<?php

/**
 * @package KantPHP
 * @author  Zhenqiang Zhang <zhenqiang.zhang@hotmail.com>
 * @copyright (c) KantPHP Studio, All rights reserved.
 * @license http://www.opensource.org/licenses/BSD-3-Clause  The BSD 3-Clause License
 */
namespace Kant\Http;

/**
 * ResponseHeaderBag is a container for Response HTTP headers.
 */
class ResponseHeaderBag extends HeaderBag
{

    const COOKIES_FLAT = 'flat';

    const COOKIES_ARRAY = 'array';

    const DISPOSITION_ATTACHMENT = 'attachment';

    const DISPOSITION_INLINE = 'inline';

    /**
     *
     * @var array
     */
    protected $computedCacheControl = array();

    /**
     *
     * @var array
     */
    protected $cookies = array();

    /**
     *
     * @var array
     */
    protected $headerNames = array();

    /**
     * Constructor.
     *
     * @param array $headers
     *            An array of HTTP headers
     */
    public function __construct(array $headers = array())
    {
        parent::__construct($headers);
        
        if (!isset($this->headers['cache-control'])) {
            $this->set('Cache-Control', '');
        }
    }

    /**
     *
     * {@inheritdoc}
     *
     */
    public function __toString()
    {
        $cookies = '';
        foreach ($this->getCookies() as $cookie) {
            $cookies .= 'Set-Cookie: ' . $cookie . "\r\n";
        }
        
        ksort($this->headerNames);
        
        return parent::__toString() . $cookies;
    }

    /**
     * Returns the headers, with original capitalizations.
     *
     * @return array An array of headers
     */
    public function allPreserveCase()
    {
        return array_combine($this->headerNames, $this->headers);
    }

    /**
     *
     * {@inheritdoc}
     *
     */
    public function replace(array $headers = array())
    {
        $this->headerNames = array();
        
        parent::replace($headers);
        
        if (!isset($this->headers['cache-control'])) {
            $this->set('Cache-Control', '');
        }
    }

    /**
     *
     * {@inheritdoc}
     *
     */
    public function set($key, $values, $replace = true)
    {
        parent::set($key, $values, $replace);
        
        $uniqueKey = str_replace('_', '-', strtolower($key));
        $this->headerNames[$uniqueKey] = $key;
        
        // ensure the cache-control header has sensible defaults
        if (in_array($uniqueKey, array(
            'cache-control',
            'etag',
            'last-modified',
            'expires'
        ))) {
            $computed = $this->computeCacheControlValue();
            $this->headers['cache-control'] = array(
                $computed
            );
            $this->headerNames['cache-control'] = 'Cache-Control';
            $this->computedCacheControl = $this->parseCacheControl($computed);
        }
        return $this;
    }

    /**
     *
     * {@inheritdoc}
     *
     */
    public function remove($key)
    {
        parent::remove($key);
        
        $uniqueKey = str_replace('_', '-', strtolower($key));
        unset($this->headerNames[$uniqueKey]);
        
        if ('cache-control' === $uniqueKey) {
            $this->computedCacheControl = array();
        }
    }

    /**
     *
     * {@inheritdoc}
     *
     */
    public function hasCacheControlDirective($key)
    {
        return array_key_exists($key, $this->computedCacheControl);
    }

    /**
     *
     * {@inheritdoc}
     *
     */
    public function getCacheControlDirective($key)
    {
        return array_key_exists($key, $this->computedCacheControl) ? $this->computedCacheControl[$key] : null;
    }

    /**
     * Sets a cookie.
     *
     * @param Cookie $cookie            
     */
    public function setCookie(Cookie $cookie)
    {
        $this->cookies[$cookie->getDomain()][$cookie->getPath()][$cookie->getName()] = $cookie;
    }

    /**
     * Removes a cookie from the array, but does not unset it in the browser.
     *
     * @param string $name            
     * @param string $path            
     * @param string $domain            
     */
    public function removeCookie($name, $path = '/', $domain = null)
    {
        if (null === $path) {
            $path = '/';
        }
        
        unset($this->cookies[$domain][$path][$name]);
        
        if (empty($this->cookies[$domain][$path])) {
            unset($this->cookies[$domain][$path]);
            
            if (empty($this->cookies[$domain])) {
                unset($this->cookies[$domain]);
            }
        }
    }

