// site-ioserver.js
// Copyright (C) 2024 DTP Technologies, LLC
// All Rights Reserved

'use strict';

import { createAdapter } from '@socket.io/redis-adapter';

import mongoose from 'mongoose';
const { ObjectId } = mongoose.Types;

const ConnectToken = mongoose.model('ConnectToken');
const Image = mongoose.model('Image'); // jshint ignore:line

import { SiteLog } from './site-log.js';
import { SiteCommon } from './site-common.js';

export class SiteIoServer extends SiteCommon {

  static get name ( ) { return 'SiteIoServer'; }
  static get slug ( ) { return 'ioServer'; }

  constructor (dtp) {
    super(dtp);
    this.dtp = dtp;
    this.log = new SiteLog(dtp, SiteIoServer);
    this.sessions = { };
  }

  async start (httpServer) {
    const { Server } = await import('socket.io');
    const { RateLimiterRedis } = await import('rate-limiter-flexible');

    this.channelJoinLimiter = new RateLimiterRedis({
      storeClient: this.dtp.redis,
      points: 30,
      duration: 60,
      blockDuration: 60 * 60,
      execEvenly: false,
      keyPrefix: 'iorl:joinchannel:',
    });

    const transports = [
      'websocket',
      // 'polling',
    ];

    this.log.info('creating Socket.io <-> Redis adapter');
    this.adapterPubClient = this.dtp.redis.duplicate();
    this.adapterSubClient = this.dtp.redis.duplicate();
    this.adapter = createAdapter(this.adapterPubClient, this.adapterSubClient);

    this.io = new Server(httpServer, { adapter: this.adapter, transports });
    this.io.adapter(this.adapter);

    this.io.on('connection', this.onSocketConnect.bind(this));
  }

  async onRedisError (error) {
    this.log.error('Redis error', { error });
  }

  async shutdown ( ) {
    this.log.alert('Socket.io server shutting down');

    for (const socketId in this.sessions) {
      const session = this.sessions[socketId];
      this.log.debug('closing socket connection', { socketId });
      await session.socket.disconnect(true);
    }
  }

  async onSocketConnect (socket) {
    const { channel: channelService } = this.dtp.services;

    this.log.debug('socket connection', { sid: socket.id });
    try {
      const token = await ConnectToken
        .findOne({ token: socket.handshake.auth.token })
        .populate([
          {
            path: 'consumer',
            select: '+membership +flags +flags.isCloaked',
            populate: [
              {
                path: 'membership',
                model: 'Membership',
                select: 'status granted expires started plan',
                strictPopulate: false,
                populate: [
                  {
                    path: 'plan',
                    model: 'MembershipPlan',
                    select: 'product.name tier'
                  },
                ],
              },
            ],
          },
        ])
        .lean();
      if (!token) {
        this.log.alert('rejecting invalid socket token', {
          sid: socket.sid,
          handshake: socket.handshake,
        });
        socket.disconnect(true);
        return;
      }

      if (token.consumer) {
        if (token.consumer.password) {
          delete token.consumer.password;
        }
        if (token.consumer.passwordSalt) {
          delete token.consumer.passwordSalt;
        }
      }

      if (token.claimed) {
        this.log.alert('rejecting use of claimed connect token', {
          sid: socket.id,
          handshake: socket.handshake,
        });
        socket.disconnect(true);
        return;
      }

      await ConnectToken.updateOne(
        { _id: token._id },
        { $set: { claimed: new Date() } },
      );
      this.log.debug('token claimed', {
        sid: socket.id,
        token: socket.handshake.auth.token,
        consumerType: token.consumerType,
        consumerId: token.consumer._id,
      });

      const session = {
        socket,
        joinedChannels: new Set(),
        joinedRooms: new Map(),
      };
      this.sessions[socket.id] = session;

      session.onSocketDisconnect = this.onSocketDisconnect.bind(this, session);
      socket.on('disconnect', session.onSocketDisconnect);

      session.onJoinChannel = this.onJoinChannel.bind(this, session);
      socket.on('join', session.onJoinChannel);

      session.onLeaveChannel = this.onLeaveChannel.bind(this, session);
      socket.on('leave', session.onLeaveChannel);

