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

/** Central linked definitions with explicit, atomic propagation through the guarded schema review. */
final class LinkedDefinitions {
    private static $booted = false;
    private static $resolved_input = null;
    private static $resolved_output = array();
    public static function boot() {
        if (self::$booted) { return; } self::$booted = true;
        add_filter('customfields_validate_field_schema', array(__CLASS__, 'field_schema'), 30, 3);
        add_filter('customfields_validate_groups', array(__CLASS__, 'validate'), 20);
        add_filter('customfields_registered_groups', array(__CLASS__, 'resolve'));
        add_filter('customfields_storage_error', array(__CLASS__, 'storage_error'), 1, 3);
        add_filter('customfields_sanitize_value', array(__CLASS__, 'sanitize'), 99, 4);
        add_action('admin_enqueue_scripts', array(__CLASS__, 'assets'), 40);
        add_action('wp_ajax_customfields_linked_preview', array(__CLASS__, 'ajax_preview'));
        add_action('wp_ajax_customfields_linked_apply', array(__CLASS__, 'ajax_apply'));
    }
    private static function error($message) { return new \WP_Error('customfields_linked', $message, array('status' => 409)); }
    public static function field_schema($field, $raw, $depth) {
        if (is_wp_error($field) || !isset($raw['source_mode'])) { return $field; }
        if (($field['type'] ?? '') !== 'clone' || !in_array($raw['source_mode'], array('snapshot', 'linked'), true)) { return self::error(__('Definition mode must be snapshot or linked on a reusable group.', 'customfields-com')); }
        $field['source_mode'] = $raw['source_mode']; return $field;
    }
    public static function validate($groups) {
        if (is_wp_error($groups)) { return $groups; }
        $expanded = self::expand($groups, false);
        return is_wp_error($expanded) ? $expanded : $groups;
    }
    /** Always resolve linked children from the central source; cached children are an approval record. */
    public static function resolve($groups) {
        if ($groups === self::$resolved_input) { return self::$resolved_output; }
        $resolved = self::expand($groups, false);
        if (!is_wp_error($resolved)) { self::$resolved_input = $groups; self::$resolved_output = $resolved; return $resolved; }
        // A manually corrupted registry is visible for recovery but locked for ordinary content writes.
        $raw = $groups;
        // Lock at each top-level boundary; do not recursively traverse corrupt definitions again.
        if (!is_array($groups)) { return array(); }
        foreach ($groups as &$group) {
            if (!is_array($group) || !is_array($group['fields'] ?? null)) { continue; }
            foreach ($group['fields'] as &$field) { if (is_array($field)) { $field['_linked_conflict'] = $resolved->get_error_message(); } } unset($field);
        } unset($group);
        self::$resolved_input = $raw; self::$resolved_output = $groups; return $groups;
    }
    public static function storage_error($error, $value, $field) { return !empty($field['_linked_conflict']) ? self::error($field['_linked_conflict']) : $error; }
    public static function sanitize($value, $field, $raw, $context) { return !empty($field['_linked_conflict']) ? self::error($field['_linked_conflict']) : $value; }

