<?php
/**
 * Category Manipulator class
 *
 * Handles manipulation operations for product categories
 *
 * @since      1.0.0
 * @package    Studiou_WC_Product_Cat_Manage
 * @subpackage Studiou_WC_Product_Cat_Manage/includes
 */

// If this file is called directly, abort.
if (!defined('WPINC')) {
    die;
}

class Studiou_WC_Product_Cat_Manage_Manipulator {
    
    /**
     * Database handler
     *
     * @var Studiou_WC_Product_Cat_Manage_DB
     */
    private $db;
    
    /**
     * Constructor
     *
     * @param Studiou_WC_Product_Cat_Manage_DB $db Database handler
     */
    public function __construct($db) {
        $this->db = $db;
        
        // Register AJAX handlers
        // Legacy single-shot move (v1.0+). Kept for back-compat; JS now uses
        // the batched flow added in v1.7.0.
        add_action('wp_ajax_studiou_wcpcm_move_products', array($this, 'handle_move_products_ajax'));
        // v1.7.0 — M2: batched product move. Mirrors the delete-products
        // pattern: start returns the list of product IDs in the source
        // category; chunk processes 25 IDs per AJAX call. Removes the
        // single-shot timeout on large source categories.
        add_action('wp_ajax_studiou_wcpcm_move_products_start', array($this, 'handle_move_products_start_ajax'));
        add_action('wp_ajax_studiou_wcpcm_move_products_chunk', array($this, 'handle_move_products_chunk_ajax'));
        add_action('wp_ajax_studiou_wcpcm_batch_description', array($this, 'handle_batch_description_ajax'));
        add_action('wp_ajax_studiou_wcpcm_delete_products', array($this, 'handle_delete_products_ajax'));
        add_action('wp_ajax_studiou_wcpcm_delete_products_batch', array($this, 'handle_delete_products_batch_ajax'));
        add_action('wp_ajax_studiou_wcpcm_clear_media', array($this, 'handle_clear_media_ajax'));
        add_action('wp_ajax_studiou_wcpcm_clear_media_batch', array($this, 'handle_clear_media_batch_ajax'));
        add_action('wp_ajax_studiou_wcpcm_remove_unassigned_media', array($this, 'handle_remove_unassigned_media_ajax'));
        add_action('wp_ajax_studiou_wcpcm_remove_unassigned_media_batch', array($this, 'handle_remove_unassigned_media_batch_ajax'));
        add_action('wp_ajax_studiou_wcpcm_upvp_get_attributes', array($this, 'handle_upvp_get_attributes_ajax'));
        add_action('wp_ajax_studiou_wcpcm_upvp_get_attribute_values', array($this, 'handle_upvp_get_attribute_values_ajax'));
        add_action('wp_ajax_studiou_wcpcm_upvp_count', array($this, 'handle_upvp_count_ajax'));
        add_action('wp_ajax_studiou_wcpcm_upvp_apply', array($this, 'handle_upvp_apply_ajax'));

        // Tabbed manipulations page - load a tab partial on demand
        add_action('wp_ajax_studiou_wcpcm_load_tab', array($this, 'handle_load_tab_ajax'));

        // Invalidate the cached category/media counts whenever categories or
        // product <-> category relationships change.
        add_action('created_term', array($this, 'bust_count_cache'));
        add_action('edited_term', array($this, 'bust_count_cache'));
        add_action('delete_term', array($this, 'bust_count_cache'));
        add_action('set_object_terms', array($this, 'bust_count_cache'));
        add_action('deleted_term_relationships', array($this, 'bust_count_cache'));

        // Add a test AJAX handler to verify AJAX is working
        add_action('wp_ajax_studiou_wcpcm_test', array($this, 'handle_test_ajax'));

        // Debug: Log that the handler is being registered
        if (defined('WP_DEBUG') && WP_DEBUG) {
            error_log('STUDIOU WC: AJAX handlers registered - move_products, batch_description, delete_products, and clear_media');
        }
    }

    /**
     * Invalidate the cached category / media-category count data.
     *
     * Hooked to term and term-relationship changes so the counts shown on the
     * manipulations tabs stay accurate.
     */
    public function bust_count_cache() {
        delete_transient('studiou_wcpcm_category_counts');
        delete_transient('studiou_wcpcm_media_cat_counts');
    }

    /**
     * Handle AJAX request to render a Category Manipulations tab partial.
     *
     * Each tab partial fetches only its own data, so the manipulations page
     * shell can render instantly and heavy calculations run on demand.
     */
    public function handle_load_tab_ajax() {
        // Clean any output buffers to prevent JSON corruption
        while (ob_get_level()) {
            ob_end_clean();
        }

        // Check nonce
        if (!isset($_POST['nonce']) || !wp_verify_nonce($_POST['nonce'], 'studiou-wcpcm-nonce')) {
            wp_send_json_error(array(
                'message' => __('Security check failed', 'studiou-wc-product-cat-manage')
            ));
            return;
        }

        // Check permissions
        if (!current_user_can('manage_woocommerce')) {
            wp_send_json_error(array(
                'message' => __('You do not have sufficient permissions', 'studiou-wc-product-cat-manage')
            ));
            return;
        }

        $tab = isset($_POST['tab']) ? sanitize_key($_POST['tab']) : '';
        $allowed = array('move', 'batch-description', 'delete-products', 'clear-media', 'remove-unassigned', 'upvp', 'notes');

        if (!in_array($tab, $allowed, true)) {
            wp_send_json_error(array(
                'message' => __('Unknown tab', 'studiou-wc-product-cat-manage')
            ));
            return;
        }

        $partial = STUDIOU_WCPCM_PLUGIN_DIR . 'views/manipulations/tab-' . $tab . '.php';

        if (!file_exists($partial)) {
            wp_send_json_error(array(
                'message' => __('Tab content not found', 'studiou-wc-product-cat-manage')
            ));
            return;
        }

        // Made available to the partial; each partial fetches only what it needs.
        $manipulator = $this;

        try {
            ob_start();
            include $partial;
            $html = ob_get_clean();

            wp_send_json_success(array(
                'tab' => $tab,
                'html' => $html
            ));
        } catch (Exception $e) {
            if (ob_get_level()) {
                ob_end_clean();
            }
            error_log('STUDIOU WC TABS: tab "' . $tab . '" render failed: ' . $e->getMessage());
            wp_send_json_error(array('message' => $e->getMessage()));
        }
    }


    /**
     * Handle AJAX batch description request
     */
    public function handle_batch_description_ajax() {
        // Clean all output buffers and prevent any output
        while (ob_get_level()) {
            ob_end_clean();
        }
        
        // Start a new output buffer to catch any unwanted output
        ob_start();
        
        // Suppress PHP errors/notices during AJAX to prevent JSON corruption
        $original_error_reporting = error_reporting();
        error_reporting(0);
        
        // Enable error logging only
        if (defined('WP_DEBUG') && WP_DEBUG) {
            error_log('STUDIOU WC: Batch description AJAX handler called');
            error_log('STUDIOU WC: POST data: ' . print_r($_POST, true));
        }
        
        try {
            // Check nonce
            if (!isset($_POST['nonce']) || !wp_verify_nonce($_POST['nonce'], 'studiou-wcpcm-nonce')) {
                wp_send_json_error(array(
                    'message' => __('Security check failed', 'studiou-wc-product-cat-manage')
                ));
            }
            
            // Check permissions
            if (!current_user_can('manage_woocommerce')) {
                wp_send_json_error(array(
                    'message' => __('You do not have sufficient permissions', 'studiou-wc-product-cat-manage')
                ));
            }
            
            // Validate input
            if (!isset($_POST['selected_categories']) || !isset($_POST['description'])) {
                wp_send_json_error(array(
                    'message' => __('Missing required parameters', 'studiou-wc-product-cat-manage')
                ));
            }
            
            $selected_categories = array_map('intval', $_POST['selected_categories']);
            $description = sanitize_textarea_field($_POST['description']);
            
            // Debug logging
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('STUDIOU WC: Batch description operation started - Categories: ' . implode(', ', $selected_categories));
                error_log('STUDIOU WC: Description: ' . $description);
            }
            
            // Validate categories
            if (empty($selected_categories)) {
                wp_send_json_error(array(
                    'message' => __('Please select at least one category', 'studiou-wc-product-cat-manage')
                ));
            }
            
            // Execute batch description operation
            $result = $this->update_categories_description($selected_categories, $description);
            
            // Debug logging
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('STUDIOU WC: Batch description operation completed - Updated: ' . $result['updated_count'] . ' categories');
                error_log('STUDIOU WC: Sending success response: ' . print_r($result, true));
            }
            
            // Clean any output that might have been generated
            ob_clean();
            
            // Return success response
            wp_send_json_success(array(
                'message' => $result['message'],
                'updated_count' => $result['updated_count'],
                'failed_count' => isset($result['failed_count']) ? $result['failed_count'] : 0
            ));
            
        } catch (Exception $e) {
            // Debug logging
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('STUDIOU WC: Batch description operation failed - ' . $e->getMessage());
                error_log('STUDIOU WC: Exception trace: ' . $e->getTraceAsString());
            }
            
            // Clean any output that might have been generated
            ob_clean();
            
            wp_send_json_error(array(
                'message' => sprintf(
                    __('Error during batch description operation: %s', 'studiou-wc-product-cat-manage'),
                    $e->getMessage()
                )
            ));
        } finally {
            // Restore original error reporting
            error_reporting($original_error_reporting);
            
            // End the output buffer
            ob_end_clean();
        }
    }
    
    /**
     * Handle AJAX move products request
     */
    public function handle_move_products_ajax() {
        // Clean all output buffers and prevent any output
        while (ob_get_level()) {
            ob_end_clean();
        }
        
        // Start a new output buffer to catch any unwanted output
        ob_start();
        
        // Suppress PHP errors/notices during AJAX to prevent JSON corruption
        $original_error_reporting = error_reporting();
        error_reporting(0);
        
        // Enable error logging only
        if (defined('WP_DEBUG') && WP_DEBUG) {
            error_log('STUDIOU WC: AJAX handler called');
            error_log('STUDIOU WC: POST data: ' . print_r($_POST, true));
        }
        
        try {
            // Check nonce
            if (!isset($_POST['nonce']) || !wp_verify_nonce($_POST['nonce'], 'studiou-wcpcm-nonce')) {
                wp_send_json_error(array(
                    'message' => __('Security check failed', 'studiou-wc-product-cat-manage')
                ));
            }
            
