import React from "react"
import PropTypes from "prop-types"
import { Transition } from 'react-transition-group';
import * as util from "util";
import * as os from "os";
import * as path from "path";
import * as fs from "fs";
import { LocalStorage } from "node-localstorage";
import * as olm from "olm/olm_legacy.js"
global.Olm = olm

import * as matrix from "matrix-js-sdk";
import {uuid} from "uuidv4"

import Message from "./message";
import Dock from "./dock";
import Header from "./header";
import EmojiSelector from './emoji-selector';

import './styles.scss';


const ENCRYPTION_CONFIG = { "algorithm": "m.megolm.v1.aes-sha2" };
const ENCRYPTION_NOTICE = "Messages in this chat are secured with end-to-end encryption."
const UNENCRYPTION_NOTICE = "Messages in this chat are not encrypted."
const RESTARTING_UNENCRYPTED_CHAT_MESSAGE = "Restarting chat without encryption."
const WAIT_TIME_MS = 120000 // 2 minutes
const CHAT_IS_OFFLINE_NOTICE = "Chat is offline"

const DEFAULT_MATRIX_SERVER = "https://matrix.rhok.space/"
const DEFAULT_BOT_ID = "@help-bot:rhok.space"
const DEFAULT_TERMS_URL = "https://tosdr.org/"
const DEFAULT_ROOM_NAME = "Support Chat"
const DEFAULT_INTRO_MESSAGE = "This chat application does not collect any of your personal data or any data from your use of this service."
const DEFAULT_AGREEMENT_MESSAGE = "Do you want to continue?"
const DEFAULT_CONFIRMATION_MESSAGE = "Waiting for a facilitator to join the chat..."
const DEFAULT_EXIT_MESSAGE = "The chat is closed. You may close this window."
const DEFAULT_ANONYMOUS_DISPLAY_NAME="Anonymous"
const DEFAULT_CHAT_UNAVAILABLE_MESSAGE = "The chat service is not available right now. Please try again later."
const DEFAULT_WAIT_MESSAGE = "Please be patient, our online facilitators are currently responding to other support requests."


class ChatBox extends React.Component {
  constructor(props) {
    super(props)
    this.initialState = {
      opened: false,
      showDock: true,
      client: null,
      ready: true,
      accessToken: null,
      userId: null,
      password: null,
      localStorage: null,
      messages: [],
      inputValue: "",
      errors: [],
      roomId: null,
      typingStatus: null,
      awaitingAgreement: true,
      emojiSelectorOpen: false,
      facilitatorInvited: false,
      isMobile: true,
      isSlowConnection: true,
      decryptionErrors: {},
      messagesInFlight: []
    }
    this.state = this.initialState
    this.chatboxInput = React.createRef();
    this.messageWindow = React.createRef();
    this.termsUrl = React.createRef();
  }

  detectMobile = () => {
    let isMobile = false;

    if ( /Android|webOS|iPhone|iPad|iPod|BlackBerry|IEMobile|Opera Mini/i.test(navigator.userAgent) ) {
      isMobile = true;
    }

    if (screen.width < 767) {
      isMobile = true;
    }

    this.setState({ isMobile })
  }

  detectSlowConnection = () => {
    let isSlowConnection = false;

    const connection = navigator.connection || navigator.mozConnection || navigator.webkitConnection;

    if (typeof connection !== 'undefined' || connection === null) {
      const connectionType = connection.effectiveType;
      const slowConnections = ['slow-2g', '2g']

      isSlowConnection = slowConnections.includes(connectionType)
    }

    this.setState({ isSlowConnection })
  }

  handleToggleOpen = () => {
    this.setState((prev) => {
      let { showDock } = prev;
      if (!prev.opened) {
        showDock = false;
      }
      return {
        showDock,
        opened: !prev.opened,
      };
    });
  }

  toggleEmojiSelector = (e) => {
    e.preventDefault();
    this.setState({ emojiSelectorOpen: !this.state.emojiSelectorOpen })
  }

  closeEmojiSelector = () => {
    this.setState({ emojiSelectorOpen: false })
  }

  handleWidgetExit = () => {
    this.setState({
      showDock: true,
    });
  }

  handleWidgetEnter = () => {
    if (this.state.awaitingAgreement) {
      this.termsUrl.current.focus()
    } else {
      this.chatboxInput.current.focus()
    }
  }

  handleExitChat = () => {
    if (this.state.client) {
      this.exitChat()
    } else {
      this.setState(this.initialState)
    }
  }