    private static function expand($groups, $refresh) {
        if (!is_array($groups) || count($groups) > Schema::MAX_GROUPS) { return self::error(__('The linked registry is invalid.', 'customfields-com')); }
        $map = array(); foreach ($groups as $group) { if (!is_array($group) || !is_string($group['key'] ?? null) || isset($map[$group['key']]) || !is_array($group['fields'] ?? null)) { return self::error(__('A linked source group is invalid.', 'customfields-com')); } $map[$group['key']] = $group; }
        $walk = function($fields, $path, $depth, &$nodes) use (&$walk, $map, $refresh) {
            if (!is_array($fields) || $depth > Local\Fields::MAX_DEPTH) { return self::error(__('The linked children exceed the supported nesting depth or have an invalid shape.', 'customfields-com')); }
            $result = array();
            foreach ($fields as $field) {
                if (!is_array($field) || ++$nodes > Local\Fields::MAX_SCHEMA_FIELDS) { return self::error(__('A linked group exceeds 200 resolved schema fields.', 'customfields-com')); }
                $type = $field['type'] ?? '';
                if (in_array($type, array('group', 'clone', 'repeater', 'flexible'), true) && $depth >= Local\Fields::MAX_DEPTH) { return self::error(__('Linked definitions may use at most three container levels.', 'customfields-com')); }
                if ($type === 'clone' && ($field['source_mode'] ?? '') === 'linked') {
                    $key = $field['source_group'] ?? '';
                    if (!isset($map[$key]) || in_array($key, $path, true)) { return self::error(__('A linked definition has a missing source or a dependency cycle. Restore its source or unlink it explicitly.', 'customfields-com')); }
                    $children = $walk($map[$key]['fields'], array_merge($path, array($key)), $depth + 1, $nodes);
                    if (is_wp_error($children)) { return $children; }
                    $hash = Local\Fields::fingerprint($children);
                    if (!$refresh && (!is_string($field['source_hash'] ?? null) || !hash_equals($hash, $field['source_hash']) || Local\Fields::fingerprint($field['sub_fields'] ?? array()) !== $hash)) {
                        return self::error(__('A linked source changed. Use “Review linked updates” to check every downstream field and saved value before applying it.', 'customfields-com'));
                    }
                    $field['sub_fields'] = $children;
                    if ($refresh) { $field['source_hash'] = $hash; $field['source_title'] = $map[$key]['title']; }
                } else {
                    if (isset($field['sub_fields'])) { $field['sub_fields'] = $walk($field['sub_fields'], $path, $depth + 1, $nodes); if (is_wp_error($field['sub_fields'])) { return $field['sub_fields']; } }
                    if (isset($field['layouts']) && !is_array($field['layouts'])) { return self::error(__('The linked layouts have an invalid shape.', 'customfields-com')); }
                    foreach ($field['layouts'] ?? array() as $i => $layout) { $children = $walk(is_array($layout) ? ($layout['sub_fields'] ?? null) : null, $path, $depth + 1, $nodes); if (is_wp_error($children)) { return $children; } $field['layouts'][$i]['sub_fields'] = $children; }
                }
                $result[] = $field;
            }
            return $result;
        };
        $result = array();
        foreach ($groups as $group) { $nodes = 0; $fields = $walk($group['fields'], array($group['key']), 0, $nodes); if (is_wp_error($fields)) { return $fields; } $group['fields'] = $fields; $result[] = $group; }
        return $result;
    }

    /** Preview a complete proposed registry. Only this path refreshes every linked approval together. */
    public static function preview($groups) {
        if (!current_user_can('manage_options')) { return self::error(__('Administrator access is required.', 'customfields-com')); }
        $expanded = self::expand($groups, true);
        if (is_wp_error($expanded)) { return $expanded; }
        $encoded = wp_json_encode($expanded);
        if (false === $encoded || strlen($encoded) > Schema::MAX_BYTES) { return self::error(__('The resolved schema exceeds 1 MB.', 'customfields-com')); }
        return Local\Workflows::preview_schema($expanded, array('kind' => 'linked-definitions'));
    }
    public static function apply($id) {
        if (!current_user_can('manage_options')) { return self::error(__('Administrator access is required.', 'customfields-com')); }
        // The shared preview is user/session-bound; confirm its context before invoking the common transactional restore.
        // Workflow implementations own the private key. A context guard binds the transaction itself.
        $guard = static function($review) {
            if (($review['context']['kind'] ?? '') !== 'linked-definitions') { throw new \RuntimeException(__('This review is not a linked-definition update.', '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.
        };
        add_action('customfields_schema_review_committing', $guard, 1);
        try { return Local\Workflows::restore($id); }
        finally { remove_action('customfields_schema_review_committing', $guard, 1); }
    }
    public static function assets($hook) {
        if ($hook !== 'toplevel_page_customfields') { return; }
        wp_enqueue_script('customfields-linked', CUSTOMFIELDS_LOCAL_URL . 'linked.js', array('customfields-builder', 'wp-i18n'), CUSTOMFIELDS_VERSION, true);
        wp_set_script_translations('customfields-linked', 'customfields-com', CUSTOMFIELDS_PATH . 'languages');
        wp_localize_script('customfields-linked', 'CustomFieldsLinked', array('ajax' => admin_url('admin-ajax.php'), 'nonce' => wp_create_nonce('customfields_linked')));
    }
    private static function require_administrator() {
        if (!current_user_can('manage_options')) {
            wp_send_json_error(array('message' => __('Administrator access is required.', 'customfields-com')), 403);
        }
    }