            // Check permissions
            if (!current_user_can('manage_woocommerce')) {
                wp_send_json_error(array(
                    'message' => __('You do not have sufficient permissions', 'studiou-wc-product-cat-manage')
                ));
            }
            
            // Validate input
            if (!isset($_POST['source_category']) || !isset($_POST['target_category'])) {
                wp_send_json_error(array(
                    'message' => __('Missing required parameters', 'studiou-wc-product-cat-manage')
                ));
            }
            
            $source_category_id = intval($_POST['source_category']);
            $target_category_id = intval($_POST['target_category']);
            
            // Debug logging
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('STUDIOU WC: Move operation started - Source: ' . $source_category_id . ', Target: ' . $target_category_id);
            }
            
            // Validate categories
            if ($source_category_id === $target_category_id) {
                wp_send_json_error(array(
                    'message' => __('Source and target categories must be different', 'studiou-wc-product-cat-manage')
                ));
            }
            
            if ($source_category_id <= 0 || $target_category_id <= 0) {
                wp_send_json_error(array(
                    'message' => __('Invalid category selection', 'studiou-wc-product-cat-manage')
                ));
            }
            
            // Execute move operation
            $result = $this->move_products_between_categories($source_category_id, $target_category_id);
            
            // Debug logging
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('STUDIOU WC: Move operation completed - Moved: ' . $result['moved_count'] . ' products');
                error_log('STUDIOU WC: Sending success response: ' . print_r($result, true));
            }
            
            // Clean any output that might have been generated
            ob_clean();
            
            // Return success response
            wp_send_json_success(array(
                'message' => $result['message'],
                'moved_count' => $result['moved_count'],
                'source_count' => $result['source_count'],
                'target_count' => $result['target_count'],
                'failed_count' => isset($result['failed_count']) ? $result['failed_count'] : 0
            ));
            
        } catch (Exception $e) {
            // Debug logging
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('STUDIOU WC: Move operation failed - ' . $e->getMessage());
                error_log('STUDIOU WC: Exception trace: ' . $e->getTraceAsString());
            }
            
            // Clean any output that might have been generated
            ob_clean();
            
            wp_send_json_error(array(
                'message' => sprintf(
                    __('Error during move operation: %s', 'studiou-wc-product-cat-manage'),
                    $e->getMessage()
                )
            ));
        } finally {
            // Restore original error reporting
            error_reporting($original_error_reporting);
            
            // End the output buffer
            ob_end_clean();
        }
    }
    
    /**
     * v1.7.0 — M2: batched product move, step 1 (start).
     *
     * Returns the list of product IDs in the source category. JS chunks
     * them and calls handle_move_products_chunk_ajax in batches.
     */
    public function handle_move_products_start_ajax() {
        while (ob_get_level()) { ob_end_clean(); }

        if (!isset($_POST['nonce']) || !wp_verify_nonce($_POST['nonce'], 'studiou-wcpcm-nonce')) {
            wp_send_json_error(array('message' => __('Security check failed', 'studiou-wc-product-cat-manage')));
        }
        if (!current_user_can('manage_woocommerce')) {
            wp_send_json_error(array('message' => __('You do not have sufficient permissions', 'studiou-wc-product-cat-manage')));
        }

        $source = isset($_POST['source_category']) ? intval($_POST['source_category']) : 0;
        $target = isset($_POST['target_category']) ? intval($_POST['target_category']) : 0;

        if ($source <= 0 || $target <= 0) {
            wp_send_json_error(array('message' => __('Invalid category selection', 'studiou-wc-product-cat-manage')));
        }
        if ($source === $target) {
            wp_send_json_error(array('message' => __('Source and target categories must be different', 'studiou-wc-product-cat-manage')));
        }

        $source_term = get_term($source, 'product_cat');
        $target_term = get_term($target, 'product_cat');
        if (is_wp_error($source_term) || !$source_term || is_wp_error($target_term) || !$target_term) {
            wp_send_json_error(array('message' => __('Invalid category specified', 'studiou-wc-product-cat-manage')));
        }

        $product_ids = $this->get_products_in_category($source);
        wp_send_json_success(array(
            'product_ids' => array_values(array_map('intval', $product_ids)),
            'total'       => count($product_ids),
            'source_name' => $source_term->name,
            'target_name' => $target_term->name,
        ));
    }

    /**
     * v1.7.0 — M2: batched product move, step 2 (chunk).
     *
     * Moves the supplied product IDs from source to target category.
     * wp_set_post_terms is idempotent, so a re-run of an already-moved
     * chunk (e.g. after a network retry) is safe.
     */
    public function handle_move_products_chunk_ajax() {
        while (ob_get_level()) { ob_end_clean(); }

        if (!isset($_POST['nonce']) || !wp_verify_nonce($_POST['nonce'], 'studiou-wcpcm-nonce')) {
            wp_send_json_error(array('message' => __('Security check failed', 'studiou-wc-product-cat-manage')));
        }
        if (!current_user_can('manage_woocommerce')) {
            wp_send_json_error(array('message' => __('You do not have sufficient permissions', 'studiou-wc-product-cat-manage')));
        }

        $source = isset($_POST['source_category']) ? intval($_POST['source_category']) : 0;
        $target = isset($_POST['target_category']) ? intval($_POST['target_category']) : 0;
        $ids    = isset($_POST['product_ids']) && is_array($_POST['product_ids'])
                    ? array_values(array_map('intval', $_POST['product_ids']))
                    : array();

        if ($source <= 0 || $target <= 0 || $source === $target || empty($ids)) {
            wp_send_json_error(array('message' => __('Invalid request', 'studiou-wc-product-cat-manage')));
        }

        $moved = 0;
        $failed = 0;
        foreach ($ids as $pid) {
            $current = wp_get_post_terms($pid, 'product_cat', array('fields' => 'ids'));
            if (is_wp_error($current)) {
                $failed++;
                continue;
            }
            $new = array_diff($current, array($source));
            $new[] = $target;
            $new = array_values(array_unique($new));
            $r = wp_set_post_terms($pid, $new, 'product_cat');
            if (is_wp_error($r)) {
                $failed++;
            } else {
                $moved++;
            }
        }

        wp_send_json_success(array(
            'moved'  => $moved,
            'failed' => $failed,
        ));
    }

    /**
     * Move all products from source category to target category
     *
     * @param int $source_category_id Source category ID
     * @param int $target_category_id Target category ID
     * @return array Result with counts and message
     * @throws Exception On error
     */
    public function move_products_between_categories($source_category_id, $target_category_id) {
        // Get source and target category terms
        $source_category = get_term($source_category_id, 'product_cat');
        $target_category = get_term($target_category_id, 'product_cat');
        
        if (is_wp_error($source_category) || is_wp_error($target_category)) {
            throw new Exception(__('Invalid category specified', 'studiou-wc-product-cat-manage'));
        }
        
        // Get initial count of products in source category using direct DB query
        $initial_source_count = $this->get_category_product_count($source_category_id);
        
        // Check if source category has any products
        if ($initial_source_count === 0) {
            $message = sprintf(
                __('No products found in source category "%s". Nothing to move.', 'studiou-wc-product-cat-manage'),
                $source_category->name
            );
            
            return array(
                'moved_count' => 0,
                'source_count' => 0,
                'target_count' => $this->get_category_product_count($target_category_id),
                'message' => $message
            );
        }
        
        // Get all products in source category using direct DB query
        $products = $this->get_products_in_category($source_category_id);
        $moved_count = 0;
        $failed_count = 0;
        
        if (defined('WP_DEBUG') && WP_DEBUG) {
            error_log('STUDIOU WC: Found ' . count($products) . ' products in category ' . $source_category->name . ' for moving');
        }
        
        // Move each product
        foreach ($products as $product_id) {
            // Get current categories for the product
            $current_categories = wp_get_post_terms($product_id, 'product_cat', array('fields' => 'ids'));
            
            if (is_wp_error($current_categories)) {
                $failed_count++;
                if (defined('WP_DEBUG') && WP_DEBUG) {
                    error_log('STUDIOU WC: Error getting categories for product ' . $product_id . ': ' . $current_categories->get_error_message());
                }
                continue;
            }
            
            // Remove source category and add target category
            $new_categories = array_diff($current_categories, array($source_category_id));
            $new_categories[] = $target_category_id;
            
            // Update product categories
            $result = wp_set_post_terms($product_id, $new_categories, 'product_cat');
            
            if (!is_wp_error($result)) {
                $moved_count++;
                if (defined('WP_DEBUG') && WP_DEBUG) {
                    error_log('STUDIOU WC: Successfully moved product ' . $product_id . ' from category ' . $source_category_id . ' to ' . $target_category_id);
                }
            } else {
                $failed_count++;
                if (defined('WP_DEBUG') && WP_DEBUG) {
                    error_log('STUDIOU WC: Error moving product ' . $product_id . ': ' . $result->get_error_message());
                }
            }
        }
        
        // Get updated counts using direct DB query
        $source_count = $this->get_category_product_count($source_category_id);
        $target_count = $this->get_category_product_count($target_category_id);
        
        // Generate detailed result message
        if ($moved_count === 0 && count($products) > 0) {
            $message = sprintf(
                __('Failed to move any products from "%s" to "%s". All %d products encountered errors during the move operation.', 'studiou-wc-product-cat-manage'),
                $source_category->name,
                $target_category->name,
                count($products)
            );
        } else {
            $message = sprintf(
                __('Moved %d products from "%s" to "%s". Source category now has %d products, target category now has %d products.', 'studiou-wc-product-cat-manage'),
                $moved_count,
                $source_category->name,
                $target_category->name,
                $source_count,
                $target_count
            );
            
            if ($failed_count > 0) {
                $message .= ' ' . sprintf(
                    __('Note: %d products failed to move due to errors.', 'studiou-wc-product-cat-manage'),
                    $failed_count
                );
            }
        }
        
        return array(
            'moved_count' => $moved_count,
            'source_count' => $source_count,
            'target_count' => $target_count,
            'failed_count' => $failed_count,
            'message' => $message
        );
    }
    
    /**
     * Get product count for a category
     *
     * @param int $category_id Category ID
     * @return int Product count
     */
    private function get_category_product_count($category_id) {
        global $wpdb;
        
