<?php
/*
 * The MIT License
 *
 * Copyright (c) 2019 Payout, s.r.o. (https://payout.one/)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in all
 * copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

namespace Payout;

use Exception;

/**
 * Class Connection
 *
 * HTTP connection using cURL library.
 *
 * @package Payout
 * @since   0.1.0
 */
class Connection
{
    const TYPE_JSON = 'application/json';

    /**
     * @var string $base_url API base URL
     * @var $curl
     * @var array $headers HTTP request headers
     * @var mixed $response HTTP response
     */
    private $base_url, $token, $curl, $headers = array(), $response;

    /**
     * Connection constructor.
     *
     * @param string $base_url
     */
    public function __construct($base_url)
    {
        $this->base_url = $base_url;
        $this->curl = curl_init();

        curl_setopt_array($this->curl, array(
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_ENCODING => '',
            CURLOPT_MAXREDIRS => 10,
            CURLOPT_TIMEOUT => 0,
            CURLOPT_FOLLOWLOCATION => false,
            CURLOPT_HTTP_VERSION => CURL_HTTP_VERSION_1_1
        ));
    }

    /**
     * Add a custom header to the request.
     *
     * @param string $header HTTP request field name
     * @param string $value HTTP request field value
     */
    public function addHeader($header, $value)
    {
        $this->headers[$header] = "$header: $value";
    }

    /**
     * Clear previously cached request data and prepare for
     * making a fresh request.
     */
    private function initializeRequest()
    {
        $this->response = '';
        $this->addHeader('Content-Type', self::TYPE_JSON);
        $this->addHeader('Accept', self::TYPE_JSON);

        curl_setopt($this->curl, CURLOPT_HTTPHEADER, $this->headers);
    }

    /**
     * Authenticate API connection. Make an HTTP POST request to the
     * authorization endpoint  and obtain access token.
     *
     * @param string $url
     * @param string $client_id Payout client ID
     * @param string $client_secret Payout client secret
     *
     * @return mixed
     * @throws Exception
     */
    public function authenticate($url, $client_id, $client_secret)
    {
        $this->initializeRequest();

        $credentials = json_encode(array(
            'client_id' => $client_id,
            'client_secret' => $client_secret
        ));

        curl_setopt($this->curl, CURLOPT_URL, $this->base_url . $url);
        curl_setopt($this->curl, CURLOPT_POSTFIELDS, $credentials);

        $this->response = curl_exec($this->curl);

        return $this->handleResponse();
    }

    /**
     * Make an HTTP POST request to the specified endpoint.
     *
     * @param string $url URL to which we send the request
     * @param mixed $body Data payload (JSON string or raw data)
     *
     * @return mixed
     * @throws Exception
     */
    public function post($url, $body, $idempotency_key)
    {
        $this->addHeader('Authorization', 'Bearer ' . $this->token);

        if (!is_null($idempotency_key)) {
            $this->addHeader('idempotency-key', $idempotency_key);
        }
        
        $this->initializeRequest();

        if (!is_string($body)) {
            $body = json_encode($body);
        }

        curl_setopt($this->curl, CURLOPT_URL, $this->base_url . $url);
        curl_setopt($this->curl, CURLOPT_POSTFIELDS, $body);

        $this->response = curl_exec($this->curl);

        return $this->handleResponse();
    }

    /**
     * Make an HTTP GET request to the specified endpoint.
     *
     * @param string $url URL to retrieve
     * @param array|bool $query Optional array of query string parameters
     *
     * @return mixed
     * @throws Exception
     */
    public function get($url, $query = false)
    {
        $this->addHeader('Authorization', 'Bearer ' . $this->token);
        $this->initializeRequest();

        if (is_array($query)) {
            $url .= '?' . http_build_query($query);
        }

        curl_setopt($this->curl, CURLOPT_CUSTOMREQUEST, 'GET');
        curl_setopt($this->curl, CURLOPT_URL, $this->base_url . $url);
        curl_setopt($this->curl, CURLOPT_POST, false);
        curl_setopt($this->curl, CURLOPT_PUT, false);
        curl_setopt($this->curl, CURLOPT_HTTPGET, true);

        $this->response = curl_exec($this->curl);

        return $this->handleResponse();
    }

    /**
     * Check the response for possible errors and handle the response body returned.
     *
     * @return mixed the value encoded in json in appropriate PHP type.
     * @throws Exception
     */
    private function handleResponse()
    {
        if (curl_error($this->curl)) {
            throw new Exception('Payout error: ' . curl_error($this->curl));
        }

        $response = json_decode($this->response);

        if (isset($response->errors)) {
            wc_get_logger()->log('debug', 'Payout response errors: ' . json_encode($response->errors), ['source' => 'payout-errors']);
            throw new Exception('Payout error: ' . json_encode($response->errors));
        }

        if (isset($response->token)) {
            $this->token = $response->token;
        }

        return $response;
    }
}