content/lyric/index.tsx

import React, {useCallback, useEffect, useMemo, useRef, useState} from 'react';
import {LayoutRectangle, StyleSheet, Text, View} from 'react-native';
import rpx from '@/utils/rpx';
import useDelayFalsy from '@/hooks/useDelayFalsy';
import {
    FlatList,
    Gesture,
    GestureDetector,
    TapGestureHandler,
} from 'react-native-gesture-handler';
import {fontSizeConst} from '@/constants/uiConst';
import {IconButtonWithGesture} from '@/components/base/iconButton';
import Loading from '@/components/base/loading';
import globalStyle from '@/constants/globalStyle';
import {showPanel} from '@/components/panels/usePanel';
import LyricManager from '@/core/lyricManager';
import TrackPlayer from '@/core/trackPlayer';
import {musicIsPaused} from '@/utils/trackUtils';
import delay from '@/utils/delay';
import DraggingTime from './draggingTime';
import LyricItemComponent from './lyricItem';
import PersistStatus from '@/core/persistStatus';
import LyricOperations from './lyricOperations';
import MediaExtra from '@/core/mediaExtra';
import {IParsedLrcItem} from '@/utils/lrcParser';

const ITEM_HEIGHT = rpx(92);

interface IItemHeights {
    blankHeight?: number;
    [k: number]: number;
}

interface IProps {
    onTurnPageClick?: () => void;
}

const fontSizeMap = {
    0: rpx(24),
    1: rpx(30),
    2: rpx(36),
    3: rpx(42),
} as Record<number, number>;

export default function Lyric(props: IProps) {
    const {onTurnPageClick} = props;

    const {loading, meta, lyrics, hasTranslation} =
        LyricManager.useLyricState();
    const currentLrcItem = LyricManager.useCurrentLyric();
    const showTranslation = PersistStatus.useValue(
        'lyric.showTranslation',
        false,
    );
    const fontSizeKey = PersistStatus.useValue('lyric.detailFontSize', 1);
    const fontSizeStyle = useMemo(
        () => ({
            fontSize: fontSizeMap[fontSizeKey!],
        }),
        [fontSizeKey],
    );

    const [draggingIndex, setDraggingIndex, setDraggingIndexImmi] =
        useDelayFalsy<number | undefined>(undefined, 2000);
    const musicState = TrackPlayer.useMusicState();

    const [layout, setLayout] = useState<LayoutRectangle>();

    const listRef = useRef<FlatList<IParsedLrcItem> | null>();

    const currentMusicItem = TrackPlayer.useCurrentMusic();
    const associateMusicItem = currentMusicItem
        ? MediaExtra.get(currentMusicItem)?.associatedLrc
        : null;
    // 是否展示拖拽
    const dragShownRef = useRef(false);

    // 组件是否挂载
    const isMountedRef = useRef(true);

    // 用来缓存高度
    const itemHeightsRef = useRef<IItemHeights>({});

    // 设置空白组件，获取组件高度
    const blankComponent = useMemo(() => {
        return (
            <View
                style={styles.empty}
                onLayout={evt => {
                    itemHeightsRef.current.blankHeight =
                        evt.nativeEvent.layout.height;
                }}
            />
        );
    }, []);

    const handleLyricItemLayout = useCallback(
        (index: number, height: number) => {
            itemHeightsRef.current[index] = height;
        },
        [],
    );

    // 滚到当前item
    const scrollToCurrentLrcItem = useCallback(() => {
        if (!listRef.current) {
            return;
        }
        const currentLrcItem = LyricManager.getCurrentLyric();
        const lyrics = LyricManager.getLyricState().lyrics;
        if (currentLrcItem?.index === -1 || !currentLrcItem) {
            listRef.current?.scrollToIndex({
                index: 0,
                viewPosition: 0.5,
            });
        } else {
            listRef.current?.scrollToIndex({
                index: Math.min(currentLrcItem.index ?? 0, lyrics.length - 1),
                viewPosition: 0.5,
            });
        }
    }, []);

    const delayedScrollToCurrentLrcItem = useMemo(() => {
        let sto: number;

        return () => {
            if (sto) {
                clearTimeout(sto);
            }
            sto = setTimeout(() => {
                if (isMountedRef.current) {
                    scrollToCurrentLrcItem();
                }
            }, 200) as any;
        };
    }, []);

