<?php

namespace PayPalHttp;

use PayPalHttp\Serializer\Form;
use PayPalHttp\Serializer\Json;
use PayPalHttp\Serializer\Multipart;
use PayPalHttp\Serializer\Text;

/**
 * Class Encoder
 * @package PayPalHttp
 *
 * Encoding class for serializing and deserializing request/response.
 */
class Encoder
{
    private $serializers = [];

    public function __construct()
    {
        $this->serializers[] = new Json();
        $this->serializers[] = new Text();
        $this->serializers[] = new Multipart();
        $this->serializers[] = new Form();
    }

    public function serializeRequest(HttpRequest $request)
    {
        if (! array_key_exists('content-type', $request->headers)) {
            $message = 'HttpRequest does not have Content-Type header set';
            echo $message;

            throw new \Exception($message);
        }

        $contentType = $request->headers['content-type'];
        /** @var Serializer $serializer */
        $serializer = $this->serializer($contentType);

        if (is_null($serializer)) {
            $message = sprintf('Unable to serialize request with Content-Type: %s. Supported encodings are: %s', $contentType, implode(', ', $this->supportedEncodings()));
            echo $message;

            throw new \Exception($message);
        }

        if (! (is_string($request->body) || is_array($request->body))) {
            $message = 'Body must be either string or array';
            echo $message;

            throw new \Exception($message);
        }

        $serialized = $serializer->encode($request);

        if (array_key_exists('content-encoding', $request->headers) && $request->headers['content-encoding'] === 'gzip') {
            $serialized = gzencode($serialized);
        }

        return $serialized;
    }

    public function deserializeResponse($responseBody, $headers)
    {

        if (! array_key_exists('content-type', $headers)) {
            $message = 'HTTP response does not have Content-Type header set';
            echo $message;

            throw new \Exception($message);
        }

        $contentType = $headers['content-type'];
        $contentType = strtolower($contentType);
        /** @var Serializer $serializer */
        $serializer = $this->serializer($contentType);

        if (is_null($serializer)) {
            throw new \Exception(sprintf('Unable to deserialize response with Content-Type: %s. Supported encodings are: %s', $contentType, implode(', ', $this->supportedEncodings())));
        }

        if (array_key_exists('content-encoding', $headers) && $headers['content-encoding'] === 'gzip') {
            $responseBody = gzdecode($responseBody);
        }

        return $serializer->decode($responseBody);
    }

    private function serializer($contentType)
    {
        /** @var Serializer $serializer */
        foreach ($this->serializers as $serializer) {
            try {
                if (preg_match($serializer->contentType(), $contentType) == 1) {
                    return $serializer;
                }
            } catch (\Exception $ex) {
                $message = sprintf('Error while checking content type of %s: %s', get_class($serializer), $ex->getMessage());
                echo $message;

                throw new \Exception($message, $ex->getCode(), $ex);
            }
        }

        return null;
    }

    private function supportedEncodings()
    {
        $values = [];
        /** @var Serializer $serializer */
        foreach ($this->serializers as $serializer) {
            $values[] = $serializer->contentType();
        }

        return $values;
    }
}
