<?php
namespace CustomFields;

defined('ABSPATH') || exit;

/** Ordered references with a bounded, explicitly configured reciprocal edge. */
final class Relationships {
    const MAX_ITEMS = 100;
    private static $expected = array();
    public static function boot() {
        add_filter('customfields_field_types', array(__CLASS__, 'types'));
        add_filter('customfields_validate_field_schema', array(__CLASS__, 'schema'), 20, 3);
        add_filter('customfields_sanitize_value', array(__CLASS__, 'sanitize'), 30, 4);
        add_filter('customfields_storage_error', array(__CLASS__, 'storage'), 30, 3);
        add_filter('customfields_validate_group_schema', array(__CLASS__, 'group_schema'), 25, 2);
        add_action('customfields_render_field', array(__CLASS__, 'render'), 30, 3);
        add_action('customfields_field_editor_settings', array(__CLASS__, 'settings'), 30, 2);
        add_action('wp_ajax_customfields_relationship_search', array(__CLASS__, 'search'));
        add_action('admin_enqueue_scripts', array(__CLASS__, 'admin_assets'));
        add_filter('customfields_editor_contexts', array(__CLASS__, 'contexts'), 30, 2);
        add_filter('customfields_draft_contexts', array(__CLASS__, 'contexts'), 30, 4);
    }
    public static function contexts($contexts,$values,$raw=null,$id=0) {
        foreach (customfields_get_groups() as $group) {
            $items=$values[$group['key']]??null;if (!is_array($items)) { continue; }
            foreach ($group['fields'] as $field) {
                if ($field['type']!=='relationship' || !array_key_exists($field['name'],$items)) { continue; }
                $stored=$items[$field['name']];$fingerprint=self::hash($stored);
                if ($raw!==null) {
                    $stored=metadata_exists('post',$id,$field['name'])?get_post_meta($id,$field['name'],true):$field['default'];
                    $submitted=$raw[$group['key']][$field['name']]??array();
                    $fingerprint=is_string($submitted['__fingerprint']??null)?$submitted['__fingerprint']:self::hash($stored);
                }
                $contexts['customfields_values['.$group['key'].']['.$field['name'].']']=array('fingerprint'=>$fingerprint,'stored'=>$stored);
            }
        }
        return $contexts;
    }
    public static function types($types) { $types['relationship'] = __('Related items (searchable multiple)', 'customfields-com'); return $types; }
    private static function error($message) { return new \WP_Error('cf_relationship', $message); }
    public static function hash($value) { return hash('sha256', wp_json_encode($value)); }
    public static function schema($field, $raw, $depth = 0) {
        if (is_wp_error($field) || $field['type'] !== 'relationship') { return $field; }
        $kind = $raw['relationship_object'] ?? 'post';
        if (!in_array($kind, array('post','user','term'), true)) { return self::error(__('Relationships support posts, users or taxonomy terms.', 'customfields-com')); }
        $field['relationship_object'] = $kind;
        foreach (array('relationship_post_types'=>array('post'),'relationship_taxonomies'=>array('category')) as $key=>$default) {
            $value = $raw[$key] ?? $default;
            if (is_string($value)) { $value = preg_split('/[\s,]+/', trim($value), -1, PREG_SPLIT_NO_EMPTY); }
            if (!is_array($value) || count($value) > 30 || !$value) { return self::error(__('Choose 1–30 content type or taxonomy names.', 'customfields-com')); }
            foreach ($value as $slug) { if (!is_string($slug) || !preg_match('/^[a-z][a-z0-9_-]{0,31}$/D', $slug) || strpos($slug,'wp_') === 0 || in_array($slug,array('revision','attachment','nav_menu_item','custom_css','customize_changeset'),true)) { return self::error(__('Use editable content type and taxonomy names.', 'customfields-com')); } }
            $field[$key] = array_values(array_unique($value));
        }
        $maximum = $raw['relationship_max'] ?? 20;
        if (filter_var($maximum, FILTER_VALIDATE_INT) === false || (int)$maximum < 1 || (int)$maximum > self::MAX_ITEMS) { return self::error(__('Relationship limit must be 1–100.', 'customfields-com')); }
        $field['relationship_max'] = (int)$maximum;
        $inverse = $raw['relationship_inverse'] ?? '';
        if (!is_string($inverse) || ($inverse !== '' && (!preg_match('/^field_[a-zA-Z0-9_-]{1,80}$/D', $inverse) || $depth !== 0))) { return self::error(__('Reciprocal relationships require a top-level field key. Nested fields cannot maintain inverse edges.', 'customfields-com')); }
