import type { types } from 'mediasoup'
import type { Namespace, RemoteSocket, Socket, Server as SocketServer } from 'socket.io'
import { consola } from 'consola'

interface ChadClient {
  id: string
  username: string
  inputMuted: boolean
  outputMuted: boolean
}

interface ProducerShort {
  producerId: types.Producer['id']
  kind: types.MediaKind
}

interface ErrorCallbackResult {
  error: string
}

interface SuccessCallbackResult {
  ok: true
}

type EventCallback<T = SuccessCallbackResult> = (result: T | ErrorCallbackResult) => void

interface ClientToServerEvents {
  join: (
    options: {
      username: string
      rtpCapabilities: types.RtpCapabilities
    },
    cb: EventCallback<{ id: string, username: string }[]>
  ) => void
  getRtpCapabilities: (
    cb: EventCallback<types.RtpCapabilities>
  ) => void
  createTransport: (
    options: {
      producing: boolean
      consuming: boolean
    },
    cb: EventCallback<Pick<types.WebRtcTransport, 'id' | 'iceParameters' | 'iceCandidates' | 'dtlsParameters'>>
  ) => void
  connectTransport: (
    options: {
      transportId: types.WebRtcTransport['id']
      dtlsParameters: types.WebRtcTransport['dtlsParameters']
    },
    cb: EventCallback
  ) => void
  produce: (
    options: {
      transportId: types.WebRtcTransport['id']
      kind: types.MediaKind
      rtpParameters: types.RtpParameters
    },
    cb: EventCallback<{ id: types.Producer['id'] }>
  ) => void
  closeProducer: (
    options: {
      producerId: types.Producer['id']
    },
    cb: EventCallback
  ) => void
  pauseProducer: (
    options: {
      producerId: types.Producer['id']
    },
    cb: EventCallback
  ) => void
  resumeProducer: (
    options: {
      producerId: types.Producer['id']
    },
    cb: EventCallback
  ) => void
  pauseConsumer: (
    options: {
      consumerId: types.Consumer['id']
    },
    cb: EventCallback
  ) => void
  resumeConsumer: (
    options: {
      consumerId: types.Consumer['id']
    },
    cb: EventCallback
  ) => void
  updateClient: (
    options: Partial<Omit<ChadClient, 'id'>>,
    cb: EventCallback
  ) => void
}

interface ServerToClientEvents {
  newPeer: (arg: ChadClient) => void
  producers: (arg: ProducerShort[]) => void
  newConsumer: (
    arg: {
      peerId: string
      producerId: types.Producer['id']
      id: types.Consumer['id']
      kind: types.MediaKind
      rtpParameters: types.RtpParameters
      type: types.ConsumerType
      appData: types.Producer['appData']
      producerPaused: types.Consumer['producerPaused']
    },
    cb: EventCallback
  ) => void
  peerClosed: (arg: string) => void
  consumerClosed: (arg: { consumerId: string }) => void
  consumerPaused: (arg: { consumerId: string }) => void
  consumerResumed: (arg: { consumerId: string }) => void
  consumerScore: (arg: { consumerId: string, score: types.ConsumerScore }) => void
  clientChanged: (clientId: ChadClient['id'], client: ChadClient) => void
}

interface InterServerEvent {}

interface SocketData {
  joined: boolean
  username: string
  inputMuted: boolean
  outputMuted: boolean
  rtpCapabilities: types.RtpCapabilities
  transports: Map<types.WebRtcTransport['id'], types.WebRtcTransport>
  producers: Map<types.Producer['id'], types.Producer>
  consumers: Map<types.Consumer['id'], types.Consumer>
}

export default function (io: SocketServer, router: types.Router) {
  const namespace: Namespace<ClientToServerEvents, ServerToClientEvents, InterServerEvent, SocketData> = io.of('/webrtc')

  namespace.on('connection', (socket) => {
    consola.info('[WebRtc]', 'Client connected', socket.id)

    socket.data.joined = false

    socket.data.username = socket.id
    socket.data.inputMuted = false
    socket.data.outputMuted = false

    socket.data.transports = new Map()
    socket.data.producers = new Map()
    socket.data.consumers = new Map()

    socket.on('join', async ({ username, rtpCapabilities }, cb) => {
      if (socket.data.joined) {
        consola.error('[WebRtc]', 'Already joined')
        cb({ error: 'Already joined' })
      }

      socket.data.joined = true
      socket.data.username = username
      socket.data.rtpCapabilities = rtpCapabilities

      const joinedSockets = await getJoinedSockets()

      cb(joinedSockets.map((s) => {
        return {
          id: s.id,
          username: s.data.username,
        }
      }))

      for (const joinedSocket of joinedSockets.filter(joinedSocket => joinedSocket.id !== socket.id)) {
        for (const producer of joinedSocket.data.producers.values()) {
          createConsumer(
            socket,
            joinedSocket,
            producer,
          )
        }
      }

