<?php
namespace Zadex\Admin;

defined('ABSPATH') || exit;

use Zadex\Library\Kits;
use Zadex\Library\SiteKit;
use Zadex\Settings;

/**
 * Admin page "Zadex → Import / Export" (manage_options): download a site kit zip, import one, and set the
 * remote template library URL.
 *
 * admin-post actions: zadex_kit_export, zadex_kit_import, zadex_library_url (all nonce-checked).
 */
final class ImportExport
{
    public const PAGE = 'zadex-kit';
    public const EXPORT = 'zadex_kit_export';
    public const IMPORT = 'zadex_kit_import';
    public const LIBRARY_URL = 'zadex_library_url';
    public const REPORT = 'zadex_kit_report_';
    public const MAX_UPLOAD = 67108864; // 64 MB

    private SiteKit $kit;
    private Settings $settings;
    private Kits $kits;

    public function __construct(SiteKit $kit, Settings $settings, Kits $kits)
    {
        $this->kit = $kit;
        $this->settings = $settings;
        $this->kits = $kits;
    }

    public function register(): void
    {
        // After Admin::menu() (priority 10) so the "Zadex" parent exists.
        add_action('admin_menu', [$this, 'menu'], 20);
        add_action('admin_post_' . self::EXPORT, [$this, 'handle_export']);
        add_action('admin_post_' . self::IMPORT, [$this, 'handle_import']);
        add_action('admin_post_' . self::LIBRARY_URL, [$this, 'handle_library_url']);
    }

    public function menu(): void
    {
        add_submenu_page('zadex', __('Import / Export', 'zadex'), __('Import / Export', 'zadex'), 'manage_options', self::PAGE, [$this, 'render']);
    }

    public static function page_url(array $args = []): string
    {
        return add_query_arg(array_merge(['page' => self::PAGE], $args), admin_url('admin.php'));
    }

    public static function max_upload(): int
    {
        $max = (int) apply_filters('zadex/kit/max_upload', self::MAX_UPLOAD);
        if (function_exists('wp_max_upload_size')) {
            $max = min($max, (int) wp_max_upload_size());
        }
        return max(1, $max);
    }

    private function require_capability(): void
    {
        if (!current_user_can('manage_options')) {
            wp_die(esc_html__('You are not allowed to do this.', 'zadex'), '', ['response' => 403]);
        }
    }

    public function handle_export(): void
    {
        $this->require_capability();
        check_admin_referer(self::EXPORT);
        $ids = isset($_POST['pages']) && is_array($_POST['pages']) ? array_filter(array_map('absint', wp_unslash($_POST['pages']))) : [];
        $library = !empty($_POST['library']);
        $global = !empty($_POST['global']);
        $tmp = function_exists('wp_tempnam') ? (string) wp_tempnam('zadex-kit.zip') : (string) tempnam(sys_get_temp_dir(), 'zxk');
        $result = $this->kit->export_zip($tmp, array_values($ids), $library, $global);
        if (is_wp_error($result)) {
            wp_delete_file($tmp);
            wp_die(esc_html($result->get_error_message()));
        }
        $name = 'zadex-kit-' . gmdate('Y-m-d') . '.zip';
        // Anything already buffered (notices printed by other code in debug mode) would corrupt the zip.
        while (ob_get_level() > 0) {
            ob_end_clean();
        }
        nocache_headers();
        header('Content-Type: application/zip');
        header('Content-Disposition: attachment; filename="' . $name . '"');
        header('Content-Length: ' . (string) filesize($tmp));
        // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_readfile -- streams our own temp zip to the browser; WP_Filesystem has no streaming read.
        readfile($tmp);
        wp_delete_file($tmp);
        exit;
    }

    /**
     * Validates an uploaded kit (`$_FILES['kit']`).
     *
     * @return string|\WP_Error path of the uploaded temp file
     */
    public static function validate_upload($file)
    {
        if (!is_array($file) || !isset($file['tmp_name'], $file['name'], $file['error'])) {
            return new \WP_Error('zadex_no_file', __('Choose a kit file (.zip) to import.', 'zadex'));
        }
        if ((int) $file['error'] !== 0) {
            return new \WP_Error('zadex_upload_error', __('The upload failed. The file may be larger than the server allows.', 'zadex'));
        }
        if (strtolower(pathinfo((string) $file['name'], PATHINFO_EXTENSION)) !== 'zip') {
            return new \WP_Error('zadex_bad_type', __('A site kit is a .zip file.', 'zadex'));
        }
        $size = (int) ($file['size'] ?? 0);
        if ($size <= 0 || $size > self::max_upload()) {
            return new \WP_Error('zadex_too_large', __('The kit file is empty or too large.', 'zadex'));
        }
        $tmp = (string) $file['tmp_name'];
        if (!is_file($tmp) || (function_exists('is_uploaded_file') && !is_uploaded_file($tmp) && !apply_filters('zadex/kit/allow_local_file', false, $tmp))) {
            return new \WP_Error('zadex_no_file', __('Choose a kit file (.zip) to import.', 'zadex'));
        }
        // Only the 4-byte zip signature of the PHP upload temp file is read; WP_Filesystem has no partial read.
        $fh = fopen($tmp, 'rb'); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fopen -- reads the zip magic bytes of the upload temp file.
        $magic = $fh ? (string) fread($fh, 4) : ''; // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fread -- see above.
        if ($fh) {
            fclose($fh); // phpcs:ignore WordPress.WP.AlternativeFunctions.file_system_operations_fclose -- see above.
        }
        if ($magic !== "PK\x03\x04") {
            return new \WP_Error('zadex_bad_type', __('The file is not a valid zip archive.', 'zadex'));
        }
        return $tmp;
    }

