import { duration2text, printD, printW } from '../extensions/Extension';
import { LyricController } from '../LyricController';
import { Lyric } from '../bean/Lyric';
import { ListAdapter } from '../extensions/ListAdapter';
import { LyricLine } from '../bean/LyricLine';
import { LyricWord } from '../bean/LyricWord';
import { transverter, TransverterType, TransverterLanguage } from "@nutpi/chinese_transverter"
import { curves, LengthMetrics } from '@kit.ArkUI';

/**
 * A component to display the lyric with scroll animation.
 * This component only support api 10+.
 *
 * The custom setter include the lyric text style, fade style of edge, the line space, scroll animation duration,
 * the cache size to draw out of screen.
 */
@Component
export struct LyricView2 {
    /**
     * The lyricConfig for LyricView.
     */
    controller: LyricController = new LyricController()
    /**
     * Enable the lyric scroll to do seek action or not.
     * If false, the onSeekAction callback will not invoke anymore.
     */
    enableSeek: boolean = true
    /**
     * The color of seek button and duration text.
     */
    seekUIColor: ResourceColor = '#000000'
    /**
     * The color of the seek location line.
     */
    seekLineColor: ResourceColor = '#0d000000'
    /**
     * The seek ui style.
     */
    seekUIStyle: 'seekLine' | 'listItem' = 'listItem'
    /**
     * The seek callback for scroll the lyric.
     * If return true, you must handle this action to do seek action of media player.
     * If return false, the lyric view will scroll to current index of the media playing position.
     */
    onSeekAction: (position: number) => boolean = () => false
    private currentLyric: Lyric | null = null
    private scroller = new Scroller()
    private listAdapter = new ListAdapter<LyricLine>()
    private w = 0 // the width of this view.
    private h = 0 // the height of this view.
    @State currentIndex: number = 0 // the focused index of the lyric line list.
    @State isLyricEmpty: boolean = true // is no lyric.
    @State textSize: number = 16
    @State isSingleLine: boolean = false
    @State lineSpace: number = 16
    @State textWeight: number = FontWeight.Medium
    @State textHighlightSize: number = 18
    @State textColor: string = '#000000'
    @State textHighlightColor: string = '#000000'
    @State isHighlightBold: boolean = false
    @State alignMode: 'left' | 'center' = 'center'
    @State emptyHint: string = ''
    @State cacheSize: number = 3
    @State animDuration: number = 300
    @State isUserTouching: boolean = false
    @State seekPosition: number = -1
    @State scrollDurationText: string = '00:00'
    @State seekIndex: number = -1
    private seekUiHideTimeout = -1
    private autoHideSeekUIDuration = 2000
    @State isLoadingData: boolean = false
    private loadTimeout = -1
    @State isHightLightCenter: boolean = true
    @State currentMediaPosition: number = 0
    @State transverterType: number = 0

    private onDataChangedListener = (lyric: Lyric | null) => {
        clearTimeout(this.loadTimeout)
        this.isLoadingData = true
        this.loadData(lyric)
        this.loadTimeout = setTimeout(() => {
            this.isLoadingData = false
        }, 300)
    }
    private onPositionChangedListener = (mediaPosition: number) => {
        // 如果是纯文本歌词，不进行位置同步
        if (this.currentLyric && this.currentLyric.isPlainText) {
            this.currentMediaPosition = mediaPosition
            return
        }
        this.currentMediaPosition = mediaPosition
        this.onPositionChanged(mediaPosition)
    }
    private onInvalidatedListener = (reLayout: boolean) => {
        this.getAttrFromController()
        if (reLayout && this.currentIndex > 0) {
            this.animateToIndex(this.currentIndex)
        }
    }

    private loadData(lyric: Lyric | null) {
        this.currentLyric = lyric;
        if (this.w > 0 && this.h > 0) {
            if (this.currentLyric) {
                this.listAdapter.clear(false);
                let lyricLines = this.currentLyric.lyricList;
                if (lyricLines!==undefined&&lyricLines.length > 0) {
                    let first = lyricLines[0].beginTime;
                    // fill the top empty gap 注释掉修复 歌曲不播放的时候，可以显示完整的歌词，而不是显示一两行
                    // for (let i = 0; i < this.centerOffsetSize; i++) {
                    //     this.listAdapter.addData(new LyricLine(' ', 0, first), false);
                    // }
                    lyricLines.forEach((line) => {
                        this.listAdapter.addData(line, false);
                    });
                    // fill the bottom empty gap
                    // let last = lyricLines[lyricLines.length - 1].nextTime;
                    // for (let i = 0; i < this.centerOffsetSize; i++) {
                    //     this.listAdapter.addData(new LyricLine(' ', last + i, last + i), false);
                    // }

