(function (root, factory) {
    const detector = typeof module === 'object' && module.exports
        ? require('./channelLanguageDetection.js')
        : root.ChannelLanguageDetection;
    const fusion = typeof module === 'object' && module.exports
        ? require('./channelLanguageFusion.js')
        : root.ChannelLanguageFusion;
    const service = factory(detector, fusion);
    if (typeof module === 'object' && module.exports) module.exports = service;
    if (root) root.ChannelVariantGrouping = service;
})(typeof globalThis !== 'undefined' ? globalThis : this, function (languageDetection, languageFusion) {
    const QUALITY_TOKENS = new Set([
        '4k', 'uhd', 'fhd', 'fullhd', 'hd', 'sd', 'hevc', 'h265', 'h264',
        '1080p', '1080i', '720p', '576p', '480p'
    ]);

    const REGION_PREFIX = /^(?:(?:\|\s*[a-z]{2,3}\s*\|)|(?:[a-z]{2,3}(?:-[a-z]{2,3})?\s*\|))\s*/i;

    function words(value) {
        return String(value || '')
            .normalize('NFKD')
            .replace(/[\u0300-\u036f]/g, '')
            .toLowerCase()
            .replace(REGION_PREFIX, '')
            .replace(/[|()[\]{}_.,:;+/\\-]+/g, ' ')
            .split(/\s+/)
            .filter(Boolean);
    }

    function normalizeChannelName(name) {
        return words(name).filter(token => !QUALITY_TOKENS.has(token)).join(' ').trim();
    }

    function displayNameForFingerprint(fingerprint) {
        return fingerprint.split(' ').map(token => {
            if (token === 'bein') return 'beIN';
            if (/^\d+$/.test(token)) return token;
            return token.charAt(0).toUpperCase() + token.slice(1);
        }).join(' ');
    }

    function getVariantKey(channel) {
        return `${channel.sourceId}:${channel.id}`;
    }

    function getQuality(channel) {
        const tokens = words(channel.name);
        if (tokens.includes('4k') || tokens.includes('uhd')) return '4K';
        if (tokens.includes('fhd') || tokens.includes('fullhd') || tokens.includes('1080p') || tokens.includes('1080i')) return 'Full HD';
        if (tokens.includes('hd') || tokens.includes('720p')) return 'HD';
        if (tokens.includes('sd') || tokens.includes('576p') || tokens.includes('480p')) return 'SD';
        return 'Standard';
    }

    function qualityScore(channel) {
        return { '4K': 4, 'Full HD': 3, HD: 2, Standard: 1, SD: 0 }[getQuality(channel)] ?? 1;
    }

    function choosePreferredVariant(variants, options) {
        const selectedKey = options.selectedVariantKey;
        const selected = variants.find(variant => getVariantKey(variant) === selectedKey);
        if (selected && (options.showHidden || !options.isHidden(selected))) return selected;

        const requestedLanguageCandidate = options.channelLanguagePreference || options.preferredLanguage;
        const requestedLanguage = variants.some(variant => variant.language.code === requestedLanguageCandidate)
            ? requestedLanguageCandidate
            : null;
        const majorityLanguage = options.majorityLanguage;
        return variants.map((variant, index) => ({ variant, index })).sort((aEntry, bEntry) => {
            const a = aEntry.variant;
            const b = bEntry.variant;
            const hiddenDifference = Number(options.isHidden(a)) - Number(options.isHidden(b));
            if (!options.showHidden && hiddenDifference) return hiddenDifference;
            if (requestedLanguage && requestedLanguage !== 'auto') {
                const languageDifference = Number(b.language.code === requestedLanguage) - Number(a.language.code === requestedLanguage);
                if (languageDifference) return languageDifference;
            } else if (majorityLanguage) {
                const majorityDifference = Number(b.language.code === majorityLanguage) - Number(a.language.code === majorityLanguage);
                if (majorityDifference) return majorityDifference;
            }
            const favoriteDifference = Number(options.isFavorite(b)) - Number(options.isFavorite(a));
            if (favoriteDifference) return favoriteDifference;
            return qualityScore(b) - qualityScore(a) || aEntry.index - bEntry.index;
        })[0].variant;
    }

    function groupChannels(channels, options = {}) {
        const isFavorite = options.isFavorite || (() => false);
        const isHidden = options.isHidden || (() => false);
        const showHidden = Boolean(options.showHidden);
        const selectedVariants = options.selectedVariants || new Map();
        const languagePreferences = options.languagePreferences || new Map();
        const buckets = new Map();