  exitChat = async () => {
    if (!this.state.client) return null;

    await this.state.client.leave(this.state.roomId)

    const auth = {
      type: 'm.login.password',
      user: this.state.userId,
      identifier: {
          type: "m.id.user",
          user: this.state.userId,
      },
      password: this.state.password,
    };

    await this.state.client.deactivateAccount(auth, true)
    await this.state.client.stopClient()
    await this.state.client.clearStores()

    this.state.localStorage.clear()
    this.setState(this.initialState)
  }

  createLocalStorage = async (deviceId, sessionId) => {
    let localStorage = global.localStorage;
    if (typeof localStorage === "undefined" || localStorage === null) {
      const deviceDesc = `matrix-chat-${deviceId}-${sessionId}`
      const localStoragePath = path.resolve(path.join(os.homedir(), ".local-storage", deviceDesc))
      localStorage = new LocalStorage(localStoragePath);
    }
    return localStorage;
  }

  createClientWithAccount = async () => {
    const tmpClient = matrix.createClient(this.props.matrixServerUrl)

    try {
      await tmpClient.registerRequest({})
    } catch(err) {
      const username = uuid()
      const password = uuid()
      const sessionId = err.data.session

      const account = await tmpClient.registerRequest({
        auth: {session: sessionId, type: "m.login.dummy"},
        inhibit_login: false,
        password: password,
        username: username,
        x_show_msisdn: true,
      })

      const localStorage = await this.createLocalStorage(account.device_id, sessionId)

      this.setState({
        accessToken: account.access_token,
        userId: account.user_id,
        username: username,
        password: password,
        localStorage: localStorage,
        sessionId: sessionId,
        deviceId: account.device_id,
      })

      let opts = {
        baseUrl: this.props.matrixServerUrl,
        accessToken: account.access_token,
        userId: account.user_id,
        deviceId: account.device_id,
        sessionStore: new matrix.WebStorageSessionStore(localStorage),
      }

      return matrix.createClient(opts)
    }
  }

  initializeChat = async () => {
    this.setState({ ready: false })

    const client = await this.createClientWithAccount()
    this.setState({
      client: client
    })
    client.setDisplayName(this.props.anonymousDisplayName)
    this.setMatrixListeners(client)

    try {
      await client.initCrypto()
    } catch(err) {
      return this.initializeUnencryptedChat()
    }

    await client.startClient()
    await this.createRoom(client)
  }

  initializeUnencryptedChat = async () => {
    if (this.state.client) {
      this.state.client.leave(this.state.roomId)
      this.state.client.stopClient()
      this.state.client.clearStores()
      this.state.localStorage.clear()
    }

    this.setState({
      ready: false,
      facilitatorInvited: false,
      decryptionErrors: {},
      roomId: null,
      typingStatus: null,
      client: null,
      isCryptoEnabled: false,
    })

    this.displayBotMessage({ body: RESTARTING_UNENCRYPTED_CHAT_MESSAGE })

    let opts = {
      baseUrl: this.props.matrixServerUrl,
      accessToken: this.state.accessToken,
      userId: this.state.userId,
      deviceId: this.state.deviceId,
    }

    let client;
    client = matrix.createClient(opts)
    this.setState({
      client: client,
    })

    try {
      this.setMatrixListeners(client)
      client.setDisplayName(this.props.anonymousDisplayName)
      await this.createRoom(client)
      await client.startClient()
      this.displayBotMessage({ body: UNENCRYPTION_NOTICE })
    } catch(err) {
      console.log("error", err)
      this.handleInitError(err)
    }

  }

  handleInitError = (err) => {
    console.log("error", err)
    this.displayBotMessage({ body: this.props.chatUnavailableMessage })
    this.setState({ ready: true })
  }

  handleDecryptionError = async (event, err) => {
    if (this.state.client) {
      const isCryptoEnabled = await this.state.client.isCryptoEnabled()
      const isRoomEncrypted = this.state.client.isRoomEncrypted(this.state.roomId)

      if (!isCryptoEnabled || !isRoomEncrypted) {
        return this.initializeUnencryptedChat()
      }
    }

    const eventId = event.getId()
    this.displayFakeMessage({ body: '** Unable to decrypt message **' }, event.getSender(), eventId)
    this.setState({ decryptionErrors: { [eventId]: true }})
  }

  verifyAllRoomDevices = async (client, room) => {
    if (!room) return;
    if (!client) return;
    if (!this.state.isCryptoEnabled) return;