                }

                this.listAdapter.notifyDataReload();
            } else {
                this.listAdapter.clear(true);
            }
        }
        this.isLyricEmpty = this.listAdapter.isEmpty();
        this.currentIndex = 0;
        this.animateToIndex(0);

    }

    private getAttrFromController() {
        this.currentLyric = this.controller.getLyric()
        this.textSize = this.controller.getTextSize()
        this.transverterType = this.controller.getTransverterType()
        this.isSingleLine = this.controller.getSingleLine()
        this.blurDegree = this.controller.getBlurDegree()
        this.isHightLightCenter = this.controller.getHightLightCenter()
        this.lineSpace = this.controller.getLineSpace()
        this.textColor = this.controller.getTextColor()
        this.textHighlightColor = this.controller.getHighlightColor()
        this.textHighlightSize = this.controller.getHighlightScale() * this.textSize
        this.isHighlightBold = this.controller.isHighlightBold()
        this.animDuration = this.controller.getAnimationDuration()
        this.cacheSize = this.controller.getCacheSize()
        this.emptyHint = this.controller.getEmptyHint()
        this.alignMode = this.controller.getAlignMode()
        this.textWeight = this.controller.getTextWeight()
    }

    aboutToAppear() {
        if (this.controller == null) {
            throw new Error('The lyric lyricConfig is not set!')
        }
        this.controller.onDataChangedListener = this.onDataChangedListener
        this.controller.onPositionChangedListener = this.onPositionChangedListener
        this.controller.onInvalidated = this.onInvalidatedListener
        this.getAttrFromController()

        // 初始化时将滚动位置设置为顶部
        this.scroller.scrollToIndex(0, true, ScrollAlign.START);
    }

    @Builder
    EmptyView() {
        Text(this.emptyHint)
            .fontSize(this.textSize)
            .fontColor(this.textColor)
    }

    @State blurDegree: number = 3



    // 优化建议代码示例：增加滚动节流
    private lastScrollTime: number = 0
    private scrollThrottle: number = 100 // 100ms节流
    @Builder
    LyricListView() {
        List({ space: this.lineSpace - 16, scroller: this.scroller }) {
            LazyForEach(this.listAdapter, (item: LyricLine, index: number) => {
                ListItem() {
                    Stack() {
                        // 逐字歌词渲染
                        if (item.hasWords() && item.words.length > 0) {
                            this.WordByWordLyric(item, index)
                        } else {
                            // 普通歌词渲染（原有逻辑）
                            this.NormalLyricLine(item, index)
                        }

                        if (this.seekUIStyle == 'listItem' && index == this.seekIndex && item.text.length > 0
                            && this.enableSeek && this.isUserTouching){
                            this.JumpProgress()
                        }


                    }
                    .align(Alignment.End)

