<?php

declare(strict_types=1);
namespace FacetCore\WordPress;

/** Bridges WooCommerce taxonomy assignments to the existing FacetCore index.
 * No indexing runs on public search requests; product/term changes keep it current.
 */
final class AttributeIndex
{
    public function hooks(): void
    {
        add_action('woocommerce_new_product', [$this, 'syncProduct'], 30);
        add_action('woocommerce_update_product', [$this, 'syncProduct'], 30);
        add_action('set_object_terms', [$this, 'termsAssigned'], 30, 4);
        add_action('deleted_term_relationships', function ($objectId, $ttIds, $taxonomy): void { $this->termsAssigned($objectId, [], $ttIds, $taxonomy); }, 30, 3);
        foreach (['created_term', 'edited_term', 'delete_term'] as $hook) { add_action($hook, [$this, 'termChanged'], 30, 3); }
        add_action('woocommerce_attribute_updated', [$this, 'attributeChanged']);
        add_action('woocommerce_attribute_deleted', [$this, 'attributeDeleted']);
    }

    public function facet(int $attributeId): ?array
    {
        global $wpdb;
        $repo = new Repository();
        $id = (int) $wpdb->get_var($wpdb->prepare('SELECT id FROM %i WHERE slug=%s', $repo->facetTable(), 'wc-attribute-' . $attributeId));
        return $id ? $repo->facet($id) : null;
    }

    public function ensure(array $config): void
    {
        $attrs = TableConfiguration::attributes();
        foreach ($config['filters'] as $key) { if (isset($attrs[$key])) { $this->rebuild($attrs[$key]); } }
    }

    public function rebuild(array $attribute): void
    {
        global $wpdb;
        $previous = $wpdb->suppress_errors(true);
        try { $this->rebuildAttribute($attribute); }
        catch (\Throwable $error) { $this->recordSync(true); throw $error; }
        finally { $wpdb->suppress_errors($previous); }
    }

    private function rebuildAttribute(array $attribute): void
    {
        global $wpdb;
        $repo = new Repository(); $facet = $this->facet($attribute['id']);
        $id = $facet ? (int) $facet['id'] : $repo->createFacet($attribute['label'], 'wc-attribute-' . $attribute['id']);
        if (!$id) { throw new \RuntimeException('Cannot create attribute index.'); }
        if ($wpdb->update($repo->facetTable(), ['name' => $attribute['label'], 'enabled' => 0], ['id' => $id]) === false) { throw new \RuntimeException('Cannot update attribute index.'); }
        $terms = get_terms(['taxonomy' => $attribute['taxonomy'], 'hide_empty' => false]);
        if (is_wp_error($terms)) { throw new \RuntimeException('Attribute terms unavailable.'); }
        $map = []; $old = (array) get_option('facetcore_attribute_terms_' . $attribute['id'], []);
        $wpdb->query('START TRANSACTION');
        try {
            foreach ($terms as $term) {
                $value = isset($old[$term->term_id]) ? (int) $old[$term->term_id] : 0;
                $valid = $value && (int) $wpdb->get_var($wpdb->prepare('SELECT COUNT(*) FROM %i WHERE id=%d AND facet_id=%d', $repo->valueTable(), $value, $id));
                $same = (int) $wpdb->get_var($wpdb->prepare('SELECT id FROM %i WHERE facet_id=%d AND label=%s', $repo->valueTable(), $id, $term->name));
                if ($same) { $value = $same; }
                elseif ($valid) { if ($wpdb->update($repo->valueTable(), ['label' => $term->name], ['id' => $value]) === false) { throw new \RuntimeException('Cannot update attribute value.'); } }
                else { $value = $repo->createValue($id, $term->name); }
                if (!$value) { throw new \RuntimeException('Cannot index attribute value.'); }
                $map[$term->term_id] = $value;
            }
            if ($wpdb->delete($repo->productValueTable(), ['facet_id' => $id]) === false) { throw new \RuntimeException('Cannot refresh product attributes.'); }
            foreach ($terms as $term) {
                $sql = $wpdb->prepare("INSERT IGNORE INTO %i (product_id,facet_id,value_id) SELECT r.object_id,%d,%d FROM %i r INNER JOIN %i p ON p.ID=r.object_id WHERE r.term_taxonomy_id=%d AND p.post_type='product'", $repo->productValueTable(), $id, $map[$term->term_id], $wpdb->term_relationships, $wpdb->posts, $term->term_taxonomy_id);
                // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared -- $sql was built by $wpdb->prepare() on the previous line.
                if ($wpdb->query($sql) === false) { throw new \RuntimeException('Cannot index product attributes.'); }
            }
            $keep = array_values(array_unique(array_map('intval', $map))) ?: [0];
            // The placeholder count is generated from the integer ID list; all identifiers and values remain bound.
            $keepPlaceholders = implode(',', array_fill(0, count($keep), '%d'));
            // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQLPlaceholders.ReplacementsWrongNumber -- $keepPlaceholders contains only generated %d placeholders; %i, facet ID and every keep ID are bound below.
            if ($wpdb->query($wpdb->prepare('DELETE FROM %i WHERE facet_id=%d AND id NOT IN (' . $keepPlaceholders . ')', $repo->valueTable(), $id, ...$keep)) === false) { throw new \RuntimeException('Cannot refresh attribute values.'); }
            $wpdb->query('COMMIT');
            update_option('facetcore_attribute_terms_' . $attribute['id'], $map, false);
            $this->recordSync(false);
        } catch (\Throwable $e) { $wpdb->query('ROLLBACK'); throw $e; }
    }