    public function handle_import(): void
    {
        $this->require_capability();
        check_admin_referer(self::IMPORT);
        $options = [
            'status'  => isset($_POST['status']) && sanitize_key(wp_unslash($_POST['status'])) === 'publish' ? 'publish' : 'draft',
            'global'  => !empty($_POST['global']),
            'library' => !empty($_POST['library']),
        ];
        $path = self::validate_upload(UploadedFile::from_request('kit', self::IMPORT));
        $report = null;
        if (is_wp_error($path)) {
            $report = ['error' => $path->get_error_message()];
        } else {
            $result = $this->kit->import_zip($path, $options);
            $report = is_wp_error($result) ? ['error' => $result->get_error_message()] : $result;
        }
        if (is_string($path) && is_file($path)) {
            wp_delete_file($path);
        }
        set_transient(self::REPORT . get_current_user_id(), $report, 600);
        wp_safe_redirect(self::page_url());
        exit;
    }

    public function handle_library_url(): void
    {
        $this->require_capability();
        check_admin_referer(self::LIBRARY_URL);
        $url = isset($_POST['library_url']) ? trim(esc_url_raw(wp_unslash($_POST['library_url']))) : '';
        $this->kits->flush_cache();
        $this->settings->update(['library_url' => preg_match('#^https?://#i', $url) ? $url : '']);
        $this->kits->flush_cache();
        Notices::add(self::PAGE, __('Template library source saved.', 'zadex'));
        wp_safe_redirect(self::page_url());
        exit;
    }

    public function render(): void
    {
        if (!current_user_can('manage_options')) {
            return;
        }
        $pages = $this->kit->exportable_pages();
        // The import report is stored per user by handle_import() and shown once, on this screen only.
        $report = get_transient(self::REPORT . get_current_user_id());
        if ($report !== false) {
            delete_transient(self::REPORT . get_current_user_id());
        }
        echo '<div class="wrap zadex-kit" data-testid="zadex-kit-page">';
        echo '<h1>' . esc_html__('Import / Export', 'zadex') . '</h1>';
        $this->render_report($report);
        Notices::render(self::PAGE);

        // Export.
        echo '<h2>' . esc_html__('Export a site kit', 'zadex') . '</h2>';
        echo '<p>' . esc_html__('Downloads a .zip with the selected Zadex pages, your saved templates, the site settings (colours, fonts, breakpoints) and every image they use.', 'zadex') . '</p>';
        echo '<form method="post" action="' . esc_url(admin_url('admin-post.php')) . '" id="zadex-kit-export">';
        wp_nonce_field(self::EXPORT);
        echo '<input type="hidden" name="action" value="' . esc_attr(self::EXPORT) . '">';
        if ($pages) {
            echo '<fieldset style="max-height:260px;overflow:auto;border:1px solid #c3c4c7;background:#fff;padding:8px 12px;max-width:640px"><legend class="screen-reader-text">' . esc_html__('Pages', 'zadex') . '</legend>';
            echo '<p style="margin:4px 0 8px"><button type="button" class="button-link" data-zadex-check="all">' . esc_html__('Select all', 'zadex') . '</button> · <button type="button" class="button-link" data-zadex-check="none">' . esc_html__('Select none', 'zadex') . '</button></p>';
            foreach ($pages as $p) {
                echo '<label style="display:block;margin:2px 0"><input type="checkbox" name="pages[]" value="' . esc_attr((string) $p['id']) . '" checked> ' . esc_html($p['title'] !== '' ? $p['title'] : __('(no title)', 'zadex')) . ' <span class="description">(' . esc_html($p['type'] . ', ' . $p['status']) . ')</span></label>';
            }
            echo '</fieldset>';
        } else {
            echo '<p class="description">' . esc_html__('No pages are built with Zadex yet; the kit will contain the site settings and templates only.', 'zadex') . '</p>';
        }
        echo '<p><label><input type="checkbox" name="library" value="1" checked> ' . esc_html__('Include saved templates', 'zadex') . '</label><br>';
        echo '<label><input type="checkbox" name="global" value="1" checked> ' . esc_html__('Include site settings', 'zadex') . '</label></p>';
        submit_button(__('Download kit', 'zadex'), 'primary', 'submit', false, ['id' => 'zadex-kit-download']);
        echo '</form>';
        wp_register_script('zadex-kit-export', false, [], ZADEX_VERSION, true);
        wp_add_inline_script('zadex-kit-export', 'document.querySelectorAll("[data-zadex-check]").forEach(function(b){b.addEventListener("click",function(){var on=b.getAttribute("data-zadex-check")==="all";document.querySelectorAll("#zadex-kit-export input[name=\'pages[]\']").forEach(function(c){c.checked=on;});});});');
        wp_enqueue_script('zadex-kit-export');