        $field['relationship_inverse'] = $inverse;
        if (!isset($raw['default']) || $raw['default'] === '') { $field['default'] = array(); }
        elseif (is_string($raw['default'])) { $field['default'] = json_decode($raw['default'], true); }
        if ($inverse !== '' && $field['default'] !== array()) { return self::error(__('Reciprocal fields must start empty; defaults cannot create saved inverse edges.', 'customfields-com')); }
        return $field;
    }
    public static function in_scope($id, $field, $permission = true) {
        $kind = $field['relationship_object'];
        if ($kind === 'post') {
            $post = get_post($id);
            return $post && in_array($post->post_type,$field['relationship_post_types'],true) && !in_array($post->post_status,array('trash','auto-draft'),true) && (!$permission || current_user_can('read_post',$id));
        }
        if ($kind === 'user') { return (bool)get_userdata($id) && (!$permission || current_user_can('list_users') || get_current_user_id() === (int)$id); }
        $term = get_term($id);
        $taxonomy = $term && !is_wp_error($term) ? get_taxonomy($term->taxonomy) : null;
        return $taxonomy && in_array($term->taxonomy,$field['relationship_taxonomies'],true) && (!$permission || current_user_can($taxonomy->cap->assign_terms));
    }
    public static function sanitize($clean, $field, $raw, $context = array()) {
        if (($field['type'] ?? '') !== 'relationship') { return $clean; }
        $stored = !empty($context['has_stored_value']) ? ($context['stored_value'] ?? array()) : ($field['default'] ?? array());
        $trusted = !empty($field['_validating_default']) || !empty($field['_checking_storage']);
        if ($raw === '' || $raw === null) { $raw = array(); }
        if (!is_array($raw)) { return self::error(__('Expected an ordered list of related item IDs.', 'customfields-com')); }
        if (isset($raw['__fingerprint'])) {
            $expected = $raw['__fingerprint']; unset($raw['__fingerprint']);
            if (!$trusted && (!is_string($expected) || !hash_equals(self::hash($stored), $expected))) { return self::error(__('These relationships changed elsewhere. Reload before replacing them.', 'customfields-com')); }
        }
        unset($raw['__present']);
        if (count($raw) > ($field['relationship_max'] ?? 20)) { return self::error(__('Too many related items.', 'customfields-com')); }
        $out = array();
        foreach ($raw as $key=>$id) {
            if (!ctype_digit((string)$key) || !is_scalar($id) || !preg_match('/^[1-9][0-9]*$/D',(string)$id) || (float)$id > PHP_INT_MAX) { return self::error(__('Related item IDs must be positive integers.', 'customfields-com')); }
            $id = (int)$id;
            // Preserve an existing inaccessible link without revealing its label or granting a new selection.
            $retained = !$trusted && !empty($context['has_stored_value']) && in_array($id,is_array($stored)?$stored:array(),true);
            if (empty($field['_checking_storage']) && ((!self::in_scope($id,$field,false) && !$retained) || (!$trusted && !self::in_scope($id,$field,true) && !$retained))) { return self::error(__('A selected item is unavailable or outside this field’s allowed scope.', 'customfields-com')); }
            if (in_array($id,$out,true)) { return self::error(__('Each related item may appear only once.', 'customfields-com')); }
            $out[] = $id;
        }
        if (!$trusted && isset($context['object_kind'],$context['object_id'])) { self::$expected[$context['object_kind'].':'.$context['object_id'].':'.$field['name']] = self::hash($stored); }
        return $out;
    }
    public static function storage($error, $value, $field) {
        if (($field['type'] ?? '') !== 'relationship') { return $error; }
        $field['_checking_storage'] = true; $field['required'] = false;
        $checked = self::sanitize(null,$field,$value);
        if (!is_wp_error($checked) && $checked !== $value) { return self::error(__('Stored relationships need a canonical ordered integer-ID list before editing.','customfields-com')); }
        return is_wp_error($checked) ? $checked : $error;
    }
    public static function group_matches($group,$kind,$id) {
        if (($group['target'] ?? 'post') !== $kind) { return false; }
        if ($kind === 'post') { return Editor::matches($group,get_post($id)); }
        if ($kind === 'user') { return (bool)get_userdata($id); }
        if ($kind === 'term') { $term=get_term($id); return $term && !is_wp_error($term) && in_array($term->taxonomy,$group['taxonomies']??array(),true); }