        channels.forEach(channel => {
            const fingerprint = channel.logicalFingerprint || normalizeChannelName(channel.name) || `channel-${getVariantKey(channel)}`;
            if (!buckets.has(fingerprint)) buckets.set(fingerprint, []);
            buckets.get(fingerprint).push(channel);
        });

        return Array.from(buckets, ([fingerprint, rawVariants]) => {
            const variants = rawVariants.map(variant => {
                const algo = languageDetection.detectLanguage(variant, { sourceName: variant.sourceName });
                const result = options.languageResults?.get(getVariantKey(variant));
                return {
                    ...variant,
                    ...languageFusion.applyLanguageMode(algo, result, options.languageMode || 'algo')
                };
            });
            const visibleVariants = variants.filter(variant => !isHidden(variant));
            const selectableVariants = showHidden ? variants : visibleVariants;
            const languageCounts = selectableVariants.reduce((counts, variant) => {
                counts[variant.language.code] = (counts[variant.language.code] || 0) + 1;
                return counts;
            }, {});
            const majorityLanguage = Object.entries(languageCounts)
                .filter(([code]) => code !== 'unknown')
                .sort((a, b) => b[1] - a[1])[0]?.[0];
            const preferredVariant = choosePreferredVariant(variants, {
                isHidden,
                isFavorite,
                showHidden,
                selectedVariantKey: selectedVariants.get(fingerprint),
                channelLanguagePreference: languagePreferences.get(fingerprint),
                preferredLanguage: options.preferredLanguage,
                majorityLanguage
            });
            const availableLanguages = [...new Map(selectableVariants.map(variant => [
                variant.language.code,
                variant.language
            ])).values()];
            const aggregateScores = {};
            selectableVariants.forEach(variant => Object.entries(variant.languageScores).forEach(([code, score]) => {
                aggregateScores[code] = (aggregateScores[code] || 0) + score;
            }));
            const scoreTotal = Object.values(aggregateScores).reduce((sum, score) => sum + score, 0);
            const languageScores = Object.fromEntries(Object.entries(aggregateScores).map(([code, score]) => [
                code, Math.round(score / scoreTotal * 100)
            ]));
            return {
                ...preferredVariant,
                id: preferredVariant.logicalId || `logical:${fingerprint}`,
                fingerprint,
                displayName: preferredVariant.logicalDisplayName || displayNameForFingerprint(fingerprint),
                name: preferredVariant.logicalDisplayName || displayNameForFingerprint(fingerprint),
                variants,
                visibleVariants,
                preferredVariant,
                language: preferredVariant.language,
                languageScores,
                availableLanguages,
                selectedVariantId: getVariantKey(preferredVariant),
                isFavorite: variants.some(isFavorite),
                isHidden: visibleVariants.length === 0,
                groupTitle: preferredVariant.groupTitle,
                tvgLogo: preferredVariant.tvgLogo,
                tvgId: preferredVariant.tvgId
            };
        }).filter(channel => showHidden || !channel.isHidden);
    }

    function orderFlatChannels(channels) {
        return channels.map((channel, index) => ({ channel, index })).sort((a, b) => {
            const favoriteDifference = Number(b.channel.isFavorite) - Number(a.channel.isFavorite);
            return favoriteDifference || a.index - b.index;
        }).map(entry => entry.channel);
    }

    function shouldUseFavoritesGroup(listMode) {
        return listMode === 'grouped';
    }

    function selectVariantByLanguage(logicalChannel, languageCode, options = {}) {
        const isFavorite = options.isFavorite || (() => false);
        const isHidden = options.isHidden || (() => false);
        const visible = (logicalChannel?.variants || []).filter(variant => !isHidden(variant));
        if (!visible.length) return null;
        const preferredVisible = visible.find(variant => getVariantKey(variant) === getVariantKey(logicalChannel.preferredVariant));
        if (!languageCode || languageCode === 'auto') return preferredVisible || visible[0];
        const matching = languageCode && languageCode !== 'auto'
            ? visible.filter(variant => variant.language?.code === languageCode)
            : visible;
        const candidates = matching.length ? matching : (preferredVisible ? [preferredVisible] : visible);
        return candidates.map((variant, index) => ({ variant, index })).sort((a, b) =>
            Number(isFavorite(b.variant)) - Number(isFavorite(a.variant)) ||
            qualityScore(b.variant) - qualityScore(a.variant) ||
            a.index - b.index
        )[0].variant;
    }

    return {
        normalizeChannelName,
        displayNameForFingerprint,
        getVariantKey,
        getQuality,
        groupChannels,
        orderFlatChannels,
        selectVariantByLanguage,
        shouldUseFavoritesGroup
    };
});