                }
                .padding(8)
                .border({ radius: 12 })
                // .backgroundColor(this.seekUIStyle == 'listItem' && index == this.seekIndex && item.text.length > 0
                //     && this.enableSeek && this.isUserTouching ? '#80a9a9a9' : '#00000000')
                .onClick(() => {
                    if (this.seekUIStyle == 'listItem' && index == this.seekIndex && item.text.length > 0) {
                        if (this.seekIndex != -1 && this.seekIndex != this.currentIndex) {
                            this.handleSeekAction();
                        }
                    }
                })
            },
                (item: LyricLine, index: number) => {
                    return item.text + '_' + index + '_' + item.beginTime + '_' + item.nextTime
                })
        }
        .width('100%')
        .height('100%')
        .layoutWeight(1)
        .scrollBar(BarState.Off)
        .fadingEdge(true,{fadingEdgeLength:LengthMetrics.percent(20)})
        .edgeEffect(EdgeEffect.Spring)
        .contentEndOffset(this.h / 3)
        .contentStartOffset(this.isUserTouching?this.h / 3:0)
        .cachedCount(this.cacheSize)
        // .chainAnimation(true)
        // .animation({
        //     curve: curves.springCurve(100, 10, 80, 10),
        //     duration: 500
        // })
        .visibility(this.isLoadingData ? Visibility.Hidden : Visibility.Visible)
        .onScrollIndex((_, __, center) => {
            const now = Date.now()
            if (now - this.lastScrollTime  < this.scrollThrottle)  return
            this.lastScrollTime  = now
            // 纯文本歌词不支持 seek 操作
            if (this.isUserTouching && !(this.currentLyric && this.currentLyric.isPlainText)) {
                //修复The value of "index" is out of range. It must be >= 0 && <= -1. Received value is: -1
                if (center >= 0 && center < this.listAdapter.totalCount()) {
                    this.seekIndex = center;
                    let targetPosition = this.listAdapter.getData(center).beginTime;
                    this.scrollDurationText = duration2text(targetPosition);
                } else {
                    // 处理 center 不在范围内的情况
                    console.error(`Index out of range: ${center}`);
                }
                // this.seekIndex = center
                // let targetPosition = this.listAdapter.getData(center).beginTime
                // this.scrollDurationText = duration2text(targetPosition)
            }
        })
        .onTouch((event) => {
            let motion = event.touches[0]
            switch (motion.type) {
                case TouchType.Down:
                    clearTimeout(this.seekUiHideTimeout)
                    break
                case TouchType.Move:
                    this.isUserTouching = true
                    break
                case TouchType.Up:
                case TouchType.Cancel:
                    // 纯文本歌词不需要自动滚动回顶部
                    if (this.currentLyric && this.currentLyric.isPlainText) {
                        this.seekUiHideTimeout = setTimeout(() => {
                            this.seekIndex = -1
                            this.isUserTouching = false
                            // 纯文本歌词不调用 animateToIndex，保持在当前位置
                        }, this.autoHideSeekUIDuration)
                    } else {
                        this.seekUiHideTimeout = setTimeout(() => {
                            this.seekIndex = -1
                            this.isUserTouching = false
                            this.animateToIndex(this.currentIndex)
                        }, this.autoHideSeekUIDuration)
                    }
            }
        })
    }
    // 普通歌词渲染（原有逻辑）
    @Builder
    NormalLyricLine(item: LyricLine, index: number) {
        Column(){
            Text(item.text)
                .fontSize(index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ?this.textSize*this.controller.getHighlightScale():this.textSize)
                .textAlign(this.alignMode == 'center' ? TextAlign.Center : TextAlign.Start)
                .fontColor(index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ? this.textHighlightColor : this.textColor)
                .fontWeight(index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) && this.isHighlightBold ? FontWeight.Bold : this.textWeight)
                .padding(this.isSingleLine?0:{ top:5,bottom:5 })
                .visibility(this.isSingleLine?
                    (index >= this.currentIndex && index <= this.currentIndex + 1 ? Visibility.Visible : Visibility.None)
                    : Visibility.Visible)
                .width(this.alignMode == 'center' ? '100%' :index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ?'95%': '80%')
                .animation({
                    duration: 150,
                    curve: Curve.Linear
                })
                .blendMode(
                    index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ? BlendMode.DST_IN : undefined,
                    index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ? BlendApplyType.OFFSCREEN : undefined
                )

            // 中文翻译（整行显示）
            if (item.translation)  {

            Text(item.translation)
                .fontSize(index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ?this.textSize*this.controller.getHighlightScale():this.textSize)
                .fontColor(this.currentMediaPosition >= item.beginTime ?
                    index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ? this.textHighlightColor : this.textColor : this.textColor)
                .fontWeight(index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) && this.isHighlightBold ? FontWeight.Bold : this.textWeight)
                .padding(this.isSingleLine?{ bottom:2 }:{ bottom:5 })
                .textAlign(this.alignMode == 'center' ? TextAlign.Center : TextAlign.Start)
                .visibility(this.isSingleLine?
                    (index >= this.currentIndex && index <= this.currentIndex + 1 ? Visibility.Visible : Visibility.None)
                    : Visibility.Visible)
                .blendMode(
                    index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ? BlendMode.DST_IN : undefined,
                    index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ? BlendApplyType.OFFSCREEN : undefined
                )
                .width(this.alignMode == 'center' ? '100%' :index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ?'95%': '80%')
                .animation({
                    duration: 150,
                    curve: Curve.Linear
                })

            }
        }
        // 在 Row 上应用渐变
        .linearGradient(index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ? {
            direction: GradientDirection.Right,
            colors: this.getLyricItemLinearGradient(item, index)
        } : undefined)
        .blendMode(
            index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ? BlendMode.SRC_OVER : undefined,
            index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ? BlendApplyType.OFFSCREEN : undefined
        )


