CountLogTypeOnLevelsCommand.php

<?php

namespace App\Command;

use Symfony\Component\Console\Command\Command;
use Symfony\Component\Console\Input\InputArgument;
use Symfony\Component\Console\Input\InputInterface;
use Symfony\Component\Console\Output\OutputInterface;

use App\Domain\LogEntry;
use App\Application\LogsSummarizer;

final class CountLogTypeOnLevelsCommand extends Command
{
    private CONST LOGS_PATH = "var/log/";
    private CONST LOGS_EXTENSION = ".log";
    private $logEntries = [];

    protected static $defaultName = 'count-log-type-on-levels';

    protected function configure(): void
    {
        $this
            ->setDescription('Print (not dump) a log summary. That is, the number of log entries aggregated by their level for the selected levels on all the log files')
            ->addArgument('levels', InputArgument::IS_ARRAY, 'Log levels');
    }

    private function isLogFile(): callable
    {
        return function(string $fileName): bool {
            return substr($fileName, strlen($fileName) - 4, strlen($fileName) - 1) === self::LOGS_EXTENSION;
        };
    }

    protected function execute(InputInterface $input, OutputInterface $output): void
    {
        $levelsFilter = array_map('strtoupper', $input->getArgument('levels'));
        $files = array_filter(scandir(self::LOGS_PATH), $this->isLogFile());

        $logsSummarizer = new LogsSummarizer();

        foreach ($files as $logFileNameToRead) {
            $lines = file(self::LOGS_PATH . $logFileNameToRead);
            foreach ($lines as $line) {
                $this->logEntries[] = LogEntry::fromJsonString($line);;
            }
        }

        $logSummary = $logsSummarizer($this->logEntries, $levelsFilter);
        foreach ($logSummary as $logLevel => $logLevelOccurrences) {
            $output->writeln("Hay " . $logLevelOccurrences . " logs del tipo " . $logLevel);
        }       
    }
}

LogsSummarizer.php

<?php

namespace App\Application;

use App\Domain\LogsSummary;

final class LogsSummarizer
{
    private static $holdingCantLeveLog = [];
    private CONST ALL_LEVELS = ["WARNING", "INFO", "DEBUG", "ERROR"];

    public function withAllLevel():
    {

    }

    public function __invoke(array $logEntries, array $logLevelsFilter): LogsSummary
    {
        $allLogEntriesSummary = LogsSummary::from(...$logEntries);

        return $allLogEntriesSummary->filterBy($logLevelsFilter);
    }
}

LogsSummary.php

<?php

declare(strict_types = 1);

namespace App\Domain;

final class LogsSummary
{
    private $logEntries = [];

    public static function from(LogEntry ...$logEntries): LogsSummary
    {
        $summary = new self();

        array_map($summary->logEntryAdder(), $logEntries);

        return $summary;
    }

    public function logEntryAdder(): callable
    {
        return function(LogEntry $logEntry): void {
            $this->addLogEntry($logEntry);
        };
    }

    public function addLogEntry(LogEntry $logEntry): void
    {
        $this->logEntries[$logEntry->level()][] = $logEntry;
    }

    public function errorLevelOccurrences(): int
    {
        return count($this->logEntries[self::ERROR_LEVEL]);
    }

    public function filterBy(array $logLevelsFilter): LogsSummary
    {

    }
}