        // Import.
        echo '<hr><h2>' . esc_html__('Import a site kit', 'zadex') . '</h2>';
        /* translators: %s: maximum upload file size, e.g. "8 MB". */
        echo '<p>' . esc_html(sprintf(__('Creates the kit\'s pages, adds its templates and images to this site and applies its site settings. Maximum file size: %s.', 'zadex'), size_format(self::max_upload()))) . '</p>';
        echo '<form method="post" enctype="multipart/form-data" action="' . esc_url(admin_url('admin-post.php')) . '" id="zadex-kit-import">';
        wp_nonce_field(self::IMPORT);
        echo '<input type="hidden" name="action" value="' . esc_attr(self::IMPORT) . '">';
        echo '<p><input type="file" name="kit" accept=".zip,application/zip" required></p>';
        echo '<p>' . esc_html__('Create pages as', 'zadex') . ': <label><input type="radio" name="status" value="draft" checked> ' . esc_html__('Drafts', 'zadex') . '</label> <label><input type="radio" name="status" value="publish"> ' . esc_html__('Published', 'zadex') . '</label></p>';
        echo '<p><label><input type="checkbox" name="global" value="1" checked> ' . esc_html__('Apply the kit\'s site settings (colours, fonts, breakpoints)', 'zadex') . '</label><br>';
        echo '<label><input type="checkbox" name="library" value="1" checked> ' . esc_html__('Import saved templates', 'zadex') . '</label></p>';
        submit_button(__('Import kit', 'zadex'), 'primary', 'submit', false, ['id' => 'zadex-kit-import-submit']);
        echo '</form>';

        // Remote library.
        echo '<hr><h2>' . esc_html__('Template library source', 'zadex') . '</h2>';
        echo '<p>' . esc_html__('URL of a kits.json index for the editor\'s template library. Leave empty to use the starter kits bundled with Zadex. Remote results are cached for 12 hours.', 'zadex') . '</p>';
        echo '<form method="post" action="' . esc_url(admin_url('admin-post.php')) . '">';
        wp_nonce_field(self::LIBRARY_URL);
        echo '<input type="hidden" name="action" value="' . esc_attr(self::LIBRARY_URL) . '">';
        echo '<p><input type="url" class="regular-text" name="library_url" value="' . esc_attr((string) $this->settings->get('library_url', '')) . '" placeholder="https://example.com/kits.json"></p>';
        submit_button(__('Save source', 'zadex'), 'secondary', 'submit', false);
        echo '</form>';
        echo '</div>';
    }

    /** @param array<string, mixed>|false $report */
    private function render_report($report): void
    {
        if (!is_array($report)) {
            return;
        }
        if (isset($report['error'])) {
            echo '<div class="notice notice-error" data-testid="zadex-kit-error"><p>' . esc_html((string) $report['error']) . '</p></div>';
            return;
        }
        $pages = is_array($report['pages'] ?? null) ? $report['pages'] : [];
        echo '<div class="notice notice-success" data-testid="zadex-kit-report"><p><strong>' . esc_html__('Kit imported.', 'zadex') . '</strong> ';
        echo esc_html(sprintf(
            /* translators: 1: pages, 2: templates, 3: media files */
            __('%1$d pages, %2$d templates and %3$d media files were created.', 'zadex'),
            count($pages),
            (int) ($report['library'] ?? 0),
            (int) ($report['media'] ?? 0)
        ));
        if (!empty($report['global'])) {
            echo ' ' . esc_html__('Site settings were applied.', 'zadex');
        }
        echo '</p>';
        if ($pages) {
            echo '<ul style="list-style:disc;margin-left:20px">';
            foreach ($pages as $p) {
                $id = (int) ($p['id'] ?? 0);
                $link = function_exists('get_edit_post_link') ? (string) get_edit_post_link($id) : '';
                echo '<li data-zadex-imported="' . esc_attr((string) $id) . '"><a href="' . esc_url($link) . '">' . esc_html((string) ($p['title'] ?? '')) . '</a></li>';
            }
            echo '</ul>';
        }
        foreach (is_array($report['errors'] ?? null) ? $report['errors'] : [] as $err) {
            echo '<p class="description">' . esc_html((string) $err) . '</p>';
        }
        echo '</div>';
    }
}