<?php
/**
 * Plugin Name:       Advanced Custom Feeds for WooCommerce
 * Plugin URI:        https://wp-zip.com
 * Description:       Generate XML/CSV product feeds for WooCommerce with caching, options and feed management.
 * Version:           1.0.0
 * Author:            Pranav MT
 * Author URI:        https://wp-zip.com
 * License:           GPLv2 or later
 * License URI:       https://www.gnu.org/licenses/gpl-2.0.html
 * Text Domain:       advanced-custom-feeds-for-woocommerce
 * Domain Path:       /languages
 * Requires at least: 5.5
 * Requires PHP:      7.4
 */

if ( ! defined( 'ABSPATH' ) ) {
    exit;
}

define( 'ACFW_PLUGIN_FILE', __FILE__ );
define( 'ACFW_PLUGIN_DIR', plugin_dir_path( __FILE__ ) );
define( 'ACFW_PLUGIN_URL', plugin_dir_url( __FILE__ ) );
define( 'ACFW_OPTION_KEY', 'acfw_settings' );
define( 'ACFW_VERSION', '1.0.0' );

class ACFW_Plugin {

    public function __construct() {
        add_action( 'admin_menu', array( $this, 'register_menu' ) );
        add_action( 'admin_init', array( $this, 'maybe_handle_actions' ) );
        add_action( 'admin_enqueue_scripts', array( $this, 'enqueue_admin_assets' ) );
        register_activation_hook( ACFW_PLUGIN_FILE, array( $this, 'on_activate' ) );
    }

    public function on_activate() {
        $defaults = array(
            'feeds' => array(), // store feed definitions keyed by slug
            'general' => array(
                'include_out_of_stock' => 'no',
                'enable_cache' => 'yes',
                'cache_expiry' => 3600,
                'max_additional_images' => 3,
            ),
        );
        if ( false === get_option( ACFW_OPTION_KEY ) ) {
            update_option( ACFW_OPTION_KEY, $defaults );
        }
    }

    public function enqueue_admin_assets( $hook ) {
        if ( strpos( $hook, 'acfw-settings' ) === false && $hook !== 'toplevel_page_acfw-settings' ) return;
    wp_enqueue_style( 'acfw-admin', ACFW_PLUGIN_URL . 'assets/admin.css', array(), ACFW_VERSION );
    }

    public function register_menu() {
        add_menu_page( 'ACFW Feeds', 'ACFW Feeds', 'manage_options', 'acfw-settings', array( $this, 'settings_page' ), 'dashicons-alt' );
    }

    private function get_options() {
        $opts = get_option( ACFW_OPTION_KEY, array() );
        return wp_parse_args( $opts, array(
            'feeds' => array(),
            'general' => array(
                'include_out_of_stock' => 'no',
                'enable_cache' => 'yes',
                'cache_expiry' => 3600,
                'max_additional_images' => 3,
            ),
        ) );
    }

    public function maybe_handle_actions() {
        if ( ! current_user_can( 'manage_options' ) ) return;

        // handle create/update feed
        if ( isset( $_POST['acfw_save_feed'] ) ) {
            check_admin_referer( 'acfw_save_feed_action', 'acfw_nonce' );
            $this->save_feed_from_post();
            wp_safe_redirect( admin_url( 'admin.php?page=acfw-settings&tab=feeds&saved=1' ) );
            exit;
        }

        // handle generate feed
        if ( isset( $_POST['acfw_generate_feed'] ) ) {
            check_admin_referer( 'acfw_generate_feed_action', 'acfw_nonce' );
            // feed_slug sanitized via sanitize_title ensuring safe key for file naming.
            $slug   = isset( $_POST['feed_slug'] ) ? sanitize_title( wp_unslash( $_POST['feed_slug'] ) ) : '';
            $format = isset( $_POST['feed_format'] ) ? sanitize_key( wp_unslash( $_POST['feed_format'] ) ) : 'xml';
            if ( ! in_array( $format, array( 'xml','csv' ), true ) ) {
                $format = 'xml';
            }
            if ( $slug ) {
                $this->generate_feed( $slug, $format );
            }
            wp_safe_redirect( admin_url( 'admin.php?page=acfw-settings&tab=feeds&generated=' . rawurlencode( $slug ) . '&format=' . $format ) );
            exit;
        }

