<?php
/**
 * Product export class
 *
 * Handles product export to CSV files
 *
 * @since      1.4.0
 * @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_Manage_Product_Export {

    /**
     * @var Studiou_WC_Product_Manage_Product_DB
     */
    private $db;

    /**
     * Constructor
     *
     * @param Studiou_WC_Product_Manage_Product_DB $db Database instance
     */
    public function __construct($db) {
        $this->db = $db;
        // v1.6.4 — gated download endpoint, mirroring the category export.
        add_action('admin_init', array($this, 'handle_export_download'));
    }

    /**
     * Return (and lazily create) the guarded export directory.
     *
     * @return string Absolute path with trailing slash.
     */
    private function get_export_dir() {
        $upload_dir = wp_upload_dir();
        $dir = trailingslashit($upload_dir['basedir']) . 'studiou-wcpcm-product-exports/';
        if (!file_exists($dir)) {
            wp_mkdir_p($dir);
        }
        // Guard against direct access. Cheap idempotent writes.
        $idx = $dir . 'index.php';
        if (!file_exists($idx)) {
            @file_put_contents($idx, '<?php // Silence is golden.');
        }
        $ht = $dir . '.htaccess';
        if (!file_exists($ht)) {
            @file_put_contents($ht, "Deny from all\n");
        }
        return $dir;
    }

    /**
     * Delete export files older than 24 hours. Called on every new export.
     */
    private function prune_old_exports() {
        $dir = $this->get_export_dir();
        $cutoff = time() - DAY_IN_SECONDS;
        $files = glob($dir . 'product-export-*.csv');
        if (!is_array($files)) { return; }
        foreach ($files as $f) {
            $mtime = @filemtime($f);
            if ($mtime !== false && $mtime < $cutoff) {
                @unlink($f);
            }
        }
    }

    /**
     * v1.6.4 — gated CSV download.
     *
     * Hooked on admin_init. Verifies nonce + manage_woocommerce capability +
     * that the requested file is a bare basename inside the export dir
     * (defends against path traversal), then streams via readfile().
     */
    public function handle_export_download() {
        if (!isset($_GET['page']) || $_GET['page'] !== 'studiou-product-export') {
            return;
        }
        if (!isset($_GET['action']) || $_GET['action'] !== 'studiou_wcpcm_download_product_export') {
            return;
        }
        if (!isset($_GET['_wpnonce']) || !wp_verify_nonce($_GET['_wpnonce'], 'studiou-wcpcm-product-export-download')) {
            return;
        }

        if (!current_user_can('manage_woocommerce')) {
            wp_die(__('You do not have sufficient permissions', 'studiou-wc-product-cat-manage'));
        }

        $requested = isset($_GET['file']) ? (string) $_GET['file'] : '';
        // Bare basename only — no slashes, no .., no directory components.
        if ($requested === '' || $requested !== basename($requested) || strpos($requested, '..') !== false) {
            wp_die(__('Invalid file', 'studiou-wc-product-cat-manage'));
        }
        // Only our own filename shape: product-export-<32 hex>.csv
        if (!preg_match('/^product-export-[a-f0-9]{32}\.csv$/', $requested)) {
            wp_die(__('Invalid file', 'studiou-wc-product-cat-manage'));
        }

        $dir = $this->get_export_dir();
        $path = $dir . $requested;
        if (!file_exists($path)) {
            wp_die(__('Export file not found. Please try exporting again.', 'studiou-wc-product-cat-manage'));
        }

        // Belt-and-braces realpath check to prevent symlink escape.
        $real_dir = realpath($dir);
        $real_path = realpath($path);
        if ($real_dir === false || $real_path === false || strpos($real_path, $real_dir) !== 0) {
            wp_die(__('Invalid file', 'studiou-wc-product-cat-manage'));
        }

        header('Content-Type: text/csv; charset=utf-8');
        header('Content-Disposition: attachment; filename=product-export-' . date('Y-m-d-H-i-s') . '.csv');
        header('Content-Length: ' . filesize($real_path));
        header('Pragma: no-cache');
        header('Expires: 0');
        readfile($real_path);
        exit;
    }