    let members = (await room.getEncryptionTargetMembers()).map(x => x["userId"])
    let memberkeys = await client.downloadKeys(members);
    for (const userId in memberkeys) {
      for (const deviceId in memberkeys[userId]) {
        await client.setDeviceVerified(userId, deviceId);
      }
    }
  }

  createRoom = async (client) => {
    const currentDate = new Date()
    const chatDate = currentDate.toLocaleDateString()
    const chatTime = currentDate.toLocaleTimeString()
    let roomConfig = {
      room_alias_name: `private-support-chat-${uuid()}`,
      invite: [this.props.botId],
      visibility: 'private',
      name: `${chatTime}, ${chatDate} - ${this.props.roomName}`,
    }

    const isCryptoEnabled = await client.isCryptoEnabled()

    if (isCryptoEnabled) {
      roomConfig.initial_state = [
        {
          type: 'm.room.encryption',
          state_key: '',
          content: ENCRYPTION_CONFIG,
        },
      ]
    }

    const { room_id } = await client.createRoom(roomConfig)

    client.setPowerLevel(room_id, this.props.botId, 100)

    this.setState({
      roomId: room_id,
      isCryptoEnabled
    })
  }

  sendMessage = async (message) => {
    if (this.state.client && this.state.roomId) {
      try {
        await this.state.client.sendTextMessage(this.state.roomId, message)
      } catch(err) {
          switch (err["name"]) {
          case "UnknownDeviceError":
            Object.keys(err.devices).forEach((userId) => {
              Object.keys(err.devices[userId]).map(async (deviceId) => {
                await this.state.client.setDeviceKnown(userId, deviceId, true);
              });
            });
            this.sendMessage(message)
            break;
          default:
            this.displayBotMessage({ body: "Your message was not sent." })
            console.log("Error sending message", err);
        }
      }
    }
  }

  displayFakeMessage = (content, sender, messageId=uuid()) => {
    const msgList = [...this.state.messages]
    const msg = {
      id: messageId,
      type: 'm.room.message',
      sender: sender,
      roomId: this.state.roomId,
      content: content,
    }
    msgList.push(msg)

    this.setState({ messages: msgList })
  }

  displayBotMessage = (content, roomId) => {
    const msgList = [...this.state.messages]
    const msg = {
      id: uuid(),
      type: 'm.room.message',
      sender: this.props.botId,
      roomId: roomId || this.state.roomId,
      content: content,
    }
    msgList.push(msg)

    this.setState({ messages: msgList })
  }

  handleMessageEvent = event => {
    const message = {
      id: event.getId(),
      type: event.getType(),
      sender: event.getSender(),
      roomId: event.getRoomId(),
      content: event.getContent(),
    }

    if (message.content.showToUser && message.content.showToUser !== this.state.userId) {
      return;
    }

    if (message.content.body.startsWith('!bot') && message.sender !== this.state.userId) {
      return;
    }

    const messagesInFlight = [...this.state.messagesInFlight]
    const placeholderMessageIndex = messagesInFlight.findIndex(msg => msg === message.content.body)
    if (placeholderMessageIndex > -1) {
      messagesInFlight.splice(placeholderMessageIndex, 1)
      this.setState({ messagesInFlight })
    }

    // check for decryption error message and replace with decrypted message
    // or push message to messages array
    const messages = [...this.state.messages]
    const decryptionErrors = {...this.state.decryptionErrors}
    delete decryptionErrors[message.id]
    const existingMessageIndex = messages.findIndex(({ id }) => id === message.id)

    if (existingMessageIndex > -1) {
      messages.splice(existingMessageIndex, 1, message)
    } else {
      messages.push(message)
    }

    this.setState({ messages, decryptionErrors })
  }


  handleKeyDown = (e) => {
    switch (e.keyCode) {
      case 27:
        if (this.state.emojiSelectorOpen) {
          this.closeEmojiSelector()
        } else if (this.state.opened) {
          this.handleToggleOpen()
        };
      default:
        break;
    }
  }

  setMatrixListeners = client => {
    client.on("Room.timeline", (event, room) => {
      const eventType = event.getType()
      const content = event.getContent()
      const sender = event.getSender()

      if (eventType === "m.room.encryption") {
        this.displayBotMessage({ body: ENCRYPTION_NOTICE }, room.room_id)
        this.verifyAllRoomDevices(client, room)
      }

