<?php
namespace Digiter\BuilderStudio;
defined('ABSPATH') || exit;

/** Bounded declarative conditions shared by rendering and public endpoints. */
final class DisplayRules {
    public static function clean($raw): array {
        if ($raw === null || $raw === []) { return []; }
        if (!is_array($raw) || !in_array($raw['relation'] ?? '', ['AND','OR'], true) || !is_array($raw['groups'] ?? null) || !array_is_list($raw['groups']) || count($raw['groups']) > 8) {
            throw new \InvalidArgumentException('Display rules need AND/OR groups, at most eight groups.');
        }
        $groups=[];
        foreach ($raw['groups'] as $group) {
            if (!is_array($group) || !in_array($group['relation'] ?? '', ['AND','OR'], true) || !is_array($group['rules'] ?? null) || !array_is_list($group['rules']) || !$group['rules'] || count($group['rules']) > 8) { throw new \InvalidArgumentException('Each display group needs one to eight conditions.'); }
            $rules=[];
            foreach ($group['rules'] as $rule) {
                if (!is_array($rule) || !in_array($rule['kind'] ?? '', ['role','term','field'], true) || !in_array($rule['operator'] ?? '', ['eq','ne','contains','gt','gte','lt','lte','empty','not-empty'], true)) { throw new \InvalidArgumentException('Unsupported display condition.'); }
                if (!is_string($rule['key'] ?? '') || !is_scalar($rule['value'] ?? '')) { throw new \InvalidArgumentException('Invalid display condition value.'); }
                $rules[]=['kind'=>$rule['kind'],'key'=>Document::text($rule['key'] ?? '',80),'operator'=>$rule['operator'],'value'=>Document::text((string)($rule['value'] ?? ''),300)];
            }
            $groups[]=['relation'=>$group['relation'],'rules'=>$rules];
        }
        return $groups ? ['relation'=>$raw['relation'],'groups'=>$groups] : [];
    }
    public static function compare($actual,string $operator,string $expected): bool {
        if (!is_scalar($actual) && $actual!==null) { return false; }
        $actual=is_bool($actual)?($actual?'1':'0'):(string)$actual;
        switch ($operator) {
            case 'eq': return $actual===$expected;
            case 'ne': return $actual!==$expected;
            case 'contains': return $expected!=='' && str_contains($actual,$expected);
            case 'empty': return $actual==='';
            case 'not-empty': return $actual!=='';
            case 'gt': case 'gte': case 'lt': case 'lte':
                if (!is_numeric($actual)||!is_numeric($expected)) { return false; }
                return match($operator) {'gt'=>(float)$actual>(float)$expected,'gte'=>(float)$actual>=(float)$expected,'lt'=>(float)$actual<(float)$expected,'lte'=>(float)$actual<=(float)$expected};
        }
        return false;
    }
    private static function condition(array $rule,int $context): bool {
        $key=$rule['key'];$op=$rule['operator'];$value=$rule['value'];
        if ($rule['kind']==='role') {
            if (!in_array($op,['eq','ne'],true) || !isset(wp_roles()->roles[$value])) { return false; }
            $match=in_array($value,wp_get_current_user()->roles,true);
            return $op==='eq'?$match:!$match;
        }
        if ($rule['kind']==='term') {
            $tax=get_taxonomy($key);
            if (!$context || !$tax || !$tax->public || !in_array(get_post_type($context),$tax->object_type,true) || !ctype_digit($value) || !term_exists((int)$value,$key) || !in_array($op,['eq','ne'],true)) { return false; }
            $match=has_term((int)$value,$key,$context);
            return $op==='eq'?$match:!$match;
        }
        // Missing, deleted, protected or no-longer-public definitions fail closed,
        // including a "not equal" condition. Their value is never returned to UI.
        $field=$context?(QueryFields::catalog((string)get_post_type($context))[$key]??null):null;
        if (!$field) { return false; }
        $actual=DynamicData::public_meta($context,$key);
        if(in_array($field['type'],['number','integer'],true)&&in_array($op,['eq','ne'],true)){
            if(!is_numeric($actual)||!is_numeric($value)){return false;}
            return $op==='eq'?(float)$actual===(float)$value:(float)$actual!==(float)$value;
        }
        return self::compare($actual,$op,$value);
    }
    public static function explain(array $style,int $context=0): array {
        $reasons=[];$audience=$style['audience']??'all';
        foreach(['start','end'] as $key){
            $value=$style[$key]??'';
            if($value!==''&&Document::date($value)===''){return ['visible'=>false,'reasons'=>['Display rules are invalid.'],'groups'=>[]];}
        }
        if (($audience==='members'&&!is_user_logged_in())||($audience==='guests'&&is_user_logged_in())) { $reasons[]='The audience condition is not met.'; }
        if (!empty($style['start'])&&time()<strtotime($style['start'])) { $reasons[]='The scheduled start has not been reached.'; }
        if (!empty($style['end'])&&time()>=strtotime($style['end'])) { $reasons[]='The scheduled end has been reached.'; }
        try { $rules=self::clean($style['visibility']??[]); }
        catch (\InvalidArgumentException $e) { return ['visible'=>false,'reasons'=>['Display rules are invalid.'],'groups'=>[]]; }
        $groups=[];
        foreach ($rules['groups']??[] as $group) {
            $results=array_map(static fn($rule)=>self::condition($rule,$context),$group['rules']);
            $groups[]=['matches'=>$group['relation']==='AND'?!in_array(false,$results,true):in_array(true,$results,true),'conditions'=>$results];
        }
        if ($groups) {
            $matches=array_column($groups,'matches');
            if (!(($rules['relation']==='AND')?!in_array(false,$matches,true):in_array(true,$matches,true))) { $reasons[]='The display conditions are not met.'; }
        }
        return ['visible'=>!$reasons,'reasons'=>$reasons,'groups'=>$groups];
    }
    public static function visible(array $style,int $context=0): bool { return self::explain($style,$context)['visible']; }
}