<?php
if (!defined('ABSPATH')) {
    exit;
}

class AILM_CSV_Handler
{

    private $plugin_name;

    public function __construct($plugin_name = 'ailinkmaster-internal-auto-manager')
    {
        $this->plugin_name = $plugin_name;
        add_action('admin_post_ailm_handle_actions', [$this, 'route_csv_actions']);
    }

    public function route_csv_actions()
    {
        if (!current_user_can('manage_options')) {
            wp_die(esc_html__('You do not have sufficient permissions to access this page.', 'ailinkmaster-internal-auto-manager'));
        }

        check_admin_referer('ailm_form_nonce');

        $submit_action = isset($_POST['submit_action']) ? sanitize_text_field(wp_unslash($_POST['submit_action'])) : '';

        if ($submit_action === 'ailm_export_csv') {
            $this->export_csv();
        } elseif ($submit_action === 'ailm_import_csv') {
            $this->import_csv();
        } else {
            // Action is not related to CSV (e.g., saving settings).
            // Return control so class-ailm-settings-tab.php can handle it.
            return;
        }
    }

    private function export_csv()
    {
        global $wpdb;

        // 1. Get allowed post types from settings
        $post_types = get_option('ailm_allowed_post_types', ['post', 'page']);

        // 2. Get ALL published posts of these types
        $all_posts = get_posts([
            'post_type' => $post_types,
            'post_status' => 'publish',
            'posts_per_page' => -1,
            'fields' => 'ids',
            'orderby' => 'ID',
            'order' => 'DESC'
        ]);

        header('Content-Type: text/csv; charset=utf-8');
        header('Content-Disposition: attachment; filename=ailm_universal_export_' . wp_date('Y-m-d') . '.csv');

        $output = fopen('php://output', 'w');
        fprintf($output, chr(0xEF) . chr(0xBB) . chr(0xBF)); // BOM for Excel

        // Add link_origin column to indicate the source of the link
        fputcsv($output, ['donor_id', 'donor_url', 'keyword', 'target_url', 'target_id', 'link_origin', 'action']);

        if (!empty($all_posts)) {
            $scout_table = $wpdb->prefix . 'ailm_link_monitor'; // Adjust table name if needed

            foreach ($all_posts as $donor_id) {
                $donor_url = get_permalink($donor_id);
                $has_links = false;

                // --- SOURCE 1: AILM Links (from meta fields) ---
                // DEPRECATED v2.0: _ailm_frozen_map meta is replaced by wp_ailm_link_rules.
                /*
                $frozen_map = get_post_meta( $donor_id, '_ailm_frozen_map', true );
                if ( is_array( $frozen_map ) && ! empty( $frozen_map ) ) {
                    foreach ( $frozen_map as $link ) {
                        fputcsv( $output, [
                            $donor_id,
                            $donor_url,
                            $link['word'] ?? '',
                            $link['url'] ?? '',
                            $link['target_id'] ?? '',
                            'ailm',
                            ''
                        ] );
                        $has_links = true;
                    }
                }
                */

                // v2.0: Read from unified rules table.
                if (class_exists('AILM_Link_Repository')) {
                    $rules = AILM_Link_Repository::get_rules_for_donor($donor_id);
                    foreach ($rules as $rule) {
                        fputcsv($output, [
                            $donor_id,
                            $donor_url,
                            $rule->anchor,
                            $rule->target_url,
                            $rule->target_id,
                            'ailm',
                            ''
                        ]);
                        $has_links = true;
                    }
                }

                // --- SOURCE 2: Manual links (from scanner table) ---
                // Check if the monitor table exists
                // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching
                if ($wpdb->get_var($wpdb->prepare("SHOW TABLES LIKE %s", $scout_table))) {
                    // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching, PluginCheck.Security.DirectDB.UnescapedDBParameter
                    $manual_links = $wpdb->get_results($wpdb->prepare(
                        "SELECT url, anchor FROM {$scout_table} WHERE post_id = %d AND link_origin = %s", // phpcs:ignore WordPress.DB.PreparedSQL.InterpolatedNotPrepared -- Table name built from $wpdb->prefix.
                        $donor_id,
                        'manual'
                    ));

                    if (!empty($manual_links)) {
                        foreach ($manual_links as $m_link) {
                            fputcsv($output, [
                                $donor_id,
                                $donor_url,
                                $m_link->anchor,
                                $m_link->url,
                                url_to_postid($m_link->url), // Try to find target ID
                                'manual', // Origin
                                ''
                            ]);
                            $has_links = true;
                        }
                    }
                }

