import type { ProductVariantInput, TargetingRule, WidgetSizeConfig } from './types';

const ONE_SIZE_LABELS = new Set( [
	'onesize', 'os', 'tagliaunica', 'tallaunica', 'tailleunique', 'einheitsgrosse',
	'tamanhounico', 'maatuniek', 'uniwersalny', 'unisize', 'freesize', 'unica', 'unico',
] );

export function normalizeSizeLabel( label: unknown ): string {
	if ( typeof label !== 'string' ) return '';
	return label
		.normalize( 'NFKD' )
		.replace( /[\u0300-\u036f]/g, '' )
		// Product data must normalize identically regardless of the shopper's
		// browser locale (notably Turkish casing rules).
		.toLowerCase()
		.replace( /[^a-z0-9]+/g, '' );
}

function eligibleSizeLabels( guideLabels: unknown, variants: ProductVariantInput[] ): Set<string> {
	if ( ! Array.isArray( guideLabels ) || ! Array.isArray( variants ) ) return new Set();
	const guide = new Set( guideLabels.map( normalizeSizeLabel ).filter( Boolean ) );
	const matched = new Set<string>();
	for ( const variant of variants ) {
		if ( ! variant || variant.available !== true ) continue;
		const label = normalizeSizeLabel( variant.size_label );
		if ( label && ! ONE_SIZE_LABELS.has( label ) && guide.has( label ) ) matched.add( label );
	}
	return matched;
}

export function sizeFeatureEnabled(
	rule: TargetingRule | undefined,
	categories: string[],
	productId: string
): boolean {
	if ( ! rule || ( rule.mode !== 'include' && rule.mode !== 'exclude' ) ) return true;
	const matched = categories.some( ( category ) => ( rule.categories || [] ).includes( category ) ) ||
		( rule.productIds || [] ).map( String ).includes( String( productId ) );
	return rule.mode === 'include' ? matched : ! matched;
}

export function sizeGuideForProduct(
	size: WidgetSizeConfig,
	categories: string[],
	variants: ProductVariantInput[],
	productId = ''
) {
	if ( ! Array.isArray( size.guides ) ) return null;
	const guides = size.guides.filter((guide) => guide && (guide.categories == null || (typeof guide.categories === 'object' && !Array.isArray(guide.categories) && [guide.categories.categories, guide.categories.productIds].every((list) => list == null || (Array.isArray(list) && list.every((value) => typeof value === 'string'))))));
	const explicit = guides.find( ( guide ) => ( guide.categories?.productIds || [] ).includes( productId ) );
	const assigned = guides.find( ( guide ) =>
		( guide.categories?.categories || [] ).some( ( category ) => categories.includes( category ) )
	);
	const fallback = guides.find( ( guide ) => ( guide.categories?.categories || [] ).length === 0 && ( guide.categories?.productIds || [] ).length === 0 );
	const guide = explicit || assigned || fallback || null;
	if ( ! guide ) return null;
	return eligibleSizeLabels( guide.labels, variants ).size >= 2 ? guide : null;
}

export function isSizeEligible(
	size: WidgetSizeConfig | undefined,
	categories: string[],
	productId: string,
	variants: ProductVariantInput[]
): boolean {
	if ( ! size?.hasSizeGuide || ! Array.isArray( variants ) ) return false;
	return sizeFeatureEnabled( size.targeting, categories, productId ) &&
		sizeGuideForProduct( size, categories, variants, productId ) !== null;
}

export function sizeGuideResolution(
	size: WidgetSizeConfig,
	categories: string[],
	variants: ProductVariantInput[],
	productId = ''
): 'product_id' | 'collection' | 'shop_default' | 'none' {
	const guide = sizeGuideForProduct( size, categories, variants, productId );
	if ( ! guide ) return 'none';
	if ( guide.categories?.productIds?.includes( productId ) ) return 'product_id';
	if ( ! ( 'categories' in guide ) ) return 'shop_default';
	return ( guide.categories?.categories || [] ).length > 0 ? 'collection' : 'shop_default';
}