        // Use direct database query for more accurate counting
        $sql = "
            SELECT COUNT(DISTINCT p.ID) 
            FROM {$wpdb->posts} p
            INNER JOIN {$wpdb->term_relationships} tr ON p.ID = tr.object_id
            INNER JOIN {$wpdb->term_taxonomy} tt ON tr.term_taxonomy_id = tt.term_taxonomy_id
            WHERE tt.term_id = %d 
            AND tt.taxonomy = 'product_cat'
            AND p.post_type = 'product'
            AND p.post_status IN ('publish', 'private', 'draft')
        ";
        
        $count = $wpdb->get_var($wpdb->prepare($sql, $category_id));
        
        if (defined('WP_DEBUG') && WP_DEBUG) {
            error_log('STUDIOU WC: Category ' . $category_id . ' product count (direct DB query): ' . intval($count));
        }
        
        return intval($count);
    }
    
    /**
     * Get all products in a category
     *
     * @param int $category_id Category ID
     * @return array Array of product IDs
     */
    private function get_products_in_category($category_id) {
        global $wpdb;
        
        // Use direct database query to get products
        $sql = "
            SELECT DISTINCT p.ID 
            FROM {$wpdb->posts} p
            INNER JOIN {$wpdb->term_relationships} tr ON p.ID = tr.object_id
            INNER JOIN {$wpdb->term_taxonomy} tt ON tr.term_taxonomy_id = tt.term_taxonomy_id
            WHERE tt.term_id = %d 
            AND tt.taxonomy = 'product_cat'
            AND p.post_type = 'product'
            AND p.post_status IN ('publish', 'private', 'draft')
        ";
        
        $products = $wpdb->get_col($wpdb->prepare($sql, $category_id));
        
        if (defined('WP_DEBUG') && WP_DEBUG) {
            error_log('STUDIOU WC: Found ' . count($products) . ' products in category ' . $category_id . ' (direct DB query)');
            if (!empty($products)) {
                error_log('STUDIOU WC: Product IDs: ' . implode(', ', array_slice($products, 0, 10)) . (count($products) > 10 ? ' (showing first 10)' : ''));
            }
        }
        
        return $products ? array_map('intval', $products) : array();
    }
    
    /**
     * Update descriptions for multiple categories
     *
     * @param array $category_ids Array of category IDs
     * @param string $description New description for categories
     * @return array Result with counts and message
     * @throws Exception On error
     */
    public function update_categories_description($category_ids, $description) {
        $updated_count = 0;
        $failed_count = 0;
        $category_names = array();
        
        // Debug logging
        if (defined('WP_DEBUG') && WP_DEBUG) {
            error_log('STUDIOU WC: Starting batch description update for ' . count($category_ids) . ' categories');
        }
        
        // Update each category
        foreach ($category_ids as $category_id) {
            // Get category term
            $category = get_term($category_id, 'product_cat');
            
            if (is_wp_error($category) || !$category) {
                $failed_count++;
                if (defined('WP_DEBUG') && WP_DEBUG) {
                    error_log('STUDIOU WC: Error getting category ' . $category_id . ': ' . ($category ? $category->get_error_message() : 'Category not found'));
                }
                continue;
            }
            
            // Update category description
            $result = wp_update_term($category_id, 'product_cat', array(
                'description' => $description
            ));
            
            if (!is_wp_error($result)) {
                $updated_count++;
                $category_names[] = $category->name;
                if (defined('WP_DEBUG') && WP_DEBUG) {
                    error_log('STUDIOU WC: Successfully updated description for category ' . $category_id . ' (' . $category->name . ')');
                }
            } else {
                $failed_count++;
                if (defined('WP_DEBUG') && WP_DEBUG) {
                    error_log('STUDIOU WC: Error updating category ' . $category_id . ': ' . $result->get_error_message());
                }
            }
        }
        
        // Generate result message
        if ($updated_count === 0) {
            $message = sprintf(
                __('Failed to update any category descriptions. %d categories encountered errors.', 'studiou-wc-product-cat-manage'),
                $failed_count
            );
        } else {
            $message = sprintf(
                __('Successfully updated descriptions for %d categories: %s', 'studiou-wc-product-cat-manage'),
                $updated_count,
                implode(', ', array_slice($category_names, 0, 5)) . ($updated_count > 5 ? sprintf(__(', and %d more', 'studiou-wc-product-cat-manage'), $updated_count - 5) : '')
            );
            
            if ($failed_count > 0) {
                $message .= ' ' . sprintf(
                    __('Note: %d categories failed to update due to errors.', 'studiou-wc-product-cat-manage'),
                    $failed_count
                );
            }
        }
        
        return array(
            'updated_count' => $updated_count,
            'failed_count' => $failed_count,
            'message' => $message
        );
    }
    
    /**
     * Get all categories with product counts for select lists.
     *
     * Transient-cached wrapper around get_categories_with_counts_uncached().
     * The N+1 per-category count queries are expensive on large stores, so the
     * result is cached for 5 minutes and busted on any category change.
     *
     * @return array Array of categories with ID, name, and product count
     */
    public function get_categories_with_counts() {
        $data = get_transient('studiou_wcpcm_category_counts');

        if (false === $data) {
            $data = $this->get_categories_with_counts_uncached();
            set_transient('studiou_wcpcm_category_counts', $data, 5 * MINUTE_IN_SECONDS);
        }

        return $data;
    }

    /**
     * Get all categories with product counts for select lists (uncached).
     *
     * Queries the product_cat terms directly via $wpdb instead of get_terms()
     * on purpose: the WooCommerce Protected Categories plugin filters
     * get_terms() and hides protected categories in admin-ajax / front-end
     * contexts. Since v1.6.0 the manipulations tabs fetch this list inside an
     * admin-ajax request, so get_terms() would drop protected categories from
     * the dropdowns. Admins must be able to see and operate on every category,
     * protected ones included, so we bypass the term-query filters entirely.
     *
     * @return array Array of categories with ID, name, and product count
     */
    public function get_categories_with_counts_uncached() {
        global $wpdb;

        // v1.7.1 — M9: replace the per-category get_category_product_count()
        // loop (N+1) with a single aggregate query. The naive
        // term_relationships count would over-count trashed/pending/
        // auto-draft products because trashing a product does NOT remove
        // its term relationship — a category emptied via "Delete products
        // in category" could still display a non-zero count. So we JOIN
        // wp_posts and apply the SAME filters get_category_product_count()
        // uses (post_type='product', post_status IN publish/private/draft),
        // with the filters in the ON clause so zero-count categories
        // survive the LEFT JOIN.
        $sql = $wpdb->prepare("
            SELECT t.term_id, t.name, COUNT(DISTINCT p.ID) AS cnt
            FROM {$wpdb->terms} t
            INNER JOIN {$wpdb->term_taxonomy} tt ON t.term_id = tt.term_id
            LEFT JOIN {$wpdb->term_relationships} tr ON tr.term_taxonomy_id = tt.term_taxonomy_id
            LEFT JOIN {$wpdb->posts} p
                ON p.ID = tr.object_id
               AND p.post_type = %s
               AND p.post_status IN ('publish','private','draft')
            WHERE tt.taxonomy = %s
            GROUP BY t.term_id, t.name
            ORDER BY t.name ASC
        ", 'product', 'product_cat');

        $rows = $wpdb->get_results($sql);

        $categories_with_counts = array();
        if (!empty($rows)) {
            foreach ($rows as $row) {
                $count = (int) $row->cnt;
                $categories_with_counts[] = array(
                    'id' => (int) $row->term_id,
                    'name' => $row->name,
                    'count' => $count,
                    'display_name' => sprintf('%s (%d products)', $row->name, $count),
                );
            }
        }

        return $categories_with_counts;
    }

    /**
     * Handle AJAX delete products request (initial request to get product IDs)
     */
    public function handle_delete_products_ajax() {
        // Clean all output buffers and prevent any output
        while (ob_get_level()) {
            ob_end_clean();
        }

        // Start a new output buffer to catch any unwanted output
        ob_start();

        // Suppress PHP errors/notices during AJAX to prevent JSON corruption
        $original_error_reporting = error_reporting();
        error_reporting(0);

        // Enable error logging only
        if (defined('WP_DEBUG') && WP_DEBUG) {
            error_log('STUDIOU WC: Delete products AJAX handler called');
            error_log('STUDIOU WC: POST data: ' . print_r($_POST, true));
        }

        try {
            // Check nonce
            if (!isset($_POST['nonce']) || !wp_verify_nonce($_POST['nonce'], 'studiou-wcpcm-nonce')) {
                wp_send_json_error(array(
                    'message' => __('Security check failed', 'studiou-wc-product-cat-manage')
                ));
            }

            // Check permissions
            if (!current_user_can('manage_woocommerce')) {
                wp_send_json_error(array(
                    'message' => __('You do not have sufficient permissions', 'studiou-wc-product-cat-manage')
                ));
            }

            // Validate input
            if (!isset($_POST['delete_categories'])) {
                wp_send_json_error(array(
                    'message' => __('Missing required parameters', 'studiou-wc-product-cat-manage')
                ));
            }

            $category_ids = array_map('intval', $_POST['delete_categories']);

            // Debug logging
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('STUDIOU WC: Delete products operation started - Categories: ' . implode(', ', $category_ids));
            }

            // Validate categories
            if (empty($category_ids)) {
                wp_send_json_error(array(
                    'message' => __('Please select at least one category', 'studiou-wc-product-cat-manage')
                ));
            }

            // Get all products from selected categories
            $product_ids = $this->get_products_from_categories($category_ids);

            // Debug logging
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('STUDIOU WC: Found ' . count($product_ids) . ' products to delete');
            }

            // Clean any output that might have been generated
            ob_clean();

            // Return product IDs for batch processing
            wp_send_json_success(array(
                'product_ids' => $product_ids,
                'total_count' => count($product_ids),
                'message' => sprintf(
                    __('Found %d products to delete', 'studiou-wc-product-cat-manage'),
                    count($product_ids)
                )
            ));

        } catch (Exception $e) {
            // Debug logging
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('STUDIOU WC: Delete products operation failed - ' . $e->getMessage());
                error_log('STUDIOU WC: Exception trace: ' . $e->getTraceAsString());
            }

            // Clean any output that might have been generated
            ob_clean();

            wp_send_json_error(array(
                'message' => sprintf(
                    __('Error during delete operation: %s', 'studiou-wc-product-cat-manage'),
                    $e->getMessage()
                )
            ));
        } finally {
            // Restore original error reporting
            error_reporting($original_error_reporting);