      if (eventType === "m.room.message" && !this.state.isCryptoEnabled) {
        if (event.isEncrypted()) {
          return;
        }
        this.handleMessageEvent(event)
      }

      if (eventType === "m.room.member" && content.membership === "invite" && sender === this.props.botId) {
        this.setState({ facilitatorInvited: true })
      }

      if (eventType === "m.room.member" && content.membership === "join" && sender !== this.props.botId && sender !== this.state.userId) {
        this.verifyAllRoomDevices(client, room)
        this.setState({ facilitatorId: sender, ready: true })
        window.clearInterval(this.state.timeoutId)
      }
    });


    client.on("Event.decrypted", (event, err) => {
      if (err) {
        return this.handleDecryptionError(event, err)
      }
      if (event.getType() === "m.room.message") {
        const content = event.getContent()

        if (content.msgtype === "m.notice" && content.body === CHAT_IS_OFFLINE_NOTICE) {
          this.setState({ ready: true })
          return window.clearInterval(this.state.timeoutId)
        }
        this.handleMessageEvent(event)
      }
    });

    client.on("RoomMember.typing", (event, member) => {
      if (member.typing && member.roomId === this.state.roomId) {
        this.setState({ typingStatus: `${member.name} is typing...` })
      }
      else {
        this.setState({ typingStatus: null })
      }
    });
  }

  componentDidUpdate(prevProps, prevState) {
    if (prevState.messages.length !== this.state.messages.length) {
      if (this.messageWindow.current.scrollTo) {
        this.messageWindow.current.scrollTo(0, this.messageWindow.current.scrollHeight)
      }
    }

    if (!prevState.facilitatorInvited && this.state.facilitatorInvited) {
      this.displayBotMessage({ body: this.props.confirmationMessage })
    }

    if (!prevState.opened && this.state.opened) {
      this.detectMobile()
      // not sure what to do with this
      // this.detectSlowConnection()
    }
  }

  componentDidMount() {
    document.addEventListener("keydown", this.handleKeyDown, false);
    window.addEventListener('beforeunload', this.exitChat)
  }

  componentWillUnmount() {
    document.removeEventListener("keydown", this.handleKeyDown, false);
    window.removeEventListener('beforeunload', this.exitChat)
    this.exitChat();
  }

  handleInputChange = e => {
    this.setState({ inputValue: e.target.value })
  }

  handleAcceptTerms = () => {
    this.setState({ awaitingAgreement: false })
    this.startWaitTimeForFacilitator()
    try {
      this.initializeChat()
    } catch(err) {
      this.handleInitError(err)
    }
  }

  startWaitTimeForFacilitator = () => {
    const timeoutId = window.setInterval(() => {
      if (!this.state.facilitatorId) {
        this.displayBotMessage({ body: this.props.waitMessage })
      }
    }, WAIT_TIME_MS)

    this.setState({ timeoutId })
  }

  handleRejectTerms = () => {
    this.exitChat()
    this.displayBotMessage({ body: this.props.exitMessage })
  }

  handleSubmit = e => {
    e.preventDefault()
    const message = this.state.inputValue
    if (!Boolean(message)) return null;

    if (this.state.isCryptoEnabled && !(this.state.client.isRoomEncrypted(this.state.roomId) && this.state.client.isCryptoEnabled())) return null;

    if (this.state.client && this.state.roomId) {
      const messagesInFlight = [...this.state.messagesInFlight]
      messagesInFlight.push(message)
      this.setState({ inputValue: "", messagesInFlight }, () => this.sendMessage(message))
      this.chatboxInput.current.focus()
    }
  }

  onEmojiClick = (event, emojiObject) => {
    event.preventDefault()
    const { emoji } = emojiObject;
    this.setState({
      inputValue: this.state.inputValue.concat(emoji),
      emojiSelectorOpen: false,
    }, this.chatboxInput.current.focus())
  }

  render() {
    const { ready, messages, messagesInFlight, inputValue, userId, roomId, typingStatus, opened, showDock, emojiSelectorOpen, isMobile, decryptionErrors } = this.state;
    const inputLabel = 'Send a message...'

    return (
      <div className="docked-widget" role="complementary">
        <Transition in={opened} timeout={250} onExited={this.handleWidgetExit} onEntered={this.handleWidgetEnter}>
          {(status) => {
            return (
            <div className={`widget widget-${status}`} aria-hidden={!opened}>
              <div id="ocrcc-chatbox" aria-haspopup="dialog">
                <Header handleToggleOpen={this.handleToggleOpen} opened={opened} handleExitChat={this.handleExitChat} />

