<?php

namespace Modules\Core\Search;

use Illuminate\Database\Eloquent\Builder;
use Illuminate\Database\Eloquent\Model;
use Lunar\Models\Currency;
use Lunar\Models\Price;
use Lunar\Models\Product;
use Lunar\Models\ProductVariant;
use Lunar\Search\ProductIndexer as BaseProductIndexer;
use Modules\Core\Review\Models\ProductReview;
use Spatie\MediaLibrary\MediaCollections\Models\Media;

/**
 * Extends Lunar's own indexer so Modules\Core\Catalog\ProductService can serve both
 * listing/filtering AND single-product lookups from Meilisearch alone — one data
 * source, no separate database read path for a product detail page. Adds:
 *   - collections (ids, filterable) and collection_names (display)
 *   - slugs (every locale's Url::slug for the product, filterable) — lets
 *     ProductService::getBySlug() resolve a product from the index directly, with
 *     no database read at all
 *   - price (cheapest variant, filterable) and full per-variant pricing
 *   - variants: sku, stock, purchasable, option values, prices, media
 *   - the full media gallery (not just the single thumbnail Lunar's base indexer sends)
 *   - tags
 *   - reviews: public-safe fields only (see mapReview() — reviewer_email is deliberately
 *     excluded, it's PII with no storefront use), including staff replies, plus an
 *     average rating
 *   - channel_ids (filterable) — Lunar's base indexer only indexes "status" as
 *     filterable, not channel assignment, so search results can't otherwise be
 *     scoped to products actually assigned+enabled on the current sales channel
 *
 * A review is created/edited independently of its product (Modules\Core\Providers\
 * ReviewServiceProvider re-indexes the product on review create/update/delete), so
 * this data doesn't go stale between full reindexes.
 *
 * New fields aren't filterable in Meilisearch until `php artisan lunar:meilisearch:setup`
 * re-syncs index settings, and existing documents need `lunar:search:index --refresh` to
 * pick up the new shape — see docs/product-listing.md. If SCOUT_QUEUE is enabled, the
 * queue worker also needs restarting after deploying changes to this class (see
 * docs/lunar.md "Gotchas" — a running worker keeps stale indexer code in memory).
 */
class ProductIndexer extends BaseProductIndexer
{
    public function getFilterableFields(): array
    {
        return [
            ...parent::getFilterableFields(),
            'id',
            'brand',
            'collections',
            'price',
            'slugs',
            'channel_ids',
        ];
    }

    public function makeAllSearchableUsing(Builder $query): Builder
    {
        return parent::makeAllSearchableUsing($query)->with([
            'collections',
            'media',
            'tags',
            'urls',
            'variants.images',
            'variants.prices',
            'variants.values.option',
        ]);
    }

    public function toSearchableArray(Model $model): array
    {
        /** @var Product $model */
        $data = parent::toSearchableArray($model);

        $currency = Currency::getDefault();
        $reviews = ProductReview::where('product_id', $model->id)->with('media')->get();

        $data['collections'] = $model->collections->pluck('id')->map(fn ($id) => (string) $id)->all();
        $data['collection_names'] = $model->collections->map(fn ($collection) => $collection->translateAttribute('name'))->all();
        $data['slugs'] = $model->urls->pluck('slug')->unique()->values()->all();
        $data['tags'] = $model->tags->pluck('value')->all();
        $data['media'] = $model->media->map(fn (Media $media) => $this->mapMedia($media))->all();
        $data['variants'] = $model->variants->map(fn (ProductVariant $variant) => $this->mapVariant($variant, $currency))->all();
        $data['price'] = $this->cheapestPrice($model, $currency);
        $data['reviews'] = $reviews->map(fn (ProductReview $review) => $this->mapReview($review))->all();
        $data['review_count'] = $reviews->count();
        $data['average_rating'] = $reviews->isEmpty() ? null : round($reviews->avg('rating'), 1);
        $data['channel_ids'] = $model->channels()
            ->wherePivot('enabled', true)
            ->pluck('id')
            ->toArray();

        return $data;
    }

    private function mapVariant(ProductVariant $variant, Currency $currency): array
    {
        return [
            'id' => $variant->id,
            'sku' => $variant->sku,
            'stock' => $variant->stock,
            'purchasable' => $variant->purchasable,
            'options' => $variant->values->map(fn ($value) => [
                'option' => $this->translatedName($value->option->name),
                'value' => $this->translatedName($value->name),
                'meta' => $value->meta,
            ])->all(),
            'prices' => $variant->prices->map(fn (Price $price) => [
                'currency_id' => $price->currency_id,
                'customer_group_id' => $price->customer_group_id,
                'price' => $price->price->decimal(),
                'compare_price' => $price->compare_price?->decimal(),
                'min_quantity' => $price->min_quantity,
            ])->all(),
            'media' => $variant->images->map(fn (Media $media) => $this->mapMedia($media))->all(),
        ];
    }

    /**
     * Public-safe fields only — reviewer_email is PII with no storefront use and is
     * deliberately excluded, unlike every other column on the review. reply/replied_at
     * (the staff response) are included since they're meant to be shown alongside the
     * review on the storefront.
     */
    private function mapReview(ProductReview $review): array
    {
        return [
            'id' => $review->id,
            'title' => $review->title,
            'body' => $review->body,
            'rating' => $review->rating,
            'reviewed_at' => $review->reviewed_at?->timestamp,
            'reviewer_name' => $review->reviewer_name,
            'reply' => $review->reply,
            'replied_at' => $review->replied_at?->timestamp,
            'location' => $review->location,
            'media' => $review->media->map(fn (Media $media) => $this->mapMedia($media))->all(),
        ];
    }

    /**
     * ProductOption/ProductOptionValue's `name` is a plain locale-keyed array cast
     * (AsArrayObject) directly on the column — unlike Product/Collection/Brand, it is
     * not stored in attribute_data. Lunar's translateAttribute() only reads
     * attribute_data, so it silently returns null for these two models; this reads
     * the array directly instead. Falls back to the first available locale if the
     * current one is missing. Not a general replacement for translateAttribute() —
     * every other translated field in this indexer (product/collection name and
     * description) genuinely is attribute_data-backed and translateAttribute() is
     * correct for those.
     */
    private function translatedName(mixed $name): ?string
    {
        $names = is_array($name) ? $name : (array) $name;

        return $names[app()->getLocale()] ?? reset($names) ?: null;
    }

    private function mapMedia(Media $media): array
    {
        return [
            'id' => $media->id,
            'url' => $media->getUrl(),
            'thumb' => $media->getUrl('small'),
        ];
    }

    /**
     * The cheapest variant's base price (no customer group) in the default currency,
     * as a float in major units — e.g. 19.99, not 1999. Null if the product has no
     * variant with a price in that currency yet, so it's excluded from price filters
     * rather than sorting to the bottom as if it were free.
     */
    private function cheapestPrice(Product $model, Currency $currency): ?float
    {
        $price = $model->variants
            ->flatMap(fn ($variant) => $variant->prices)
            ->filter(fn ($price) => $price->currency_id === $currency->id && $price->customer_group_id === null)
            ->min(fn ($price) => $price->price->value);

        return $price !== null ? $price / (10 ** $currency->decimal_places) : null;
    }
}