    public function syncProduct(int $productId, ?string $taxonomy = null): void
    {
        if (get_post_type($productId) !== 'product') { return; }
        global $wpdb;
        $repo = new Repository();
        $previousErrors = $wpdb->suppress_errors(true);
        $transaction = false;
        try {
            $attributes = TableConfiguration::attributes();
            $indexed = [];
            $facets = $repo->facets();
            if ($wpdb->last_error !== '') { throw new \RuntimeException('Attribute index unavailable.'); }
            foreach ($facets as $facet) {
                if (strpos($facet['slug'], 'wc-attribute-') !== 0) { continue; }
                $attributeId = (int) substr($facet['slug'], strlen('wc-attribute-'));
                $attribute = $attributes['attribute:' . $attributeId] ?? null;
                if (!$attribute || ($taxonomy !== null && $taxonomy !== $attribute['taxonomy'])) { continue; }
                $indexed[$attribute['taxonomy']] = ['facet' => (int) $facet['id'], 'attribute' => $attributeId];
            }
            if (!$indexed) { return; }
            // One taxonomy read and one existing-assignment read replace per-attribute reads.
            $terms = wp_get_object_terms($productId, array_keys($indexed));
            if (is_wp_error($terms)) { throw new \RuntimeException('Attribute terms unavailable.'); }
            $existing = $repo->productValues($productId);
            $assignments = [];
            foreach ($indexed as $tax => $index) {
                if (isset($existing[$index['facet']]) || $taxonomy === $tax) { $assignments[$index['facet']] = []; }
            }
            foreach ($terms as $term) {
                $index = $indexed[$term->taxonomy];
                $map = (array) get_option('facetcore_attribute_terms_' . $index['attribute'], []);
                if (isset($map[$term->term_id])) { $assignments[$index['facet']][] = (int) $map[$term->term_id]; }
            }
            if (!$assignments) { return; }
            $wpdb->query('START TRANSACTION'); $transaction = true;
            $facetIds = array_map('intval', array_keys($assignments));
            $facetPlaceholders = implode(',', array_fill(0, count($facetIds), '%d'));
            // The placeholder count follows the non-empty assignment facet ID list.
            // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQLPlaceholders.ReplacementsWrongNumber -- $facetPlaceholders contains only generated %d placeholders; %i, product ID and every facet ID are bound below.
            if ($wpdb->query($wpdb->prepare('DELETE FROM %i WHERE product_id=%d AND facet_id IN (' . $facetPlaceholders . ')', $repo->productValueTable(), $productId, ...$facetIds)) === false) { throw new \RuntimeException('Index update failed.'); }
            $rows = [];
            foreach ($assignments as $facetId => $values) {
                foreach (array_unique($values) as $valueId) { $rows[] = [$productId, (int) $facetId, (int) $valueId]; }
            }
            if ($rows) {
                $rowPlaceholders = implode(',', array_fill(0, count($rows), '(%d,%d,%d)'));
                $values = array_merge(...$rows);
                // phpcs:ignore WordPress.DB.PreparedSQL.NotPrepared, WordPress.DB.PreparedSQLPlaceholders.ReplacementsWrongNumber, PluginCheck.Security.DirectDB.UnescapedDBParameter -- $rowPlaceholders is only repeated literal (%d,%d,%d) tuples; the table and all tuple values are bound in this prepare() call.
                if ($wpdb->query($wpdb->prepare('INSERT IGNORE INTO %i (product_id,facet_id,value_id) VALUES ' . $rowPlaceholders, $repo->productValueTable(), ...$values)) === false) { throw new \RuntimeException('Index update failed.'); }
            }
            $wpdb->query('COMMIT'); $transaction = false;
            $this->recordSync(false);
        } catch (\Throwable $error) {
            if ($transaction) { $wpdb->query('ROLLBACK'); }
            $this->recordSync(true);
        } finally { $wpdb->suppress_errors($previousErrors); }
    }