    /**
     * Export products by category IDs
     *
     * @param array $category_ids Array of category IDs
     * @return string CSV content
     */
    public function export_products($category_ids, &$row_count = null) {
        $product_ids = $this->db->get_products_by_categories($category_ids);

        if (empty($product_ids)) {
            return '';
        }

        // Define CSV header
        $header = array(
            'ID', 'Typ', 'Katalogové číslo', 'Jméno', 'Nadřazené', 'Krátký popis', 'Popis',
            'Název 1 vlastnosti', 'Hodnota(y) 1 vlastnosti', 'Kategorie', 'Obrázky', 'Běžná cena',
            'Vlastnost 1 viditelnost', 'Vlastnost 1 globální', 'Vlastnost 1 varianta',
            'Povolit zákaznické recenze?', 'Minimum Quantity', 'Maximum Quantity'
        );

        // Start CSV output
        $csv = '';
        $csv .= '"' . implode('","', $header) . '"' . "\n";

        // v1.7.1 — L2: accumulate the count during generation. The previous
        // substr_count("\n") - 1 over-counted whenever any field (typically
        // the product description) contained a newline.
        $count = 0;

        // Process each product
        foreach ($product_ids as $product_id) {
            $product = wc_get_product($product_id);
            if (!$product) {
                continue;
            }

            // Only export variable products and variations
            if (!$product->is_type('variable') && !$product->is_type('variation')) {
                continue;
            }

            $csv .= $this->format_product_row($product);
            $count++;
        }

        if (func_num_args() >= 2) {
            $row_count = $count;
        }

        return $csv;
    }

    /**
     * Format product data as CSV row
     *
     * @param WC_Product $product Product object
     * @return string CSV row
     */
    private function format_product_row($product) {
        $row = array();

        // ID
        $row[] = $product->get_id();

        // Typ (Type)
        $row[] = $product->is_type('variation') ? 'variation' : 'variable';

        // Katalogové číslo (SKU)
        $row[] = $product->get_sku();

        // Jméno (Name)
        $row[] = $product->get_name();

        // Nadřazené (Parent) - only for variations
        if ($product->is_type('variation')) {
            $parent_id = $product->get_parent_id();
            if ($parent_id) {
                $parent = wc_get_product($parent_id);
                $row[] = $parent ? $parent->get_sku() : '';
            } else {
                $row[] = '';
            }
        } else {
            $row[] = '';
        }

        // Krátký popis (Short description)
        $row[] = $product->get_short_description();

        // Popis (Description)
        $row[] = $product->get_description();

        // Název 1 vlastnosti (Attribute 1 name)
        // Hodnota(y) 1 vlastnosti (Attribute 1 value(s))
        $attributes = $product->get_attributes();
        $attribute_name = '';
        $attribute_values = '';
        $attribute_visible = '0';
        $attribute_global = '0';
        $attribute_variation = '0';

        if (!empty($attributes)) {
            $first_attribute = reset($attributes);

            if ($first_attribute instanceof WC_Product_Attribute) {
                $attribute_name = $first_attribute->get_name();

                // Remove 'pa_' prefix if present
                if (strpos($attribute_name, 'pa_') === 0) {
                    $attribute_name = substr($attribute_name, 3);
                }

                // Get attribute values
                if ($product->is_type('variation')) {
                    // For variations, get the specific value
                    $variation_attributes = $product->get_variation_attributes();
                    if (!empty($variation_attributes)) {
                        $attribute_values = reset($variation_attributes);
                    }
                } else {
                    // For variable products, get all options
                    $options = $first_attribute->get_options();
                    if (is_array($options)) {
                        $attribute_values = implode('|', $options);
                    }
                }

                $attribute_visible = $first_attribute->get_visible() ? '1' : '0';
                $attribute_global = $first_attribute->is_taxonomy() ? '1' : '0';
                $attribute_variation = $first_attribute->get_variation() ? '1' : '0';
            }
        }

        $row[] = $attribute_name;
        $row[] = $attribute_values;

        // Kategorie (Categories) - with full hierarchy for subcategories
        $category_ids = $product->get_category_ids();
        $category_names = array();
        foreach ($category_ids as $cat_id) {
            $category_path = $this->get_category_path($cat_id);
            if ($category_path) {
                $category_names[] = $category_path;
            }
        }
        $row[] = implode('|', $category_names);