            // End the output buffer
            ob_end_clean();
        }
    }

    /**
     * Handle AJAX delete products batch request (processes products in batches)
     */
    public function handle_delete_products_batch_ajax() {
        // Clean all output buffers and prevent any output
        while (ob_get_level()) {
            ob_end_clean();
        }

        // Start a new output buffer to catch any unwanted output
        ob_start();

        // Suppress PHP errors/notices during AJAX to prevent JSON corruption
        $original_error_reporting = error_reporting();
        error_reporting(0);

        // Enable error logging only
        if (defined('WP_DEBUG') && WP_DEBUG) {
            error_log('STUDIOU WC: Delete products batch AJAX handler called');
            error_log('STUDIOU WC: POST data: ' . print_r($_POST, true));
        }

        try {
            // Check nonce
            if (!isset($_POST['nonce']) || !wp_verify_nonce($_POST['nonce'], 'studiou-wcpcm-nonce')) {
                wp_send_json_error(array(
                    'message' => __('Security check failed', 'studiou-wc-product-cat-manage')
                ));
            }

            // Check permissions
            if (!current_user_can('manage_woocommerce')) {
                wp_send_json_error(array(
                    'message' => __('You do not have sufficient permissions', 'studiou-wc-product-cat-manage')
                ));
            }

            // Validate input
            if (!isset($_POST['product_ids'])) {
                wp_send_json_error(array(
                    'message' => __('Missing required parameters', 'studiou-wc-product-cat-manage')
                ));
            }

            $product_ids = array_map('intval', $_POST['product_ids']);

            // Debug logging
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('STUDIOU WC: Processing batch of ' . count($product_ids) . ' products for deletion');
            }

            // Delete products in this batch
            $result = $this->delete_products_batch($product_ids);

            // Debug logging
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('STUDIOU WC: Batch deletion completed - Deleted: ' . $result['deleted_count'] . ', Failed: ' . $result['failed_count']);
            }

            // Clean any output that might have been generated
            ob_clean();

            // Return success response
            wp_send_json_success(array(
                'deleted_count' => $result['deleted_count'],
                'failed_count' => $result['failed_count'],
                'failed_products' => $result['failed_products']
            ));

        } catch (Exception $e) {
            // Debug logging
            if (defined('WP_DEBUG') && WP_DEBUG) {
                error_log('STUDIOU WC: Delete products batch operation failed - ' . $e->getMessage());
                error_log('STUDIOU WC: Exception trace: ' . $e->getTraceAsString());
            }

            // Clean any output that might have been generated
            ob_clean();

            wp_send_json_error(array(
                'message' => sprintf(
                    __('Error during delete batch operation: %s', 'studiou-wc-product-cat-manage'),
                    $e->getMessage()
                )
            ));
        } finally {
            // Restore original error reporting
            error_reporting($original_error_reporting);

            // End the output buffer
            ob_end_clean();
        }
    }

    /**
     * Get all products from multiple categories
     *
     * @param array $category_ids Array of category IDs
     * @return array Array of unique product IDs (including parent products with variants)
     */
    private function get_products_from_categories($category_ids) {
        global $wpdb;

        if (empty($category_ids)) {
            return array();
        }

        $placeholders = implode(',', array_fill(0, count($category_ids), '%d'));

        // Get all products from selected categories (both simple and parent products)
        $sql = "
            SELECT DISTINCT p.ID
            FROM {$wpdb->posts} p
            INNER JOIN {$wpdb->term_relationships} tr ON p.ID = tr.object_id
            INNER JOIN {$wpdb->term_taxonomy} tt ON tr.term_taxonomy_id = tt.term_taxonomy_id
            WHERE tt.term_id IN ($placeholders)
            AND tt.taxonomy = 'product_cat'
            AND p.post_type = 'product'
            AND p.post_status IN ('publish', 'private', 'draft', 'pending', 'trash')
        ";

        $products = $wpdb->get_col($wpdb->prepare($sql, $category_ids));

        if (defined('WP_DEBUG') && WP_DEBUG) {
            error_log('STUDIOU WC: Found ' . count($products) . ' products in categories ' . implode(', ', $category_ids));
        }

        return $products ? array_map('intval', $products) : array();
    }

    /**
     * Delete a batch of products and their variants
     *
     * @param array $product_ids Array of product IDs to delete
     * @return array Result with counts
     */
    private function delete_products_batch($product_ids) {
        $deleted_count = 0;
        $failed_count = 0;
        $failed_products = array();

        foreach ($product_ids as $product_id) {
            try {
                // Get the product object
                $product = wc_get_product($product_id);

                if (!$product) {
                    $failed_count++;
                    $failed_products[] = $product_id;
                    if (defined('WP_DEBUG') && WP_DEBUG) {
                        error_log('STUDIOU WC: Product ' . $product_id . ' not found');
                    }
                    continue;
                }

                // If it's a variable product, delete all variations first
                if ($product->is_type('variable')) {
                    $variations = $product->get_children();
                    if (defined('WP_DEBUG') && WP_DEBUG) {
                        error_log('STUDIOU WC: Deleting ' . count($variations) . ' variations for product ' . $product_id);
                    }

                    foreach ($variations as $variation_id) {
                        $variation = wc_get_product($variation_id);
                        if ($variation) {
                            $variation->delete(true); // true = force delete permanently
                        }
                    }
                }

                // Delete the product permanently
                $result = $product->delete(true); // true = force delete permanently

                if ($result) {
                    $deleted_count++;
                    if (defined('WP_DEBUG') && WP_DEBUG) {
                        error_log('STUDIOU WC: Successfully deleted product ' . $product_id);
                    }
                } else {
                    $failed_count++;
                    $failed_products[] = $product_id;
                    if (defined('WP_DEBUG') && WP_DEBUG) {
                        error_log('STUDIOU WC: Failed to delete product ' . $product_id);
                    }
                }

            } catch (Exception $e) {
                $failed_count++;
                $failed_products[] = $product_id;
                if (defined('WP_DEBUG') && WP_DEBUG) {
                    error_log('STUDIOU WC: Exception deleting product ' . $product_id . ': ' . $e->getMessage());
                }
            }
        }

        return array(
            'deleted_count' => $deleted_count,
            'failed_count' => $failed_count,
            'failed_products' => $failed_products
        );
    }

    /**
     * Get all media categories with file counts for select lists.
     *
     * Transient-cached wrapper around get_media_categories_with_counts_uncached().
     *
     * @return array Array of media categories with ID, name, and file count
     */
    public function get_media_categories_with_counts() {
        $data = get_transient('studiou_wcpcm_media_cat_counts');

        if (false === $data) {
            $data = $this->get_media_categories_with_counts_uncached();
            set_transient('studiou_wcpcm_media_cat_counts', $data, 5 * MINUTE_IN_SECONDS);
        }

        return $data;
    }

    /**
     * Get all media categories with file counts for select lists (uncached).
     *
     * @return array Array of media categories with ID, name, and file count
     */
    public function get_media_categories_with_counts_uncached() {
        $taxonomy = $this->get_media_category_taxonomy();

        if (!$taxonomy) {
            return array();
        }

        $args = array(
            'taxonomy' => $taxonomy,
            'orderby' => 'name',
            'hide_empty' => false,
        );

        $categories = get_terms($args);
        $categories_with_counts = array();

        if (!is_wp_error($categories)) {
            foreach ($categories as $category) {
                $file_count = $this->get_media_category_file_count($category->term_id, $taxonomy);

                $categories_with_counts[] = array(
                    'id' => $category->term_id,
                    'name' => $category->name,
                    'count' => $file_count,
                    'display_name' => sprintf('%s (%d %s)', $category->name, $file_count, __('files', 'studiou-wc-product-cat-manage'))
                );
            }
        }

        return $categories_with_counts;
    }

    /**
     * Get the media category taxonomy name
     *
     * Checks for common media category taxonomies used by popular plugins
     *
     * @return string|false Taxonomy name or false if none found
     */
    private function get_media_category_taxonomy() {
        $possible_taxonomies = array(
            'media_category',
            'attachment_category',
            'media-category',
        );

        foreach ($possible_taxonomies as $taxonomy) {
            if (taxonomy_exists($taxonomy)) {
                error_log('STUDIOU WC MEDIA: Detected media taxonomy: ' . $taxonomy);
                return $taxonomy;
            }
        }

        // Try to find any taxonomy registered for attachments
        $attachment_taxonomies = get_object_taxonomies('attachment', 'names');
        if (!empty($attachment_taxonomies)) {
            // Filter out built-in taxonomies
            $custom_taxonomies = array_filter($attachment_taxonomies, function($tax) {
                return !in_array($tax, array('post_tag', 'category', 'post_format'));
            });
            if (!empty($custom_taxonomies)) {
                $found = reset($custom_taxonomies);
                error_log('STUDIOU WC MEDIA: Auto-detected attachment taxonomy: ' . $found);
                return $found;
            }
        }

        error_log('STUDIOU WC MEDIA: No media category taxonomy found. Registered attachment taxonomies: ' . implode(', ', $attachment_taxonomies ?? array()));
        return false;
    }

    /**
     * Get file count for a media category
     *
     * @param int $category_id Category term ID
     * @param string $taxonomy Taxonomy name
     * @return int File count
     */
    private function get_media_category_file_count($category_id, $taxonomy) {
        global $wpdb;

        $sql = "
            SELECT COUNT(DISTINCT p.ID)
            FROM {$wpdb->posts} p
            INNER JOIN {$wpdb->term_relationships} tr ON p.ID = tr.object_id
            INNER JOIN {$wpdb->term_taxonomy} tt ON tr.term_taxonomy_id = tt.term_taxonomy_id
            WHERE tt.term_id = %d
            AND tt.taxonomy = %s
            AND p.post_type = 'attachment'
        ";

        $count = $wpdb->get_var($wpdb->prepare($sql, $category_id, $taxonomy));

        return intval($count);
    }

    /**
     * Get all media IDs from multiple media categories
     *
     * @param array $category_ids Array of category term IDs
     * @return array Array of unique attachment IDs
     */
    private function get_media_from_categories($category_ids) {
        global $wpdb;