    }



    /**
     * 计算卡拉OK渐变 - 同色系从浅到深的平滑过渡
     */
    getLyricItemLinearGradient(item: LyricLine, index: number): [ResourceColor, number][] {
        // 只对当前播放行且包含逐字数据的行应用卡拉OK效果
        if (index !== this.currentIndex  || item.words.length === 0) {
            //console.info('heanup', `getLyricItemLinearGradient - 非高亮行或无逐字数据: index=${index}, currentIndex=${this.currentIndex}, hasWords=${item.hasWords()}, wordsCount=${item.words.length}`)
            return [[Color.White, 0.0], [Color.White, 1.0]]
        }

        // 计算该行歌词的总时长
        let lyricDuration: number
        if (index < this.listAdapter.totalCount() - 1) {
            const nextLine = this.listAdapter.getData(index + 1)
            lyricDuration = nextLine.beginTime - item.beginTime
        } else {
            // 最后一行，使用 nextTime（如果有）或者估计时长
            lyricDuration = item.nextTime > item.beginTime ? item.nextTime - item.beginTime : 5000
        }

        //console.info('heanup', `getLyricItemLinearGradient - index=${index}, lyricDuration=${lyricDuration}, currentMediaPosition=${this.currentMediaPosition}, itemBeginTime=${item.beginTime}`)

        if (lyricDuration <= 0) {
            console.info('heanup', `getLyricItemLinearGradient - 歌词时长<=0, 返回透明`)
            return [[Color.Transparent, 0.0], [Color.Transparent, 1.0]]
        }

        // 计算当前播放进度（0-1之间）
        let diff = this.currentMediaPosition - item.beginTime
        let value = diff / lyricDuration

        value = Math.max(0, Math.min(1, value))

        return [[this.textHighlightColor, 0.0],
            [this.textHighlightColor, value],
            [this.textColor, value],
            [this.textColor, 1.0]]
    }

    /**
     * 计算逐字歌词的卡拉OK渐变效果
     * 该方法针对逐字歌词格式，根据当前播放进度和每个字的时间信息计算渐变
     * @param item 当前歌词行
     * @param word 当前字的信息
     * @param index 当前行索引
     * @returns 渐变颜色数组
     */
    getWordByWordLyricLyricItemLinearGradient(item: LyricLine, word: LyricWord, index: number): [ResourceColor, number][] {
        // 非高亮行或无效数据，返回透明
        if (index !== this.currentIndex || !word || !word.word) {
            //console.info('heanup', `getWordByWordLyricLyricItemLinearGradient - 非高亮行或无效word: index=${index}, currentIndex=${this.currentIndex}`)
            return [[Color.White, 0.0], [Color.White, 1.0]]
        }

        // 计算该字的播放进度
        const wordEndTime = word.startTime + word.duration
        const wordDuration = word.duration

        // 异常情况处理
        if (wordDuration <= 0) {
            //console.info('heanup', `getWordByWordLyricLyricItemLinearGradient - word时长<=0: startTime=${word.startTime}, duration=${word.duration}`)
            // 如果时长无效，检查当前播放位置是否已到达开始时间
            if (this.currentMediaPosition >= word.startTime) {
                // 已开始播放，全部高亮
                return [[this.textHighlightColor, 0.0], [this.textHighlightColor, 1.0]]
            } else {
                // 未开始播放，全部普通颜色
                return [[this.textColor, 0.0], [this.textColor, 1.0]]
            }
        }

        // 计算当前在该字内的播放进度（0-1之间）
        let progress = 0
        if (this.currentMediaPosition < word.startTime) {
            // 还没播放到这个字
            progress = 0
        } else if (this.currentMediaPosition >= wordEndTime) {
            // 这个字已经播放完
            progress = 1
        } else {
            // 正在播放这个字，计算进度
            const diff = this.currentMediaPosition - word.startTime
            progress = diff / wordDuration
            progress = Math.max(0, Math.min(1, progress))
        }

        console.info('heanup', `getWordByWordLyricLyricItemLinearGradient - word=${word.word}, progress=${progress}, currentPos=${this.currentMediaPosition}, wordStart=${word.startTime}, wordEnd=${wordEndTime}`)

        // 返回卡拉OK渐变效果
        // 0.0 到 progress：高亮色（已播放部分）
        // progress 到 1.0：普通色（未播放部分）
        return [[this.textHighlightColor, 0.0],
            [this.textHighlightColor, progress],
            [this.textColor, progress],
            [this.textColor, 1.0]]
    }

    @Builder
    WordByWordLyric(item: LyricLine, index: number) {
        Column() {
            Row({ space: 0 }) {
                ForEach(item.words, (word: LyricWord, wordIndex: number) => {


