/*
 * Copyright (C) Contributors to the Suwayomi project
 *
 * This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/.
 */

import DownloadIcon from '@mui/icons-material/Download';
import { Box, CardActionArea, styled } from '@mui/material';
import Avatar from '@mui/material/Avatar';
import Card from '@mui/material/Card';
import CardContent from '@mui/material/CardContent';
import IconButton from '@mui/material/IconButton';
import Typography from '@mui/material/Typography';
import React, { useCallback, useContext, useEffect, useMemo, useState } from 'react';
import { Link, useLocation } from 'react-router-dom';
import { useTranslation } from 'react-i18next';
import { t as translate } from 'i18next';
import { GroupedVirtuoso } from 'react-virtuoso';
import { IChapter, IMangaChapter, IQueue } from '@/typings';
import requestManager from '@/lib/RequestManager';
import LoadingPlaceholder from '@/components/util/LoadingPlaceholder';
import EmptyView from '@/components/util/EmptyView';
import DownloadStateIndicator from '@/components/molecules/DownloadStateIndicator';
import NavbarContext from '@/components/context/NavbarContext';

const StyledGroupedVirtuoso = styled(GroupedVirtuoso)(({ theme }) => ({
    // 64px header
    height: 'calc(100vh - 64px)',
    [theme.breakpoints.down('sm')]: {
        // 64px header (margin); 64px menu (margin);
        height: 'calc(100vh - 64px - 64px)',
    },
}));

const StyledGroupHeader = styled(Typography, { shouldForwardProp: (prop) => prop !== 'isFirstItem' })<{
    isFirstItem: boolean;
}>(({ theme, isFirstItem }) => ({
    paddingLeft: '24px',
    // 16px - 10px (bottom padding of the group items)
    paddingTop: '6px',
    paddingBottom: '16px',
    fontWeight: 700,
    textTransform: 'uppercase',
    backgroundColor: theme.palette.background.default,
    [theme.breakpoints.down('sm')]: {
        // 16px - 8px (margin of header)
        paddingTop: isFirstItem ? '8px' : '6px',
    },
}));

const StyledGroupItemWrapper = styled(Box, { shouldForwardProp: (prop) => prop !== 'isLastItem' })<{
    isLastItem: boolean;
}>(({ isLastItem }) => ({
    padding: '0 10px',
    paddingBottom: isLastItem ? '0' : '10px',
}));

function epochToDate(epoch: number) {
    const date = new Date(0); // The 0 there is the key, which sets the date to the epoch
    date.setUTCSeconds(epoch);
    return date;
}

function isTheSameDay(first: Date, second: Date) {
    return (
        first.getDate() === second.getDate() &&
        first.getMonth() === second.getMonth() &&
        first.getFullYear() === second.getFullYear()
    );
}

function getDateString(date: Date) {
    const today = new Date();
    if (isTheSameDay(today, date)) return translate('global.date.label.today');
    // calculate yesterday
    const yesterday = new Date();
    yesterday.setDate(today.getDate() - 1);
    if (isTheSameDay(yesterday, date)) return translate('global.date.label.yesterday');
    return date.toLocaleDateString();
}

const groupByDate = (updates: IMangaChapter[]): [date: string, items: number][] => {
    if (!updates.length) {
        return [];
    }

    const dateToItemMap = new Map<string, number>();
    updates.forEach((item) => {
        const date = getDateString(epochToDate(item.chapter.fetchedAt));
        dateToItemMap.set(date, (dateToItemMap.get(date) ?? 0) + 1);
    });

    return [...dateToItemMap.entries()];
};

const initialQueue = {
    status: 'Stopped',
    queue: [],
} as IQueue;

const Updates: React.FC = () => {
    const { t } = useTranslation();
    const location = useLocation();

