<?php declare(strict_types=1);

namespace Orbit;

/**
 * Response
 *
 * See the following website for description of the response spec
 * https://gemini.circumlunar.space/docs/specification.html
 *
 * @package Orbit
 */
class Response
{
    const STATUS_INPUT = 10;
    const STATUS_SENSITIVE_INPUT = 11;
    const STATUS_SUCCESS = 20;
    const STATUS_REDIRECT_TEMPORARY = 30;
    const STATUS_REDIRECT_PERMANENT = 31;
    const STATUS_TEMPORARY_FAILURE = 40;
    const STATUS_SERVER_UNAVAILABLE = 41;
    const STATUS_CGI_ERROR = 42;
    const STATUS_PROXY_ERROR = 43;
    const STATUS_SLOW_DOWN = 44;
    const STATUS_PERMANENT_FAILURE = 50;
    const STATUS_NOT_FOUND = 51;
    const STATUS_GONE = 52;
    const STATUS_PROXY_REQUEST_REFUSED = 53;
    const STATUS_BAD_REQUEST = 59;
    const STATUS_CLIENT_CERTIFICATE_REQUIRED = 60;
    const STATUS_CERTIFICATE_NOT_AUTHORISED = 61;
    const STATUS_CERTIFICATE_NOT_VALID = 62;

    public $status = "";
    public $meta = "";
    public $body = "";
    public $filepath;

    /**
     * Constructor
     *
     * @param string $status
     * @param string $meta
     * @return void
     */
    public function __construct($status = "", $meta = "")
    {
        $this->status = $status;
        $this->meta = $meta;
    }

    /**
     * Get a header to be sent to client
     *
     * @return string
     */
    public function getHeader(): string
    {
        return sprintf("%s %s\r\n", $this->status, $this->meta);
    }

    /**
     * Send response body to client
     *
     * @param resource $client
     * @return int|false Number of bytes written
     */
    public function send($client): int
    {
        if (!is_resource($client)) {
            throw new \Exception("Invalid resource to write to");
        }
        $result = fwrite($client, $this->getHeader());

        if (!$result) {
            throw new \Exception("Failed to write to client");
        }

        if ($this->filepath) {
            if (is_dir($this->filepath)) {
                throw new \Exception("Cannot serve directory '{$this->filepath}'");
            }

            if (!file_exists($this->filepath)) {
                throw new \Exception("Error reading file '{$this->filepath}'");
            }

            $fp = fopen($this->filepath, "rb");

            if (false === $fp) {
                throw new \Exception("Cannot read file '{$this->filepath}'");
            }

            $size = filesize($this->filepath);

            $result = 1;
            while (!feof($fp) && $result) {
                // If the client cancels, bail out before trying large files
                // So, result will be 0 if the client cancels (broken socket)
                $result = fwrite($client, fread($fp, 8192));
            }
            fclose($fp);
            return $size;
        } else {
            $body = $this->getBody();
            fwrite($client, $body);
            return mb_strlen($body);
        }
    }

    /**
     * Set response body
     *
     * @param string $body
     * @return void
     */
    public function setBody(string $body = ''): void
    {
        $this->body = $body;
    }

    /**
     * Get response body
     *
     * @return string
     */
    public function getBody(): string
    {
        if ($this->filepath) {
            $this->body = file_get_contents($this->filepath);
        }

        return $this->body;
    }

    /**
     * Set static file
     *
     * Indicates this response should consist of a static file on disk
     *
     * @param mixed $filepath
     * @return void
     */
    public function setStaticFile(string $filepath): void
    {
        $this->filepath = $filepath;
    }

    /**
     * Set response status
     *
     * @param int $status
     * @return void
     */
    public function setStatus(int $status): void
    {
        $this->status = $status;
    }

    /**
     * Get status
     *
     * @return int
     */
    public function getStatus(): int
    {
        return $this->status;
    }

    /**
     * Set response meta value
     *
     * @param string $meta
     * @return void
     */
    public function setMeta($meta): void
    {
        $this->meta = $meta;
    }

    /**
     * Get meta
     *
     * @return string Meta value
     */
    public function getMeta(): string
    {
        return $this->meta;
    }
}