<?php

declare(strict_types=1);
namespace App\Services\Freenode;

use RuntimeException;
use Symfony\Component\Process\Process;

/** Native core checks run per complete config, with bisection only when a config fails. */
final class NativeValidator
{
    public int $checks = 0;
    public array $rejected = [];
    private string $dir;
    private float $startedAt;
    private ?int $failureIndex = null;

    public function __construct(private string $singbox, private string $mihomo, private ?array $clashTemplate = null, ?string $dataDirectory = null)
    {
        $this->startedAt = microtime(true);
        if ($dataDirectory !== null) {
            foreach (['Country.mmdb', 'geoip.metadb'] as $file) {
                if (!is_readable($dataDirectory.'/'.$file)) throw new RuntimeException('missing_offline_geoip');
            }
        }
        $this->dir = sys_get_temp_dir().'/freenode-check-'.bin2hex(random_bytes(8));
        mkdir($this->dir, 0700, true);
        if ($dataDirectory !== null) foreach (['Country.mmdb', 'geoip.metadb'] as $file) symlink($dataDirectory.'/'.$file, $this->dir.'/'.$file);
    }

    public function __destruct()
    {
        foreach (glob($this->dir.'/*') ?: [] as $p) if (is_file($p)) @unlink($p);
        @rmdir($this->dir);
    }

    public function check(string $format, string $content): bool
    {
        $binary = $format === 'singbox' ? $this->singbox : $this->mihomo;
        if (!is_executable($binary)) throw new RuntimeException('native_validator_not_executable:'.$format);
        $remaining = 240 - (microtime(true) - $this->startedAt);
        if ($remaining <= 0) throw new RuntimeException('native_validation_batch_timeout');
        $file = $this->dir.'/'.bin2hex(random_bytes(6)).($format === 'clash' ? '.yaml' : '.json');
        file_put_contents($file, $content); chmod($file, 0600);
        $command = $format === 'singbox' ? [$binary, 'check', '-c', $file] : [$binary, '-t', '-d', $this->dir, '-f', $file];
        $process = new Process($command);
        $process->setTimeout(min(45, $remaining));
        try {
            $process->run();
            $this->checks++;
            $this->failureIndex = null;
            // Native diagnostics stay in memory. Extract only the structured node index.
            $diagnostic = $process->getErrorOutput().$process->getOutput();
            $pattern = $format === 'singbox' ? '/outbound(?:s)?\[(\d+)\]/' : '/proxy (\d+):/';
            if (!$process->isSuccessful() && preg_match($pattern, $diagnostic, $match)) {
                $this->failureIndex = (int) $match[1] - ($format === 'singbox' ? 2 : 0);
            }
            return $process->isSuccessful();
        } finally {
            @unlink($file);
        }
    }

    public function filter(string $format, array $nodes): array
    {
        $render = fn (array $rows) => $this->render($format, $rows);
        if (!$this->check($format, $render([]))) throw new RuntimeException('invalid_template_or_core:'.$format);
        return $this->partition($format, $nodes, $render);
    }

    public function render(string $format, array $nodes): string
    {
        return $format === 'singbox' ? Renderer::singbox($nodes) : Renderer::clash($nodes, $this->clashTemplate);
    }

    private function partition(string $format, array $nodes, callable $render): array
    {
        if (!$nodes) return [];
        while ($nodes) {
            if ($this->check($format, $render($nodes))) return $nodes;
            $keys = array_keys($nodes);
            if ($this->failureIndex === null || !isset($keys[$this->failureIndex])) break;
            $key = $keys[$this->failureIndex];
            $this->rejected[$format][] = $key;
            unset($nodes[$key]);
        }
        if (!$nodes) return [];
        if (count($nodes) === 1) {
            $this->rejected[$format][] = array_key_first($nodes);
            return [];
        }
        $chunks = array_chunk($nodes, (int) ceil(count($nodes) / 2), true);
        $good = [];
        foreach ($chunks as $chunk) $good += $this->partition($format, $chunk, $render);
        // Builder validates the final complete config once, including cross-node constraints.
        return $good;
    }
}