    const { setTitle, setAction } = useContext(NavbarContext);
    const {
        data: pages = [{ hasNextPage: false, page: [] }],
        isLoading,
        size: loadedPages,
        setSize: setPages,
    } = requestManager.useGetRecentlyUpdatedChapters();
    const { hasNextPage } = pages[pages.length - 1];
    const updateEntries = useMemo(
        () => pages.map((page) => page.page).reduce((lastPageChapters, chapters) => [...lastPageChapters, ...chapters]),
        [pages],
    );
    const groupedUpdates = useMemo(() => groupByDate(updateEntries), [updateEntries]);
    const groupCounts: number[] = useMemo(() => groupedUpdates.map((group) => group[1]), [groupedUpdates]);

    const [, setWsClient] = useState<WebSocket>();
    const [{ queue }, setQueueState] = useState<IQueue>(initialQueue);

    useEffect(() => {
        const wsc = requestManager.getDownloadWebSocket();
        wsc.onmessage = (e) => {
            const data = JSON.parse(e.data) as IQueue;
            setQueueState(data);
        };

        setWsClient(wsc);

        return () => wsc.close();
    }, []);

    useEffect(() => {
        setTitle(t('updates.title'));

        setAction(null);
    }, [t]);

    if (!isLoading && updateEntries.length === 0) {
        return <EmptyView message={t('updates.error.label.no_updates_available')} />;
    }

    const downloadForChapter = (chapter: IChapter) => {
        const { index, mangaId } = chapter;
        return queue.find((q) => index === q.chapterIndex && mangaId === q.mangaId);
    };

    const downloadChapter = (chapter: IChapter) => {
        requestManager.addChapterToDownloadQueue(chapter.mangaId, chapter.index);
    };

    const loadMore = useCallback(() => {
        if (!hasNextPage) {
            return;
        }

        setPages(loadedPages + 1);
    }, [hasNextPage, loadedPages]);

    return (
        <StyledGroupedVirtuoso
            style={{
                // override Virtuoso default values and set them with class
                height: 'undefined',
            }}
            components={{
                Footer: () => (isLoading ? <LoadingPlaceholder usePadding /> : null),
            }}
            overscan={window.innerHeight * 0.5}
            endReached={loadMore}
            groupCounts={groupCounts}
            groupContent={(index) => (
                <StyledGroupHeader variant="h5" isFirstItem={index === 0}>
                    {groupedUpdates[index][0]}
                </StyledGroupHeader>
            )}
            itemContent={(index) => {
                const { chapter, manga } = updateEntries[index];
                const download = downloadForChapter(chapter);

                return (
                    <StyledGroupItemWrapper key={index} isLastItem={index === updateEntries.length - 1}>
                        <Card>
                            <CardActionArea
                                component={Link}
                                to={`/manga/${chapter.mangaId}/chapter/${chapter.index}`}
                                state={location.state}
                            >
                                <CardContent
                                    sx={{
                                        display: 'flex',
                                        justifyContent: 'space-between',
                                        alignItems: 'center',
                                        padding: 2,
                                    }}
                                >
                                    <Box sx={{ display: 'flex' }}>
                                        <Avatar
                                            variant="rounded"
                                            sx={{
                                                width: 56,
                                                height: 56,
                                                flex: '0 0 auto',
                                                marginRight: 2,
                                                imageRendering: 'pixelated',
                                            }}
                                            src={requestManager.getValidImgUrlFor(manga.thumbnailUrl)}
                                        />
                                        <Box sx={{ display: 'flex', flexDirection: 'column' }}>
                                            <Typography variant="h5" component="h2">
                                                {manga.title}
                                            </Typography>
                                            <Typography variant="caption" display="block" gutterBottom>
                                                {chapter.name}
                                            </Typography>
                                        </Box>
                                    </Box>
                                    {download && <DownloadStateIndicator download={download} />}
                                    {download == null && !chapter.downloaded && (
                                        <IconButton
                                            onClick={(e) => {
                                                e.stopPropagation();
                                                e.preventDefault();
                                                downloadChapter(chapter);
                                            }}
                                            size="large"
                                        >
                                            <DownloadIcon />
                                        </IconButton>
                                    )}
                                </CardContent>
                            </CardActionArea>
                        </Card>
                    </StyledGroupItemWrapper>
                );
            }}
        />
    );
};

export default Updates;