<?php
/**
 * @author Frank Karlitschek <frank@nextcloud.com>
 *
 * @license AGPL-3.0
 *
 * This code is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License, version 3,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License, version 3,
 * along with this program.  If not, see <http://www.gnu.org/licenses/>
 *
 */

namespace OCA\ServerInfo\OperatingSystems;

use OCA\ServerInfo\Resources\Disk;
use OCA\ServerInfo\Resources\Memory;

class DefaultOs implements IOperatingSystem {

	/**
	 * @return bool
	 */
	public function supported(): bool {
		return true;
	}

	public function getMemory(): Memory {
		$data = new Memory();

		try {
			$meminfo = $this->readContent('/proc/meminfo');
		} catch (\RuntimeException $e) {
			return $data;
		}

		$matches = [];
		$pattern = '/(?<Key>(?:MemTotal|MemFree|MemAvailable|SwapTotal|SwapFree)+):\s+(?<Value>\d+)\s+(?<Unit>\w{2})/';

		$result = preg_match_all($pattern, $meminfo, $matches);
		if ($result === 0 || $result === false) {
			return $data;
		}

		foreach ($matches['Key'] as $i => $key) {
			// Value is always in KB: https://github.com/torvalds/linux/blob/c70672d8d316ebd46ea447effadfe57ab7a30a50/fs/proc/meminfo.c#L58-L60
			$value = (int)($matches['Value'][$i] / 1024);

			switch ($key) {
				case 'MemTotal':
					$data->setMemTotal($value);
					break;
				case 'MemFree':
					$data->setMemFree($value);
					break;
				case 'MemAvailable':
					$data->setMemAvailable($value);
					break;
				case 'SwapTotal':
					$data->setSwapTotal($value);
					break;
				case 'SwapFree':
					$data->setSwapFree($value);
					break;
			}
		}

		return $data;
	}

	public function getCpuName(): string {
		$data = 'Unknown Processor';

		try {
			$cpuinfo = $this->readContent('/proc/cpuinfo');
		} catch (\RuntimeException $e) {
			return $data;
		}

		$matches = [];
		$pattern = '/model name\s:\s(.+)/';

		$result = preg_match_all($pattern, $cpuinfo, $matches);
		if ($result === 0 || $result === false) {
			return $data;
		}

		$model = $matches[1][0];
		$cores = count($matches[1]);

		if ($cores === 1) {
			$data = $model . ' (1 core)';
		} else {
			$data = $model . ' (' . $cores . ' cores)';
		}

		return $data;
	}

	/**
	 * @return string
	 */
	public function getTime() {
		$uptime = shell_exec('date');
		return $uptime;
	}

	public function getUptime(): int {
		$data = -1;

		try {
			$uptime = $this->readContent('/proc/uptime');
		} catch (\RuntimeException $e) {
			return $data;
		}

		[$uptimeInSeconds,] = array_map('intval', explode(' ', $uptime));

		return $uptimeInSeconds;
	}

	/**
	 * @return string
	 */
	public function getTimeServers() {
		$servers = shell_exec('cat /etc/ntp.conf 2>/dev/null |grep  \'^pool\' | cut -f 2 -d " "');
		$servers .= ' ' . shell_exec('cat /etc/systemd/timesyncd.conf 2>/dev/null |grep  \'^NTP=\' | cut -f 2 -d " "');
		return $servers;
	}

	/**
	 * @return string
	 */
	public function getNetworkInfo() {
		$result = [];
		$result['hostname'] = \gethostname();
		$dns = shell_exec('cat /etc/resolv.conf |grep -i \'^nameserver\'|head -n1|cut -d \' \' -f2');
		$result['dns'] = $dns;
		$gw = shell_exec('ip route | awk \'/default/ { print $3 }\'');
		$result['gateway'] = $gw;
		return $result;
	}

	/**
	 * @return string
	 */
	public function getNetworkInterfaces() {
		$interfaces = glob('/sys/class/net/*');
		$result = [];

		foreach ($interfaces as $interface) {
			$iface              = [];
			$iface['interface'] = basename($interface);
			$iface['mac']       = shell_exec('ip addr show dev ' . $iface['interface'] . ' | grep "link/ether " | cut -d \' \' -f 6  | cut -f 1 -d \'/\'');
			$iface['ipv4']      = shell_exec('ip addr show dev ' . $iface['interface'] . ' | grep "inet " | cut -d \' \' -f 6  | cut -f 1 -d \'/\'');
			$iface['ipv6']      = shell_exec('ip -o -6 addr show ' . $iface['interface'] . ' | sed -e \'s/^.*inet6 \([^ ]\+\).*/\1/\'');
			if ($iface['interface'] !== 'lo') {
				$iface['status'] = shell_exec('cat /sys/class/net/' . $iface['interface'] . '/operstate');
				$iface['speed']  = shell_exec('cat /sys/class/net/' . $iface['interface'] . '/speed');
				if ($iface['speed'] !== '') {
					$iface['speed'] = $iface['speed'] . 'Mbps';
				} else {
					$iface['speed'] = 'unknown';
				}

				$duplex = shell_exec('cat /sys/class/net/' . $iface['interface'] . '/duplex');
				if ($duplex !== '') {
					$iface['duplex'] = 'Duplex: ' . $duplex;
				} else {
					$iface['duplex'] = '';
				}
			} else {
				$iface['status'] = 'up';
				$iface['speed']  = 'unknown';
				$iface['duplex'] = '';
			}
			$result[] = $iface;
		}

		return $result;
	}

	public function getDiskInfo(): array {
		$data = [];

		try {
			$disks = $this->executeCommand('df -TPk');
		} catch (\RuntimeException $e) {
			return $data;
		}

		$matches = [];
		$pattern = '/^(?<Filesystem>[\S]+)\s*(?<Type>\w+)\s*(?<Blocks>\d+)\s*(?<Used>\d+)\s*(?<Available>\d+)\s*(?<Capacity>\d+%)\s*(?<Mounted>[\w\/-]+)$/m';

		$result = preg_match_all($pattern, $disks, $matches);
		if ($result === 0 || $result === false) {
			return $data;
		}

		foreach ($matches['Filesystem'] as $i => $filesystem) {
			if (in_array($matches['Type'][$i], ['tmpfs', 'devtmpfs'], false)) {
				continue;
			}

			$disk = new Disk();
			$disk->setDevice($filesystem);
			$disk->setFs($matches['Type'][$i]);
			$disk->setUsed((int)($matches['Used'][$i] / 1024));
			$disk->setAvailable((int)($matches['Available'][$i] / 1024));
			$disk->setPercent($matches['Capacity'][$i]);
			$disk->setMount($matches['Mounted'][$i]);

			$data[] = $disk;
		}

		return $data;
	}

	protected function readContent(string $filename): string {
		$data = @file_get_contents($filename);
		if ($data === false || $data === '') {
			throw new \RuntimeException('Unable to read: "' . $filename . '"');
		}
		return $data;
	}

	protected function executeCommand(string $command): string {
		$output = @shell_exec(escapeshellcmd($command));
		if ($output === null || $output === '') {
			throw new \RuntimeException('No output for command: "' . $command . '"');
		}
		return $output;
	}
}