import React, { useEffect, useState, useRef, useCallback } from 'react';

import Message from './Message';
import MessageInput from './MessageInput';
import Spinner from './Spinner';
import Avatar from './Avatar';
import { UserLink } from './UserInfo';
import Button from './Button';

import { format, embedUrls } from '../utils/embed';

import { getMessages, comment, update, markReadTracker, fetchUserUri, updateAvatar } from '../api';

import { bubbleStyle, chatItemStyle } from './helpers/BubbleStyle';

import './Thread.css';

let isMounted;

/**
 * @param {{
    msg: import('../api').Message,
    draft: string,
    visitor: import('../api').User,
    active: number,
    setActive: function,
    onStartEditing: function,
    postComment: function
  }} props
 */
function Comment({ msg, draft, visitor, active, setActive, onStartEditing, postComment }) {
  const embedRef = useRef();
  const msgRef = useRef();
  const [author, setAuthor] = useState(msg.user);
  useEffect(() => {
    if (msgRef.current) {
      embedUrls(msgRef.current.querySelectorAll('a'), embedRef.current);
      if (!embedRef.current.hasChildNodes()) {
        embedRef.current.style.display = 'none';
      }
    }
  }, []);
  useEffect(() => {
    isMounted = true;
    if (author.uri) {
      fetchUserUri(author.uri).then(response => {
        if (isMounted) {
          setAuthor(response.data);
        }
      });
    }
    return () => {
      isMounted = false;
    };
  }, [author.uri]);
  return (
    <div style={chatItemStyle(visitor, msg)}>
      <div className="msg-header">
        <Avatar user={author} link={author.uri}>
          <div className="msg-ts">
            {msg.replyto > 0 &&
              (
                <UserLink user={msg.to} />
              )}
          </div>
        </Avatar>
      </div>
      {
        msg.body &&
        <div style={bubbleStyle(visitor, msg)}>
          <div ref={msgRef}>
            <p dangerouslySetInnerHTML={{ __html: format(msg.body, msg.mid.toString(), (msg.tags || []).indexOf('code') >= 0) }} />
          </div>
        </div>
      }
      {
        msg.photo &&
        <div className="msg-media">
          <a href={`//i.juick.com/p/${msg.mid}-${msg.rid}.${msg.attach}`} data-fname={`${msg.mid}-${msg.rid}.${msg.attach}`}>
            <img src={`//i.juick.com/p/${msg.mid}-${msg.rid}.${msg.attach}`} alt="" />
          </a>
        </div>
      }
      <div className="embedContainer" ref={embedRef} />
      {
        active === msg.rid && <MessageInput data={msg} text={draft || ''} onSend={postComment}>Write a comment...</MessageInput>
      }
      <div className="msg-links">
        {
          visitor.uid > 0 ? (
            <>
              {active === msg.rid || <span style={linkStyle} onClick={() => setActive(msg.rid)}>Reply</span>}
              {
                visitor.uid == msg.user.uid &&
                <>
                  <span>&nbsp;&middot;&nbsp;</span>
                  <span style={linkStyle} onClick={() => onStartEditing(msg)}>Edit</span>
                </>
              }
            </>
          ) : (
              <>
                <span>&nbsp;&middot;&nbsp;</span>{active === msg.rid || <Button>Reply</Button>}
              </>
            )
        }
      </div>
    </div>
  );
}

/**
 * @param {{
     match: import('react-router').match,
     location: import('history').Location,
     visitor: import('../api').SecureUser
     connection: EventSource
  }} props
 */
export default function Thread(props) {
  const [message, setMessage] = useState((props.location.state || {}).msg || {});
  const [replies, setReplies] = useState([]);
  const [loading, setLoading] = useState(false);
  const [active, setActive] = useState(0);
  const [editing, setEditing] = useState({});
  const [hash, setHash] = useState(props.visitor.hash);
  const { mid } = props.match.params;

  let loadReplies = useCallback(() => {
    document.body.scrollTop = 0;
    document.documentElement.scrollTop = 0;
    setReplies([]);
    setLoading(true);
    let params = {
      mid: mid
    };
    params.hash = hash;
    getMessages('/api/thread', params)
      .then(response => {
        if (!message.mid) {
          setMessage(response.data.shift());
        }
        setReplies(response.data);
        setLoading(false);
        setActive(0);
      }
      ).catch(ex => {
        console.log(ex);
      });
  }, [hash, message.mid, mid]);
  let onReply = useCallback((json) => {
    const msg = JSON.parse(json.data);
    if (msg.mid == message.mid) {
      setReplies(oldReplies => {
        return [...oldReplies, msg];
      });
    }
  }, [message]);

  let postComment = useCallback((template) => {
    const { mid, rid, body, attach } = template;
    let commentAction = editing.rid ? update(mid, editing.rid, body) : comment(mid, rid, body, attach);
    commentAction.then(res => {
      setEditing({});
      loadReplies();
    })
      .catch(console.log);
  }, [editing.rid, loadReplies]);

  let startEditing = (reply) => {
    setActive(reply.replyto);
    setEditing(reply);
  };

  useEffect(() => {
    setActive(0);
    loadReplies();
  }, [loadReplies]);
  useEffect(() => {
    if (props.connection.addEventListener && message.mid) {
      props.connection.addEventListener('msg', onReply);
    }
    return () => {
      if (props.connection.removeEventListener && message.mid) {
        props.connection.removeEventListener('msg', onReply);
      }
    };
  }, [props.connection, message.mid, onReply]);

  const loaders = Math.min(message.replies || 0, 10);
  return (
    <>
      {
        message.mid ? (
          <Message data={message} visitor={props.visitor}>
            {active === (message.rid || 0) && <MessageInput data={message} text={editing.body || ''} onSend={postComment}>Write a comment...</MessageInput>}
          </Message>
        ) : (
            <Spinner />
          )
      }
      {
        message.replies && <ul id="replies">
          {
            !loading ? replies.map((msg) => (
              <li id={msg.rid} key={msg.rid}>
                <Comment msg={msg} draft={msg.rid === editing.replyto ? editing.body : ''} visitor={props.visitor} active={active} setActive={setActive} onStartEditing={startEditing} postComment={postComment} />
              </li>
            )) : (
                <>
                  {Array(loaders).fill().map((it, i) => <Spinner key={i} />)}
                </>
              )
          }
        </ul>
      }
    </>
  );
}

/**
 * @type React.CSSProperties
 */
const linkStyle = {
  cursor: 'pointer'
};