        $taxonomy = $this->get_media_category_taxonomy();

        error_log('STUDIOU WC MEDIA: get_media_from_categories called - taxonomy: ' . ($taxonomy ?: 'false') . ', category_ids: ' . implode(', ', $category_ids));

        if (!$taxonomy || empty($category_ids)) {
            error_log('STUDIOU WC MEDIA: No taxonomy or empty category_ids, returning empty');
            return array();
        }

        $placeholders = implode(',', array_fill(0, count($category_ids), '%d'));

        $sql = "
            SELECT DISTINCT p.ID
            FROM {$wpdb->posts} p
            INNER JOIN {$wpdb->term_relationships} tr ON p.ID = tr.object_id
            INNER JOIN {$wpdb->term_taxonomy} tt ON tr.term_taxonomy_id = tt.term_taxonomy_id
            WHERE tt.term_id IN ($placeholders)
            AND tt.taxonomy = %s
            AND p.post_type = 'attachment'
        ";

        $params = array_merge($category_ids, array($taxonomy));
        $media = $wpdb->get_col($wpdb->prepare($sql, ...$params));

        error_log('STUDIOU WC MEDIA: Query found ' . ($media ? count($media) : 0) . ' media files');

        return $media ? array_map('intval', $media) : array();
    }

    /**
     * Delete a batch of media files permanently
     *
     * @param array $media_ids Array of attachment IDs to delete
     * @return array Result with counts
     */
    private function delete_media_batch($media_ids) {
        global $wpdb;

        $deleted_count = 0;
        $failed_count = 0;
        $failed_media = array();
        $affected_term_ids = array();
        $taxonomy = $this->get_media_category_taxonomy();

        // Ensure required file functions are loaded
        if (!function_exists('wp_delete_attachment')) {
            require_once ABSPATH . 'wp-admin/includes/post.php';
        }
        if (!function_exists('wp_delete_file')) {
            require_once ABSPATH . 'wp-includes/functions.php';
        }

        error_log('STUDIOU WC MEDIA: delete_media_batch called with ' . count($media_ids) . ' media IDs');

        foreach ($media_ids as $media_id) {
            try {
                $attachment = get_post($media_id);

                if (!$attachment || $attachment->post_type !== 'attachment') {
                    $failed_count++;
                    $failed_media[] = $media_id;
                    error_log('STUDIOU WC MEDIA: Media file ' . $media_id . ' not found or not an attachment');
                    continue;
                }

                // Collect affected term IDs before deletion for count update
                if ($taxonomy) {
                    $terms = wp_get_object_terms($media_id, $taxonomy, array('fields' => 'ids'));
                    if (!is_wp_error($terms)) {
                        $affected_term_ids = array_merge($affected_term_ids, $terms);
                    }
                }

                // Get file paths BEFORE deletion
                $file = get_attached_file($media_id);
                $meta = wp_get_attachment_metadata($media_id);
                $upload_dir = wp_get_upload_dir();

                error_log('STUDIOU WC MEDIA: Deleting media ID ' . $media_id . ', file: ' . ($file ?: 'none'));

                // Attempt standard WordPress deletion
                wp_delete_attachment($media_id, true);

                // Verify the post was actually deleted
                $still_exists = $wpdb->get_var($wpdb->prepare(
                    "SELECT ID FROM {$wpdb->posts} WHERE ID = %d",
                    $media_id
                ));

                if ($still_exists) {
                    error_log('STUDIOU WC MEDIA: wp_delete_attachment did not delete post ' . $media_id . ', forcing manual deletion');

                    // Force manual deletion: remove term relationships
                    $all_taxonomies = get_object_taxonomies('attachment');
                    if (!empty($all_taxonomies)) {
                        wp_delete_object_term_relationships($media_id, $all_taxonomies);
                    }

                    // Remove all post meta
                    $wpdb->delete($wpdb->postmeta, array('post_id' => $media_id));

                    // Remove the post itself
                    $wpdb->delete($wpdb->posts, array('ID' => $media_id));

                    // Clean cache
                    clean_post_cache($media_id);
                }

                // Delete physical files from disk
                if ($file && file_exists($file)) {
                    @unlink($file);
                    error_log('STUDIOU WC MEDIA: Deleted main file: ' . $file);
                }

                // Delete thumbnail/intermediate sizes
                if (!empty($meta['sizes']) && !empty($upload_dir['basedir'])) {
                    $file_dir = !empty($file) ? trailingslashit(dirname($file)) : '';
                    foreach ($meta['sizes'] as $size => $sizeinfo) {
                        if (!empty($sizeinfo['file'])) {
                            $intermediate_file = $file_dir . $sizeinfo['file'];
                            if (file_exists($intermediate_file)) {
                                @unlink($intermediate_file);
                            }
                        }
                    }
                }

                // Final verification
                $final_check = $wpdb->get_var($wpdb->prepare(
                    "SELECT ID FROM {$wpdb->posts} WHERE ID = %d",
                    $media_id
                ));

                if (!$final_check) {
                    $deleted_count++;
                    error_log('STUDIOU WC MEDIA: Successfully deleted media file ' . $media_id);
                } else {
                    $failed_count++;
                    $failed_media[] = $media_id;
                    error_log('STUDIOU WC MEDIA: FAILED to delete media file ' . $media_id . ' even after manual cleanup');
                }

            } catch (Exception $e) {
                $failed_count++;
                $failed_media[] = $media_id;
                error_log('STUDIOU WC MEDIA: Exception deleting media file ' . $media_id . ': ' . $e->getMessage());
            }
        }

        // Force update term counts for affected categories
        if ($taxonomy && !empty($affected_term_ids)) {
            $affected_term_ids = array_unique($affected_term_ids);
            wp_update_term_count_now($affected_term_ids, $taxonomy);
            error_log('STUDIOU WC MEDIA: Updated term counts for term IDs: ' . implode(', ', $affected_term_ids));
        }

        error_log('STUDIOU WC MEDIA: Batch result - deleted: ' . $deleted_count . ', failed: ' . $failed_count);

        return array(
            'deleted_count' => $deleted_count,
            'failed_count' => $failed_count,
            'failed_media' => $failed_media
        );
    }

    /**
     * Handle AJAX clear media request (initial request to get media IDs)
     */
    public function handle_clear_media_ajax() {
        while (ob_get_level()) {
            ob_end_clean();
        }

        ob_start();

        $original_error_reporting = error_reporting();
        error_reporting(0);

        error_log('STUDIOU WC MEDIA: Clear media AJAX handler called');
        error_log('STUDIOU WC MEDIA: POST data: ' . print_r($_POST, true));

        try {
            if (!isset($_POST['nonce']) || !wp_verify_nonce($_POST['nonce'], 'studiou-wcpcm-nonce')) {
                error_log('STUDIOU WC MEDIA: Nonce verification failed');
                wp_send_json_error(array(
                    'message' => __('Security check failed', 'studiou-wc-product-cat-manage')
                ));
                return;
            }

            if (!current_user_can('manage_woocommerce')) {
                error_log('STUDIOU WC MEDIA: Permission check failed');
                wp_send_json_error(array(
                    'message' => __('You do not have sufficient permissions', 'studiou-wc-product-cat-manage')
                ));
                return;
            }

            if (!isset($_POST['media_categories'])) {
                error_log('STUDIOU WC MEDIA: media_categories not in POST data');
                wp_send_json_error(array(
                    'message' => __('Missing required parameters', 'studiou-wc-product-cat-manage')
                ));
                return;
            }

            $category_ids = array_map('intval', $_POST['media_categories']);

            if (empty($category_ids)) {
                error_log('STUDIOU WC MEDIA: Empty category_ids after intval mapping');
                wp_send_json_error(array(
                    'message' => __('Please select at least one category', 'studiou-wc-product-cat-manage')
                ));
                return;
            }

            $media_ids = $this->get_media_from_categories($category_ids);

            error_log('STUDIOU WC MEDIA: Found ' . count($media_ids) . ' media files to delete from categories: ' . implode(', ', $category_ids));

            ob_clean();

            wp_send_json_success(array(
                'media_ids' => $media_ids,
                'total_count' => count($media_ids),
                'message' => sprintf(
                    __('Found %d media files to delete', 'studiou-wc-product-cat-manage'),
                    count($media_ids)
                )
            ));

        } catch (Exception $e) {
            error_log('STUDIOU WC MEDIA: Clear media operation failed - ' . $e->getMessage());
            error_log('STUDIOU WC MEDIA: Exception trace: ' . $e->getTraceAsString());

            ob_clean();

            wp_send_json_error(array(
                'message' => sprintf(
                    __('Error during clear media operation: %s', 'studiou-wc-product-cat-manage'),
                    $e->getMessage()
                )
            ));
        } finally {
            error_reporting($original_error_reporting);
            ob_end_clean();
        }
    }

    /**
     * Handle AJAX clear media batch request (processes media in batches)
     */
    public function handle_clear_media_batch_ajax() {
        while (ob_get_level()) {
            ob_end_clean();
        }

        ob_start();

        $original_error_reporting = error_reporting();
        error_reporting(0);

        error_log('STUDIOU WC MEDIA: Clear media batch AJAX handler called');

        try {
            if (!isset($_POST['nonce']) || !wp_verify_nonce($_POST['nonce'], 'studiou-wcpcm-nonce')) {
                error_log('STUDIOU WC MEDIA: Batch nonce verification failed');
                wp_send_json_error(array(
                    'message' => __('Security check failed', 'studiou-wc-product-cat-manage')
                ));
                return;
            }

            if (!current_user_can('manage_woocommerce')) {
                error_log('STUDIOU WC MEDIA: Batch permission check failed');
                wp_send_json_error(array(
                    'message' => __('You do not have sufficient permissions', 'studiou-wc-product-cat-manage')
                ));
                return;
            }

            if (!isset($_POST['media_ids'])) {
                error_log('STUDIOU WC MEDIA: media_ids not in POST data');
                wp_send_json_error(array(
                    'message' => __('Missing required parameters', 'studiou-wc-product-cat-manage')
                ));
                return;
            }

            $media_ids = array_map('intval', $_POST['media_ids']);

            error_log('STUDIOU WC MEDIA: Processing batch of ' . count($media_ids) . ' media files for deletion');

            $result = $this->delete_media_batch($media_ids);

            error_log('STUDIOU WC MEDIA: Batch completed - Deleted: ' . $result['deleted_count'] . ', Failed: ' . $result['failed_count']);

            ob_clean();

            wp_send_json_success(array(
                'deleted_count' => $result['deleted_count'],
                'failed_count' => $result['failed_count'],
                'failed_media' => $result['failed_media']
            ));

