<?php
declare(strict_types=1);

namespace MageSail\Magesail\Model;

use Magento\Framework\App\Filesystem\DirectoryList;
use Magento\Framework\Shell;

/**
 * Single source of truth for tunnel PID/key state and process checks.
 */
class TunnelStatus
{
    public function __construct(
        private readonly Shell $shell,
        private readonly DirectoryList $directoryList
    ) {
    }

    public function getPidFilePath(): string
    {
        return $this->directoryList->getPath(DirectoryList::VAR_DIR) . '/magesail.pid';
    }

    public function getKeyFilePath(): string
    {
        return $this->directoryList->getPath(DirectoryList::VAR_DIR) . '/magesail.key';
    }

    public function getLogFilePath(): string
    {
        return $this->directoryList->getPath(DirectoryList::VAR_DIR) . '/log/magesail_tunnel.log';
    }

    /**
     * @return array{running: bool, pid: int|null, key: string|null}
     */
    public function getStatus(): array
    {
        $pidFile = $this->getPidFilePath();
        $keyFile = $this->getKeyFilePath();
        if (!\is_file($pidFile)) {
            return ['running' => false, 'pid' => null, 'key' => null];
        }
        $pid = (int) trim((string) file_get_contents($pidFile));
        if ($pid <= 0) {
            return ['running' => false, 'pid' => null, 'key' => null];
        }
        if (!$this->isProcessAlive($pid)) {
            @unlink($pidFile);
            $kf = $this->getKeyFilePath();
            if (\is_file($kf)) {
                @unlink($kf);
            }
            return ['running' => false, 'pid' => null, 'key' => null];
        }
        $key = null;
        if (\is_file($keyFile)) {
            $key = trim((string) file_get_contents($keyFile));
            if ($key === '') {
                $key = null;
            }
        }
        return ['running' => true, 'pid' => $pid, 'key' => $key];
    }

    public function isRunning(): bool
    {
        return $this->getStatus()['running'];
    }

    public function isProcessAlive(int $pid): bool
    {
        if ($pid <= 0) {
            return false;
        }
        try {
            $this->shell->execute("ps -p %s > /dev/null 2>&1", [$pid]);
            return true;
        } catch (\Exception $e) {
            return false;
        }
    }

    /**
     * If PID file exists but process is dead, remove pid/key files.
     */
    public function cleanupStaleState(): void
    {
        $pidFile = $this->getPidFilePath();
        if (!\is_file($pidFile)) {
            return;
        }
        $pid = (int) trim((string) file_get_contents($pidFile));
        if ($pid <= 0 || !$this->isProcessAlive($pid)) {
            @unlink($pidFile);
            $keyFile = $this->getKeyFilePath();
            if (\is_file($keyFile)) {
                @unlink($keyFile);
            }
        }
    }
}