<?php

use KupShop\I18nBundle\Entity\Currency;
use KupShop\KupShopBundle\Context\CurrencyContext;
use KupShop\KupShopBundle\Util\Compat\ServiceContainer;

class CNB
{
    private static $url = 'https://www.cnb.cz/cs/financni_trhy/devizovy_trh/kurzy_devizoveho_trhu/denni_kurz.txt';

    // Allowed difference in percent between old and new currency
    private static $allow_difference = 10;

    /**
     * @param false $admin
     *
     * @throws Exception
     */
    public static function updateCurrencies($admin = false)
    {
        $new_currencies = self::getSharedCurrencies();

        $currencyContext = ServiceContainer::getService(CurrencyContext::class);
        $em = ServiceContainer::getService('doctrine.orm.entity_manager');

        $currencies = $currencyContext->getAll();

        $defaultCurrency = $currencyContext->getDefaultId();
        if ($defaultCurrency == 'CZK') {
            $conversionRate = DecimalConstants::one();
        } else {
            $conversionRate = DecimalConstants::one()->div($new_currencies[$defaultCurrency]);
        }

        $new_currencies['CZK'] = DecimalConstants::one();

        /** @var Currency $currency */
        foreach ($currencies as $currency) {
            if ($currency->getSync() == 'Y') {
                $currency_name = $currency->getId();
                if (!empty($new_currencies[$currency_name])) {
                    $value = self::prepPrice($new_currencies[$currency_name]);
                    if (!$currency->getCorrections()->isZero()) {
                        $value = $value->add(self::prepPrice($currency->getCorrections()));
                    }

                    $value = $value->mul($conversionRate);

                    if ($currency->getRate()->isPositive()) {
                        $old_currency = $currency->getRate()->asFloat();
                        $new_currency = $value->asFloat();

                        $difference = ($old_currency - $new_currency) / ($old_currency / 100);

                        if (!$admin && abs($difference) > self::$allow_difference) {
                            throw new Exception('Aktualizace kurzu měn selhala. Měna "'.$currency_name.'", rozdíl '.round($difference, 2)." % !!, stará = '{$old_currency}', nová = '{$new_currency}'");
                        }
                    }

                    $currency->setRate($value);

                    $currency->setSyncDateUpdated();
                }
            }
        }
        $em->flush();

        $dispatcher = ServiceContainer::getService('event_dispatcher');
        $dispatcher->dispatch(new KupShop\KupShopBundle\Event\CNBSyncEvent(), KupShop\KupShopBundle\Event\CNBSyncEvent::NAME);
    }

    public static function prepPrice($price, $div = null)
    {
        $price = toDecimal(floatval(str_replace(',', '.', trim($price))));

        if ($div) {
            $div = toDecimal(floatval(str_replace(',', '.', trim($div))));
            if ($div->isPositive()) {
                $price = $price->div($div);
            }
        }

        return $price;
    }

    /**
     * @throws Exception
     */
    public static function getCurrency($currency): Decimal
    {
        if ($currency === 'CZK') {
            return Decimal::create(1, 20);
        }
        $currencies = static::getCurrencies();

        if (!isset($currencies[$currency])) {
            throw new Exception("CNB: Undefined currency: {$currency}");
        }

        return $currencies[$currency];
    }

    /**
     * Download actual CNB currencies and update on shared DB.
     *
     * @throws Exception
     */
    public static function updateSharedCurrencies(): void
    {
        $currencies = self::downloadCurrencies();

        foreach ($currencies as $id => $rate) {
            sqlQuery(
                'INSERT INTO kupshop_shared.cnb_currencies (id,rate)
                            VALUES (:id, :rate)
                            ON DUPLICATE KEY UPDATE id=:id, rate=:rate',
                [
                    'id' => $id,
                    'rate' => $rate,
                ]
            );
        }
    }

    /**
     * @return Decimal[]
     *
     * @throws Exception
     */
    public static function getCurrencies(): array
    {
        static $currencies = null;

        if (!$currencies) {
            $currencies = static::getSharedCurrencies();
        }

        return $currencies;
    }

    /**
     * @return Decimal[]
     *
     * @throws Exception
     */
    private static function downloadCurrencies(): array
    {
        $currencies_file = self::downloadFile();

        $currencies = [];
        foreach ($currencies_file as $v) {
            $h = explode('|', $v);
            if (!empty($h[3])) {
                $currencies[$h[3]] = self::prepPrice($h[4], $h[2]);
            }
        }

        return $currencies;
    }

    /**
     * Get CNB currencies from shared db.
     */
    private static function getSharedCurrencies(): array
    {
        $result = sqlQueryBuilder()->select('id, rate')
            ->from('kupshop_shared.cnb_currencies')
            ->execute();

        $currencies = [];

        foreach ($result as $row) {
            $currencies[$row['id']] = Decimal::create($row['rate'], 20);
        }

        return $currencies;
    }

    /**
     * @throws Exception
     */
    private static function downloadFile(): array
    {
        $file = file(self::$url);

        if ($file === false) {
            throw new Exception('Soubor CNB nedostupny.');
        }

        return $file;
    }

    public static function setUrl(string $url)
    {
        self::$url = $url;
    }

    /**
     * @throws Exception
     */
    public static function convertPrice(Decimal $price, $from, $to)
    {
        $exchange_rate = self::getCurrency($from)->div(self::getCurrency($to));

        return $price->mul($exchange_rate);
    }
}