<?php

namespace Kiri\Server;

use Kiri\Abstracts\Component;
use Kiri\Server\Abstracts\TraitServer;
use Swoole\Process;
use function config;

class State extends Component
{

    use TraitServer;


    public array $servers = [];


    /**
     * @return void
     */
    public function init(): void
    {
        $this->servers = config('servers.server.ports');
    }


    /**
     * @return bool
     * @throws
     */
    public function isRunner(): bool
    {
        if ($this->getPidFilePid() !== null || $this->getNamedServerPids() !== []) {
            return true;
        }

        $ports = $this->sortService($this->servers);
        foreach ($ports as $config) {
            if (checkPortIsAlready($config->port)) {
                return true;
            }
        }
        return false;
    }


    /**
     * @param $port
     * @throws
     */
    public function exit($port): void
    {
        $pids = $this->collectStopPids((int)$port);
        if ($pids === []) {
            return;
        }

        $this->terminatePids($pids, SIGTERM, 30);

        $remaining = array_values(array_filter($pids, [$this, 'isProcessAlive']));
        if ($remaining !== []) {
            $this->terminatePids($remaining, SIGKILL, 10);
        }

        if (!checkPortIsAlready((int)$port)) {
            @unlink(storage('.swoole.pid'));
        }
    }


    private function collectStopPids(int $port): array
    {
        $pids = [];

        $pidFilePid = $this->getPidFilePid();
        if ($pidFilePid !== null) {
            $pids[] = $pidFilePid;
            $pids = array_merge($pids, $this->getDescendantPids($pidFilePid));
        }

        $pids = array_merge($pids, $this->getNamedServerPids());

        $portPid = checkPortIsAlready($port);
        if ($portPid !== false) {
            $pids[] = (int)$portPid;
            $pids = array_merge($pids, $this->getDescendantPids((int)$portPid));
        }

        $currentPid = getmypid();
        $pids = array_values(array_unique(array_filter(array_map('intval', $pids), function (int $pid) use ($currentPid) {
            return $pid > 1 && $pid !== $currentPid;
        })));
        rsort($pids);

        return $pids;
    }


    private function terminatePids(array $pids, int $signal, int $rounds): void
    {
        for ($i = 0; $i < $rounds; $i++) {
            $alive = false;
            foreach ($pids as $pid) {
                if (!$this->isProcessAlive($pid)) {
                    continue;
                }
                $alive = true;
                @Process::kill($pid, $signal);
            }

            if (!$alive) {
                return;
            }

            usleep(100000);
        }
    }


    private function getPidFilePid(): ?int
    {
        $pidFile = storage('.swoole.pid');
        if (!is_file($pidFile)) {
            return null;
        }

        $pid = (int)trim((string)file_get_contents($pidFile));
        if ($pid <= 1 || !$this->isProcessAlive($pid)) {
            return null;
        }

        return $pid;
    }


    private function getDescendantPids(int $parentPid): array
    {
        $processes = $this->listProcesses();
        $children = [];
        foreach ($processes as $process) {
            $children[(int)$process['ppid']][] = (int)$process['pid'];
        }

        $result = [];
        $stack = [$parentPid];
        while ($stack !== []) {
            $pid = array_pop($stack);
            foreach ($children[$pid] ?? [] as $childPid) {
                $result[] = $childPid;
                $stack[] = $childPid;
            }
        }

        return $result;
    }


    private function getNamedServerPids(): array
    {
        $siteId = '[' . config('site.id', 'system-service') . ']';
        $pids = [];
        foreach ($this->listProcesses() as $process) {
            $command = $process['command'];
            if (!str_contains($command, $siteId)) {
                continue;
            }
            if (!preg_match('/\\]\\..+\\[[0-9]+\\]/', $command)) {
                continue;
            }
            $pids[] = (int)$process['pid'];
        }

        return $pids;
    }


    private function listProcesses(): array
    {
        $lines = [];
        exec('ps -eo pid=,ppid=,args=', $lines);

        $processes = [];
        foreach ($lines as $line) {
            $line = trim($line);
            if ($line === '') {
                continue;
            }

            $parts = preg_split('/\s+/', $line, 3);
            if (count($parts) < 3) {
                continue;
            }

            $processes[] = [
                'pid' => (int)$parts[0],
                'ppid' => (int)$parts[1],
                'command' => $parts[2],
            ];
        }

        return $processes;
    }


    private function isProcessAlive(int $pid): bool
    {
        return $pid > 1 && @Process::kill($pid, 0);
    }

}