    public function termsAssigned($objectId, $terms, $ttIds, $taxonomy): void
    {
        if (strpos((string) $taxonomy, 'pa_') === 0) { $this->syncProduct((int) $objectId, (string) $taxonomy); }
    }
    public function termChanged($termId, $ttId, $taxonomy): void
    {
        $this->safeSync(function () use ($taxonomy): void {
            foreach (TableConfiguration::attributes() as $attr) { if ($attr['taxonomy'] === $taxonomy && $this->facet($attr['id'])) { $this->rebuild($attr); } }
        });
    }
    public function attributeDeleted($id): void
    {
        $this->safeSync(function () use ($id): void {
            $facet = $this->facet((int) $id);
            if ($facet) { (new Repository())->deleteFacet((int) $facet['id']); }
            delete_option('facetcore_attribute_terms_' . (int) $id);
        });
    }

    public function attributeChanged($id): void
    {
        // WooCommerce finishes renaming taxonomy data before shutdown.
        add_action('shutdown', function () use ($id): void {
            $this->safeSync(function () use ($id): void {
            delete_transient('wc_attribute_taxonomies');
            \WC_Cache_Helper::invalidate_cache_group('woocommerce-attributes');
            foreach (TableConfiguration::attributes() as $attr) { if ($attr['id'] === (int) $id && $this->facet((int) $id)) {
                if (!taxonomy_exists($attr['taxonomy'])) { register_taxonomy($attr['taxonomy'], 'product'); }
                $this->rebuild($attr);
            } }
            });
        });
    }

    private function recordSync(bool $error): void
    {
        // A later successful product save cannot repair a previously failed product.
        // Only a complete explicit rebuild clears an outstanding health warning.
        $previous = (array) get_option('facetcore_sync_status', []);
        update_option('facetcore_sync_status', ['time' => current_time('mysql'), 'error' => $error || !empty($previous['error'])], false);
    }

    private function safeSync(callable $operation): void
    {
        global $wpdb;
        $previous = $wpdb->suppress_errors(true);
        try { $operation(); if ($wpdb->last_error !== '') { $this->recordSync(true); } }
        catch (\Throwable $error) { $this->recordSync(true); }
        finally { $wpdb->suppress_errors($previous); }
    }
}