        } catch (Exception $e) {
            error_log('STUDIOU WC MEDIA: Clear media batch operation failed - ' . $e->getMessage());
            error_log('STUDIOU WC MEDIA: Exception trace: ' . $e->getTraceAsString());

            ob_clean();

            wp_send_json_error(array(
                'message' => sprintf(
                    __('Error during clear media batch operation: %s', 'studiou-wc-product-cat-manage'),
                    $e->getMessage()
                )
            ));
        } finally {
            error_reporting($original_error_reporting);
            ob_end_clean();
        }
    }

    /**
     * Get count of unassigned unused media files
     *
     * @return int Count of media files not in any category and not referenced
     */
    public function get_unassigned_unused_media_count() {
        $ids = $this->get_unassigned_unused_media_ids();
        return count($ids);
    }

    /**
     * Get IDs of media files that are not assigned to any media category
     * and not used as featured image, product gallery image, or attached to any post.
     *
     * @return array Array of attachment IDs
     */
    public function get_unassigned_unused_media_ids() {
        global $wpdb;

        $taxonomy = $this->get_media_category_taxonomy();

        // Base query: all attachments not used as featured image and not attached to a post
        $sql = "
            SELECT a.ID
            FROM {$wpdb->posts} a
            LEFT JOIN {$wpdb->postmeta} pm_thumb
                ON a.ID = CAST(pm_thumb.meta_value AS UNSIGNED)
                AND pm_thumb.meta_key = '_thumbnail_id'
            WHERE a.post_type = 'attachment'
            AND a.post_parent = 0
            AND pm_thumb.meta_id IS NULL
        ";

        // If media category taxonomy exists, also exclude categorized media
        if ($taxonomy) {
            $sql .= $wpdb->prepare("
                AND a.ID NOT IN (
                    SELECT tr.object_id
                    FROM {$wpdb->term_relationships} tr
                    INNER JOIN {$wpdb->term_taxonomy} tt ON tr.term_taxonomy_id = tt.term_taxonomy_id
                    WHERE tt.taxonomy = %s
                )
            ", $taxonomy);
        }

        $media_ids = $wpdb->get_col($sql);

        if (empty($media_ids)) {
            return array();
        }

        $media_ids = array_map('intval', $media_ids);

        // Filter out media used in WooCommerce product galleries (_product_image_gallery)
        $gallery_meta = $wpdb->get_col(
            "SELECT meta_value FROM {$wpdb->postmeta} WHERE meta_key = '_product_image_gallery' AND meta_value != ''"
        );

        if (!empty($gallery_meta)) {
            $gallery_ids = array();
            foreach ($gallery_meta as $gallery_value) {
                $ids = array_map('intval', array_filter(explode(',', $gallery_value)));
                $gallery_ids = array_merge($gallery_ids, $ids);
            }
            $gallery_ids = array_unique($gallery_ids);

            if (!empty($gallery_ids)) {
                $media_ids = array_diff($media_ids, $gallery_ids);
            }
        }

        // v1.6.2 — narrow blast radius. The base query above does not see
        // attachments referenced from term meta (WooCommerce product-category
        // images are stored as termmeta 'thumbnail_id'), nor customizer images
        // (custom logo, site icon, header image). Without these exclusions,
        // running "Remove Not Assigned Media" silently destroys category
        // artwork. NOTE: content-embedded, ACF/meta-field, and downloadable-
        // product images are still NOT detected — see the warning in
        // tab-remove-unassigned.php. The preview-list inversion (plan-02) is
        // what makes the operation actually safe.
        $extra_excluded = array();

        $termmeta_ids = $wpdb->get_col(
            "SELECT DISTINCT meta_value FROM {$wpdb->termmeta}
             WHERE meta_key = 'thumbnail_id'
               AND meta_value > 0"
        );
        foreach ($termmeta_ids as $tm_id) {
            $tm_id = (int) $tm_id;
            if ($tm_id) { $extra_excluded[$tm_id] = true; }
        }

        foreach (array(
            (int) get_theme_mod('custom_logo'),
            (int) get_option('site_icon'),
        ) as $cust_id) {
            if ($cust_id) { $extra_excluded[$cust_id] = true; }
        }

        $hdr = get_theme_mod('header_image_data');
        if (is_object($hdr) && !empty($hdr->attachment_id)) {
            $extra_excluded[(int) $hdr->attachment_id] = true;
        }

        if (!empty($extra_excluded)) {
            $media_ids = array_diff($media_ids, array_keys($extra_excluded));
        }

        error_log('STUDIOU WC MEDIA: Found ' . count($media_ids) . ' unassigned unused media files');

        return array_values($media_ids);
    }

    /**
     * Handle AJAX remove unassigned media request (get IDs)
     */
    public function handle_remove_unassigned_media_ajax() {
        while (ob_get_level()) {
            ob_end_clean();
        }

        ob_start();

        $original_error_reporting = error_reporting();
        error_reporting(0);

        error_log('STUDIOU WC MEDIA: Remove unassigned media AJAX handler called');

        try {
            if (!isset($_POST['nonce']) || !wp_verify_nonce($_POST['nonce'], 'studiou-wcpcm-nonce')) {
                wp_send_json_error(array('message' => __('Security check failed', 'studiou-wc-product-cat-manage')));
                return;
            }

            if (!current_user_can('manage_woocommerce')) {
                wp_send_json_error(array('message' => __('You do not have sufficient permissions', 'studiou-wc-product-cat-manage')));
                return;
            }

            $media_ids = $this->get_unassigned_unused_media_ids();

            error_log('STUDIOU WC MEDIA: Found ' . count($media_ids) . ' unassigned unused media files to delete');

            ob_clean();

            wp_send_json_success(array(
                'media_ids' => $media_ids,
                'total_count' => count($media_ids),
                'message' => sprintf(
                    __('Found %d unused uncategorized media files to delete', 'studiou-wc-product-cat-manage'),
                    count($media_ids)
                )
            ));

        } catch (Exception $e) {
            error_log('STUDIOU WC MEDIA: Remove unassigned media failed - ' . $e->getMessage());
            ob_clean();
            wp_send_json_error(array(
                'message' => sprintf(__('Error: %s', 'studiou-wc-product-cat-manage'), $e->getMessage())
            ));
        } finally {
            error_reporting($original_error_reporting);
            ob_end_clean();
        }
    }

    /**
     * Handle AJAX remove unassigned media batch request
     */
    public function handle_remove_unassigned_media_batch_ajax() {
        while (ob_get_level()) {
            ob_end_clean();
        }

        ob_start();

        $original_error_reporting = error_reporting();
        error_reporting(0);

        error_log('STUDIOU WC MEDIA: Remove unassigned media batch AJAX handler called');

        try {
            if (!isset($_POST['nonce']) || !wp_verify_nonce($_POST['nonce'], 'studiou-wcpcm-nonce')) {
                wp_send_json_error(array('message' => __('Security check failed', 'studiou-wc-product-cat-manage')));
                return;
            }

            if (!current_user_can('manage_woocommerce')) {
                wp_send_json_error(array('message' => __('You do not have sufficient permissions', 'studiou-wc-product-cat-manage')));
                return;
            }

            if (!isset($_POST['media_ids'])) {
                wp_send_json_error(array('message' => __('Missing required parameters', 'studiou-wc-product-cat-manage')));
                return;
            }

            $media_ids = array_map('intval', $_POST['media_ids']);

            error_log('STUDIOU WC MEDIA: Processing batch of ' . count($media_ids) . ' unassigned media for deletion');

            $result = $this->delete_media_batch($media_ids);

            error_log('STUDIOU WC MEDIA: Unassigned batch completed - Deleted: ' . $result['deleted_count'] . ', Failed: ' . $result['failed_count']);

            ob_clean();

            wp_send_json_success(array(
                'deleted_count' => $result['deleted_count'],
                'failed_count' => $result['failed_count'],
                'failed_media' => $result['failed_media']
            ));

        } catch (Exception $e) {
            error_log('STUDIOU WC MEDIA: Unassigned media batch failed - ' . $e->getMessage());
            ob_clean();
            wp_send_json_error(array(
                'message' => sprintf(__('Error: %s', 'studiou-wc-product-cat-manage'), $e->getMessage())
            ));
        } finally {
            error_reporting($original_error_reporting);
            ob_end_clean();
        }
    }

    // ========================================================================
    // Update Product Variant Prices (UPVP) — v1.5.3
    // Bulk-update regular_price on product_variation records by category +
    // attribute filter. Touches only product records; never order items, carts,
    // or historical order data.
    // ========================================================================

    /**
     * Get list of attribute "heads" usable for variations.
     *
     * Source 1: every wc_get_attribute_taxonomies() entry (global attributes)
     *           — key = 'pa_<slug>', is_taxonomy = true.
     * Source 2: distinct meta_key starting with 'attribute_' on product_variation
     *           rows that are NOT global taxonomies (custom product-level
     *           attributes flagged for variations) — key = '<slug>',
     *           is_taxonomy = false.
     *
     * @return array [ ['key' => string, 'label' => string, 'is_taxonomy' => bool], ... ]
     */
    public function get_variation_attribute_heads() {
        global $wpdb;

        $heads = array();
        $seen  = array();

        // Source 1: global taxonomies.
        $taxonomies = function_exists('wc_get_attribute_taxonomies') ? wc_get_attribute_taxonomies() : array();
        if (!empty($taxonomies)) {
            foreach ($taxonomies as $tax) {
                $key = 'pa_' . $tax->attribute_name;
                if (isset($seen[$key])) {
                    continue;
                }
                $seen[$key] = true;
                $heads[] = array(
                    'key'         => $key,
                    'label'       => !empty($tax->attribute_label) ? $tax->attribute_label : $tax->attribute_name,
                    'is_taxonomy' => true,
                );
            }
        }

