<?php
namespace CustomFields;
defined('ABSPATH') || exit;

/** Reviewed read-only JSON imports. Exports are authenticated browser downloads. */
final class DefinitionSync {
    const STATE = 'customfields_json_sync_state';
    private static $applying = false;
    public static function boot() {
        remove_action('customfields_schema_saved', array(Portability::class, 'export_local'));
        add_action('admin_menu', array(__CLASS__, 'menu'), 25);
        add_action('admin_post_customfields_sync', array(__CLASS__, 'handle'));
        add_action('customfields_schema_review_committing', array(__CLASS__, 'committing'), 10, 2);
    }
    private static function error($message) { return new \WP_Error('customfields_sync', $message); }
    private static function key() { return 'customfields_sync_review_' . get_current_user_id(); }
    private static function hash($groups) { return hash('sha256', Schema::encode($groups)); }
    public static function directory() {
        if (!defined('CUSTOMFIELDS_JSON_DIR')) { return self::error(__('No legacy file source is configured. Download JSON or use the field builder to review an import.', 'customfields-com')); }
        return Portability::local_path(CUSTOMFIELDS_JSON_DIR, true);
    }
    /** Configured directories are read only, including all temporary and lock files. */
    public static function read() {
        $dir = self::directory(); if (is_wp_error($dir)) { return $dir; }
        $path = $dir . '/customfields-schema.json'; clearstatcache(true, $path);
        if (is_link($path) || (file_exists($path) && !is_file($path))) { return self::error(__('The schema path must be a regular file, not a link.', 'customfields-com')); }
        if (!file_exists($path)) { return array('directory' => $dir, 'hash' => null, 'groups' => null); }
        $json = Portability::read_local($path); if (is_wp_error($json)) { return $json; }
        $groups = Schema::decode($json); if (is_wp_error($groups)) { return $groups; }
        return array('directory' => $dir, 'hash' => hash('sha256', $json), 'groups' => $groups);
    }
    public static function status() {
        $file = self::read(); if (is_wp_error($file)) { return $file; }
        $db = self::hash(customfields_get_groups()); $state = get_option(self::STATE, array());
        $same = $file['groups'] !== null && $db === self::hash($file['groups']);
        $tracked = ($state['directory'] ?? '') === $file['directory'];
        $file_changed = !$tracked || $file['hash'] !== ($state['file_hash'] ?? null);
        $db_changed = !$tracked || $db !== ($state['schema_hash'] ?? null);
        $file['schema_hash'] = $db;
        $file['status'] = $same ? 'synchronized' : ($file['hash'] === null ? 'missing' : ($file_changed && $db_changed ? 'conflict' : ($file_changed ? 'file_changed' : 'database_changed')));
        return $file;
    }
    /** Serialize site imports without creating a lock file in the source directory. */
    private static function lock() {
        global $wpdb;
        $name = 'customfields_sync_' . substr(hash('sha256', DB_NAME . ':' . $wpdb->options), 0, 40);
        $locked = $wpdb->get_var($wpdb->prepare('SELECT GET_LOCK(%s, 0)', $name)); // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Connection-scoped import lock; WordPress has no advisory-lock API and the result must not be cached.
        return (string) $locked === '1' ? $name : self::error(__('Another definition import is running, or the database cannot acquire its lock. Try again later.', 'customfields-com'));
    }
    private static function unlock($lock) {
        global $wpdb;
        $wpdb->get_var($wpdb->prepare('SELECT RELEASE_LOCK(%s)', $lock)); // phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery,WordPress.DB.DirectDatabaseQuery.NoCaching -- Release the connection-scoped import lock acquired above.
