<?php
namespace VPSManager;

require_once __DIR__ . '/Config.php';

final class Graphite
{
    public const RANGES = ['1h' => '-1h', '6h' => '-6h', '24h' => '-24h', '7d' => '-7d', '30d' => '-30d'];
    private const SUFFIXES = [
        'load1' => 'load.load.shortterm',
        'load5' => 'load.load.midterm',
        'load15' => 'load.load.longterm',
        'used' => 'memory.memory-used',
        'free' => 'memory.memory-free',
        'rx' => 'interface-eth0.if_octets.rx',
        'tx' => 'interface-eth0.if_octets.tx',
    ];
    private $baseUrl;
    private $transport;

    public function __construct(array $config, ?callable $transport = null)
    {
        $this->baseUrl = Config::url($config, 'graphite_url');
        $this->transport = $transport ?? [self::class, 'request'];
    }

    public static function range($value): string
    {
        return is_string($value) && isset(self::RANGES[$value]) ? $value : '24h';
    }

    public static function validUuid($uuid): bool
    {
        return is_string($uuid) && preg_match('/\A[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}\z/i', $uuid) === 1;
    }

    // Only WHMCS-authorized module parameters may be passed here; never request UUID/type.
    public function getForService(array $params, $range = '24h'): array
    {
        $fields = $params['customfields'] ?? [];
        if (($fields['vtype'] ?? null) !== 'lx' || !self::validUuid($fields['uuid'] ?? null)) {
            throw new \InvalidArgumentException('Servicio no compatible con las métricas LX.');
        }
        $range = self::range($range);
        $targets = [];
        foreach (self::SUFFIXES as $key => $suffix) {
            $targets[$key] = 'lx.' . $fields['uuid'] . '.' . $suffix;
        }
        $query = 'format=json&from=' . rawurlencode(self::RANGES[$range]) . '&until=now&maxDataPoints=1000';
        foreach ($targets as $target) {
            $query .= '&target=' . rawurlencode($target);
        }
        $response = call_user_func($this->transport, $this->baseUrl . '/render/?' . $query);
        if (!is_array($response) || ($response['status'] ?? 0) !== 200 || !is_string($response['body'] ?? null)) {
            throw new \RuntimeException('Graphite HTTP error.');
        }
        $raw = json_decode($response['body'], true, 32);
        if (substr(ltrim($response['body']), 0, 1) !== '[' || json_last_error() !== JSON_ERROR_NONE || !is_array($raw) || !array_is_list($raw)) {
            throw new \RuntimeException('Graphite JSON error.');
        }
        $series = array_fill_keys(array_keys($targets), []);
        $seen = [];
        foreach ($raw as $row) {
            if (!is_array($row) || !is_string($row['target'] ?? null)) {
                throw new \RuntimeException('Graphite series error.');
            }
            $key = array_search($row['target'], $targets, true);
            if ($key === false) {
                continue; // Never expose unrequested targets or metadata.
            }
            if (isset($seen[$key]) || !is_array($row['datapoints'] ?? null) || count($row['datapoints']) > 10000) {
                throw new \RuntimeException('Graphite series error.');
            }
            $seen[$key] = true;
            $points = [];
            foreach ($row['datapoints'] as $point) {
                if (!is_array($point) || count($point) !== 2 || !array_is_list($point)
                    || !is_int($point[1]) || $point[1] < 0 || $point[1] > 253402300799) {
                    throw new \RuntimeException('Graphite datapoint error.');
                }
                $value = $point[0];
                if ($value !== null && ((!is_int($value) && !is_float($value)) || !is_finite((float) $value) || $value < 0)) {
                    throw new \RuntimeException('Graphite value error.');
                }
                if (array_key_exists($point[1], $points)) {
                    throw new \RuntimeException('Graphite duplicate timestamp.');
                }
                $points[$point[1]] = $value;
            }
            ksort($points, SORT_NUMERIC);
            foreach ($points as $timestamp => $value) {
                $series[$key][] = ['x' => $timestamp * 1000, 'y' => $value];
            }
        }
        // Align memory by timestamps, never by index; absent data stays null.
        $used = array_column($series['used'], 'y', 'x');
        $free = array_column($series['free'], 'y', 'x');
        $times = array_unique(array_merge(array_keys($used), array_keys($free)));
        sort($times, SORT_NUMERIC);
        $total = [];
        $percent = [];
        foreach ($times as $time) {
            $u = $used[$time] ?? null;
            $f = $free[$time] ?? null;
            $sum = $u !== null && $f !== null ? $u + $f : null;
            if ($sum !== null && !is_finite((float) $sum)) {
                throw new \RuntimeException('Graphite memory overflow.');
            }
            $total[] = ['x' => $time, 'y' => $sum];
            $percent[] = ['x' => $time, 'y' => $sum !== null && $sum > 0 ? ($u / $sum) * 100 : null];
        }
        return [
            'range' => $range,
            'load' => ['1 min' => $series['load1'], '5 min' => $series['load5'], '15 min' => $series['load15']],
            'memory' => ['Usada' => $series['used'], 'Total' => $total],
            'memoryPercent' => $percent,
            'network' => ['RX' => $series['rx'], 'TX' => $series['tx']], // bytes/s; presentation converts once.
        ];
    }

    private static function request(string $url): array
    {
        if (!function_exists('curl_init')) {
            throw new \RuntimeException('Graphite transport unavailable.');
        }
        $ch = curl_init($url);
        $body = '';
        curl_setopt_array($ch, [
            CURLOPT_CONNECTTIMEOUT => 3,
            CURLOPT_TIMEOUT => 5,
            CURLOPT_FOLLOWLOCATION => false,
            CURLOPT_PROTOCOLS => CURLPROTO_HTTPS,
            CURLOPT_SSL_VERIFYPEER => true,
            CURLOPT_SSL_VERIFYHOST => 2,
            CURLOPT_HTTPHEADER => ['Accept: application/json'],
            CURLOPT_WRITEFUNCTION => static function ($handle, $chunk) use (&$body) {
                if (strlen($body) + strlen($chunk) > 2097152) {
                    return 0;
                }
                $body .= $chunk;
                return strlen($chunk);
            },
        ]);
        try {
            $ok = curl_exec($ch);
            $status = curl_getinfo($ch, CURLINFO_HTTP_CODE);
            if ($ok === false) {
                throw new \RuntimeException('Graphite transport error.');
            }
            return ['status' => $status, 'body' => $body];
        } finally {
            curl_close($ch);
        }
    }
}