// express 설정 파일
import express from "express";
import cors from "cors";
import { Server } from "socket.io";
import http from "http";
import wrtc from "wrtc";
import cookieParser from "cookie-parser";
import mainRouter from "./routes/index.js";

const app = express();
app.use(cors());
const server = http.createServer(app);
const io = new Server(server, {
  cors: {
    origin: "http://localhost:3000",
    methods: ["GET", "POST"],
  },
});
app.use(express.json());
app.use(express.urlencoded({ extended: true }));
app.use(cookieParser());

app.use("/api", mainRouter);

let receiverPCs = {};
let senderPCs = {};
let users = {};
let socketToRoom = {};

const pc_config = {
  iceServers: [
    // {
    //   urls: 'stun:[STUN_IP]:[PORT]',
    //   'credentials': '[YOR CREDENTIALS]',
    //   'username': '[USERNAME]'
    // },
    {
      urls: "stun:stun.l.google.com:19302",
    },
  ],
};

const isIncluded = (array, id) => {
  let len = array.length;
  for (let i = 0; i < len; i++) {
    if (array[i].id === id) return true;
  }
  return false;
};

const createReceiverPeerConnection = (socketID, socket, roomID) => {
  let pc = new wrtc.RTCPeerConnection(pc_config);

  if (receiverPCs[socketID]) receiverPCs[socketID] = pc;
  else receiverPCs = { ...receiverPCs, [socketID]: pc };

  pc.onicecandidate = (e) => {
    //console.log(`socketID: ${socketID}'s receiverPeerConnection icecandidate`);
    socket.to(socketID).emit("getSenderCandidate", {
      candidate: e.candidate,
    });
  };

  pc.oniceconnectionstatechange = (e) => {
    //console.log(e);
  };

  pc.ontrack = (e) => {
    if (users[roomID]) {
      if (!isIncluded(users[roomID], socketID)) {
        users[roomID].push({
          id: socketID,
          stream: e.streams[0],
        });
      } else return;
    } else {
      users[roomID] = [
        {
          id: socketID,
          stream: e.streams[0],
        },
      ];
    }
    socket.broadcast.to(roomID).emit("userEnter", { id: socketID });
  };

  return pc;
};

const createSenderPeerConnection = (
  receiverSocketID,
  senderSocketID,
  socket,
  roomID
) => {
  let pc = new wrtc.RTCPeerConnection(pc_config);

  if (senderPCs[senderSocketID]) {
    senderPCs[senderSocketID].filter((user) => user.id !== receiverSocketID);
    senderPCs[senderSocketID].push({ id: receiverSocketID, pc: pc });
  } else
    senderPCs = {
      ...senderPCs,
      [senderSocketID]: [{ id: receiverSocketID, pc: pc }],
    };

  pc.onicecandidate = (e) => {
    //console.log(`socketID: ${receiverSocketID}'s senderPeerConnection icecandidate`);
    socket.to(receiverSocketID).emit("getReceiverCandidate", {
      id: senderSocketID,
      candidate: e.candidate,
    });
  };

  pc.oniceconnectionstatechange = (e) => {
    //console.log(e);
  };

  const sendUser = users[roomID].filter((user) => user.id === senderSocketID);
  sendUser[0].stream.getTracks().forEach((track) => {
    pc.addTrack(track, sendUser[0].stream);
  });

  return pc;
};

const getOtherUsersInRoom = (socketID, roomID) => {
  let allUsers = [];

  if (!users[roomID]) return allUsers;

  let len = users[roomID].length;
  for (let i = 0; i < len; i++) {
    if (users[roomID][i].id === socketID) continue;
    allUsers.push({ id: users[roomID][i].id });
  }

  return allUsers;
};

const deleteUser = (socketID, roomID) => {
  let roomUsers = users[roomID];
  if (!roomUsers) return;
  roomUsers = roomUsers.filter((user) => user.id !== socketID);
  users[roomID] = roomUsers;
  if (roomUsers.length === 0) {
    delete users[roomID];
  }
  delete socketToRoom[socketID];
};

const closeRecevierPC = (socketID) => {
  if (!receiverPCs[socketID]) return;

  receiverPCs[socketID].close();
  delete receiverPCs[socketID];
};

const closeSenderPCs = (socketID) => {
  if (!senderPCs[socketID]) return;

  let len = senderPCs[socketID].length;
  for (let i = 0; i < len; i++) {
    senderPCs[socketID][i].pc.close();
    let _senderPCs = senderPCs[senderPCs[socketID][i].id];
    let senderPC = _senderPCs.filter((sPC) => sPC.id === socketID);
    if (senderPC[0]) {
      senderPC[0].pc.close();
      senderPCs[senderPCs[socketID][i].id] = _senderPCs.filter(
        (sPC) => sPC.id !== socketID
      );
    }
  }

  delete senderPCs[socketID];
};

io.on("connection", (socket) => {
  console.log("socket connection complete");
  socket.on("joinRoom", (data) => {
    try {
      let allUsers = getOtherUsersInRoom(data.id, data.roomID);
      io.to(data.id).emit("allUsers", { users: allUsers });
    } catch (error) {
      console.log(error);
    }
  });

  socket.on("senderOffer", async (data) => {
    try {
      socketToRoom[data.senderSocketID] = data.roomID;
      let pc = createReceiverPeerConnection(
        data.senderSocketID,
        socket,
        data.roomID
      );
      await pc.setRemoteDescription(data.sdp);
      let sdp = await pc.createAnswer({
        offerToReceiveAudio: true,
        offerToReceiveVideo: true,
      });
      await pc.setLocalDescription(sdp);
      socket.join(data.roomID);
      io.to(data.senderSocketID).emit("getSenderAnswer", { sdp });
    } catch (error) {
      console.log(error);
    }
  });

  socket.on("senderCandidate", async (data) => {
    try {
      let pc = receiverPCs[data.senderSocketID];
      await pc.addIceCandidate(new wrtc.RTCIceCandidate(data.candidate));
    } catch (error) {
      console.log(error);
    }
  });

  socket.on("receiverOffer", async (data) => {
    try {
      let pc = createSenderPeerConnection(
        data.receiverSocketID,
        data.senderSocketID,
        socket,
        data.roomID
      );
      await pc.setRemoteDescription(data.sdp);
      let sdp = await pc.createAnswer({
        offerToReceiveAudio: false,
        offerToReceiveVideo: false,
      });
      await pc.setLocalDescription(sdp);
      io.to(data.receiverSocketID).emit("getReceiverAnswer", {
        id: data.senderSocketID,
        sdp,
      });
    } catch (error) {
      console.log(error);
    }
  });

  socket.on("receiverCandidate", async (data) => {
    try {
      const senderPC = senderPCs[data.senderSocketID].filter(
        (sPC) => sPC.id === data.receiverSocketID
      );
      await senderPC[0].pc.addIceCandidate(
        new wrtc.RTCIceCandidate(data.candidate)
      );
    } catch (error) {
      console.log(error);
    }
  });

  socket.on("disconnect", () => {
    try {
      let roomID = socketToRoom[socket.id];

      deleteUser(socket.id, roomID);
      closeRecevierPC(socket.id);
      closeSenderPCs(socket.id);

      socket.broadcast.to(roomID).emit("userExit", { id: socket.id });
    } catch (error) {
      console.log(error);
    }
  });
});

export default server;