        // handle clear cache
        if ( isset( $_POST['acfw_clear_cache'] ) ) {
            check_admin_referer( 'acfw_clear_cache_action', 'acfw_nonce' );
            $slug = isset( $_POST['feed_slug'] ) ? sanitize_title( wp_unslash( $_POST['feed_slug'] ) ) : '';
            if ( $slug ) {
                $this->clear_feed_cache( $slug );
            }
            wp_safe_redirect( admin_url( 'admin.php?page=acfw-settings&tab=feeds&cleared=' . rawurlencode( $slug ) ) );
            exit;
        }

        // handle general settings save
        if ( isset( $_POST['acfw_save_general'] ) ) {
            check_admin_referer( 'acfw_save_general_action', 'acfw_nonce' );
            $opts = $this->get_options();
            $g = $opts['general'];
            $g['include_out_of_stock']   = isset( $_POST['include_out_of_stock'] ) ? 'yes' : 'no';
            $g['enable_cache']          = isset( $_POST['enable_cache'] ) ? 'yes' : 'no';
            $g['cache_expiry']          = isset( $_POST['cache_expiry'] ) ? intval( wp_unslash( $_POST['cache_expiry'] ) ) : $g['cache_expiry'];
            $g['max_additional_images'] = isset( $_POST['max_additional_images'] ) ? intval( wp_unslash( $_POST['max_additional_images'] ) ) : $g['max_additional_images'];
            $opts['general'] = $g;
            update_option( ACFW_OPTION_KEY, $opts );
            wp_safe_redirect( admin_url( 'admin.php?page=acfw-settings&tab=settings&saved=1' ) );
            exit;
        }
    }

    private function save_feed_from_post() {
        $opts  = $this->get_options();
        $name  = isset( $_POST['feed_name'] ) ? sanitize_text_field( wp_unslash( $_POST['feed_name'] ) ) : '';
        $slug_raw = isset( $_POST['feed_slug'] ) ? wp_unslash( $_POST['feed_slug'] ) : '';
        $slug  = $slug_raw !== '' ? sanitize_title( $slug_raw ) : sanitize_title( $name );
        $fmt_raw = isset( $_POST['feed_format'] ) ? sanitize_key( wp_unslash( $_POST['feed_format'] ) ) : 'xml';
        $format = in_array( $fmt_raw, array( 'xml','csv' ), true ) ? $fmt_raw : 'xml';

        if ( ! $name || ! $slug ) {
            return; // invalid
        }

        $opts['feeds'][ $slug ] = array(
            'name'    => $name,
            'slug'    => $slug,
            'format'  => $format,
            'created' => time(),
        );

        update_option( ACFW_OPTION_KEY, $opts );
    }

    public function settings_page() {
        $opts = $this->get_options();
    $tab = isset( $_GET['tab'] ) ? sanitize_key( wp_unslash( $_GET['tab'] ) ) : 'feeds';
        ?>
        <div class="wrap">
            <h1>Advanced Custom Feeds for WooCommerce (ACFW)</h1>
            <h2 class="nav-tab-wrapper">
                <?php
                $tabs = array(
                    'feeds'    => __( 'Feeds', 'advanced-custom-feeds-for-woocommerce' ),
                    'settings' => __( 'Settings', 'advanced-custom-feeds-for-woocommerce' ),
                    'info'     => __( 'FAQ & Info', 'advanced-custom-feeds-for-woocommerce' ),
                );
                foreach ( $tabs as $t_slug => $label ) {
                    $url  = esc_url( admin_url( 'admin.php?page=acfw-settings&tab=' . $t_slug ) );
                    $cls  = $tab === $t_slug ? 'nav-tab nav-tab-active' : 'nav-tab';
                    echo '<a class="' . esc_attr( $cls ) . '" href="' . $url . '">' . esc_html( $label ) . '</a>';// phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped -- Escaped above
                }
                ?>
            </h2>

