import React, { Component } from 'react';
import { withStyles, CircularProgress, Typography, Paper, Button, Chip, Avatar, Slide} from '@material-ui/core';
import {styles} from './PageLayout.styles';
import Post from '../components/Post';
import { Status } from '../types/Status';
import Mastodon, { StreamListener } from 'megalodon';
import {withSnackbar} from 'notistack';
import ArrowUpwardIcon from '@material-ui/icons/ArrowUpward';

interface IPublicPageState {
    posts?: [Status];
    backlogPosts?: [Status] | null;
    viewIsLoading: boolean;
    viewDidLoad?: boolean;
    viewDidError?: boolean;
    viewDidErrorCode?: any;
}


class PublicPage extends Component<any, IPublicPageState> {

    client: Mastodon;
    streamListener: StreamListener;

    constructor(props: any) {
        super(props);

        this.state = {
            viewIsLoading: true,
            backlogPosts: null
        }

        this.client = new Mastodon(localStorage.getItem('access_token') as string, localStorage.getItem('baseurl') as string + "/api/v1");
        this.streamListener = this.client.stream('/streaming/public');
        
    }

    componentWillMount() {
        this.streamListener.on('connect', () => {
            this.client.get('/timelines/public', {limit: 40}).then((resp: any) => {
                let statuses: [Status] = resp.data;
                this.setState({
                    posts: statuses,
                    viewIsLoading: false,
                    viewDidLoad: true,
                    viewDidError: false
                })
            }).catch((resp: any) => {
                this.setState({
                    viewIsLoading: false,
                    viewDidLoad: true,
                    viewDidError: true,
                    viewDidErrorCode: String(resp)
                })
                this.props.enqueueSnackbar("Failed to get posts.", { 
                    variant: 'error',
                });
            })
        });

        this.streamListener.on('update', (status: Status) => {
            let queue = this.state.backlogPosts;
            if (queue !== null && queue !== undefined) { queue.unshift(status); } else { queue = [status] }
            this.setState({ backlogPosts: queue });
        })

        this.streamListener.on('delete', (id: number) => {
            let posts = this.state.posts;
            if (posts) {
                posts.forEach((post: Status) => {
                    if (posts && parseInt(post.id) === id) {
                        posts.splice(posts.indexOf(post), 1);
                    }
                })
                this.setState({ posts });
            }
        })

        this.streamListener.on('error', (err: Error) => {
            this.setState({
                viewDidError: true,
                viewDidErrorCode: err.message
            })
            this.props.enqueueSnackbar("An error occured.", { 
                variant: 'error',
            });
        })

        this.streamListener.on('heartbeat', () => {
            
        })
    }

    componentWillUnmount() {
        this.streamListener.stop();
    }

    insertBacklog() {
        window.scrollTo(0, 0);
        let posts = this.state.posts;
        let backlog = this.state.backlogPosts;
        if (posts && backlog && backlog.length > 0) {
            let push = backlog.concat(posts);
            this.setState({ posts: push as [Status], backlogPosts: null })
        }
    }

    loadMoreTimelinePieces() {
        this.setState({ viewDidLoad: false, viewIsLoading: true})
        if (this.state.posts) {
            this.client.get('/timelines/public', { max_id: this.state.posts[this.state.posts.length - 1].id, limit: 20 }).then((resp: any) => {
                let newPosts: [Status] = resp.data;
                let posts = this.state.posts as [Status];
                newPosts.forEach((post: Status) => {
                    posts.push(post);
                });
                this.setState({
                    viewIsLoading: false,
                    viewDidLoad: true,
                    posts
                })
            }).catch((err: Error) => {
                this.setState({
                    viewIsLoading: false,
                    viewDidError: true,
                    viewDidErrorCode: err.message
                })
                this.props.enqueueSnackbar("Failed to get posts", { 
                    variant: 'error',
                });
            })
        }
    }

    render() {
        const {classes} = this.props;

        return (
            <div className={classes.pageLayoutMaxConstraints}>
                {
                    this.state.backlogPosts?
                    <div className={classes.pageTopChipContainer}>
                        <div className={classes.pageTopChips}>
                            <Slide direction="down" in={true}>
                                <Chip
                                    avatar={
                                        <Avatar>
                                            <ArrowUpwardIcon/>
                                        </Avatar>
                                    }
                                    label={`View ${this.state.backlogPosts.length} new post${this.state.backlogPosts.length > 1? "s": ""}`}
                                    color="primary"
                                    className={classes.pageTopChip}
                                    onClick={() => this.insertBacklog()}
                                    clickable
                                />                            
                            </Slide>
                        </div>
                    </div>: null
                }
                { this.state.posts?
                    <div>
                        {this.state.posts.map((post: Status) => {
                            return <Post key={post.id} post={post} client={this.client}/>
                        })}
                        <br/>
                        {
                            this.state.viewDidLoad && !this.state.viewDidError? <div style={{textAlign: "center"}} onClick={() => this.loadMoreTimelinePieces()}><Button variant="contained">Load more</Button></div>: null
                        }
                    </div>:
                    <span/>
                }
                {
                    this.state.viewDidError? 
                        <Paper className={classes.errorCard}>
                            <Typography variant="h4">Bummer.</Typography>
                            <Typography variant="h6">Something went wrong when loading this timeline.</Typography>
                            <Typography>{this.state.viewDidErrorCode? this.state.viewDidErrorCode: ""}</Typography>
                        </Paper>: 
                        <span/>
                }
                {
                    this.state.viewIsLoading?
                    <div style={{ textAlign: 'center' }}><CircularProgress className={classes.progress} color="primary" /></div>:
                    <span/>
                }
            </div>
        );
    }
}

export default withStyles(styles)(withSnackbar(PublicPage));