import React from 'react'
import Head from 'next/head'
import io from 'socket.io-client'

import constants from '../constants.json'
import LoadingIndicator from '../components/LoadingIndicator'
import styles from './chat.module.css'

function countAllMessages(msgs) {
  return Object.keys(msgs).reduce((acc, key) => {
    return acc + msgs[key].length
  }, 0)
}

function groupMessages(msgs, currUser) {
  return msgs.reduce((acc, msg) => {
    const group =
      parseInt(msg.sender) !== parseInt(currUser) ? msg.sender : msg.reciever
    return {
      ...acc,
      [group]: [msg],
    }
  }, {})
}

function addMsgsToGroup(msgGroup, msgs, user) {
  let res = { ...msgGroup }
  msgs.forEach((msg) => {
    res = addMsgToGroup(
      res,
      msg.reciever === user ? { ...msg, unread: 0 } : msg,
      user
    )
  })
  return res
}

function addMsgToGroup(msgGroup, msg, user) {
  const group =
    parseInt(msg.sender) === parseInt(user) ? msg.reciever : msg.sender
  if (!msgGroup[group]) {
    msgGroup[group] = []
  }
  return {
    ...msgGroup,
    [group]: [...msgGroup[group], msg],
  }
}

function SeenMarker() {
  return (
    <span className={styles.unreadMarker} key={`unread_marker`}>
      Látta
    </span>
  )
}
function NewMarker() {
  return (
    <span className={styles.newMarker} key={`unread_marker`}>
      Új üzenet
    </span>
  )
}

export default class Chat extends React.Component {
  constructor(props) {
    super(props)

    this.state = {
      msgs: {},
      currMsg: '',
      connected: false,
      selectedUser: 0,
    }
    if (props.refetchGlobalData) {
      props.refetchGlobalData()
    }
    if (props.globalData && !isNaN(props.globalData.userId)) {
      this.state.user = props.globalData.userId
      // this.connect(this.props.globalData.userId)
    }
  }

  componentDidUpdate(prevProps, prevState) {
    if (!prevProps.globalData.userId && this.props.globalData.userId) {
      this.setState({
        user: this.props.globalData.userId,
      })
      // this.connect(this.props.globalData.userId)
    }

    if (
      countAllMessages(prevState.msgs) !== countAllMessages(this.state.msgs) ||
      prevState.selectedUser !== this.state.selectedUser
    ) {
      this.scrollToChatBottom()
    }
  }

  componentWillUnmount() {
    console.info('Chat disconnect')
    if (this.socket) {
      this.socket.disconnect()
    }
  }

  scrollToChatBottom() {
    const objDiv = document.getElementById('messages')
    if (objDiv) {
      objDiv.scrollTop = objDiv.scrollHeight
    }
  }

  handleErrors(err) {
    alert(err.message)
    console.error(err)
  }

  connect(user) {
    const { connected } = this.state
    if (connected) {
      console.warn('Already connected ...')
      return
    }
    // https://socket.io/docs/v4/handling-cors/#Configuration
    const socket = io(`${constants.apiUrl}`, {
      withCredentials: true,
      extraHeaders: {
        'qmining-chat': 'qmining-chat',
      },
    })

    socket.on('connect', () => {
      console.info(`Connected as user ${user}`)
      socket.emit('join', { id: user })
    })
    socket.on('connect_error', (err) => this.handleErrors(err))
    socket.on('connect_failed', (err) => this.handleErrors(err))

    socket.on('prev messages', (data) => {
      const { prevMsgs } = data
      const { user } = this.state
      this.setState({
        msgs: groupMessages(prevMsgs, user),
        connected: true,
      })
    })

    socket.on('chat message read', (data) => {
      const { userReadMsg } = data
      this.partnerReadChatMessage(userReadMsg)
    })

    socket.on('chat message open', (data) => {
      const { msgs, user, selectedUser } = this.state
      if (msgs[selectedUser].length <= 1) {
        this.setState({
          msgs: addMsgsToGroup(msgs, data, user),
        })
      }
    })