                <div className="message-window" ref={this.messageWindow}>
                  <div className="messages">
                    <div className={`message from-bot`}>
                      <div className="text">{ this.props.introMessage }</div>
                    </div>

                    <div className={`message from-bot`}>
                      <div className="text">Please read the full <a href={this.props.termsUrl} ref={this.termsUrl} target='_blank' rel='noopener noreferrer'>terms and conditions</a>. By using this chat, you agree to these terms.</div>
                    </div>

                    <div className={`message from-bot`}>
                      <div className="text">{ this.props.agreementMessage }</div>
                    </div>

                    <div className={`message from-bot`}>
                      <div className="text buttons">
                        {`👉`}
                        <button className="btn" id="accept" onClick={this.handleAcceptTerms}>YES</button>
                        <button className="btn" id="reject" onClick={this.handleRejectTerms}>NO</button>
                      </div>
                    </div>

                    {
                      messages.map((message, index) => {
                        return(
                          <Message key={message.id} message={message} userId={userId} botId={this.props.botId} client={this.state.client} />
                        )
                      })
                    }

                    {
                      messagesInFlight.map((message, index) => {
                        return(
                          <Message key={`message-inflight-${index}`} message={{ content: { body: message }}} placeholder={true} />
                        )
                      })
                    }

                    { typingStatus &&
                      <div className="notices">
                        <div role="status">{typingStatus}</div>
                      </div>
                    }

                    { Boolean(Object.keys(decryptionErrors).length) &&
                      <div className={`message from-bot`}>
                        <div className="text buttons">
                          {`Restart chat without encryption?`}
                          <button className="btn" id="accept" onClick={this.initializeUnencryptedChat}>RESTART</button>
                        </div>
                      </div>
                    }

                    { !ready && <div className={`loader`}>loading...</div> }
                  </div>
                </div>
                <div className="input-window">
                  <form onSubmit={this.handleSubmit}>
                    <div className="message-input-container">
                      <input
                        id="message-input"
                        type="text"
                        onChange={this.handleInputChange}
                        value={inputValue}
                        aria-label={inputLabel}
                        placeholder={inputLabel}
                        autoFocus={true}
                        ref={this.chatboxInput}
                      />
                      {
                        (status === "entered") && !isMobile &&
                        <EmojiSelector
                          onEmojiClick={this.onEmojiClick}
                          emojiSelectorOpen={emojiSelectorOpen}
                          toggleEmojiSelector={this.toggleEmojiSelector}
                          closeEmojiSelector={this.closeEmojiSelector}
                        />
                      }
                    </div>
                    <input type="submit" value="Send" id="submit" onClick={this.handleSubmit} />
                  </form>
                </div>
              </div>
            </div>
            )}
          }
        </Transition>
        {showDock && !roomId && <Dock handleToggleOpen={this.handleToggleOpen} />}
        {showDock && roomId && <Header handleToggleOpen={this.handleToggleOpen} opened={opened} handleExitChat={this.handleExitChat} />}
      </div>
    );
  }
};

ChatBox.propTypes = {
  matrixServerUrl: PropTypes.string.isRequired,
  botId: PropTypes.string.isRequired,
  termsUrl: PropTypes.string,
  introMessage: PropTypes.string,
  roomName: PropTypes.string,
  agreementMessage: PropTypes.string,
  confirmationMessage: PropTypes.string,
  exitMessage: PropTypes.string,
  chatUnavailableMessage: PropTypes.string,
  anonymousDisplayName: PropTypes.string,
  waitMessage: PropTypes.string,
}

ChatBox.defaultProps = {
  matrixServerUrl: DEFAULT_MATRIX_SERVER,
  botId: DEFAULT_BOT_ID,
  termsUrl: DEFAULT_TERMS_URL,
  roomName: DEFAULT_ROOM_NAME,
  introMessage: DEFAULT_INTRO_MESSAGE,
  agreementMessage: DEFAULT_AGREEMENT_MESSAGE,
  confirmationMessage: DEFAULT_CONFIRMATION_MESSAGE,
  exitMessage: DEFAULT_EXIT_MESSAGE,
  anonymousDisplayName: DEFAULT_ANONYMOUS_DISPLAY_NAME,
  chatUnavailableMessage: DEFAULT_CHAT_UNAVAILABLE_MESSAGE,
  waitMessage: DEFAULT_WAIT_MESSAGE,
}

export default ChatBox;