        // Source 2: existing variation postmeta (attribute_*).
        $sql = "
            SELECT DISTINCT pm.meta_key
              FROM {$wpdb->postmeta} pm
              INNER JOIN {$wpdb->posts} v ON v.ID = pm.post_id
             WHERE v.post_type = 'product_variation'
               AND v.post_status IN ('publish','private')
               AND pm.meta_key LIKE %s
        ";
        $rows = $wpdb->get_col($wpdb->prepare($sql, $wpdb->esc_like('attribute_') . '%'));
        if (!empty($rows)) {
            foreach ($rows as $meta_key) {
                $slug = substr($meta_key, strlen('attribute_'));
                if ($slug === '' || isset($seen[$slug])) {
                    continue;
                }
                $seen[$slug] = true;
                $heads[] = array(
                    'key'         => $slug,
                    'label'       => wc_attribute_label($slug),
                    'is_taxonomy' => (strpos($slug, 'pa_') === 0) || taxonomy_exists($slug),
                );
            }
        }

        // Source 3: variable parent products' _product_attributes postmeta.
        // Catches attributes flagged "Used for variations" on the product's
        // Attributes tab, even when (a) the attribute is a custom non-global
        // entry, or (b) no variations have been generated yet.
        $sql_parents = "
            SELECT pm.meta_value
              FROM {$wpdb->postmeta} pm
              INNER JOIN {$wpdb->posts} p ON p.ID = pm.post_id
             WHERE p.post_type = 'product'
               AND p.post_status IN ('publish','private','draft')
               AND pm.meta_key = '_product_attributes'
        ";
        $serialized_rows = $wpdb->get_col($sql_parents);
        if (!empty($serialized_rows)) {
            foreach ($serialized_rows as $serialized) {
                $attrs = maybe_unserialize($serialized);
                if (!is_array($attrs)) {
                    continue;
                }
                foreach ($attrs as $attr_key => $attr_data) {
                    if (!is_array($attr_data) || empty($attr_data['is_variation'])) {
                        continue;
                    }
                    $is_taxonomy = !empty($attr_data['is_taxonomy']);
                    $name = isset($attr_data['name']) ? $attr_data['name'] : $attr_key;
                    $key  = $is_taxonomy ? $name : sanitize_title($name);
                    if ($key === '' || isset($seen[$key])) {
                        continue;
                    }
                    $seen[$key] = true;
                    $heads[] = array(
                        'key'         => $key,
                        'label'       => $is_taxonomy ? wc_attribute_label($key) : $name,
                        'is_taxonomy' => $is_taxonomy,
                    );
                }
            }
        }

        // Sort alphabetically by label.
        usort($heads, function($a, $b) {
            return strcasecmp($a['label'], $b['label']);
        });

        return $heads;
    }

    /**
     * Get distinct values for the given attribute key, scoped to existing
     * variations (and optionally to a set of parent product categories).
     *
     * For taxonomy attributes (pa_*) the meta_value is the term slug; we
     * resolve labels via get_term_by('slug', ..., $taxonomy).
     *
     * @param string $attribute_key  E.g. 'pa_color' or 'size'.
     * @param int[]  $category_ids   Optional list of parent product_cat term IDs.
     * @return array [ ['value' => string, 'label' => string], ... ]
     */
    public function get_variation_attribute_values($attribute_key, $category_ids = array()) {
        global $wpdb;

        $attribute_key = sanitize_text_field($attribute_key);
        if ($attribute_key === '') {
            return array();
        }

        $meta_key = 'attribute_' . wc_sanitize_taxonomy_name($attribute_key);

        $params = array($meta_key);

        $cat_join  = '';
        $cat_where = '';
        if (!empty($category_ids)) {
            $cat_ids = array_map('intval', $category_ids);
            $cat_ids = array_filter($cat_ids, function($v) { return $v > 0; });
            if (!empty($cat_ids)) {
                $placeholders = implode(',', array_fill(0, count($cat_ids), '%d'));
                $cat_join  = "
                    INNER JOIN {$wpdb->term_relationships} tr ON p.ID = tr.object_id
                    INNER JOIN {$wpdb->term_taxonomy} tt ON tr.term_taxonomy_id = tt.term_taxonomy_id
                ";
                $cat_where = "
                    AND tt.taxonomy = 'product_cat'
                    AND tt.term_id IN ($placeholders)
                ";
                $params = array_merge($params, $cat_ids);
            }
        }

        $sql = "
            SELECT DISTINCT pm.meta_value
              FROM {$wpdb->postmeta} pm
              INNER JOIN {$wpdb->posts} v ON v.ID = pm.post_id
                       AND v.post_type = 'product_variation'
                       AND v.post_status IN ('publish','private')
              INNER JOIN {$wpdb->posts} p ON p.ID = v.post_parent
                       AND p.post_type = 'product'
              $cat_join
             WHERE pm.meta_key = %s
               AND pm.meta_value <> ''
               $cat_where
        ";

        $values = $wpdb->get_col($wpdb->prepare($sql, ...$params));

        $is_taxonomy = (strpos($attribute_key, 'pa_') === 0) || taxonomy_exists($attribute_key);

        // Fallback: if SQL returned no values but the attribute exists on a
        // variable parent's _product_attributes (e.g. variations not generated
        // yet, or custom attribute), parse pipe-separated values from there.
        if (empty($values)) {
            $sanitized_key = $is_taxonomy
                ? (strpos($attribute_key, 'pa_') === 0 ? $attribute_key : 'pa_' . $attribute_key)
                : sanitize_title($attribute_key);

            $sql_parents = "
                SELECT pm.meta_value
                  FROM {$wpdb->postmeta} pm
                  INNER JOIN {$wpdb->posts} p ON p.ID = pm.post_id
                 WHERE p.post_type = 'product'
                   AND p.post_status IN ('publish','private','draft')
                   AND pm.meta_key = '_product_attributes'
            ";
            $rows = $wpdb->get_col($sql_parents);
            $values = array();
            if (!empty($rows)) {
                foreach ($rows as $serialized) {
                    $attrs = maybe_unserialize($serialized);
                    if (!is_array($attrs) || !isset($attrs[$sanitized_key])) {
                        continue;
                    }
                    $entry = $attrs[$sanitized_key];
                    if (empty($entry['is_variation'])) {
                        continue;
                    }
                    if ($is_taxonomy) {
                        // Taxonomy custom values are stored as term IDs in 'value'.
                        $term_ids = !empty($entry['value']) ? wp_parse_id_list($entry['value']) : array();
                        if (empty($term_ids)) {
                            // Or the parent uses all terms — pull them from the taxonomy.
                            $tax_name = $sanitized_key;
                            $terms = get_terms(array('taxonomy' => $tax_name, 'hide_empty' => false));
                            if (!is_wp_error($terms)) {
                                foreach ($terms as $t) {
                                    $values[] = $t->slug;
                                }
                            }
                        } else {
                            foreach ($term_ids as $tid) {
                                $term = get_term($tid, $sanitized_key);
                                if ($term && !is_wp_error($term)) {
                                    $values[] = $term->slug;
                                }
                            }
                        }
                    } else {
                        $raw = isset($entry['value']) ? (string) $entry['value'] : '';
                        if ($raw !== '') {
                            $parts = array_map('trim', explode('|', $raw));
                            foreach ($parts as $p) {
                                if ($p !== '') {
                                    $values[] = $p;
                                }
                            }
                        }
                    }
                }
                $values = array_values(array_unique($values));
            }
        }

        if (empty($values)) {
            return array();
        }

        $result = array();
        foreach ($values as $value) {
            $label = $value;
            if ($is_taxonomy) {
                $tax = (strpos($attribute_key, 'pa_') === 0) ? $attribute_key : 'pa_' . $attribute_key;
                $term = get_term_by('slug', $value, $tax);
                if ($term && !is_wp_error($term)) {
                    $label = $term->name;
                }
            }
            $result[] = array(
                'value' => $value,
                'label' => $label,
            );
        }

        usort($result, function($a, $b) {
            return strcasecmp($a['label'], $b['label']);
        });

        return $result;
    }

    /**
     * Find variations matching the filter.
     *
     * @param int[]  $category_ids
     * @param string $attribute_key
     * @param string $attribute_value
     * @return array ['count' => int, 'ids' => int[], 'sample' => array[]]
     */
    public function find_matching_variations($category_ids, $attribute_key, $attribute_value) {
        global $wpdb;

        $category_ids   = array_filter(array_map('intval', (array) $category_ids), function($v) { return $v > 0; });
        $attribute_key  = sanitize_text_field($attribute_key);
        $attribute_value = sanitize_text_field($attribute_value);

        if (empty($category_ids) || $attribute_key === '' || $attribute_value === '') {
            return array('count' => 0, 'ids' => array(), 'sample' => array());
        }

        $meta_key     = 'attribute_' . wc_sanitize_taxonomy_name($attribute_key);
        $placeholders = implode(',', array_fill(0, count($category_ids), '%d'));

        $sql = "
            SELECT DISTINCT v.ID
              FROM {$wpdb->posts} v
              INNER JOIN {$wpdb->posts} p ON p.ID = v.post_parent
              INNER JOIN {$wpdb->postmeta} pm ON pm.post_id = v.ID
              INNER JOIN {$wpdb->term_relationships} tr ON p.ID = tr.object_id
              INNER JOIN {$wpdb->term_taxonomy} tt ON tr.term_taxonomy_id = tt.term_taxonomy_id
             WHERE v.post_type = 'product_variation'
               AND v.post_status IN ('publish','private')
               AND p.post_type = 'product'
               AND tt.taxonomy = 'product_cat'
               AND tt.term_id IN ($placeholders)
               AND pm.meta_key = %s
               AND pm.meta_value = %s
        ";

        $params = array_merge($category_ids, array($meta_key, $attribute_value));
        $ids    = $wpdb->get_col($wpdb->prepare($sql, ...$params));
        $ids    = $ids ? array_map('intval', $ids) : array();

        // Build a sample (up to 20).
        $sample = array();
        $slice  = array_slice($ids, 0, 20);
        foreach ($slice as $id) {
            $variation = wc_get_product($id);
            if (!$variation) {
                continue;
            }
            $parent_id   = $variation->get_parent_id();
            $parent_name = '';
            if ($parent_id) {
                $parent = wc_get_product($parent_id);
                if ($parent) {
                    $parent_name = $parent->get_name();
                }
            }
            $sample[] = array(
                'id'            => $id,
                'sku'           => $variation->get_sku(),
                'name'          => $variation->get_name(),
                'parent_name'   => $parent_name,
                'current_price' => $variation->get_regular_price(),
            );
        }

        return array(
            'count'  => count($ids),
            'ids'    => $ids,
            'sample' => $sample,
        );
    }