    }
    private static function remember($file, $groups) {
        $state = array('directory' => $file['directory'], 'file_hash' => $file['hash'], 'schema_hash' => self::hash($groups), 'time' => time());
        update_option(self::STATE, $state, false); wp_cache_delete(self::STATE, 'options');
        if (get_option(self::STATE) !== $state) { return self::error(__('Could not save the import baseline. Review again before another import.', 'customfields-com')); }
        return true;
    }
    /** Compatibility callbacks: committed schema saves remain in the database only. */
    public static function queue($groups, $before = array()) {}
    public static function flush() {}
    public static function preview($direction) {
        if (!current_user_can('manage_options')) { return self::error(__('Administrator access required.', 'customfields-com')); }
        if ($direction !== 'import') { return self::error(__('File exports have been replaced by Download JSON. No server file was written.', 'customfields-com')); }
        $file = self::status(); if (is_wp_error($file)) { return $file; }
        $current = Schema::validate_groups(customfields_get_groups()); if (is_wp_error($current)) { return $current; }
        if ($file['groups'] === null) { return self::error(__('The configured source has no schema file. Use the field builder to review a JSON import.', 'customfields-com')); }
        $groups = $file['groups'];
        $review = Local\Workflows::preview_schema($groups, array('kind' => 'file-sync'));
        if (is_wp_error($review)) { return $review; }
        $plan = array('id' => wp_generate_uuid4(), 'direction' => $direction, 'file' => $file, 'groups' => $groups, 'review' => $review);
        set_transient(self::key(), $plan, 15 * MINUTE_IN_SECONDS); return $plan;
    }
    public static function apply($id) {
        if (!current_user_can('manage_options')) { return self::error(__('Administrator access required.', 'customfields-com')); }
        $plan = get_transient(self::key());
        if (!is_array($plan) || ($plan['direction'] ?? '') !== 'import' || !is_string($id) || !isset($plan['id']) || !is_string($plan['id']) || !hash_equals($plan['id'], $id)) { return self::error(__('The import review expired or is no longer supported. Review again.', 'customfields-com')); }
        $lock = self::lock(); if (is_wp_error($lock)) { return $lock; }
        try {
            $file = self::status(); if (is_wp_error($file)) { return $file; }
            foreach (array('directory', 'hash', 'schema_hash') as $key) { if ($file[$key] !== $plan['file'][$key]) { return self::error(__('The database or file changed after review. Review the differences again.', 'customfields-com')); } }
            self::$applying = $plan;
            $result = Local\Workflows::restore($plan['review']['id']);
            if (!is_wp_error($result)) { delete_transient(self::key()); }
            return $result;
        } finally { self::$applying = false; wp_cache_delete(self::STATE, 'options'); self::unlock($lock); }
    }
    public static function committing($preview, $groups) {
        if (($preview['context']['kind'] ?? '') !== 'file-sync') { return; }
        if (!self::$applying || self::$applying['review']['id'] !== $preview['id']) { throw new \RuntimeException(__('Apply file changes from the Definition files review.', 'customfields-com')); } // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Internal exception transport, not an HTML output sink; public handlers escape the resulting error at rendering time.
        $fresh = self::read();
        if (is_wp_error($fresh) || $fresh['hash'] !== self::$applying['file']['hash'] || $fresh['directory'] !== self::$applying['file']['directory']) { throw new \RuntimeException(__('The JSON file changed while applying the review.', 'customfields-com')); } // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Internal exception transport, not an HTML output sink; public handlers escape the resulting error at rendering time.
        $result = self::remember($fresh, $groups); if (is_wp_error($result)) { throw new \RuntimeException($result->get_error_message()); } // phpcs:ignore WordPress.Security.EscapeOutput.ExceptionNotEscaped -- Internal exception transport, not an HTML output sink; public handlers escape the resulting error at rendering time.
