<?php
namespace ProVM\Common\Implementation;

use Psr\Log\LoggerInterface;
use Psr\Log\LogLevel;
use Carbon\Carbon;

class Logger implements LoggerInterface {
  protected $output_file;
  public function __construct(string $filename) {
    if (!file_exists($filename)) {
      $f = fopen($filename, 'c');
      fclose($f);
    }
    if (!file_exists($filename)) {
      throw new \Exception('Can not create log file.');
    }
    $this->output_file = $filename;
  }
  public function emergency($message, array $context = []) {
    return $this->log(LogLevel::EMERGENCY, $message, $context);
  }
  public function alert($message, array $context = []) {
    return $this->log(LogLevel::ALERT, $message, $context);
  }
  public function critical($message, array $context = []) {
    return $this->log(LogLevel::CRITICAL, $message, $context);
  }
  public function error($message, array $context = []) {
    return $this->log(LogLevel::ERROR, $message, $context);
  }
  public function warning($message, array $context = []) {
    return $this->log(LogLevel::WARNING, $message, $context);
  }
  public function notice($message, array $context = []) {
    return $this->log(LogLevel::NOTICE, $message, $context);
  }
  public function info($message, array $context = []) {
    return $this->log(LogLevel::INFO, $message, $context);
  }
  public function debug($message, array $context = []) {
    return $this->log(LogLevel::DEBUG, $message, $context);
  }
  public function log($level, $message, array $context = []) {
    $refl = new \ReflectionClass(LogLevel::class);
    $levels = $refl->getConstants();
    if (array_search($level, array_values($levels)) === false) {
      throw new \InvalidArgumentException('Invalid log level.');
    }

    $f = Carbon::now('America/Santiago');
    $output = [
      'time' => $f->format('Y-m-d H:i:s,v'),
      'message' => $message
    ];
    if (count($context) > 0) {
      $output['context'] = $context;
    }

    $data = json_decode(trim(file_get_contents($this->output_file)));
    if ($data === null) {
      $data = [];
    }
    $data []= $output;
    file_put_contents($this->output_file, json_encode($data, \JSON_PRETTY_PRINT | \JSON_UNESCAPED_SLASHES | \JSON_UNESCAPED_UNICODE));
  }
}