      socket.broadcast.emit('newPeer', socketToClient(socket))
    })

    socket.on('getRtpCapabilities', (cb) => {
      cb(router.rtpCapabilities)
    })

    socket.on('createTransport', async ({ producing, consuming }, cb) => {
      try {
        const transport = await router.createWebRtcTransport({
          listenInfos: [
            {
              protocol: 'udp',
              ip: '0.0.0.0',
              announcedAddress: process.env.ANNOUNCED_ADDRESS || '127.0.0.1',
              portRange: {
                min: 40000,
                max: 40100,
              },
            },
          ],
          enableUdp: true,
          preferUdp: true,
          appData: {
            producing,
            consuming,
          },
        })

        socket.data.transports.set(transport.id, transport)

        cb({
          id: transport.id,
          iceParameters: transport.iceParameters,
          iceCandidates: transport.iceCandidates,
          dtlsParameters: transport.dtlsParameters,
        })

        transport.on('icestatechange', (iceState) => {
          if (iceState === 'disconnected' || iceState === 'closed') {
            consola.info('[WebRtc]', '[WebRtcTransport]', `"icestatechange" event [iceState:${iceState}], closing peer`, transport.id)

            socket.disconnect()
          }
        })

        transport.on('dtlsstatechange', (dtlsState) => {
          if (dtlsState === 'failed' || dtlsState === 'closed') {
            consola.warn('WebRtcTransport "dtlsstatechange" event [dtlsState:%s], closing peer', dtlsState)

            socket.disconnect()
          }
        })
      }
      catch (error) {
        if (error instanceof Error) {
          consola.error('[WebRtc]', '[createTransport]', error.message)
          cb({ error: error.message })
        }
      }
    })

    socket.on('connectTransport', async ({ transportId, dtlsParameters }, cb) => {
      const transport = socket.data.transports.get(transportId)

      if (!transport) {
        consola.error('[WebRtc]', '[connectTransport]', `Transport with id ${transportId} not found`)
        cb({ error: 'Transport not found' })

        return
      }

      try {
        await transport.connect({ dtlsParameters })

        cb({ ok: true })
      }
      catch (error) {
        if (error instanceof Error) {
          consola.error('[WebRtc]', '[connectTransport]', error.message)
          cb({ error: error.message })
        }
      }
    })

    socket.on('produce', async ({ transportId, kind, rtpParameters }, cb) => {
      if (!socket.data.joined) {
        consola.error('Peer not joined yet')
        cb({ error: 'Peer not joined yet' })

        return
      }

      const transport = socket.data.transports.get(transportId)

      if (!transport) {
        consola.error('[WebRtc]', '[produce]', `Transport with id ${transportId} not found`)
        cb({ error: 'Transport not found' })

        return
      }

      try {
        const producer = await transport.produce({ kind, rtpParameters, appData: { socketId: socket.id } })

        socket.data.producers.set(producer.id, producer)

        cb({ id: producer.id })

        const otherSockets = await getJoinedSockets(socket.id)

        for (const otherSocket of otherSockets) {
          createConsumer(
            otherSocket,
            socket,
            producer,
          )
        }

        // TODO: Add into the AudioLevelObserver and ActiveSpeakerObserver.
        // https://github.com/versatica/mediasoup-demo/blob/v3/server/lib/Room.js#L1276
      }
      catch (error) {
        if (error instanceof Error) {
          consola.error('[WebRtc]', '[produce]', error.message)
          cb({ error: error.message })
        }
      }
    })

    socket.on('closeProducer', async ({ producerId }, cb) => {
      if (!socket.data.joined) {
        consola.error('Peer not joined yet')
        cb({ error: 'Peer not joined yet' })

        return
      }

      const producer = socket.data.producers.get(producerId)

      if (!producer) {
        consola.error(`producer with id "${producerId}" not found`)
        cb({ error: `producer with id "${producerId}" not found` })

        return
      }

      producer.close()

      socket.data.producers.delete(producerId)

      cb({ ok: true })
    })

    socket.on('pauseProducer', async ({ producerId }, cb) => {
      if (!socket.data.joined) {
        consola.error('Peer not joined yet')
        cb({ error: 'Peer not joined yet' })

        return
      }

      const producer = socket.data.producers.get(producerId)

      if (!producer) {
        consola.error(`producer with id "${producerId}" not found`)
        cb({ error: `producer with id "${producerId}" not found` })

        return
      }

      await producer.pause()

      cb({ ok: true })
    })

    socket.on('resumeProducer', async ({ producerId }, cb) => {
      if (!socket.data.joined) {
        consola.error('Peer not joined yet')
        cb({ error: 'Peer not joined yet' })

        return
      }

      const producer = socket.data.producers.get(producerId)

      if (!producer) {
        consola.error(`producer with id "${producerId}" not found`)
        cb({ error: `producer with id "${producerId}" not found` })

