<?php
/**
 * Generic response class
 *
 * $Id$
 *
 * @author gERD Schaufelberger <gerd@php-tools.net>
 * @package WB
 */

WBClass::load( 'WBLog'
               , 'WBClock'
               , 'WBRequest'
               );

/**
 * Generic response class
 *
 *
 *
 * @version 1.0.1
 * @package WB
 */
abstract class WBResponse extends WBStdClass
{
   /**
    * response header
    * @var array
    */
    protected $_header = array();

   /**
    * response data
    * @var array
    */
    protected $_data = array();

   /**
    * the most recent checksum
    * @var string
    */
    protected $_checksum = '';

   /**
    * filters, that be applied on output
    * @var array
    */
    protected $_filters = array();

   /**
    * whether caching features should be used
    * @var bool
    */
    protected $_useCache = true;

   /**
    * HTTP-a-like status code for this response object
    *
    * Default value is 200 - HTTP-OK
    * @var int $responsestatus
    */
    protected $_responseStatus = 200;

    /**
     * maximum time to cache response
     * @var int
     */
    protected $expireAge = 3600;

    /**
     * cache control header directive
     */
    const CACHECONTROL_PRIVATE          =   'private';
    const CACHECONTROL_PUBLIC           =   'public';
    const CACHECONTROL_MUSTREVALIDATE   =   'must-revalidate';

    /**
     * cache control
     * @var string
     */
    protected $cacheControl =   self::CACHECONTROL_PRIVATE;

   /**
    * Response objects use HTTP style status codes
    *
    * Default value is 200 - OK
    * @var array $_statusCodes
    */
    protected $_statusCodes = array(
        100 => array( 'body' => true,  'msg' => 'Continue' ),
        101 => array( 'body' => true,  'msg' => 'Switching Protocols' ),
        200 => array( 'body' => true,  'msg' => 'OK' ),
        201 => array( 'body' => true,  'msg' => 'Created' ),
        202 => array( 'body' => true,  'msg' => 'Accepted' ),
        203 => array( 'body' => true,  'msg' => 'Non-Authoritative Information' ),
        204 => array( 'body' => true,  'msg' => 'No Content' ),
        205 => array( 'body' => true,  'msg' => 'Reset Content' ),
        206 => array( 'body' => true,  'msg' => 'Partial Content' ),
        300 => array( 'body' => true,  'msg' => 'Multiple Choices' ),
        301 => array( 'body' => false, 'msg' => 'Moved Permanently' ),
        302 => array( 'body' => false, 'msg' => 'Found' ),
        303 => array( 'body' => true,  'msg' => 'See Other' ),
        304 => array( 'body' => false, 'msg' => 'Not Modified' ),
        305 => array( 'body' => false, 'msg' => 'Use Proxy' ),
        306 => array( 'body' => true,  'msg' => '(Unused)' ),
        307 => array( 'body' => false, 'msg' => 'Temporary Redirect' ),
        308 => array( 'body' => false, 'msg' => 'Permanent Redirect' ),
        400 => array( 'body' => true,  'msg' => 'Bad Request' ),
        401 => array( 'body' => true,  'msg' => 'Unauthorized' ),
        402 => array( 'body' => true,  'msg' => 'Payment Required' ),
        403 => array( 'body' => true,  'msg' => 'Forbidden' ),
        404 => array( 'body' => true,  'msg' => 'Not Found' ),
        405 => array( 'body' => true,  'msg' => 'Method Not Allowed' ),
        406 => array( 'body' => true,  'msg' => 'Not Acceptable' ),
        407 => array( 'body' => true,  'msg' => 'Proxy Authentication Required' ),
        408 => array( 'body' => true,  'msg' => 'Request Timeout' ),
        409 => array( 'body' => true,  'msg' => 'Conflict' ),
        410 => array( 'body' => true,  'msg' => 'Gone' ),
        411 => array( 'body' => true,  'msg' => 'Length Required' ),
        412 => array( 'body' => true,  'msg' => 'Precondition Failed' ),
        413 => array( 'body' => true,  'msg' => 'Request Entity Too Large' ),
        414 => array( 'body' => true,  'msg' => 'Request-URI Too Long' ),
        415 => array( 'body' => true,  'msg' => 'Unsupported Media Type' ),
        416 => array( 'body' => true,  'msg' => 'Requested Range Not Satisfiable' ),
        417 => array( 'body' => true,  'msg' => 'Expectation Failed' ),
        500 => array( 'body' => true,  'msg' => 'Internal Server Error' ),
        501 => array( 'body' => true,  'msg' => 'Not Implemented' ),
        502 => array( 'body' => true,  'msg' => 'Bad Gateway' ),
        503 => array( 'body' => true,  'msg' => 'Service Unavailable' ),
        504 => array( 'body' => true,  'msg' => 'Gateway Timeout' ),
        505 => array( 'body' => true,  'msg' => 'HTTP Version Not Supported' )
    );