            <?php if ( isset($_GET['generated']) ) :
                $slug = sanitize_title( wp_unslash( $_GET['generated'] ) );
                $format = isset($_GET['format']) ? sanitize_key( wp_unslash( $_GET['format'] ) ) : 'xml';
                $file = $this->get_feed_file_path( $slug, $format );
                $url = $this->get_feed_file_url( $slug, $format );
                if ( file_exists( $file ) ) {
                    // translators: %s is the feed slug (already escaped and wrapped in <strong> tags).
                    echo '<div class="notice notice-success is-dismissible"><p>' . sprintf( esc_html__( 'Feed generated: %s', 'advanced-custom-feeds-for-woocommerce' ), '<strong>' . esc_html( $slug ) . '</strong>' ) . '</p></div>';
                    echo '<p><a class="button button-primary" href="' . esc_url( $url ) . '" target="_blank">' . esc_html__( 'View feed', 'advanced-custom-feeds-for-woocommerce' ) . '</a> <span style="margin-left:10px">' . esc_html__( 'Feed URL:', 'advanced-custom-feeds-for-woocommerce' ) . ' <code>' . esc_html( $url ) . '</code></span></p>';// phpcs:ignore WordPress.Security.EscapeOutput.OutputNotEscaped
                } else {
                    echo '<div class="notice notice-error"><p>' . esc_html__( 'Feed generation failed or file missing.', 'advanced-custom-feeds-for-woocommerce' ) . '</p></div>';
                }
            endif; ?>

            <?php if ( $tab === 'feeds' ) : ?>

                <h2>Create / Edit Feed</h2>
                <form method="post">
                    <?php // Nonce for creating/editing a feed. ?>
                    <?php wp_nonce_field( 'acfw_save_feed_action', 'acfw_nonce' ); ?>
                    <table class="form-table">
                        <tr>
                            <th><label for="feed_name">Name of the feed</label></th>
                            <td><input name="feed_name" id="feed_name" class="regular-text" required></td>
                        </tr>
                        <tr>
                            <th><label for="feed_slug">Feed slug (default the name)</label></th>
                            <td><input name="feed_slug" id="feed_slug" class="regular-text"></td>
                        </tr>
                        <tr>
                            <th><label for="feed_format">Format</label></th>
                            <td>
                                <select name="feed_format" id="feed_format">
                                    <option value="xml">XML</option>
                                    <option value="csv">CSV</option>
                                </select>
                            </td>
                        </tr>
                    </table>
                    <p class="submit"><button type="submit" name="acfw_save_feed" class="button button-primary">Save Feed</button></p>
                </form>

                <hr/>

                <h2>Existing Feeds</h2>
                <?php if ( empty($opts['feeds']) ) : ?>
                    <p>No feeds configured yet.</p>
                <?php else: ?>
                    <table class="widefat">
                        <thead><tr><th>Name</th><th>Slug</th><th>Format</th><th>Actions</th></tr></thead>
                        <tbody>
                        <?php foreach( $opts['feeds'] as $feed ) :
                            $slug = $feed['slug'];
                            $format = $feed['format'];
                            $file = $this->get_feed_file_path($slug,$format);
                            $url = $this->get_feed_file_url($slug,$format);
                            ?>
                            <tr>
                                <td><?php echo esc_html( $feed['name'] ); ?></td>
                                <td><?php echo esc_html( $slug ); ?></td>
                                <td><?php echo esc_html( strtoupper($format) ); ?></td>
                                <td>
                                    <form method="post" style="display:inline-block;margin-right:8px;">
                                        <?php // Nonce for generating a feed. ?>
                                        <?php wp_nonce_field( 'acfw_generate_feed_action', 'acfw_nonce' ); ?>
                                        <input type="hidden" name="feed_slug" value="<?php echo esc_attr( $slug ); ?>">
                                        <input type="hidden" name="feed_format" value="<?php echo esc_attr( $format ); ?>">
                                        <button class="button" name="acfw_generate_feed">Generate</button>
                                    </form>

                                    <form method="post" style="display:inline-block;margin-right:8px;">
                                        <?php // Nonce for clearing feed cache. ?>
                                        <?php wp_nonce_field( 'acfw_clear_cache_action', 'acfw_nonce' ); ?>
                                        <input type="hidden" name="feed_slug" value="<?php echo esc_attr( $slug ); ?>">
                                        <button class="button" name="acfw_clear_cache">Clear cache</button>
                                    </form>

                                    <?php if ( file_exists( $file ) ) : ?>
                                        <a class="button" href="<?php echo esc_url( $url ); ?>" target="_blank"><?php esc_html_e( 'View', 'advanced-custom-feeds-for-woocommerce' ); ?></a>
                                        <span style="margin-left:8px;"><?php esc_html_e( 'Updated:', 'advanced-custom-feeds-for-woocommerce' ); ?> <?php echo esc_html( gmdate( 'Y-m-d H:i:s', filemtime( $file ) ) ); ?></span>
                                    <?php else: ?>
                                        <span class="dashicons dashicons-warning" title="Feed file not generated yet"></span>
                                    <?php endif; ?>

