<?php

require('response.php');

class fetch {
    private bool $has_content;
    private string $method;
    private ?string $received;
    private CurlHandle $request;

    public function __construct(string $url, string $method = 'GET') {
        $this->received = null;
        $this->has_content = false;
        $this->method = $method;

        $this->request = curl_init();
        $this->setopt(CURLOPT_RETURNTRANSFER, true);
        $this->setopt(CURLOPT_FAILONERROR, true);
        $this->setopt(CURLOPT_HEADER, true);
        $this->setopt(CURLOPT_CUSTOMREQUEST, $method);
        $this->setopt(CURLOPT_URL, curl_escape($url));
    }

    public function set_json(array $content): object {
        if ($this->has_content) {
            throw new RuntimeException('JSON content already set.');
        }

        if ($this->method === 'GET' or $this->method === 'HEAD') {
            throw new TypeError("JSON request can not be GET or HEAD.");
        }

        $converted = json_encode($content);
        $headers = [ 'Content-Type: application/json' ];
        
        $this->has_content = true;
        $this->setopt(CURLOPT_POSTFIELDS, $converted);
        $this->setopt(CURLOPT_HTTPHEADER, $headers);

        return $this;
    }

    public function request(): string { 
        if ($this->received !== null) {
            return $this->received;
        }

        $result = curl_exec($this->request);
        $error = curl_error($this->request);
        $error_number = curl_errno($this->request);
        
        curl_close($this->received);
        
        if ($result !== false and $error_number === 0) {
            return $this->received = $result;
        }

        throw new RuntimeException(
            'Can not fetch request. Error code '
            .string($error_number)
            .': "'.$error.'".'
        );
    }

    private function setopt(int $option, mixed $content): void {
        curl_setopt($this->request, $option, $content);
    }
}