        return false;
    }
    public static function group_schema($group,$raw) {
        if (is_wp_error($group)) { return $group; }
        foreach ($group['fields'] as $field) {
            if (($field['type']??'') === 'relationship' && !empty($field['relationship_inverse']) && !in_array($group['target'],array('post','user','term'),true)) { return self::error(__('Reciprocal fields require a post, user or term group.','customfields-com')); }
        }
        return $group;
    }
    public static function find($key,$kind = null,$id = 0) {
        $found=null;
        foreach (customfields_get_groups() as $group) {
            if ($kind !== null && !self::group_matches($group,$kind,$id)) { continue; }
            foreach ($group['fields'] as $field) {
                if ($field['key'] === $key && $field['type'] === 'relationship') {
                    if ($found !== null) { return null; }
                    $found=array('group'=>$group,'field'=>$field);
                }
            }
        }
        return $found;
    }
    /** Called within the caller's transaction. Failure aborts forward and reverse values together. */
    public static function synchronize($group,$kind,$id,$updates,$before) {
        foreach ($group['fields'] as $field) {
            if ($field['type'] !== 'relationship' || !array_key_exists($field['name'],$updates)) { continue; }
            $name=$field['name']; $old=$before[$name] ?? array(); $new=$updates[$name];
            if (!is_array($old) || !is_array($new)) { throw new \RuntimeException(__('Relationship storage is incompatible. Nothing was changed.','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.
            $expected=self::$expected[$kind.':'.$id.':'.$name]??null; unset(self::$expected[$kind.':'.$id.':'.$name]);
            if ($expected !== null && !hash_equals($expected,self::hash($old))) { throw new \RuntimeException(__('Relationships changed during this save. Reload before replacing them.','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.
            if (empty($field['relationship_inverse'])) { continue; }
            if (!in_array($kind,array('post','user','term'),true)) { throw new \RuntimeException(__('Reciprocal relationships require a post, user or term owner.','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.
            $targets=array_unique(array_merge($old,$new)); sort($targets,SORT_NUMERIC);
            foreach ($targets as $target) {
                $added=in_array($target,$new,true); $was=in_array($target,$old,true);
                $target_kind=$field['relationship_object'];
                if ($added && $target_kind===$kind && (int)$target===(int)$id) { throw new \RuntimeException(__('Reciprocal fields cannot link an object to itself. Use a one-way relationship for self references.','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.
                if ($added === $was) { continue; }
                $target_object=$target_kind==='post'?get_post($target):($target_kind==='user'?get_userdata($target):get_term($target));
                if (!$added && (!$target_object || is_wp_error($target_object))) { continue; }
                $inverse=self::find($field['relationship_inverse'],$target_kind,$target);
                if (!$inverse || $inverse['field']['relationship_object'] !== $kind || ($inverse['field']['relationship_inverse'] ?? '') !== $field['key'] || !self::in_scope($id,$inverse['field'],false) || !Editor::can_edit($target_kind,$target,$inverse['field']['name'])) { throw new \RuntimeException(__('The inverse field must point back to this field and you must be allowed to edit both linked items.','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.
                $reverse=ContentStore::locked_value($target_kind,$target,$inverse['field']['name']);
                $reverse=$reverse['exists']?$reverse['value']:array();
                if (is_wp_error(self::storage(null,$reverse,$inverse['field']))) { throw new \RuntimeException(__('The inverse value requires a compatible schema before linking.','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.
                $reverse=array_values(array_diff($reverse,array((int)$id)));
                if ($added) { $reverse[]=(int)$id; }
                if (count($reverse)>$inverse['field']['relationship_max'] || (!$reverse && !empty($inverse['field']['required']))) { throw new \RuntimeException(__('The inverse field’s required or maximum constraint prevents this change.','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.