    }
    public static function menu() { add_submenu_page('customfields', __('Definition files', 'customfields-com'), __('Definition files', 'customfields-com'), 'manage_options', 'customfields-sync', array(__CLASS__, 'page')); }
    public static function handle() {
        if (!current_user_can('manage_options')) { wp_die('Administrator access required.', '', array('response' => 403)); }
        $nonce = isset($_POST['_wpnonce']) && is_string($_POST['_wpnonce']) ? sanitize_text_field(wp_unslash($_POST['_wpnonce'])) : '';
        if (!wp_verify_nonce($nonce, 'customfields_sync')) { wp_die(esc_html__('Your session expired. Reload the definition files page.', 'customfields-com'), '', array('response' => 403)); }
        $operation = isset($_POST['operation']) && is_string($_POST['operation']) ? sanitize_text_field(wp_unslash($_POST['operation'])) : '';
        $id = isset($_POST['review']) && is_string($_POST['review']) ? sanitize_text_field(wp_unslash($_POST['review'])) : '';
        $result = $operation === 'apply' ? self::apply($id) : self::preview($operation);
        if (is_wp_error($result)) { wp_die(esc_html($result->get_error_message()), '', array('response' => 409, 'back_link' => true)); }
        wp_safe_redirect(admin_url('admin.php?page=customfields-sync')); exit;
    }
    private static function form($operation, $label, $id = '') {
        echo '<form method="post" action="' . esc_url(admin_url('admin-post.php')) . '" style="display:inline-block;margin:8px 12px 8px 0">'; wp_nonce_field('customfields_sync');
        echo '<input type="hidden" name="action" value="customfields_sync"><input type="hidden" name="operation" value="' . esc_attr($operation) . '"><input type="hidden" name="review" value="' . esc_attr($id) . '"><button class="button button-secondary">' . esc_html($label) . '</button></form>';
    }
    public static function page() {
        if (!current_user_can('manage_options')) { return; }
        echo '<div class="wrap"><h1>' . esc_html__('Definition files', 'customfields-com') . '</h1><p>' . esc_html__('Download the current definitions as JSON or review an import in the field builder. Definitions stay in the database; no schema, temporary file or lock file is written to a server directory.', 'customfields-com') . '</p>';
        echo '<p><a class="button button-primary" href="' . esc_url(wp_nonce_url(admin_url('admin-post.php?action=customfields_export'), 'customfields_export')) . '">' . esc_html__('Download JSON', 'customfields-com') . '</a> <a class="button button-secondary" href="' . esc_url(admin_url('admin.php?page=customfields')) . '">' . esc_html__('Review a JSON import', 'customfields-com') . '</a></p>';
        if (!defined('CUSTOMFIELDS_JSON_DIR')) { echo '</div>'; return; }
        echo '<h2>' . esc_html__('Legacy file source — read only', 'customfields-com') . '</h2><p>' . esc_html__('The existing CUSTOMFIELDS_JSON_DIR setting is used only to read customfields-schema.json. Review its changes before importing. Imports replace definitions; saved content remains in place. Download JSON and manage any repository copy separately.', 'customfields-com') . '</p>';
        $status = self::status();
        if (is_wp_error($status)) { echo '<div class="notice notice-warning"><p>' . esc_html($status->get_error_message()) . '</p></div></div>'; return; }
        $labels = array('synchronized' => __('Definitions match', 'customfields-com'), 'missing' => __('No source file found', 'customfields-com'), 'conflict' => __('Definitions differ; review before importing', 'customfields-com'), 'file_changed' => __('Local file changed', 'customfields-com'), 'database_changed' => __('Database changed', 'customfields-com'));
        echo '<p><strong>' . esc_html($labels[$status['status']]) . '</strong> — <code>' . esc_html($status['directory']) . '</code></p>';
        if ($status['groups'] !== null) { self::form('import', __('Review file → database', 'customfields-com')); }
        $plan = get_transient(self::key());
        if (is_array($plan) && ($plan['direction'] ?? '') === 'import') {
            echo '<h2>' . esc_html__('Review import', 'customfields-com') . '</h2><p>' . esc_html__('Applying uses exactly this review. Any intervening schema, file or checked content changes block the import.', 'customfields-com') . '</p><pre style="max-height:420px;overflow:auto;white-space:pre-wrap">' . esc_html(wp_json_encode($plan['review']['diff'], JSON_PRETTY_PRINT | JSON_UNESCAPED_SLASHES)) . '</pre>';
            self::form('apply', __('Apply reviewed import', 'customfields-com'), $plan['id']);
        }
        echo '</div>';
    }
}