Currency.php

<?php

/**
 * based on http://openexchangerates.org/
 */
class EtuDev_Util_Currency
{

    /**
     * @var string
     */
    protected $api_key = null;

    /**
     * @var int
     */
    protected $seconds_ttl = 3600;

    /**
     * @var array
     */
    protected $currencies = array();

    /**
     * @var array
     */
    protected $rates = array();

    /**
     * @var int
     */
    protected $timestamp = null;

    /**
     * @var bool
     */
    protected $lookup_for_rates_if_needed = true;

    /**
     * @param string $api_key
     * @param int    $seconds_ttl
     */
    public function __construct($api_key, $seconds_ttl = 3600)
    {
        $this->api_key     = $api_key;
        $this->seconds_ttl = $seconds_ttl;
    }

    /**
     * @return $this
     */
    public function disableLookupForRates()
    {
        $this->lookup_for_rates_if_needed = false;
        return $this;
    }

    /**
     * @return $this
     */
    public function enableLookupForRates()
    {
        $this->lookup_for_rates_if_needed = true;
        return $this;
    }

    /**
     * check if there are no rates or if the timestamp is more than $seconds_ttl seconds in the past
     *
     * @return bool
     */
    public function isRatesTooOld()
    {
        return (!$this->rates || ($this->timestamp + $this->seconds_ttl) < time());
    }

    /**
     * @return EtuDev_Util_Currency
     */
    public function retrieveCurrenciesIfNotSet()
    {
        if (!$this->currencies) {
            $this->loadCurrencies();
        }

        return $this;
    }

    /**
     * @return bool
     */
    public function needRetrieveRates()
    {
        return $this->lookup_for_rates_if_needed && (!$this->rates || $this->isRatesTooOld());
    }

    /**
     * @return $this
     */
    public function loadRates()
    {
        $this->load();
        return $this;
    }

    /**
     * if there are no rates or if they are too old, load()
     *
     * @return EtuDev_Util_Currency
     */
    public function retrieveRatesIfNeeded()
    {
        if ($this->needRetrieveRates()) {
            $this->load();
        }
        return $this;
    }

    /**
     * public setter if it is already cached
     *
     * @param array $currencies associative array
     *
     * @return EtuDev_Util_Currency
     */
    public function setCurrencies($currencies)
    {
        $this->currencies = (array) $currencies;
        return $this;
    }

    /**
     * public setter if it is already cached
     *
     * @param array $rates
     *
     * @return EtuDev_Util_Currency
     */
    public function setRates($rates)
    {
        $this->rates = $rates;
        return $this;
    }

    /**
     * public setter if it is already cached
     *
     * @param int $timestamp
     *
     * @return EtuDev_Util_Currency
     */
    public function setTimestamp($timestamp)
    {
        $this->timestamp = $timestamp;
        return $this;
    }

    protected function loadCurrencies()
    {
        $this->currencies = (array) $this->doRequest('currencies.json');
    }

    protected function load()
    {
        $changes = $this->doRequest('latest.json');
        if ($changes) {
            $this->rates     = $changes['rates'];
            $this->timestamp = (int) $changes['timestamp'];
        }
    }

    protected function doRequest($file)
    {
        $appId = $this->api_key;

        $ch = curl_init("http://openexchangerates.org/api/{$file}?app_id={$appId}");
        curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
        curl_setopt($ch, CURLOPT_CONNECTTIMEOUT, 1);

        $json = curl_exec($ch);
        curl_close($ch);

        return json_decode($json, true);
    }

    /**
     * @return string
     */
    public function getApiKey()
    {
        return $this->api_key;
    }

    /**
     * @return array
     */
    public function getCurrencies()
    {
        return $this->currencies;
    }

    /**
     * @return array
     */
    public function getRates()
    {
        return $this->rates;
    }

    /**
     * @return int
     */
    public function getSecondsTtl()
    {
        return $this->seconds_ttl;
    }

    /**
     * @return int
     */
    public function getTimestamp()
    {
        return $this->timestamp;
    }


}