        return
      }

      await producer.resume()

      cb({ ok: true })
    })

    socket.on('pauseConsumer', async ({ consumerId }, cb) => {
      if (!socket.data.joined) {
        consola.error('Peer not joined yet')
        cb({ error: 'Peer not joined yet' })

        return
      }

      const consumer = socket.data.consumers.get(consumerId)

      if (!consumer) {
        consola.error(`consumer with id "${consumerId}" not found`)
        cb({ error: `consumer with id "${consumerId}" not found` })

        return
      }

      await consumer.pause()

      cb({ ok: true })
    })

    socket.on('resumeConsumer', async ({ consumerId }, cb) => {
      if (!socket.data.joined) {
        consola.error('Peer not joined yet')
        cb({ error: 'Peer not joined yet' })

        return
      }

      const consumer = socket.data.consumers.get(consumerId)

      if (!consumer) {
        consola.error(`consumer with id "${consumerId}" not found`)
        cb({ error: `consumer with id "${consumerId}" not found` })

        return
      }

      await consumer.resume()

      cb({ ok: true })
    })

    socket.on('updateClient', (updatedClient, cb) => {
      if (updatedClient.username) {
        socket.data.username = updatedClient.username
      }

      if (updatedClient.inputMuted) {
        socket.data.inputMuted = updatedClient.inputMuted
      }

      if (updatedClient.outputMuted) {
        socket.data.outputMuted = updatedClient.outputMuted
      }

      cb({ ok: true })

      namespace.emit('clientChanged', socket.id, socketToClient(socket))
    })

    socket.on('disconnect', () => {
      consola.info('Client disconnected:', socket.id)

      if (socket.data.joined) {
        socket.broadcast.emit('peerClosed', socket.id)
      }

      for (const transport of socket.data.transports.values()) {
        transport.close()
      }
    })
  })

  async function getJoinedSockets(excludeId?: string) {
    const sockets = await namespace.fetchSockets()

    return sockets.filter(socket => socket.data.joined && (excludeId ? excludeId !== socket.id : true))
  }

  async function createConsumer(
    consumerSocket: Socket<ClientToServerEvents, ServerToClientEvents, InterServerEvent, SocketData>,
    producerSocket: RemoteSocket<ServerToClientEvents, SocketData>,
    producer: types.Producer,
  ) {
    if (
      !consumerSocket.data.rtpCapabilities
      || !router.canConsume(
        {
          producerId: producer.id,
          rtpCapabilities: consumerSocket.data.rtpCapabilities,
        },
      )
    ) {
      return
    }

    const transport = Array.from(consumerSocket.data.transports.values())
      .find(t => t.appData.consuming)

    if (!transport) {
      consola.error('createConsumer() | Transport for consuming not found')

      return
    }

    let consumer: types.Consumer

    try {
      consumer = await transport.consume(
        {
          producerId: producer.id,
          rtpCapabilities: consumerSocket.data.rtpCapabilities,
          // Enable NACK for OPUS.
          enableRtx: true,
          paused: true,
          ignoreDtx: true,
        },
      )
    }
    catch (error) {
      consola.error('_createConsumer() | transport.consume():%o', error)

      return
    }

    consumerSocket.data.consumers.set(consumer.id, consumer)

    consumer.on('transportclose', () => {
      consumerSocket.data.consumers.delete(consumer.id)
    })

    consumer.on('producerclose', () => {
      consumerSocket.data.consumers.delete(consumer.id)

      consumerSocket.emit('consumerClosed', { consumerId: consumer.id })
    })

    consumer.on('producerpause', () => {
      consumerSocket.emit('consumerPaused', { consumerId: consumer.id })
    })

    consumer.on('producerresume', () => {
      consumerSocket.emit('consumerResumed', { consumerId: consumer.id })
    })

    consumer.on('score', (score) => {
      consumerSocket.emit('consumerScore', { consumerId: consumer.id, score })
    })

    try {
      await consumerSocket.emitWithAck(
        'newConsumer',
        {
          peerId: producerSocket.id,
          producerId: producer.id,
          id: consumer.id,
          kind: consumer.kind,
          rtpParameters: consumer.rtpParameters,
          type: consumer.type,
          appData: producer.appData,
          producerPaused: consumer.producerPaused,
        },
      )

      await consumer.resume()

      consumerSocket.emit(
        'consumerScore',
        {
          consumerId: consumer.id,
          score: consumer.score,
        },
      )
    }
    catch (error) {
      consola.error('_createConsumer() | failed:%o', error)
    }
  }

  function socketToClient(socket: Socket<ClientToServerEvents, ServerToClientEvents, InterServerEvent, SocketData>): ChadClient {
    return {
      id: socket.id,
      username: socket.data.username,
      inputMuted: socket.data.inputMuted,
      outputMuted: socket.data.outputMuted,
    }
  }
}