    /**
     * Returns an array with all cookies.
     *
     * @param string $format            
     *
     * @throws \InvalidArgumentException When the $format is invalid
     *        
     * @return array
     */
    public function getCookies($format = self::COOKIES_FLAT)
    {
        if (!in_array($format, array(
            self::COOKIES_FLAT,
            self::COOKIES_ARRAY
        ))) {
            throw new \InvalidArgumentException(sprintf('Format "%s" invalid (%s).', $format, implode(', ', array(
                self::COOKIES_FLAT,
                self::COOKIES_ARRAY
            ))));
        }
        
        if (self::COOKIES_ARRAY === $format) {
            return $this->cookies;
        }
        
        $flattenedCookies = array();
        foreach ($this->cookies as $path) {
            foreach ($path as $cookies) {
                foreach ($cookies as $cookie) {
                    $flattenedCookies[] = $cookie;
                }
            }
        }
        
        return $flattenedCookies;
    }

    /**
     * Clears a cookie in the browser.
     *
     * @param string $name            
     * @param string $path            
     * @param string $domain            
     * @param bool $secure            
     * @param bool $httpOnly            
     */
    public function clearCookie($name, $path = '/', $domain = null, $secure = false, $httpOnly = true)
    {
        $this->setCookie(new Cookie($name, null, 1, $path, $domain, $secure, $httpOnly));
    }

    /**
     * Generates a HTTP Content-Disposition field-value.
     *
     * @param string $disposition
     *            One of "inline" or "attachment"
     * @param string $filename
     *            A unicode string
     * @param string $filenameFallback
     *            A string containing only ASCII characters that
     *            is semantically equivalent to $filename. If the filename is already ASCII,
     *            it can be omitted, or just copied from $filename
     *            
     * @return string A string suitable for use as a Content-Disposition field-value.
     *        
     * @throws \InvalidArgumentException
     *
     * @see RFC 6266
     */
    public function makeDisposition($disposition, $filename, $filenameFallback = '')
    {
        if (!in_array($disposition, array(
            self::DISPOSITION_ATTACHMENT,
            self::DISPOSITION_INLINE
        ))) {
            throw new \InvalidArgumentException(sprintf('The disposition must be either "%s" or "%s".', self::DISPOSITION_ATTACHMENT, self::DISPOSITION_INLINE));
        }
        
        if ('' == $filenameFallback) {
            $filenameFallback = $filename;
        }
        
        // filenameFallback is not ASCII.
        if (!preg_match('/^[\x20-\x7e]*$/', $filenameFallback)) {
            throw new \InvalidArgumentException('The filename fallback must only contain ASCII characters.');
        }
        
        // percent characters aren't safe in fallback.
        if (false !== strpos($filenameFallback, '%')) {
            throw new \InvalidArgumentException('The filename fallback cannot contain the "%" character.');
        }
        
        // path separators aren't allowed in either.
        if (false !== strpos($filename, '/') || false !== strpos($filename, '\\') || false !== strpos($filenameFallback, '/') || false !== strpos($filenameFallback, '\\')) {
            throw new \InvalidArgumentException('The filename and the fallback cannot contain the "/" and "\\" characters.');
        }
        
        $output = sprintf('%s; filename="%s"', $disposition, str_replace('"', '\\"', $filenameFallback));
        
        if ($filename !== $filenameFallback) {
            $output .= sprintf("; filename*=utf-8''%s", rawurlencode($filename));
        }
        
        return $output;
    }

    /**
     * Returns the calculated value of the cache-control header.
     *
     * This considers several other headers and calculates or modifies the
     * cache-control header to a sensible, conservative value.
     *
     * @return string
     */
    protected function computeCacheControlValue()
    {
        if (!$this->cacheControl && ! $this->has('ETag') && ! $this->has('Last-Modified') && ! $this->has('Expires')) {
            return 'no-cache';
        }
        
        if (!$this->cacheControl) {
            // conservative by default
            return 'private, must-revalidate';
        }
        
        $header = $this->getCacheControlHeader();
        if (isset($this->cacheControl['public']) || isset($this->cacheControl['private'])) {
            return $header;
        }
        
        // public if s-maxage is defined, private otherwise
        if (!isset($this->cacheControl['s-maxage'])) {
            return $header . ', private';
        }
        
        return $header;
    }
}