    useEffect(() => {
        // 暂停且拖拽才返回
        if (
            lyrics.length === 0 ||
            draggingIndex !== undefined ||
            (draggingIndex === undefined && musicIsPaused(musicState)) ||
            lyrics[lyrics.length - 1].time < 1
        ) {
            return;
        }
        if (currentLrcItem?.index === -1 || !currentLrcItem) {
            listRef.current?.scrollToIndex({
                index: 0,
                viewPosition: 0.5,
            });
        } else {
            listRef.current?.scrollToIndex({
                index: Math.min(currentLrcItem.index ?? 0, lyrics.length - 1),
                viewPosition: 0.5,
            });
        }
        // 音乐暂停状态不应该影响到滑动，所以不放在依赖里，但是这样写不好。。
    }, [currentLrcItem, lyrics, draggingIndex]);

    useEffect(() => {
        scrollToCurrentLrcItem();
        return () => {
            isMountedRef.current = false;
        };
    }, []);

    // 开始滚动时拖拽生效
    const onScrollBeginDrag = () => {
        dragShownRef.current = true;
    };

    const onScrollEndDrag = async () => {
        if (draggingIndex !== undefined) {
            setDraggingIndex(undefined);
        }
        dragShownRef.current = false;
    };

    const onScroll = (e: any) => {
        if (dragShownRef.current) {
            const offset =
                e.nativeEvent.contentOffset.y +
                e.nativeEvent.layoutMeasurement.height / 2;

            const itemHeights = itemHeightsRef.current;
            let height = itemHeights.blankHeight!;
            if (offset <= height) {
                setDraggingIndex(0);
                return;
            }
            for (let i = 0; i < lyrics.length; ++i) {
                height += itemHeights[i] ?? 0;
                if (height > offset) {
                    setDraggingIndex(i);
                    return;
                }
            }
        }
    };

    const onLyricSeekPress = async () => {
        if (draggingIndex !== undefined) {
            const time = lyrics[draggingIndex].time + +(meta?.offset ?? 0);
            if (time !== undefined && !isNaN(time)) {
                await TrackPlayer.seekTo(time);
                await TrackPlayer.play();
                setDraggingIndexImmi(undefined);
            }
        }
    };

    const tapGesture = Gesture.Tap()
        .onStart(() => {
            onTurnPageClick?.();
        })
        .runOnJS(true);

    const unlinkTapGesture = Gesture.Tap()
        .onStart(() => {
            if (currentMusicItem) {
                MediaExtra.update(currentMusicItem, {
                    associatedLrc: undefined,
                });
                LyricManager.refreshLyric(false, true);
            }
        })
        .runOnJS(true);

    return (
        <>
            <GestureDetector gesture={tapGesture}>
                <View style={globalStyle.fwflex1}>
                    {loading ? (
                        <Loading color="white" />
                    ) : lyrics?.length ? (
                        <FlatList
                            ref={_ => {
                                listRef.current = _;
                            }}
                            onLayout={e => {
                                setLayout(e.nativeEvent.layout);
                            }}
                            viewabilityConfig={{
                                itemVisiblePercentThreshold: 100,
                            }}
                            onScrollToIndexFailed={({index}) => {
                                delay(120).then(() => {
                                    listRef.current?.scrollToIndex({
                                        index: Math.min(
                                            index ?? 0,
                                            lyrics.length - 1,
                                        ),
                                        viewPosition: 0.5,
                                    });
                                });
                            }}
                            fadingEdgeLength={120}
                            ListHeaderComponent={
                                <>
                                    {blankComponent}
                                    <View style={styles.lyricMeta}>
                                        {associateMusicItem ? (
                                            <>
                                                <Text
                                                    style={[
                                                        styles.lyricMetaText,
                                                        fontSizeStyle,
                                                    ]}
                                                    ellipsizeMode="middle"
                                                    numberOfLines={1}>
                                                    歌词关联自「
                                                    {
                                                        associateMusicItem.platform
                                                    }{' '}
                                                    -{' '}
                                                    {associateMusicItem.title ||
                                                        ''}
                                                    」
                                                </Text>

