<?php

namespace Kirby\Http;

use Exception;
use Kirby\Filesystem\F;
use Throwable;

/**
 * Representation of an Http response,
 * to simplify sending correct headers
 * and Http status codes.
 *
 * @package   Kirby Http
 * @author    Bastian Allgeier <bastian@getkirby.com>
 * @link      https://getkirby.com
 * @copyright Bastian Allgeier
 * @license   https://opensource.org/licenses/MIT
 */
class Response
{
    /**
     * Store for all registered headers,
     * which will be sent with the response
     *
     * @var array
     */
    protected $headers = [];

    /**
     * The response body
     *
     * @var string
     */
    protected $body;

    /**
     * The HTTP response code
     *
     * @var int
     */
    protected $code;

    /**
     * The content type for the response
     *
     * @var string
     */
    protected $type;

    /**
     * The content type charset
     *
     * @var string
     */
    protected $charset = 'UTF-8';

    /**
     * Creates a new response object
     *
     * @param string $body
     * @param string $type
     * @param int $code
     * @param array $headers
     * @param string $charset
     */
    public function __construct($body = '', ?string $type = null, ?int $code = null, ?array $headers = null, ?string $charset = null)
    {
        // array construction
        if (is_array($body) === true) {
            $params  = $body;
            $body    = $params['body'] ?? '';
            $type    = $params['type'] ?? $type;
            $code    = $params['code'] ?? $code;
            $headers = $params['headers'] ?? $headers;
            $charset = $params['charset'] ?? $charset;
        }

        // regular construction
        $this->body    = $body;
        $this->type    = $type ?? 'text/html';
        $this->code    = $code ?? 200;
        $this->headers = $headers ?? [];
        $this->charset = $charset ?? 'UTF-8';

        // automatic mime type detection
        if (strpos($this->type, '/') === false) {
            $this->type = F::extensionToMime($this->type) ?? 'text/html';
        }
    }

    /**
     * Improved `var_dump` output
     *
     * @return array
     */
    public function __debugInfo(): array
    {
        return $this->toArray();
    }

    /**
     * Makes it possible to convert the
     * entire response object to a string
     * to send the headers and print the body
     *
     * @return string
     */
    public function __toString(): string
    {
        try {
            return $this->send();
        } catch (Throwable $e) {
            return '';
        }
    }

    /**
     * Getter for the body
     *
     * @return string
     */
    public function body(): string
    {
        return $this->body;
    }

    /**
     * Getter for the content type charset
     *
     * @return string
     */
    public function charset(): string
    {
        return $this->charset;
    }

    /**
     * Getter for the HTTP status code
     *
     * @return int
     */
    public function code(): int
    {
        return $this->code;
    }

    /**
     * Creates a response that triggers
     * a file download for the given file
     *
     * @param string $file
     * @param string $filename
     * @param array $props Custom overrides for response props (e.g. headers)
     * @return static
     */
    public static function download(string $file, string $filename = null, array $props = [])
    {
        if (file_exists($file) === false) {
            throw new Exception('The file could not be found');
        }

        $filename ??= basename($file);
        $modified   = filemtime($file);
        $body       = file_get_contents($file);
        $size       = strlen($body);

        $props = array_replace_recursive([
            'body'    => $body,
            'type'    => F::mime($file),
            'headers' => [
                'Pragma'                    => 'public',
                'Cache-Control'             => 'no-cache, no-store, must-revalidate',
                'Last-Modified'             => gmdate('D, d M Y H:i:s', $modified) . ' GMT',
                'Content-Disposition'       => 'attachment; filename="' . $filename . '"',
                'Content-Transfer-Encoding' => 'binary',
                'Content-Length'            => $size,
                'Connection'                => 'close'
            ]
        ], $props);

        return new static($props);
    }

    /**
     * Creates a response for a file and
     * sends the file content to the browser
     *
     * @param string $file
     * @param array $props Custom overrides for response props (e.g. headers)
     * @return static
     */
    public static function file(string $file, array $props = [])
    {
        $props = array_merge([
            'body' => F::read($file),
            'type' => F::extensionToMime(F::extension($file))
        ], $props);

        return new static($props);
    }

    /**
     * Getter for single headers
     *
     * @param string $key Name of the header
     * @return string|null
     */
    public function header(string $key): ?string
    {
        return $this->headers[$key] ?? null;
    }

    /**
     * Getter for all headers
     *
     * @return array
     */
    public function headers(): array
    {
        return $this->headers;
    }

    /**
     * Creates a json response with appropriate
     * header and automatic conversion of arrays.
     *
     * @param string|array $body
     * @param int $code
     * @param bool $pretty
     * @param array $headers
     * @return static
     */
    public static function json($body = '', ?int $code = null, ?bool $pretty = null, array $headers = [])
    {
        if (is_array($body) === true) {
            $body = json_encode($body, $pretty === true ? JSON_PRETTY_PRINT|JSON_UNESCAPED_SLASHES : 0);
        }

        return new static([
            'body'    => $body,
            'code'    => $code,
            'type'    => 'application/json',
            'headers' => $headers
        ]);
    }

    /**
     * Creates a redirect response,
     * which will send the visitor to the
     * given location.
     *
     * @param string $location
     * @param int $code
     * @return static
     */
    public static function redirect(string $location = '/', int $code = 302)
    {
        return new static([
            'code' => $code,
            'headers' => [
                'Location' => Url::unIdn($location)
            ]
        ]);
    }

    /**
     * Sends all registered headers and
     * returns the response body
     *
     * @return string
     */
    public function send(): string
    {
        // send the status response code
        http_response_code($this->code());

        // send all custom headers
        foreach ($this->headers() as $key => $value) {
            header($key . ': ' . $value);
        }

        // send the content type header
        header('Content-Type:' . $this->type() . '; charset=' . $this->charset());

        // print the response body
        return $this->body();
    }

    /**
     * Converts all relevant response attributes
     * to an associative array for debugging,
     * testing or whatever.
     *
     * @return array
     */
    public function toArray(): array
    {
        return [
            'type'    => $this->type(),
            'charset' => $this->charset(),
            'code'    => $this->code(),
            'headers' => $this->headers(),
            'body'    => $this->body()
        ];
    }

    /**
     * Getter for the content type
     *
     * @return string
     */
    public function type(): string
    {
        return $this->type;
    }
}