                // --- SOURCE 3: Articles WITHOUT links ---
                // If nothing was found for the article, output one empty row so it appears in the list
                if (!$has_links) {
                    fputcsv($output, [
                        $donor_id,
                        $donor_url,
                        '', // No keyword
                        '', // No URL
                        '', // No target ID
                        'none',
                        ''
                    ]);
                }
            }
        }

        // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fclose
        fclose($output);
        exit;
    }

    private function import_csv()
    {
        $notice = 'csv_error';

        // phpcs:disable WordPress.Security.NonceVerification.Missing -- Nonce verified in route_csv_actions() via check_admin_referer().
        if (!empty($_FILES['ailm_csv_file']['tmp_name'])) {
            $file_path = sanitize_text_field($_FILES['ailm_csv_file']['tmp_name']);
        // phpcs:enable

            // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fopen
            if (($handle = fopen($file_path, "r")) !== FALSE) {
                fgetcsv($handle, 1000, ","); // Skip headers

                $updates = [];

                // Read CSV
                while (($data = fgetcsv($handle, 1000, ",")) !== FALSE) {
                    if (count($data) < 5)
                        continue;

                    $donor_id = intval($data[0]);
                    $keyword = sanitize_text_field($data[2]);
                    $target_url = esc_url_raw($data[3]);
                    $target_id = intval($data[4]);
                    $origin = isset($data[5]) ? sanitize_text_field($data[5]) : 'ailm';
                    $action = isset($data[6]) ? strtolower(sanitize_text_field($data[6])) : '';

                    // CRITICAL CHANGE:
                    // Skip manual links and empty rows (none).
                    // The plugin must not touch what was placed manually in the text.
                    if (empty($donor_id) || empty($keyword) || empty($target_url) || $origin === 'manual' || $origin === 'none') {
                        continue;
                    }

                    if (!isset($updates[$donor_id])) {
                        $updates[$donor_id] = ['keep' => []];
                    }

                    if ($action !== 'delete') {
                        // Build array for AILM links only
                        $updates[$donor_id]['keep'][] = [
                            'word' => $keyword,
                            'url' => $target_url,
                            'target_id' => $target_id,
                            'occurrence' => 1,
                            'creation_type' => $origin
                        ];
                    }
                }
                // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fclose
                fclose($handle);

                // Apply changes to the database
                // DEPRECATED v2.0: _ailm_frozen_map meta is replaced by wp_ailm_link_rules.
                foreach ($updates as $donor_id => $instructions) {
                    // Overwrite rules in the unified table
                    foreach ($instructions['keep'] as $new_link) {
                        if (class_exists('AILM_Link_Repository')) {
                            // in_html=0: CSV import defines rules to be injected;
                            // the injector will insert the <a> and mark in_html=1.
                            AILM_Link_Repository::register_link(
                                $donor_id,
                                esc_url_raw($new_link['url']),
                                sanitize_text_field($new_link['word']),
                                sanitize_text_field($new_link['creation_type']),
                                1,
                                false
                            );
                        }
                    }

                    /*
                    $final_map = [];
                    foreach ( $instructions['keep'] as $new_link ) {
                        $final_map[] = $new_link;
                    }

                    if ( empty( $final_map ) ) {
                        delete_post_meta( $donor_id, '_ailm_frozen_map' );
                    } else {
                        update_post_meta( $donor_id, '_ailm_frozen_map', $final_map );
                    }
                    */

                    // Re-scan with 404 Scout
                    if (class_exists('AILM_Scout_Scanner')) {
                        AILM_Scout_Scanner::process_post($donor_id);
                    }
                }

                $notice = 'csv_sync_success';
            }
        }

        wp_safe_redirect(admin_url('admin.php?page=' . $this->plugin_name . '&tab=settings&ailm_notice=' . $notice));
        exit;
    }
}