   /**
    * set response status code HTTP-a-like
    *
    * @param int status
    * @returns bool - true if given status is acceptable, false otherwise
    */
    public function setStatus( $status )
    {
        if( !isset( $this->_statusCodes[$status] ) ) {
            return false;
        }

        $this->_responseStatus = $status;
        return true;
    }

    /**
     * set age before cache expires
     *
     * Tell browser cache how many seconds the response is acceptable
     *
     * @param int $age seconds
     */
    public function setMaxAge($age = 3600)
    {
        $this->expireAge    =   $age;
    }

    /**
     * Use cache control
     *
     * Set either to CACHECONTROL_MUSTREVALIDATE, CACHECONTROL_PRIVATE or CACHECONTROL_PUBLIC
     *
     * @see CACHECONTROL_MUSTREVALIDATE
     * @see CACHECONTROL_PRIVATE
     * @see CACHECONTROL_PUBLIC
     * @param string $control
     */
    public function setCacheControl($control = self::CACHECONTROL_MUSTREVALIDATE)
    {
        $this->cacheControl  =   $control;
    }

    /**
     * tell whether to use caching features
     *
     * Allow to switch off caching regardless of WBParam: wb/cache/use
     * In case $use is true, WBParam: wb/cache/use decides if caching is
     * enabled.
     *
     * @param bool $use
     */
    public function useCache($use = true)
    {
        $this->_useCache    =   $use;
    }

   /**
    * append string to response data
    *
    * @param string $name of the property
    * @param bool $clear wipe out all collected data
    * @return bool true on success
    */
    public function add( $string, $clear = false )
    {
        if( $clear ) {
            $this->_data =   array();
        }

        if( empty( $string ) ) {
            return false;
        }

        if( empty( $this->_data ) ) {
            $this->_checksum =   md5( $string );
        }

        $this->_data[]   =   array(
                                'type'      =>  'string',
                                'data'      =>  $string,
                                'checksum'  =>  $this->_checksum
                                );
        return true;
    }

   /**
    * append stream to output
    *
    * @param stream $stream
    * @param string $checksum checksum of stream (md5sum or something)
    * @return bool true on success
    */
    public function addStream( $stream, $checksum )
    {
        if( empty( $this->_data ) ) {
            $this->_checksum =   $checksum;
        }
        $this->_data[]   =   array(
                                'type'      => 'stream',
                                'data'      =>  $stream,
                                'checksum'  =>  $this->_checksum
                                );
        return true;
    }

   /**
    * insert response header
    *
    * @param string name of the property
    * @param mixed $value
    * @return bool true on success
    */
    public function addHeader( $name, $value = null )
    {
        $this->_header[$name] = $value;
        return true;
    }

   /**
    * append string to response data
    *
    * @param callbacl
    * @return bool true on success
    */
    public function addOutputFilter( $callback )
    {
        if( !is_callable( $callback ) ) {
            return false;
        }

        $this->_filters[] =   $callback;
        return true;
    }

   /**
    * send
    *
    * send response to client
    *
    * @param WBRequest $request
    * @return bool true un success
    */
    public function send( WBRequest $request )
    {
        // use cache?
        if ($this->_useCache) {
            $this->_useCache    =   true;
            if (1 > WBParam::get('wb/cache/use', 1)) {
                $this->_useCache    =   false;;
            }
        }

        $start  =   WBClock::now();
        $logger =   WBLog::start(__CLASS__);
        $this->onSend($request);

        $range  =   $this->checkHeaderRange($request);
        $log    =   array(
                        'action'            =>  'send',
                        'self'              =>  $_SERVER['PHP_SELF'],
                        'status'            =>  $this->_responseStatus,
                        'size'              =>  0,
                        'memory'            =>  round(memory_get_usage() / 1024, 0) . 'k',
                        'time-send'         =>  0,
                        'time-total'        =>  0,
                        'cache'             =>  intval($this->_useCache),
                        'range'             =>  implode('-', $range)
                    );

