutBytes([]byte(roomID))
	buffer.PutUint32(uint32(len([]byte(peerID))))
	buffer.PutBytes([]byte(peerID))
	buffer.PutUint32(uint32(len([]byte(jsonCandidate))))
	buffer.PutBytes([]byte(jsonCandidate))
	buffer.Flip()
	room.Server.WriteBinary(buffer.Bytes())
}

// Обработка нового оффера от сервера для конкретного пира (при renegotiation)
func OnServerOffer(roomID string, peerID string, offer webrtc.SessionDescription) {
	room, exists := sfu.GetRoom(roomID)
	if !exists {
		logger.LogWarnMessage("tried to send server offer to non existing room " + roomID)
		return
	}
	jsonOffer, _ := json.Marshal(offer)
	buffer := bytebuffer.Allocate(
		1 + 4 + len([]byte(roomID)) + 4 + len([]byte(peerID)) + 4 + len(jsonOffer),
	)
	buffer.Put(byte(network.ON_SERVER_OFFER))
	buffer.PutUint32(uint32(len([]byte(roomID))))
	buffer.PutBytes([]byte(roomID))
	buffer.PutUint32(uint32(len([]byte(peerID))))
	buffer.PutBytes([]byte(peerID))
	buffer.PutUint32(uint32(len([]byte(jsonOffer))))
	buffer.PutBytes([]byte(jsonOffer))
	buffer.Flip()
	room.Server.WriteBinary(buffer.Bytes())
}

func OnRoomDelete(roomID string, server *connection.Connection) {
	buffer := bytebuffer.Allocate(1 + 4 + len([]byte(roomID)))
	buffer.Put(byte(network.ON_ROOM_DELETE))
	buffer.PutUint32(uint32(len([]byte(roomID))))
	buffer.PutBytes([]byte(roomID))
	buffer.Flip()
	server.WriteBinary(buffer.Bytes())
}

func OnPeerDisconnected(roomID string, peerID string, server *connection.Connection, reason sfu.DisconnectReason) {
	buffer := bytebuffer.Allocate(1 + 4 + len([]byte(roomID)) + 4 + len([]byte(peerID)) + 4)
	buffer.Put(byte(network.ON_PEER_DISCONNECTED))
	buffer.PutUint32(uint32(len([]byte(roomID))))
	buffer.PutBytes([]byte(roomID))
	buffer.PutUint32(uint32(len([]byte(peerID))))
	buffer.PutBytes([]byte(peerID))
	buffer.PutUint32(uint32(reason))
	buffer.Flip()
	server.WriteBinary(buffer.Bytes())
}