                ContentStore::write_locked($inverse['group'],$target_kind,$target,$inverse['field']['name'],$reverse);
            }
        }
    }
    /** Preload editor assets only on admin screens where these controls can appear. */
    public static function admin_assets($hook) {
        $screen = get_current_screen();
        $editor_screen = $screen && in_array($screen->base, array('post', 'profile', 'user-edit', 'term', 'edit-tags'), true);
        $plugin_screen = $screen && ($screen->parent_base ?? '') === 'customfields';
        $options_screen = $hook === 'tools_page_customfields-pro-options' || strpos($hook, 'tools_page_customfields-pro-options-') === 0;
        if (!$editor_screen && !$plugin_screen && !$options_screen) { return; }
        self::assets();
    }

    public static function assets() {
        wp_enqueue_style('customfields-content-platform',CUSTOMFIELDS_URL.'assets/content-platform.css',array(),CUSTOMFIELDS_VERSION);
        wp_enqueue_script('customfields-relationships', CUSTOMFIELDS_URL.'assets/relationships.js',array('wp-i18n'),CUSTOMFIELDS_VERSION,true);
        wp_set_script_translations('customfields-relationships', 'customfields-com', CUSTOMFIELDS_PATH . 'languages');
        wp_localize_script('customfields-relationships','CustomFieldsRelationships',array('url'=>admin_url('admin-ajax.php'),'nonce'=>wp_create_nonce('customfields_relationship_search'),'userId'=>get_current_user_id()));
    }
    private static function label($id,$field) {
        if (!self::in_scope($id,$field,true)) { return sprintf(/* translators: %d: Object ID. */ __('Unavailable item #%d','customfields-com'),$id); }
        if ($field['relationship_object'] === 'post') { return get_the_title($id) ?: sprintf(/* translators: %d: Object ID. */ __('Untitled #%d','customfields-com'),$id); }
        if ($field['relationship_object'] === 'user') { return get_userdata($id)->display_name; }
        return get_term($id)->name;
    }
    public static function render($field,$value,$name) {
        if ($field['type'] !== 'relationship') { return; }
        self::assets(); $value=is_array($value)?$value:array();
        echo '<div class="cf-relationships" data-field-key="'.esc_attr($field['key']).'" data-name="'.esc_attr($name).'" data-maximum="'.intval($field['relationship_max']).'"><input type="hidden" name="'.esc_attr($name.'[__present]').'" value="1"><input type="hidden" name="'.esc_attr($name.'[__fingerprint]').'" value="'.esc_attr(self::hash($value)).'"><ol class="cf-relationship-selected">';
        foreach ($value as $index=>$id) { echo '<li data-id="'.intval($id).'"><input type="hidden" name="'.esc_attr($name.'['.$index.']').'" value="'.intval($id).'"><span>'.esc_html(self::label($id,$field)).'</span> <button type="button" class="button cf-rel-up" aria-label="'.esc_attr__('Move earlier','customfields-com').'">↑</button> <button type="button" class="button cf-rel-down" aria-label="'.esc_attr__('Move later','customfields-com').'">↓</button> <button type="button" class="button cf-rel-remove">'.esc_html__('Remove','customfields-com').'</button></li>'; }
        echo '</ol><label>'.esc_html__('Search for related items','customfields-com').'<input type="search" class="widefat cf-relationship-search" autocomplete="off"></label><div class="cf-relationship-status" role="status"></div><ul class="cf-relationship-results"></ul><noscript><p>'.esc_html__('JavaScript is needed to search and change relationships. Existing selections are preserved.','customfields-com').'</p></noscript></div>';
    }
    public static function settings($field,$prefix) {
        echo '<fieldset class="cf-relationship-settings"'.(($field['type']??'')==='relationship'?'':' disabled hidden').'><legend>'.esc_html__('Relationship settings','customfields-com').'</legend><p>'.esc_html__('Used only for the Related items field type. One field links to one object kind.','customfields-com').'</p><label>'.esc_html__('Related object','customfields-com').' <select name="'.esc_attr($prefix.'[relationship_object]').'">';
        foreach (array('post'=>__('Posts','customfields-com'),'user'=>__('Users','customfields-com'),'term'=>__('Terms','customfields-com')) as $kind=>$label) { echo '<option value="'.esc_attr($kind).'"'.selected($field['relationship_object']??'post',$kind,false).'>'.esc_html($label).'</option>'; }
        echo '</select></label>';
        foreach (array('relationship_post_types'=>array(__('Allowed post types','customfields-com'),'post'),'relationship_taxonomies'=>array(__('Allowed taxonomies','customfields-com'),'category'),'relationship_max'=>array(__('Maximum selections','customfields-com'),20),'relationship_inverse'=>array(__('Reciprocal field key (optional)','customfields-com'),'')) as $key=>$config) {