        // Obrázky (Images)
        $image_id = $product->get_image_id();
        $row[] = $image_id ? wp_get_attachment_url($image_id) : '';

        // Běžná cena (Regular price)
        $row[] = $product->get_regular_price();

        // Vlastnost 1 viditelnost (Attribute 1 visibility)
        $row[] = $attribute_visible;

        // Vlastnost 1 globální (Attribute 1 global)
        $row[] = $attribute_global;

        // Vlastnost 1 varianta (Attribute 1 variation)
        $row[] = $attribute_variation;

        // Povolit zákaznické recenze? (Enable reviews)
        $row[] = $product->get_reviews_allowed() ? '1' : '0';

        // Minimum Quantity
        $min_qty = $product->get_meta('_minimum_quantity');
        $row[] = $min_qty ? $min_qty : '';

        // Maximum Quantity
        $max_qty = $product->get_meta('_maximum_quantity');
        $row[] = $max_qty ? $max_qty : '';

        // Format as CSV row
        $formatted_row = array();
        foreach ($row as $value) {
            // Escape double quotes
            $value = str_replace('"', '""', $value);
            $formatted_row[] = '"' . $value . '"';
        }

        return implode(',', $formatted_row) . "\n";
    }

    /**
     * Get full category path (Parent > Child format for subcategories)
     *
     * @param int $category_id Category term ID
     * @return string Category path
     */
    private function get_category_path($category_id) {
        $term = get_term($category_id, 'product_cat');

        if (!$term || is_wp_error($term)) {
            return '';
        }

        // Build path from child to root
        $path = array($term->name);
        $current_term = $term;

        while ($current_term->parent != 0) {
            $parent_term = get_term($current_term->parent, 'product_cat');
            if (!$parent_term || is_wp_error($parent_term)) {
                break;
            }
            array_unshift($path, $parent_term->name);
            $current_term = $parent_term;
        }

        // Return full path with ">" separator if subcategory, otherwise just the name
        return count($path) > 1 ? implode(' > ', $path) : $path[0];
    }

    /**
     * Generate CSV file and return download URL
     *
     * @param array $category_ids Array of category IDs
     * @return array Result with download URL or error message
     */
    public function generate_export_file($category_ids) {
        // v1.7.1 — L2: ask export_products() to return both the CSV string
        // AND the row count it accumulated during generation. substr_count
        // on "\n" over-counted whenever any product description contained
        // a newline.
        $row_count = 0;
        $csv_content = $this->export_products($category_ids, $row_count);

        if (empty($csv_content)) {
            return array(
                'success' => false,
                'message' => __('No products found in selected categories', 'studiou-wc-product-cat-manage')
            );
        }

        // v1.6.4 — write into the guarded export dir and prune anything older
        // than 24 hours. Filename gets a 32-char random token so the file is
        // unguessable even if directory listing leaks.
        $export_dir = $this->get_export_dir();
        $this->prune_old_exports();

        $token = bin2hex(random_bytes(16)); // 32 hex chars
        $filename = 'product-export-' . $token . '.csv';
        $file_path = $export_dir . $filename;

        // Write CSV content to file with UTF-8 BOM so Excel double-click
        // opens it with the correct encoding (Policy A, v1.6.2 — match the
        // category exporter, which has always written the BOM).
        $result = file_put_contents($file_path, "\xEF\xBB\xBF" . $csv_content);

        if ($result === false) {
            return array(
                'success' => false,
                'message' => __('Failed to create export file', 'studiou-wc-product-cat-manage')
            );
        }

        // Return an admin URL routed through handle_export_download(),
        // which checks the nonce + capability + basename. The raw public
        // uploads URL is no longer exposed.
        $download_url = add_query_arg(
            array(
                'page'     => 'studiou-product-export',
                'action'   => 'studiou_wcpcm_download_product_export',
                'file'     => $filename,
                '_wpnonce' => wp_create_nonce('studiou-wcpcm-product-export-download'),
            ),
            admin_url('edit.php?post_type=product')
        );

        return array(
            'success' => true,
            'message' => sprintf(
                /* translators: %d: number of exported products */
                __('Export successful! %d products exported.', 'studiou-wc-product-cat-manage'),
                $row_count
            ),
            'download_url' => $download_url
        );
    }
}