<?php
declare(strict_types=1);
namespace App\Helper;

use App\Entity\ExchangeRates;
use Doctrine\ORM\EntityManager;

class Currency
{
    public static array $currencies = ["USD","GBP","PLN","EUR","CAD"];
    public static array $currenciesCrypto = ["USDT"];
    private static string $apiUrl = "https://api.nbp.pl/api/exchangerates/rates/a/:code/:date/?format=json";
    private EntityManager $manager;
    private array $ratesPerDate;

    public function __construct(EntityManager $manager)
    {
        $this->manager = $manager;
        $this->takeRates();
    }

    public function getRate(string $currency, \DateTime $dateTime) : float
    {
        $dayOfWeek = $dateTime->format("N");
        $minusDay = 1;
        if ($dayOfWeek == 7){
            $minusDay = 2;
        } elseif ($dayOfWeek == 1) {
            $minusDay = 3;
        }
        $dateTime->modify("-$minusDay days");
        $dateStr = $dateTime->format("Ymd");

        if (isset($this->ratesPerDate[$currency]) && isset($this->ratesPerDate[$currency][$dateStr])) {
            return $this->ratesPerDate[$currency][$dateStr];
        }
        $dateCopy = clone $dateTime;
        $limitLoop = 5;
        do {
            $rate = $this->takePLNOnDate($currency, $dateCopy->format("Y-m-d"));
            if (!$rate) {
                $dateCopy->modify("-1 day");
            }
            if ($limitLoop < 1) {
                break;
            }
            $limitLoop--;
        }while($rate == 0);

        if ($rate) {
            $ratesEntity = new ExchangeRates();
            $ratesEntity->setIntRate(intval($rate * 10000));
            $ratesEntity->setStrCurrency($currency);
            $ratesEntity->setDateDate($dateTime);

            $this->manager->persist($ratesEntity);
            $this->manager->flush();
            $this->ratesPerDate[$currency][$dateStr] = $rate;
            return $rate;
        }

        return 0;
    }


    private function takePLNOnDate(string $currency, string $dateStr) : float
    {
        if (!self::isCurrencyExists($currency)) {
            return 0;
        }
        $url = strtr(self::$apiUrl,[
            ":code" => mb_strtolower($currency),
            ":date" => str_replace(".","-",$dateStr)
        ]);
        $ch = curl_init();
        curl_setopt($ch, CURLOPT_URL, $url);
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, true);
        $result=curl_exec($ch);
        curl_close($ch);
        $data = json_decode($result, true);
        if (!isset($data['rates']) || !isset($data['rates'][0]) || !isset($data['rates'][0]['mid'])) {
            return 0;
        }
        return $data['rates'][0]['mid'];
    }

    private function takeRates()
    {
        $rates = $this->manager->getRepository(ExchangeRates::class);
        $rates = $rates->findAll();

        if ($rates) {
            /** @var ExchangeRates $rate */
            foreach ($rates as $rate) {
                if (!isset($this->ratesPerDate[$rate->getStrCurrency()])) {
                    $this->ratesPerDate[$rate->getStrCurrency()] = [];
                }
                $this->ratesPerDate[$rate->getStrCurrency()][$rate->getDateDate()->format("Ymd")] = $rate->getIntRate()/10000;
            }
        }
    }


    public static function isCurrencyExists(string $currency) : bool
    {
        return in_array($currency, self::$currencies);
    }
}