                                </td>
                            </tr>
                        <?php endforeach; ?>
                        </tbody>
                    </table>
                <?php endif; ?>

            <?php elseif ( $tab === 'settings' ) :
                $g = $opts['general'];
                ?>
                <h2>General Settings</h2>
                <form method="post">
                    <?php // Nonce for saving general settings. ?>
                    <?php wp_nonce_field( 'acfw_save_general_action', 'acfw_nonce' ); ?>
                    <table class="form-table">
                        <tr>
                            <th>Include out of stock products</th>
                            <td><input type="checkbox" name="include_out_of_stock" <?php checked( $g['include_out_of_stock'], 'yes' ); ?>></td>
                        </tr>
                        <tr>
                            <th>Enable cache</th>
                            <td><input type="checkbox" name="enable_cache" <?php checked( $g['enable_cache'], 'yes' ); ?>></td>
                        </tr>
                        <tr>
                            <th>Cache expiry time (seconds)</th>
                            <td><input type="number" name="cache_expiry" value="<?php echo esc_attr( $g['cache_expiry'] ); ?>" min="0"></td>
                        </tr>
                        <tr>
                            <th>Maximum additional images per product</th>
                            <td><input type="number" name="max_additional_images" value="<?php echo esc_attr( $g['max_additional_images'] ); ?>" min="0"></td>
                        </tr>
                    </table>
                    <p class="submit"><button type="submit" name="acfw_save_general" class="button button-primary">Save Settings</button></p>
                </form>

            <?php else: // info tab ?>
                <h2>FAQ & Plugin Info</h2>
                <h3>What does this plugin do?</h3>
                <p>Generates XML or CSV product feeds for your WooCommerce store. Configure multiple feeds, generate them on demand and serve them via a URL.</p>
                <h3>Where are feeds stored?</h3>
                <p>Feeds are stored in <code>wp-content/uploads/acfw-feeds/</code> and are accessible publicly unless your server blocks access.</p>
                <h3>Support</h3>
                <p>Author: Pranav MT</p>
            <?php endif; ?>
        </div>
        <?php
    }

    private function get_feed_dir() {
        $upload = wp_upload_dir();
        $dir = trailingslashit( $upload['basedir'] ) . 'acfw-feeds/';
        if ( ! file_exists( $dir ) ) {
            wp_mkdir_p( $dir );
        }
        return $dir;
    }

    private function get_feed_file_path( $slug, $format ) {
        return $this->get_feed_dir() . $slug . '.' . $format;
    }

    private function get_feed_file_url( $slug, $format ) {
        $upload = wp_upload_dir();
        return trailingslashit( $upload['baseurl'] ) . 'acfw-feeds/' . $slug . '.' . $format;
    }

    private function clear_feed_cache( $slug ) {
        foreach ( array( 'xml', 'csv' ) as $fmt ) {
            $file = $this->get_feed_file_path( $slug, $fmt );
            if ( file_exists( $file ) ) {
                wp_delete_file( $file );
            }
        }
    }

    private function generate_feed( $slug, $format = 'xml' ) {
        // generate and save feed file
        $opts = $this->get_options();
        $g = $opts['general'];
        $include_oos = ( $g['include_out_of_stock'] === 'yes' );
        $max_images = max( 0, intval( $g['max_additional_images'] ) );

        // respect caching: if enabled and file recent, do nothing
        $file = $this->get_feed_file_path( $slug, $format );
        $use_cache = ( $g['enable_cache'] === 'yes' );
        if ( $use_cache && file_exists( $file ) ) {
            $age = time() - filemtime( $file );
            if ( $age < intval( $g['cache_expiry'] ) ) return; // keep existing file
        }

        // prepare WP_Query for products
        if ( ! class_exists( 'WooCommerce' ) && ! post_type_exists( 'product' ) ) {
            // no products, write empty feed
            $content = $this->render_empty_feed( $format );
            file_put_contents( $file, $content );
            return;
        }

    // Potentially heavy queries: meta_query and tax_query can be filtered for optimization if needed.
    $meta_query = WC()->query ? WC()->query->get_meta_query() : array();
    $tax_query = array();

        $args = array(
            'post_type' => 'product',
            'posts_per_page' => -1,
            'post_status' => 'publish',
            'meta_query' => $meta_query,
            'tax_query' => $tax_query,
        );

        if ( ! $include_oos ) {
            // only in-stock products
            $args['meta_query'][] = array(
                'key' => '_stock_status',
                'value' => 'instock',
            );
        }