                    Text(word.word)
                        .fontSize(index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ?this.textSize*this.controller.getHighlightScale():this.textSize)
                        .fontColor(this.currentMediaPosition >= word.startTime ?
                            index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ? this.textHighlightColor : this.textColor : this.textColor)
                        .fontWeight(index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText)? FontWeight.Bold : this.textWeight)
                        .margin(isEnglish(word.word) ?{ right:4 }:{})
                        .visibility(this.isSingleLine?
                            (index >= this.currentIndex && index <= this.currentIndex + 1 ? Visibility.Visible : Visibility.None)
                            : Visibility.Visible)
                        .padding(this.isSingleLine?0:{ top:5,bottom:5 })
                        // .shaderStyle(index == this.currentIndex ?{
                        //     direction: GradientDirection.Right,
                        //     colors: this.getWordByWordLyricLyricItemLinearGradient(item, word, index)
                        // }:undefined)
                        .animation({
                            duration: 150,
                            curve: Curve.Linear
                        })
                })
            }
            .justifyContent(this.alignMode === 'center' ? FlexAlign.Center : FlexAlign.Start)
            .width(this.alignMode == 'center' ? '100%' :index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ?'95%': '85%')

            // 中文翻译（整行显示）
            if (item.translation)  {
                Row({ space: 0 }) {
                    Text(item.translation)
                        .fontSize(index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ?this.textSize*this.controller.getHighlightScale():this.textSize)
                        .fontColor(this.currentMediaPosition >= item.beginTime ?
                            index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ? this.textHighlightColor : this.textColor : this.textColor)
                        .fontWeight(index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText)? FontWeight.Bold : this.textWeight)
                        .padding({ bottom:5 })
                        .padding(this.isSingleLine?{ bottom:2 }:{ bottom:5 })
                        .visibility(this.isSingleLine?
                            (index >= this.currentIndex && index <= this.currentIndex + 1 ? Visibility.Visible : Visibility.None)
                            : Visibility.Visible)
                        .animation({
                            duration: 150,
                            curve: Curve.Linear
                        })
                }
                .justifyContent(this.alignMode === 'center' ? FlexAlign.Center : FlexAlign.Start)
                .width(this.alignMode == 'center' ? '100%' :index == this.currentIndex && !(this.currentLyric && this.currentLyric.isPlainText) ?'95%': '85%')
            }
        }
        .height('auto')


    }


    //修复get Property index out of bounds
    private handleSeekAction() {
        clearTimeout(this.seekUiHideTimeout);

        let itemCount = this.listAdapter.totalCount(); // 获取数据项的总数

        // 确保 seekIndex 在有效范围内
        if (this.seekIndex >= 0 && this.seekIndex < itemCount) {
            let targetPosition = this.listAdapter.getData(this.seekIndex).beginTime;
            let isPlayerHandled = this.onSeekAction(targetPosition);
            if (!isPlayerHandled) {
                this.animateToIndex(this.currentIndex);
            }
        } else {
            console.error("Seek index out of bounds:", this.seekIndex);
            // 处理超出范围的情况，比如设定默认值或抛出错误
        }

        this.isUserTouching = false;
    }

    getTransverterText(message: string):string{
        if(this.transverterType==1){
            return    transverter({
                type: TransverterType.TRADITIONAL,
                str: message,
                language: TransverterLanguage.ZH_TW
            });
        }else if(this.transverterType==2){
            return    transverter({
                type: TransverterType.SIMPLIFIED,
                str: message,
                language: TransverterLanguage.ZH_CN
            });
        }else{
            return message;
        }

    }

    @Builder
    JumpProgress(){
        Row(){
            Row(){

                Row({space: 10}){
                    Text(this.scrollDurationText)
                        .fontSize(12)
                        .fontWeight(FontWeight.Medium)
                        .fontColor(Color.White)

                    SymbolGlyph($r('sys.symbol.play'))
                        .fontSize(13)
                        .fontColor([Color.White])
                        .alignSelf(ItemAlign.Center)
                }
                .borderRadius(10)
                .alignItems(VerticalAlign.Center)
                .height(32)
                .padding(10)
                .backgroundColor(Color.Transparent)
                .backgroundBlurStyle(BlurStyle.BACKGROUND_REGULAR,
                    { colorMode: ThemeColorMode.LIGHT, adaptiveColor: AdaptiveColor.DEFAULT, scale: 1.0 })
            }
            .transition(
                TransitionEffect
                    .scale({ x: 0.7, y: 0.7 })
                    .combine(TransitionEffect
                        .opacity(0.1)
                    )
                    .animation({
                        duration: 150,
                        curve: Curve.EaseInOut,
                    })
            )
        }
        .hitTestBehavior(HitTestMode.Transparent)
        .width(110)
        .justifyContent(FlexAlign.End)
        .backgroundColor(Color.Transparent)

