<?php
/**
 * API handler for all REST API calls
 */

namespace PayPal\Handler;

use PayPal\Auth\OAuthTokenCredential;
use PayPal\Common\PayPalUserAgent;
use PayPal\Core\PayPalConstants;
use PayPal\Core\PayPalCredentialManager;
use PayPal\Core\PayPalHttpConfig;
use PayPal\Exception\PayPalConfigurationException;
use PayPal\Exception\PayPalInvalidCredentialException;
use PayPal\Exception\PayPalMissingCredentialException;

/**
 * Class RestHandler
 */
class RestHandler implements IPayPalHandler {

	/**
	 * Private Variable
	 *
	 * @var \Paypal\Rest\ApiContext $apiContext
	 */
	private $apiContext;

	/**
	 * Construct
	 *
	 * @param \Paypal\Rest\ApiContext $apiContext
	 */
	public function __construct( $apiContext) {
		$this->apiContext = $apiContext;
	}

	/**
	 * @param PayPalHttpConfig $httpConfig
	 * @param string                    $request
	 * @param mixed                     $options
	 * @return mixed|void
	 * @throws PayPalConfigurationException
	 * @throws PayPalInvalidCredentialException
	 * @throws PayPalMissingCredentialException
	 */
	public function handle( $httpConfig, $request, $options) {
		$credential = $this->apiContext->getCredential();
		$config = $this->apiContext->getConfig();

		if ($credential == null) {
			// Try picking credentials from the config file
			$credMgr = PayPalCredentialManager::getInstance($config);
			$credValues = $credMgr->getCredentialObject();

			if (!is_array($credValues)) {
				throw new PayPalMissingCredentialException('Empty or invalid credentials passed');
			}

			$credential = new OAuthTokenCredential($credValues['clientId'], $credValues['clientSecret']);
		}

		if ($credential == null || !( $credential instanceof OAuthTokenCredential )) {
			throw new PayPalInvalidCredentialException('Invalid credentials passed');
		}

		$httpConfig->setUrl(
			rtrim(trim($this->_getEndpoint($config)), '/') .
			( isset($options['path']) ? $options['path'] : '' )
		);

		// Overwrite Expect Header to disable 100 Continue Issue
		$httpConfig->addHeader('Expect', null);

		if (!array_key_exists('User-Agent', $httpConfig->getHeaders())) {
			$httpConfig->addHeader('User-Agent', PayPalUserAgent::getValue(PayPalConstants::SDK_NAME, PayPalConstants::SDK_VERSION));
		}

		if (!is_null($credential) && $credential instanceof OAuthTokenCredential && is_null($httpConfig->getHeader('Authorization'))) {
			$httpConfig->addHeader('Authorization', 'Bearer ' . $credential->getAccessToken($config), false);
		}

		if (( $httpConfig->getMethod() == 'POST' || $httpConfig->getMethod() == 'PUT' ) && !is_null($this->apiContext->getRequestId())) {
			$httpConfig->addHeader('PayPal-Request-Id', $this->apiContext->getRequestId());
		}
		// Add any additional Headers that they may have provided
		$headers = $this->apiContext->getRequestHeaders();
		foreach ($headers as $key => $value) {
			$httpConfig->addHeader($key, $value);
		}
	}

	/**
	 * End Point
	 *
	 * @param array $config
	 *
	 * @return string
	 * @throws \PayPal\Exception\PayPalConfigurationException
	 */
	private function _getEndpoint( $config) {
		if (isset($config['service.EndPoint'])) {
			return $config['service.EndPoint'];
		} elseif (isset($config['mode'])) {
			switch (strtoupper($config['mode'])) {
				case 'SANDBOX':
					return PayPalConstants::REST_SANDBOX_ENDPOINT;
					break;
				case 'LIVE':
					return PayPalConstants::REST_LIVE_ENDPOINT;
					break;
				default:
					throw new PayPalConfigurationException('The mode config parameter must be set to either sandbox/live');
					break;
			}
		} else {
			// Defaulting to Sandbox
			return PayPalConstants::REST_SANDBOX_ENDPOINT;
		}
	}
}