        $q = new WP_Query( $args );

        $rows = array();
        while ( $q->have_posts() ) {
            $q->the_post();
            $product = wc_get_product( get_the_ID() );
            if ( ! $product ) continue;
            $row = array(
                'id' => $product->get_id(),
                'title' => $product->get_name(),
                'sku' => $product->get_sku(),
                'price' => $product->get_price(),
                'url' => $product->get_permalink(),
                'image' => wp_get_attachment_url( $product->get_image_id() ),
                'stock_status' => $product->is_in_stock() ? 'instock' : 'outofstock',
            );

            // additional images
            $gallery = $product->get_gallery_image_ids();
            $extra = array();
            if ( ! empty( $gallery ) && $max_images > 0 ) {
                $taken = array_slice( $gallery, 0, $max_images );
                foreach ( $taken as $att_id ) {
                    $extra[] = wp_get_attachment_url( $att_id );
                }
            }
            $row['additional_images'] = $extra;

            $rows[] = $row;
        }
        wp_reset_postdata();

        if ( $format === 'csv' ) {
            $content = $this->render_csv( $rows );
        } else {
            $content = $this->render_xml( $rows );
        }

        file_put_contents( $file, $content );
    }

    private function render_empty_feed( $format ) {
        if ( $format === 'csv' ) return "id,title,sku,price,url,image,stock_status,additional_images\n";
        $xml = new SimpleXMLElement( '<products/>' );
        return $xml->asXML();
    }

    private function render_csv( $rows ) {
        $headers = array( 'id','title','sku','price','url','image','stock_status','additional_images' );
        $csv_lines = array();
        $csv_lines[] = $this->csv_join( $headers );
        foreach ( $rows as $r ) {
            $csv_lines[] = $this->csv_join( array(
                $r['id'],
                $r['title'],
                $r['sku'],
                $r['price'],
                $r['url'],
                $r['image'],
                $r['stock_status'],
                implode( '|', $r['additional_images'] ),
            ) );
        }
        return implode( "\r\n", $csv_lines ) . "\r\n"; // final newline
    }

    private function csv_join( $fields ) {
        $escaped = array();
        foreach ( $fields as $field ) {
            $field = (string) $field;
            $needs_quotes = ( strpos( $field, ',' ) !== false || strpos( $field, '"' ) !== false || strpos( $field, "\n" ) !== false || strpos( $field, "\r" ) !== false );
            $field = str_replace( '"', '""', $field );
            if ( $needs_quotes ) {
                $field = '"' . $field . '"';
            }
            $escaped[] = $field;
        }
        return implode( ',', $escaped );
    }

    private function render_xml( $rows ) {
        $xml = new SimpleXMLElement( '<products/>' );
        foreach ( $rows as $r ) {
            $p = $xml->addChild( 'product' );
            $p->addChild( 'id', esc_html( $r['id'] ) );
            $p->addChild( 'title', htmlspecialchars( $r['title'] ) );
            $p->addChild( 'sku', htmlspecialchars( $r['sku'] ) );
            $p->addChild( 'price', htmlspecialchars( $r['price'] ) );
            $p->addChild( 'url', htmlspecialchars( $r['url'] ) );
            $p->addChild( 'image', htmlspecialchars( $r['image'] ) );
            $p->addChild( 'stock_status', htmlspecialchars( $r['stock_status'] ) );
            if ( ! empty( $r['additional_images'] ) ) {
                $imgs = $p->addChild( 'additional_images' );
                foreach ( $r['additional_images'] as $im ) {
                    $imgs->addChild( 'image', htmlspecialchars( $im ) );
                }
            }
        }
        // force header and formatting will be handled by file
        return $xml->asXML();
    }

}

new ACFW_Plugin();

// Note: This single-file plugin is intentionally minimal and focuses on the requested features:
// - Admin settings with tabs (Feeds / Settings / FAQ & Info)
// - Save feed definition (name, slug, format)
// - Generate feed (XML/CSV) stored under uploads/acfw-feeds/
// - Cache control via settings and clear cache per-feed
// - View feed button and feed URL after generation
//
// To use: save this file as "acfw-advanced-custom-feeds-for-woocommerce.php" inside a folder named
// "advanced-custom-feeds-for-woocommerce" in wp-content/plugins/. Then activate the plugin and go to
// the ACFW Feeds admin page.