        // do not send a data in body
        if( !$this->_statusCodes[$this->_responseStatus]['body'] ) {
            $this->sendHeader();
            $log['time-send']   =   WBClock::stop( $start, 1000, 1 ) . 'ms';
            $log['time-total']  =   WBClock::stop( null, 1000, 1 ) . 'ms';
            $logger->notice( $log );
            return true;
        }

        $size               =   $this->sendData($range);
        $log['size']        =   $size;
        $log['time-send']   =   WBClock::stop( $start, 1000, 1 ) . 'ms';
        $log['time-total']  =   WBClock::stop( null, 1000, 1 ) . 'ms';
        $logger->notice( $log );
        return true;
    }

   /**
    * send
    *
    * @return bool true un success
    */
    abstract protected function onSend( WBRequest $request );

   /**
    * send header
    *
    * @return bool true on success
    */
    protected function sendHeader()
    {
        return true;
    }

    /**
     * Check range header
     *
     *
     *
     * @param WBRequest $request
     * @return array
     */
    private function checkHeaderRange($request)
    {
        // range header make sense for status 200, only
        $status =   array(
                            200,
                            201,
                            202,
                            205,
                            206
                        );
        if (!in_array($this->_responseStatus, $status)) {
            $range  =   array(0, -1);
            return $range;
        }

        $range  =   $request->getRange();

        // set proper headers
        if (isset($this->_header['Content-Length'])) {
            $orgLength  =   $this->_header['Content-Length'];
            if (-1 == $range[1]) {
                $this->addHeader('Content-Length', ($orgLength - $range[0]));
                $this->addHeader('Content-Range', sprintf('bytes %s-%s/%s', $range[0], $orgLength - 1, $orgLength));
            }
            else {
                $this->addHeader('Content-Length', $range[1]);
                $this->addHeader('Content-Range', sprintf('bytes %s-%s/%s', $range[0], ($range[1] - 1 + $range[0]), $orgLength));
            }
        }

        // set status partial content
        if (0 != $range[0] || -1 != $range[1]) {
            $this->setStatus(206);
        }

        return $range;
    }

   /**
    * Send data
    *
    * Send all or range of data
    *
    * @todo Range support only works for single streams
    * @param array $range
    * @return int $size send bytes
    */
    protected function sendData($range)
    {
        $logger =   WBLog::start(__CLASS__);

        $size       =   0;
        $useFilter  =   true;
        if  (empty($this->_filters)) {
            $useFilter =   false;
            $this->sendHeader();
        }

        $buffer    =   '';
        for ($i = 0; $i < count( $this->_data); ++$i) {
            switch ($this->_data[$i]['type']) {
                case 'stream':
                    if (!$useFilter) {
                        echo $buffer;
                        $size   +=  strlen( $buffer );
                        $buffer =   '';
                        if (0 < $range[1] && $size >= $range[1]) {
                            break;
                        }
                    }
                    if (0 < $range[0]) {
                        fseek($this->_data[$i]['data'], $range[0], SEEK_SET);
                        $range[0]   =   0;
                    }
                    while (!feof($this->_data[$i]['data'])) {
                        $buffer .=  fgets($this->_data[$i]['data'], 8192);
                        if (!$useFilter) {
                            $oldSize    =   $size;
                            $size       +=  strlen($buffer);
                            // reached range
                            if (0 < $range[1] && $size >= $range[1]) {
                                $size   =   $range[1];
                                $buffer =   substr($buffer, 0, ($size - $oldSize));
                                echo $buffer;
                                $buffer =   '';
                                break;
                            }
                            echo $buffer;
                            $buffer =   '';
                        }
                    }
                    fclose($this->_data[$i]['data']);
                    break;

                default:
                case 'string':
                    $buffer .=  $this->_data[$i]['data'];
                    if (!$useFilter){
                        echo $buffer;
                        $size   +=  strlen( $buffer );
                        $buffer =   '';
                    }
                    break;
            }
        }

        // apply filter
        if ($useFilter) {
            foreach ($this->_filters as $filter) {
                $buffer =   call_user_func( $filter, $buffer );
            }
            $size   =   strlen($buffer);
            $this->sendHeader();
            echo $buffer;
        }
        return $size;
    }
}