    socket.on('chat message', (data) => {
      const { msgs, user } = this.state
      this.setState({
        msgs: addMsgToGroup(msgs, data, user),
      })
    })

    this.socket = socket
  }

  sendMsg() {
    const { msgs, selectedUser, currMsg, user } = this.state
    if (!currMsg) {
      return
    }
    if (this.socket && selectedUser) {
      const msg = {
        msg: currMsg,
        reciever: selectedUser,
        sender: user,
        date: new Date().getTime(),
        unread: 1,
      }
      this.socket.emit('chat message', msg)
      this.setState({
        currMsg: '',
        msgs: addMsgToGroup(msgs, msg, user),
      })
    }
  }

  partnerReadChatMessage(chatPartner) {
    const { msgs } = this.state
    this.setState({
      msgs: {
        ...msgs,
        [chatPartner]: msgs[chatPartner].map((msg) => {
          if (msg.reciever === chatPartner) {
            return {
              ...msg,
              unread: 0,
            }
          } else {
            return msg
          }
        }),
      },
    })
  }

  chatMessageRead(chatPartner) {
    const { msgs, user } = this.state
    if (this.props.refetchGlobalData) {
      this.props.refetchGlobalData()
    }
    this.socket.emit('chat message read', { chatPartner: chatPartner })
    this.setState({
      msgs: {
        ...msgs,
        [chatPartner]: msgs[chatPartner].map((msg) => {
          if (msg.reciever === user) {
            return {
              ...msg,
              unread: 0,
            }
          } else {
            return msg
          }
        }),
      },
    })
  }

  selectedUserChange(val) {
    const { msgs, selectedUser, user } = this.state
    const prevLastMessage = msgs[selectedUser]
      ? msgs[selectedUser][msgs[selectedUser].length - 1]
      : null
    if (
      prevLastMessage &&
      prevLastMessage.unread === 1 &&
      prevLastMessage.sender !== user
    ) {
      this.chatMessageRead(selectedUser)
    }
    this.setState({
      selectedUser: val,
    })
    if (!val || isNaN(val)) {
      return
    }
    const currSelectedMsgs = msgs[val]
    if (!currSelectedMsgs) {
      return
    }
    if (msgs[val].length <= 1) {
      this.socket.emit('chat message open', {
        chatPartner: val,
      })
    }
    const lastMessage = currSelectedMsgs[currSelectedMsgs.length - 1]
    if (lastMessage.unread === 1 && lastMessage.sender !== user) {
      this.chatMessageRead(val)
    }
  }

  renderChatInput() {
    const { currMsg, msgs, selectedUser, user } = this.state
    return (
      <div className={styles.chatInput}>
        <input
          autoFocus
          placeholder={'Message ...'}
          type={'text'}
          value={currMsg}
          tabIndex={0}
          onKeyUp={(e) => {
            const lastMessage = msgs[selectedUser]
              ? msgs[selectedUser][msgs[selectedUser].length - 1]
              : null
            if (
              lastMessage &&
              lastMessage.unread === 1 &&
              lastMessage.sender !== user
            ) {
              this.chatMessageRead(selectedUser)
            }
            if (e.key === 'Enter') {
              this.sendMsg()
            }
          }}
          onChange={(e) => {
            this.setState({
              currMsg: e.target.value,
            })
          }}
        />
        <div className={`buttonContainer ${styles.sendButton}`}>
          <div
            onClick={() => {
              this.sendMsg()
            }}
          >
            Send
          </div>
        </div>
      </div>
    )
  }

  renderHome() {
    return (
      <div className={styles.home}>
        <div>
          <input
            autoFocus
            type={'text'}
            onChange={(e) => {
              const val = parseInt(e.target.value)
              if (!isNaN(val)) {
                this.setState({
                  userInputVal: val,
                })
              }
            }}
            placeholder={'Címzett User ID-ja ...'}
          />
        </div>
        <div className={'buttonContainer'}>
          <div
            onClick={() => {
              const { userInputVal } = this.state
              if (isNaN(userInputVal) || userInputVal <= 0) {
                alert('Érvényes User ID-t adj meg! (számot)')
                return
              }
              this.setState({
                selectedUser: userInputVal,
                userInputVal: null,
              })
            }}
          >
            Chat!
          </div>
        </div>
        <i>Admin User ID-ja: {'"1"'}</i>
      </div>
    )
  }