    /**
     * Apply new regular price to a list of variation IDs.
     *
     * @param int[]  $variation_ids
     * @param string $new_price
     * @return array ['updated','failed','failed_ids','message']
     */
    public function apply_variant_price($variation_ids, $new_price) {
        $variation_ids = array_filter(array_map('intval', (array) $variation_ids), function($v) { return $v > 0; });

        // Validate price.
        if (!is_numeric($new_price) || (float) $new_price < 0) {
            return array(
                'updated'    => 0,
                'failed'     => 0,
                'failed_ids' => array(),
                'message'    => __('Please enter a valid new price', 'studiou-wc-product-cat-manage'),
                'error'      => true,
            );
        }

        $formatted = wc_format_decimal($new_price);
        $new_price_f = (float) $formatted;

        $updated     = 0;
        $failed      = 0;
        $failed_ids  = array();
        $parent_ids  = array();
        // v1.7.1 — L7: collect variations whose existing sale_price is higher
        // than the new regular_price. We don't auto-clamp (sale data is
        // operator-owned) but we surface the inconsistency so the operator
        // can fix it. Returned in the response so the UI can show it.
        $sale_warnings = array();

        foreach ($variation_ids as $id) {
            try {
                $variation = wc_get_product($id);
                if (!$variation || !$variation->is_type('variation')) {
                    $failed++;
                    $failed_ids[] = $id;
                    error_log('STUDIOU WC UPVP: Variation ' . $id . ' not found or not a variation');
                    continue;
                }

                $sale_price_raw = $variation->get_sale_price();
                if ($sale_price_raw !== '' && $sale_price_raw !== null) {
                    $sale_f = (float) $sale_price_raw;
                    if ($sale_f > $new_price_f) {
                        error_log(sprintf(
                            'STUDIOU WC UPVP: variation %d has sale_price %s greater than new regular_price %s — sale > regular after update; review needed',
                            $id, $sale_price_raw, $formatted
                        ));
                        $sale_warnings[] = array(
                            'id'           => $id,
                            'sale_price'   => $sale_price_raw,
                            'new_regular'  => $formatted,
                        );
                    }
                }

                $variation->set_regular_price($formatted);
                $variation->save();
                $updated++;
                $parent_id = $variation->get_parent_id();
                if ($parent_id) {
                    $parent_ids[$parent_id] = true;
                }
            } catch (Exception $e) {
                $failed++;
                $failed_ids[] = $id;
                error_log('STUDIOU WC UPVP: Exception updating variation ' . $id . ' - ' . $e->getMessage());
            }
        }

        // Re-sync parent variable products so price-range cache reflects the new prices.
        if (!empty($parent_ids) && class_exists('WC_Product_Variable')) {
            foreach (array_keys($parent_ids) as $parent_id) {
                try {
                    WC_Product_Variable::sync($parent_id);
                    if (function_exists('wc_delete_product_transients')) {
                        wc_delete_product_transients($parent_id);
                    }
                } catch (Exception $e) {
                    error_log('STUDIOU WC UPVP: Failed to sync parent ' . $parent_id . ' - ' . $e->getMessage());
                }
            }
        }

        $message = sprintf(
            __('Successfully updated %d variations.', 'studiou-wc-product-cat-manage'),
            $updated
        );
        if ($failed > 0) {
            $message .= ' ' . sprintf(
                __('Failed to update %d variations.', 'studiou-wc-product-cat-manage'),
                $failed
            );
        }

        if (!empty($sale_warnings)) {
            $message .= ' ' . sprintf(
                /* translators: %d: number of variations whose existing sale_price is now greater than the new regular_price */
                __('Warning: %d variations have a sale price greater than the new regular price (sale > regular). Review the variations and adjust the sale price.', 'studiou-wc-product-cat-manage'),
                count($sale_warnings)
            );
        }

        return array(
            'updated'       => $updated,
            'failed'        => $failed,
            'failed_ids'    => $failed_ids,
            'sale_warnings' => $sale_warnings,
            'message'       => $message,
        );
    }

    /**
     * Common AJAX preflight: nonce + capability + output buffer setup.
     * Returns false on failure (after sending JSON error), true on success.
     */
    private function upvp_preflight() {
        while (ob_get_level()) {
            ob_end_clean();
        }
        ob_start();

        if (!isset($_POST['nonce']) || !wp_verify_nonce($_POST['nonce'], 'studiou-wcpcm-nonce')) {
            ob_clean();
            wp_send_json_error(array('message' => __('Security check failed', 'studiou-wc-product-cat-manage')));
            return false;
        }
        if (!current_user_can('manage_woocommerce')) {
            ob_clean();
            wp_send_json_error(array('message' => __('You do not have sufficient permissions', 'studiou-wc-product-cat-manage')));
            return false;
        }
        return true;
    }

    /**
     * AJAX: list variation attribute heads.
     */
    public function handle_upvp_get_attributes_ajax() {
        if (!$this->upvp_preflight()) return;

        $original_error_reporting = error_reporting();
        error_reporting(0);
        try {
            $heads = $this->get_variation_attribute_heads();
            ob_clean();
            wp_send_json_success(array('attributes' => $heads));
        } catch (Exception $e) {
            error_log('STUDIOU WC UPVP: get_attributes failed - ' . $e->getMessage());
            ob_clean();
            wp_send_json_error(array('message' => $e->getMessage()));
        } finally {
            error_reporting($original_error_reporting);
            ob_end_clean();
        }
    }

    /**
     * AJAX: list values for the chosen attribute (scoped to selected categories).
     */
    public function handle_upvp_get_attribute_values_ajax() {
        if (!$this->upvp_preflight()) return;

        $original_error_reporting = error_reporting();
        error_reporting(0);
        try {
            $attribute_key = isset($_POST['attribute_key']) ? sanitize_text_field(wp_unslash($_POST['attribute_key'])) : '';
            $category_ids  = isset($_POST['category_ids']) ? array_map('intval', (array) $_POST['category_ids']) : array();

            if ($attribute_key === '') {
                ob_clean();
                wp_send_json_error(array('message' => __('Please select an attribute', 'studiou-wc-product-cat-manage')));
                return;
            }

            $values = $this->get_variation_attribute_values($attribute_key, $category_ids);
            ob_clean();
            wp_send_json_success(array('values' => $values));
        } catch (Exception $e) {
            error_log('STUDIOU WC UPVP: get_attribute_values failed - ' . $e->getMessage());
            ob_clean();
            wp_send_json_error(array('message' => $e->getMessage()));
        } finally {
            error_reporting($original_error_reporting);
            ob_end_clean();
        }
    }

    /**
     * AJAX: count + sample of variations matching the current filter.
     */
    public function handle_upvp_count_ajax() {
        if (!$this->upvp_preflight()) return;

        $original_error_reporting = error_reporting();
        error_reporting(0);
        try {
            $category_ids    = isset($_POST['category_ids']) ? array_map('intval', (array) $_POST['category_ids']) : array();
            $attribute_key   = isset($_POST['attribute_key']) ? sanitize_text_field(wp_unslash($_POST['attribute_key'])) : '';
            $attribute_value = isset($_POST['attribute_value']) ? sanitize_text_field(wp_unslash($_POST['attribute_value'])) : '';

            if (empty($category_ids)) {
                ob_clean();
                wp_send_json_error(array('message' => __('Please select at least one category', 'studiou-wc-product-cat-manage')));
                return;
            }
            if ($attribute_key === '') {
                ob_clean();
                wp_send_json_error(array('message' => __('Please select an attribute', 'studiou-wc-product-cat-manage')));
                return;
            }
            if ($attribute_value === '') {
                ob_clean();
                wp_send_json_error(array('message' => __('Please select an attribute value', 'studiou-wc-product-cat-manage')));
                return;
            }

            $result = $this->find_matching_variations($category_ids, $attribute_key, $attribute_value);

            ob_clean();
            wp_send_json_success(array(
                'count'  => $result['count'],
                'sample' => $result['sample'],
            ));
        } catch (Exception $e) {
            error_log('STUDIOU WC UPVP: count failed - ' . $e->getMessage());
            ob_clean();
            wp_send_json_error(array('message' => $e->getMessage()));
        } finally {
            error_reporting($original_error_reporting);
            ob_end_clean();
        }
    }

    /**
     * AJAX: apply new regular price to all matching variations.
     */
    public function handle_upvp_apply_ajax() {
        if (!$this->upvp_preflight()) return;

        $original_error_reporting = error_reporting();
        error_reporting(0);
        try {
            $category_ids    = isset($_POST['category_ids']) ? array_map('intval', (array) $_POST['category_ids']) : array();
            $attribute_key   = isset($_POST['attribute_key']) ? sanitize_text_field(wp_unslash($_POST['attribute_key'])) : '';
            $attribute_value = isset($_POST['attribute_value']) ? sanitize_text_field(wp_unslash($_POST['attribute_value'])) : '';
            $new_price       = isset($_POST['new_price']) ? sanitize_text_field(wp_unslash($_POST['new_price'])) : '';

            if (empty($category_ids)) {
                ob_clean();
                wp_send_json_error(array('message' => __('Please select at least one category', 'studiou-wc-product-cat-manage')));
                return;
            }
            if ($attribute_key === '' || $attribute_value === '') {
                ob_clean();
                wp_send_json_error(array('message' => __('Please select an attribute value', 'studiou-wc-product-cat-manage')));
                return;
            }
            if ($new_price === '' || !is_numeric($new_price) || (float) $new_price < 0) {
                ob_clean();
                wp_send_json_error(array('message' => __('Please enter a valid new price', 'studiou-wc-product-cat-manage')));
                return;
            }

            $matching = $this->find_matching_variations($category_ids, $attribute_key, $attribute_value);
            if ($matching['count'] === 0) {
                ob_clean();
                wp_send_json_error(array('message' => __('No variations match the current filter.', 'studiou-wc-product-cat-manage')));
                return;
            }

            $result = $this->apply_variant_price($matching['ids'], $new_price);

            ob_clean();
            wp_send_json_success(array(
                'updated'    => $result['updated'],
                'failed'     => $result['failed'],
                'failed_ids' => $result['failed_ids'],
                'message'    => $result['message'],
            ));
        } catch (Exception $e) {
            error_log('STUDIOU WC UPVP: apply failed - ' . $e->getMessage());
            ob_clean();
            wp_send_json_error(array('message' => $e->getMessage()));
        } finally {
            error_reporting($original_error_reporting);
            ob_end_clean();
        }
    }
}