            $value=$field[$key]??$config[1]; if(is_array($value)){$value=implode(', ',$value);}
            if ($key==='relationship_inverse') {
                $choices=array(''=>__('No reciprocal field','customfields-com'));
                foreach(customfields_get_groups() as $group){foreach($group['fields'] as $candidate){if($candidate['type']==='relationship'){$choices[$candidate['key']]=$group['title'].' → '.$candidate['label'].' ('.$group['target'].')';}}}
                if($value!==''&&!isset($choices[$value]))$choices[$value]=__('Unavailable field: ','customfields-com').$value;
                echo '<p><label>'.esc_html__('Reciprocal field','customfields-com').'<br><select class="widefat" name="'.esc_attr($prefix.'['.$key.']').'">';
                foreach($choices as $key_value=>$label){echo '<option value="'.esc_attr($key_value).'"'.selected($value,$key_value,false).'>'.esc_html($label).'</option>';}
                echo '</select></label></p>';
            } else { echo '<p><label>'.esc_html($config[0]).'<br><input class="widefat" name="'.esc_attr($prefix.'['.$key.']').'" value="'.esc_attr($value).'"></label></p>'; }
        }
        echo '<p class="description">'.esc_html__('Save both fields first, then choose each other as reciprocal fields. Editors must be able to edit both objects. Reciprocal self-links are not supported.','customfields-com').'</p></fieldset>';
    }
    public static function search() {
        $nonce = isset($_POST['nonce']) && is_string($_POST['nonce']) ? sanitize_text_field(wp_unslash($_POST['nonce'])) : '';
        if (!wp_verify_nonce($nonce, 'customfields_relationship_search')) { wp_send_json_error(array('message'=>__('Refresh this page to search.','customfields-com')),403); }
        $key=isset($_POST['field'])&&is_string($_POST['field'])?sanitize_text_field(wp_unslash($_POST['field'])):'';
        $kind = isset($_POST['kind']) && is_string($_POST['kind']) ? sanitize_key(wp_unslash($_POST['kind'])) : '';
        $object_id = isset($_POST['id']) && is_string($_POST['id']) ? sanitize_text_field(wp_unslash($_POST['id'])) : '';
        if ($object_id === '' || $object_id !== wp_unslash($_POST['id']) || !preg_match('/^(0|[1-9][0-9]*)$/D', $object_id) || (string) (int) $object_id !== $object_id) { // phpcs:ignore WordPress.Security.ValidatedSanitizedInput.InputNotSanitized -- The second read only compares original bytes against the sanitized ID; only the validated integer is used.
            wp_send_json_error(array('message' => __('Choose a valid content ID.', 'customfields-com')), 400);
        }
        $id = (int) $object_id;
        $found=self::find($key); $group=$found['group']??array();
        $allowed=$kind==='options' ? (($group['target']??'')==='options' && current_user_can($group['options_page']['capability']??'manage_options')) : ($found && self::group_matches($group,$kind,$id) && Editor::can_edit($kind,$id,$found['field']['name']));
        if (!$found || !$allowed) { wp_send_json_error(array('message'=>__('You cannot search this field.','customfields-com')),403); }
        $field=$found['field']; $query=isset($_POST['query'])&&is_string($_POST['query'])?sanitize_text_field(wp_unslash($_POST['query'])):'';
        if (strlen($query)>100) { wp_send_json_error(array('message'=>__('Search text is too long.','customfields-com')),400); }
        $ids=array();
        if ($field['relationship_object']==='post') {
            $query_object=new \WP_Query(array('post_type'=>$field['relationship_post_types'],'post_status'=>array('publish','private','draft','pending','future'),'s'=>$query,'posts_per_page'=>40,'fields'=>'ids','no_found_rows'=>true,'orderby'=>'title','order'=>'ASC','suppress_filters'=>false)); $ids=$query_object->posts;
        } elseif ($field['relationship_object']==='user') {
            if (current_user_can('list_users')) { $ids=get_users(array('search'=>$query!==''?'*'.$query.'*':'','search_columns'=>array('display_name'),'number'=>30,'fields'=>'ID','orderby'=>'display_name','order'=>'ASC')); }
            else { $ids=array(get_current_user_id()); }
        } else {
            $taxonomies=array_filter($field['relationship_taxonomies'],static function($slug){$tax=get_taxonomy($slug);return $tax&&current_user_can($tax->cap->assign_terms);});
            if($taxonomies){$ids=get_terms(array('taxonomy'=>$taxonomies,'hide_empty'=>false,'search'=>$query,'number'=>30,'fields'=>'ids'));}
        }
        $results=array(); if(!is_wp_error($ids)){foreach($ids as $item){if(self::in_scope((int)$item,$field,true)){$results[]=array('id'=>(int)$item,'label'=>self::label((int)$item,$field));} if(count($results)>=20){break;}}}
        wp_send_json_success(array('items'=>$results));
    }
}