  renderMsgs() {
    const { msgs, selectedUser } = this.state

    let prevMsg
    return msgs[selectedUser].reduce((acc, msg, i) => {
      if (prevMsg && prevMsg.unread === 0 && msg.unread === 1) {
        if (msg.sender === selectedUser) {
          acc.push(<NewMarker key={`marker_${i}`} />)
        } else {
          acc.push(<SeenMarker key={`marker_${i}`} />)
        }
      }
      acc.push(this.renderMsg(msg, i))
      prevMsg = msg
      if (i === msgs[selectedUser].length - 1 && msg.unread === 0) {
        if (msg.sender !== selectedUser) {
          acc.push(<SeenMarker key={`marker_${i}`} />)
        }
      }
      return acc
    }, [])
  }

  renderMsg(message, key) {
    const { date, sender, msg /* reciever */ } = message
    const { user } = this.state
    const timeString = new Date(date).toLocaleString()

    return (
      <div
        key={key}
        title={timeString}
        className={`${styles.messageContainer} ${
          sender === user ? styles.ownMsg : styles.partnerMsg
        }`}
      >
        <div className={`${styles.messageEntry}`}>{msg}</div>
      </div>
    )
  }

  renderSidebarEntryes() {
    const { msgs } = this.state
    const sorted = Object.keys(msgs).sort((a, b) => {
      const lastA = msgs[a].slice(-1)[0]
      const lastB = msgs[b].slice(-1)[0]
      return lastB.date - lastA.date
    })
    return sorted.map((key, i) => {
      return this.renderSidebarEntry(i, key)
    })
  }

  renderSidebarEntry(i, key) {
    const { selectedUser, msgs, user } = this.state
    const group = msgs[key]
    const lastMessage = group[group.length - 1]

    return (
      <div
        className={`${styles.group} ${
          lastMessage.unread === 1 && lastMessage.sender !== user
            ? styles.unread
            : ''
        } ${selectedUser === parseInt(key) ? styles.activeSidebarItem : ''}`}
        onClick={() => {
          this.selectedUserChange(parseInt(key))
        }}
        key={i}
      >
        <div>#{key}</div>
        <div>{lastMessage.msg}</div>
      </div>
    )
  }

  render() {
    const { user, msgs, connected, selectedUser } = this.state

    return (
      <div className={styles.chat}>
        <Head>
          <title>{`Connected as ${user}`}</title>
        </Head>
        {connected ? (
          <>
            <div className={styles.main}>
              <div className={styles.header}>
                {selectedUser ? `User #${selectedUser}` : ''}
              </div>
              <div className={styles.messages} id={'messages'}>
                {selectedUser === 0 ? this.renderHome() : null}
                {selectedUser && msgs[selectedUser] ? this.renderMsgs() : null}
              </div>
              {selectedUser !== 0 ? this.renderChatInput() : null}
            </div>
            <div className={styles.sidebar}>
              <div className={styles.usersContainer}>
                <div
                  className={`${styles.group} ${
                    selectedUser === 0 ? styles.activeSidebarItem : ''
                  }`}
                  onClick={() => {
                    this.selectedUserChange(0)
                  }}
                >
                  <div>Új beszélgetés</div>
                </div>
                <hr />
                {msgs && this.renderSidebarEntryes()}
              </div>
              <span className={styles.spacer} />
              <div></div>
            </div>
          </>
        ) : (
          <div>
            <LoadingIndicator />
            <input
              onChange={(e) => {
                this.setState({
                  user: parseInt(e.target.value),
                })
              }}
              type={'text'}
              placeholder={'user'}
            />
            <div
              onClick={() => {
                this.connect(this.state.user)
              }}
            >
              connect
            </div>
          </div>
        )}
      </div>
    )
  }
}