      switch (token.consumerType) {
        case 'User':
          session.user = {
            _id: token.consumer._id,
            created: token.consumer.created,
            username: token.consumer.username,
            username_lc: token.consumer.username_lc,
            displayName: token.consumer.displayName,
            flags: token.consumer.flags,
            membership: token.consumer.membership,
            balances: token.consumer.balances,
          };
          if (token.consumer.picture && token.consumer.picture.small) {
            session.user.picture = {
              small: await Image.findOne({ _id: token.consumer.picture.small }),
            };
          }

          socket.emit('user-authenticated', {
            message: 'token verified',
            user: session.user,
          });
          break;

        case 'Channel':
          session.channel = await channelService.getChannelById(token.consumer._id);
          if (session.channel.widgetKey) {
            delete session.channel.widgetKey;
            session.isWidget = true;
          }
          if (session.channel.streamKey) {
            delete session.channel.streamKey;
          }
          this.log.info('starting Channel session', { channel: session.channel.name });

          socket.emit('widget-authenticated', {
            message: 'token verified',
            channel: session.channel,
          });
          break;
      }
    } catch (error) {
      this.log.error('failed to process a socket connection', { error });
    }
  }

  async onSocketDisconnect (session, reason) {
    const { task: taskService } = this.dtp.services;

    this.log.debug('socket disconnect', {
      sid: session.socket.id,
      consumerId: (session.user || session.channel)._id,
      joinedRooms: session.joinedRooms.size,
      reason,
    });

    try {
      this.log.info('closing open task sessions for user', {
        user: {
          _id: session.user._id,
          username: session.user.username,
        },
      });
      await taskService.closeTaskSessionForUser(session.user);
    } catch (error) {
      this.log.error('failed to close active task sessions for user', {
        user: {
          _id: session.user._id,
          username: session.user.username,
        },
        error,
      });
      // fall through
    }

    if (session.onSocketDisconnect) {
      session.socket.off('disconnect', session.onSocketDisconnect);
      delete session.onSocketDisconnect;
    }

    if (session.onJoinChannel) {
      session.socket.off('join', session.onJoinChannel);
      delete session.onJoinChannel;
    }

    if (session.onLeaveChannel) {
      session.socket.off('leave', session.onLeaveChannel);
      delete session.onLeaveChannel;
    }

    delete this.sessions[session.socket.id];
  }

  async onJoinChannel (session, message) {
    const { channelType } = message;

    try {
      await this.channelJoinLimiter.consume(session.socket.id, 1);
    } catch (error) {
      session.socket.disconnect(true);
      this.log.alert('banned client IP due to channel join limit', { sip: session.socket.handshake.address });
      return;
    }

    this.log.info('onJoinChannel', {
      sid: session.socket.id,
      channelType: message.channelType,
      channelId: message.channelId,
    });
    try {
      switch (channelType) {
        case 'User':
          return this.onJoinUserChannel(session, message);
        default:
          break;
      }
    } catch (error) {
      this.log.error('failed to join channel', { error });
    }
  }

  async onJoinUserChannel (session, message) {
    if (!session.user || !session.user._id) {
      return session.socket.emit('join-result', { authResult: 'access-denied' });
    }

    const channelId = message.channelId;
    const channelComponents = channelId.split(':');
    const parsedChannelId = ObjectId.createFromHexString((channelComponents[0] === 'broadcast') ? channelComponents[1] : channelComponents[0]);

    if (parsedChannelId.equals(session.user._id)) {
      this.log.debug('user joins their own channel', {
        sid: session.socket.id,
        consumerId: parsedChannelId,
        userId: session.user._id,
        channelId: channelId,
      });
      session.joinedChannels.add(channelId);
      session.socket.join(channelId.toString());
      return session.socket.emit('join-result', {
        socketId: session.socket.id,
        channelId: channelId,
        isPersonal: true,
      });
    }

    return this.onJoinStreamChannel(session, message);
  }

  async onLeaveChannel (session, message) {
    const { channelId } = message;
    if (!session.joinedChannels.has(channelId)) {
      return;
    }

    this.log.debug('socket leaves channel', { sid: session.socket.id, user: (session.user || session.channel)._id, channelId });
    session.socket.leave(channelId);

    session.joinedChannels.delete(channelId);
  }
}