                                                <GestureDetector
                                                    gesture={unlinkTapGesture}>
                                                    <Text
                                                        style={[
                                                            styles.linkText,
                                                            fontSizeStyle,
                                                        ]}>
                                                        解除关联
                                                    </Text>
                                                </GestureDetector>
                                            </>
                                        ) : null}
                                    </View>
                                </>
                            }
                            ListFooterComponent={blankComponent}
                            onScrollBeginDrag={onScrollBeginDrag}
                            onMomentumScrollEnd={onScrollEndDrag}
                            onScroll={onScroll}
                            scrollEventThrottle={32}
                            style={styles.wrapper}
                            data={lyrics}
                            initialNumToRender={30}
                            overScrollMode="never"
                            extraData={currentLrcItem}
                            renderItem={({item, index}) => {
                                let text = item.lrc;
                                if (showTranslation && hasTranslation) {
                                    text += `\n${item?.translation ?? ''}`;
                                }

                                return (
                                    <LyricItemComponent
                                        index={index}
                                        text={text}
                                        fontSize={fontSizeStyle.fontSize}
                                        onLayout={handleLyricItemLayout}
                                        light={draggingIndex === index}
                                        highlight={
                                            currentLrcItem?.index === index
                                        }
                                    />
                                );
                            }}
                        />
                    ) : (
                        <View style={globalStyle.fullCenter}>
                            <Text style={[styles.white, fontSizeStyle]}>
                                暂无歌词
                            </Text>
                            <TapGestureHandler
                                onActivated={() => {
                                    showPanel('SearchLrc', {
                                        musicItem:
                                            TrackPlayer.getCurrentMusic(),
                                    });
                                }}>
                                <Text
                                    style={[styles.searchLyric, fontSizeStyle]}>
                                    搜索歌词
                                </Text>
                            </TapGestureHandler>
                        </View>
                    )}
                    {draggingIndex !== undefined && (
                        <View
                            style={[
                                styles.draggingTime,
                                layout?.height
                                    ? {
                                          top:
                                              (layout.height - ITEM_HEIGHT) / 2,
                                      }
                                    : null,
                            ]}>
                            <DraggingTime
                                time={
                                    (lyrics[draggingIndex]?.time ?? 0) +
                                    +(meta?.offset ?? 0)
                                }
                            />
                            <View style={styles.singleLine} />

                            <IconButtonWithGesture
                                style={styles.playIcon}
                                sizeType="small"
                                name="play"
                                onPress={onLyricSeekPress}
                            />
                        </View>
                    )}
                </View>
            </GestureDetector>
            <LyricOperations
                scrollToCurrentLrcItem={delayedScrollToCurrentLrcItem}
            />
        </>
    );
}

const styles = StyleSheet.create({
    wrapper: {
        width: '100%',
        marginVertical: rpx(48),
        flex: 1,
    },
    empty: {
        paddingTop: '70%',
    },
    white: {
        color: 'white',
    },
    lyricMeta: {
        position: 'absolute',
        width: '100%',
        flexDirection: 'row',
        justifyContent: 'center',
        alignItems: 'center',
        left: 0,
        paddingHorizontal: rpx(48),
        bottom: rpx(48),
    },
    lyricMetaText: {
        color: 'white',
        opacity: 0.8,
        maxWidth: '80%',
    },
    linkText: {
        color: '#66ccff',
        textDecorationLine: 'underline',
    },
    draggingTime: {
        position: 'absolute',
        width: '100%',
        height: ITEM_HEIGHT,
        top: '40%',
        marginTop: rpx(48),
        paddingHorizontal: rpx(18),
        right: 0,
        flexDirection: 'row',
        alignItems: 'center',
        justifyContent: 'space-between',
    },
    draggingTimeText: {
        color: '#dddddd',
        fontSize: fontSizeConst.description,
        width: rpx(90),
    },
    singleLine: {
        width: '67%',
        height: 1,
        backgroundColor: '#cccccc',
        opacity: 0.4,
    },
    playIcon: {
        width: rpx(90),
        textAlign: 'right',
        color: 'white',
    },
    searchLyric: {
        width: rpx(180),
        marginTop: rpx(14),
        paddingVertical: rpx(10),
        textAlign: 'center',
        alignSelf: 'center',
        color: '#66eeff',
        textDecorationLine: 'underline',
    },
});