    }


    @Builder
    SeekLine() {
        Row() {
            Image($r('app.media.cclyric_play'))
                .width(24)
                .height(24)
                .fillColor(this.seekUIColor)
                .objectFit(ImageFit.Fill)
                .clickEffect({ level: ClickEffectLevel.MIDDLE })
                .onClick(() => {
                    if (this.seekIndex != -1 && this.seekIndex != this.currentIndex) {
                        this.handleSeekAction()
                    }
                })
            Stack()
                .height(1)
                .layoutWeight(1)
                .backgroundColor(this.seekLineColor)
                .margin({ left: 8, right: 8 })
            Text(this.scrollDurationText)
                .fontSize(this.textSize)
                .fontColor(this.seekUIColor)
        }
        .visibility(this.enableSeek && this.isUserTouching ? Visibility.Visible : Visibility.Hidden)
        .width('100%')
        .height('100%')
        .hitTestBehavior(HitTestMode.Transparent)
        .transition(TransitionEffect.OPACITY.animation({ duration: this.animDuration }))
    }

    build() {
        Stack() {
            if (this.isLyricEmpty) {
                this.EmptyView()
            } else {
                this.LyricListView()
            }
        }
        .width('100%')
        .height('100%')
        .onAreaChange((_, newSize) => {
            printW('onSizeChanged: ' + JSON.stringify(newSize))
            this.h = newSize.height as number
            this.w = newSize.width as number
            if (this.currentLyric) {
                this.loadData(this.currentLyric)
            }
        })
    }

    aboutToDisappear() {
        clearTimeout(this.loadTimeout)
        clearTimeout(this.seekUiHideTimeout)
    }

    private getIndex(position: number): number {

        let size = this.listAdapter.totalCount()
        if (size === 0) return 0 // 空列表保护

        // 如果是纯文本歌词，始终返回 0（不滚动）
        if (this.currentLyric && this.currentLyric.isPlainText) {
            return 0
        }

        let first = this.listAdapter.getData(0).beginTime
        if (position < first) {
            return 0
        }
        let last = this.listAdapter.getData(size - 1).beginTime
        if (position > last) {
            return size - 1
        }
        for (let i = 0; i < size - 1; i++) {
            let line = this.listAdapter.getData(i)
            if (position >= line.beginTime && position < line.nextTime) {
                return i
            }
        }
        return this.currentIndex
    }

    private animateToIndex(index: number) {
        printD('animate to index= ' + index)
        this.currentIndex = index
        if (this.isUserTouching) {
            return
        }
        if(this.isHightLightCenter){
            this.scroller.scrollToIndex(index, true, ScrollAlign.CENTER)
        }else{
            // 计算目标索引，使其在居中位置上方有两条歌词
            const targetIndex = Math.max(0, index - 2);
            this.scroller.scrollToIndex(targetIndex, true, ScrollAlign.START);
        }


    }


    private onPositionChanged(mediaPosition: number) {
        if (this.isLyricEmpty) {
            // printW('The lyric data is empty!')
            return
        }
        if (this.listAdapter.isEmpty()) {
            // printW('The lyric lines is empty!')
            return
        }
        // 如果是纯文本歌词，不进行滚动同步
        if (this.currentLyric && this.currentLyric.isPlainText) {
            return
        }
        let index = this.getIndex(mediaPosition)
        if (index != this.currentIndex) {
            this.animateToIndex(index)
        }
    }
}

function  isEnglish(text: string, mode: string = 'strict', threshold: number = 0.9): boolean {
    if (!text || typeof text !== 'string') return false;

    switch (mode) {
        case 'basic':
            return /^[a-zA-Z\s.,!?'"-]+$/.test(text);
        case 'percentage':
            return checkByPercentage(text,  threshold);
        default: // strict
            return /^[\u0000-\u007F]+$/.test(text.trim());
    }
}

function checkByPercentage(text: string, threshold: number): boolean {
    const validChars = text.match(/[a-zA-Z\s.,!?'"-]/g)  || [];
    return (validChars.length  / text.length)  >= threshold;
}