    /** Only a complete, schema-sanitized group may enter a downstream review. */
    private static function sanitize_group_json($json) {
        if (!is_string($json) || strlen($json) > Schema::MAX_BYTES) {
            return self::error(__('The submitted group exceeds the schema limit.', 'customfields-com'));
        }
        $raw = json_decode($json, true, 24);
        if (JSON_ERROR_NONE !== json_last_error() || !is_array($raw) || ($raw['complete'] ?? '') !== '1') {
            return self::error(__('The group is incomplete.', 'customfields-com'));
        }
        // This validates every typed setting and sanitizes labels, defaults and nested fields.
        return Schema::validate_group($raw);
    }

    public static function ajax_preview() {
        self::require_administrator();
        $nonce = isset($_POST['nonce']) && is_string($_POST['nonce']) ? sanitize_text_field(wp_unslash($_POST['nonce'])) : '';
        if (!wp_verify_nonce($nonce, 'customfields_linked')) {
            wp_send_json_error(array('message' => __('Your session expired. Reload this page before continuing.', 'customfields-com')), 403);
        }
        $schema_hash = isset($_POST['schema_hash']) && is_string($_POST['schema_hash']) ? filter_var(wp_unslash($_POST['schema_hash']), FILTER_VALIDATE_REGEXP, array('options' => array('regexp' => '/^[a-f0-9]{64}$/D'))) : false;
        if (!is_string($schema_hash) || !hash_equals(Admin::fingerprint(), $schema_hash)) {
            wp_send_json_error(array('message' => __('The registry changed. Keep this editor open and review a fresh one before applying.', 'customfields-com')), 409);
        }
        $group = self::sanitize_group_json(isset($_POST['group_json']) && is_string($_POST['group_json']) ? wp_unslash($_POST['group_json']) : null); // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- sanitize_group_json bounds and decodes the transport, then Schema::validate_group sanitizes every supported field before any preview is stored.
        if (is_wp_error($group)) {
            wp_send_json_error(array('message' => $group->get_error_message()), 400);
        }
        $groups = get_option('customfields_groups', array());
        if (!is_array($groups)) {
            wp_send_json_error(array('message' => __('The linked registry is invalid.', 'customfields-com')), 409);
        }
        $found = false;
        foreach ($groups as &$entry) {
            if (is_array($entry) && ($entry['key'] ?? null) === $group['key']) {
                $entry = $group;
                $found = true;
            }
        }
        unset($entry);
        if (!$found) {
            $groups[] = $group;
        }
        $preview = self::preview($groups);
        if (is_wp_error($preview)) {
            wp_send_json_error(array('message' => $preview->get_error_message()), 409);
        }
        wp_send_json_success(array('id' => $preview['id'], 'diff' => $preview['diff'], 'values' => $preview['scan']['values'], 'group_key' => $group['key']));
    }

    public static function ajax_apply() {
        self::require_administrator();
        $nonce = isset($_POST['nonce']) && is_string($_POST['nonce']) ? sanitize_text_field(wp_unslash($_POST['nonce'])) : '';
        if (!wp_verify_nonce($nonce, 'customfields_linked')) {
            wp_send_json_error(array('message' => __('Your session expired. Reload this page before continuing.', 'customfields-com')), 403);
        }
        $id = isset($_POST['preview_id']) && is_string($_POST['preview_id']) ? filter_var(wp_unslash($_POST['preview_id']), FILTER_VALIDATE_REGEXP, array('options' => array('regexp' => '/^[a-f0-9]{8}-[a-f0-9]{4}-4[a-f0-9]{3}-[89ab][a-f0-9]{3}-[a-f0-9]{12}$/D'))) : false;
        $confirm = isset($_POST['confirm']) && is_string($_POST['confirm']) ? filter_var(wp_unslash($_POST['confirm']), FILTER_VALIDATE_REGEXP, array('options' => array('regexp' => '/^1$/D'))) : false;
        if ('1' !== $confirm) {
            wp_send_json_error(array('message' => __('Confirm the downstream review before applying.', 'customfields-com')), 400);
        }
        $result = self::apply($id);
        if (is_wp_error($result)) {
            wp_send_json_error(array('message' => $result->get_error_message()), 409);
        }
        $key = isset($_POST['group_key']) && is_string($_POST['group_key']) ? sanitize_text_field(wp_unslash($_POST['group_key'])) : '';
        foreach (customfields_get_groups() as $group) {
            if ($group['key'] === $key) {
                wp_send_json_success(array('group' => $group, 'schema_hash' => Admin::fingerprint(), 'message' => __('Linked definitions and their compatible downstream uses were saved.', 'customfields-com')));
            }
        }
        wp_send_json_error(array('message' => __('The review was applied, but this group is no longer available. Reload the registry.', 'customfields-com')), 409);
    }
}