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

/** Select packaged CSS rules without changing specificity or declaration order. */
final class PageCSS {
    private static ?array $manifest=null;
    private static array $emitted=[];
    private static ?string $source=null;
    private static array $compiled=[];
    public static function boot(): void {
        add_action('digibl_css_cleanup',[self::class,'cleanup']);
        if(!wp_next_scheduled('digibl_css_cleanup')){wp_schedule_event(time()+DAY_IN_SECONDS,'daily','digibl_css_cleanup');}
    }
    public static function compile(string $html): string {
        $full=self::$source??=(string)file_get_contents(DIGIBL_PATH.'assets/frontend.css');
        if(str_contains($html,'data-dbs-query') || !apply_filters('digibl_page_css_enabled',true)) {return $full;}
        if(self::$manifest===null){
            $file=DIGIBL_PATH.'data/frontend-css.json';
            self::$manifest=is_readable($file)?(json_decode(file_get_contents($file),true)?:[]):[];
        }
        $manifest=self::$manifest;
        if(($manifest['version']??0)!==1 || !hash_equals((string)($manifest['source']??''),hash('sha256',$full))){return $full;}
        // Read HTML attributes with WordPress's parser, never with a CSS regexp.
        $classes=array_fill_keys($manifest['dynamic'],true);
        $processor=new \WP_HTML_Tag_Processor($html);
        while($processor->next_tag()){
            $value=$processor->get_attribute('class');
            if(is_string($value)){foreach(preg_split('/\s+/',trim($value)) as $class){$classes[$class]=true;}}
        }
        ksort($classes);$signature=hash('sha256',implode(' ',array_keys($classes)));
        if(isset(self::$compiled[$signature])){return self::$compiled[$signature];}
        $css='';
        foreach($manifest['rules'] as $rule){
            foreach($rule['any'] as $required){
                foreach($required as $class){if(!isset($classes[$class])){continue 2;}}
                $css.=$rule['css'];break;
            }
        }
        if(count(self::$compiled)<64){self::$compiled[$signature]=$css;}
        return $css;
    }
    /** Called before the document markup; never writes draft, HTML or user data. */
    public static function stylesheet(string $html,int $source): string {
        if(wp_style_is('digibl-front','done')){return '';}
        $css=self::compile($html);
        return self::asset($css,$source,'page');
    }
    /** Generated styles are emitted by WordPress at their original cascade positions. */
    public static function layout(string $html,int $source): string { return $html; }
    private static function asset(string $css,int $source,string $kind): string {
        if($css===''){return '';}
        $key=hash('sha256',get_current_blog_id().'|'.DIGIBL_VERSION.'|'.$css);
        if(isset(self::$emitted[$kind.$key])){return '';}
        self::$emitted[$kind.$key]=true;
        $uploads=wp_upload_dir(null,false);
        $directory=trailingslashit($uploads['basedir']).'digiter-builder/css';
        $name=$kind.'-'.absint($source).'-'.$key.'.css';
        $file=$directory.'/'.$name;
        if(empty($uploads['error']) && (is_dir($directory)||wp_mkdir_p($directory))){
            if(!is_file($file) && wp_is_writable($directory)){
                $temp=@tempnam($directory,'dbs-');
                if($temp!==false){
                    $written=@file_put_contents($temp,$css,LOCK_EX);
                    if($written===strlen($css)){@LocalFiles::get()->chmod($temp,0644);if(!@LocalFiles::get()->move($temp,$file)){@wp_delete_file($temp);}}
                    else{@wp_delete_file($temp);}
                }
            }
            if(is_readable($file) && @filesize($file)===strlen($css)){
                if(@filemtime($file)<time()-DAY_IN_SECONDS){@LocalFiles::get()->touch($file);}
                return Assets::stylesheet(trailingslashit($uploads['baseurl']).'digiter-builder/css/'.$name,$kind.'-'.$key);
            }
        }
        // Read-only/object-storage uploads must never result in an unstyled page.
        return Assets::inline_style($css,$kind.'-'.$key);
    }
    public static function cleanup(): void {
        $uploads=wp_upload_dir(null,false);$dir=trailingslashit($uploads['basedir']).'digiter-builder/css';
        if(!is_dir($dir)||!is_readable($dir)){return;}
        $checked=0;$cutoff=time()-45*DAY_IN_SECONDS;
        foreach(new \DirectoryIterator($dir) as $file){
            if($file->isDot()||$file->isLink()||!$file->isFile()){continue;}
            if(++$checked>2000){break;}
            if(preg_match('/^(?:page|layout)-\d+-[a-f0-9]{64}\.css$/D',$file->getFilename())&&$file->getMTime()<$cutoff){@wp_delete_file($file->getPathname());}
        }
    }
}