<?php

//-------------------------------------------------------------------
// gRESTbook.php: an example RESTy web service for a Guestbook
//-------------------------------------------------------------------
// For more info, see: http://muellerware.org/projects/gRESTbook/
//-------------------------------------------------------------------
// Copyright (c) 2007 Patrick Mueller
// Using the MIT license: 
//    http://www.opensource.org/licenses/mit-license.php
//-------------------------------------------------------------------
// 2007/03/xx - Patrick Mueller - pmuellr@yahoo.com
//-------------------------------------------------------------------

require_once 'Zend/Json.php';

require_once 'gRESTbookData.php';
require_once 'gRESTbookURL.php';

//-------------------------------------------------------------------
// This class models the incoming request; basically it's just
// parsing up the 'CGI' variables and placing them in the class's
// properties.
//-------------------------------------------------------------------
class Request {

    //-------------------------------------------------------------------
    // get a 'CGI' variable; return blank if not there
    //-------------------------------------------------------------------
    private function getServerVar($key) {
        if (isset($_SERVER[$key])) return $_SERVER[$key];
        return '';
    }

    //-------------------------------------------------------------------
    // get the 'CGI' variables we're interested in, and normalize
    //-------------------------------------------------------------------
    public function __construct() {
        $this->requestMethod  = $this->getServerVar('REQUEST_METHOD');
        $this->queryString    = $this->getServerVar('QUERY_STRING');
        $this->pathInfo       = $this->getServerVar('PATH_INFO');
        $this->accept         = $this->getServerVar('HTTP_ACCEPT');
        $this->acceptEncoding = $this->getServerVar('HTTP_ACCEPT_ENCODING');
        $this->acceptCharset  = $this->getServerVar('HTTP_ACCEPT_CHARSET');
        $this->contentType    = $this->getServerVar('CONTENT_TYPE');
        
        // if no path info provided, set to /
        if ("" == $this->pathInfo) $this->pathInfo = "/";
        
        // get the next path element in the path info;
        // for the container itself (no path element provided),
        // this will be the empty string
        $pieces = explode('/', $this->pathInfo);
        $this->resourceName = $pieces[1];
        
    }
    
    //-------------------------------------------------------------------
    // diagnostic method to dump the variables to the HTTP response,
    // and leave.
    //-------------------------------------------------------------------
    public function dump() {
        header('Content-Type: text/plain');
        echo (string) $this;
        exit;
    }
    
    //-------------------------------------------------------------------
    // nice human readable description of the class
    //-------------------------------------------------------------------
    public function __toString() {
        $result  = __CLASS__ . "{\n";
        $result .= "  requestMethod:  $this->requestMethod\n";
        $result .= "  queryString:    $this->queryString\n";
        $result .= "  pathInfo:       $this->pathInfo\n";
        $result .= "  resourceName:   $this->resourceName\n";
        $result .= "  accept:         $this->accept\n";
        $result .= "  acceptEncoding: $this->acceptEncoding\n";
        $result .= "  acceptCharset:  $this->acceptCharset\n";
        $result .= "  contentType:    $this->contentType\n";
        $result .= "}";
        
        return $result;
    }
    
}


//-------------------------------------------------------------------
// function to set the HTTP status code, and leave; used for
// error returns
//-------------------------------------------------------------------
function httpStatus($code, $message) {
    header("HTTP/1.1 $code $message");
    exit;
}

//-------------------------------------------------------------------
// de-multiplex the service requests against the collection
//-------------------------------------------------------------------
function handleCollection($request) {
    switch ($request->requestMethod) {
        case 'GET':
            handleCollectionGet($request);
            break;
        
        case 'POST':
            handleCollectionPost($request);
            break;
        
        default:
            httpStatus(405, "Method Not Allowed");
            break;
    }
    
}

//-------------------------------------------------------------------
// de-multiplex the service requests for items
//-------------------------------------------------------------------
function handleItem($request, $resourceName) {
    
    switch ($request->requestMethod) {
        case 'GET':
            handleItemGet($request, $resourceName);
            break;
        
        case 'PUT':
            handleItemPut($request, $resourceName);
            break;
        
        case 'DELETE':
            handleItemDelete($request, $resourceName);
            break;
    
        default:
            httpStatus(405, "Method Not Allowed");
            break;
    }
}

//-------------------------------------------------------------------
// return a list of entries in the collection
//-------------------------------------------------------------------
function handleCollectionGet($request) {
    $db      = $request->db;
    $entries = $db->query();
    
    if (strstr($request->accept,'text/json')) {
        header('Content-Type: text/json');
        print Zend_Json::encode($entries);
        return;
    }
    
    header('Content-Type: text/html');
    print "<ul>\n";
    
    foreach ($entries as $entry) {
        $line = '<li><a href="' . $entry . '">' . $entry . "</a></li>\n";
    }
    
    print "</ul>\n";
}

//-------------------------------------------------------------------
// add a new entry to the collection
//-------------------------------------------------------------------
function handleCollectionPost($request) {
    $db = $request->db;
    
    if ($request->ContentType != 'text/json') {
        httpStatus(415, 'Unsupported Media Type');
    }
    
    $data = file_get_contents("php://input");
    $entry = GRESTbookEntry::fromJSON($data);
    $db->create($entry);
    
    header('Location: ' . gRESTbookURL . '/' . $entry->id);
}

//-------------------------------------------------------------------
// get an entry from the collection
//-------------------------------------------------------------------
function handleItemGet($request, $resourceName) {
    $db = $request->db;
    
    $entry = $db->read($resourceName);
    if (null == $entry) {
        httpStatus(404, 'Not found');
        return;
    }
    
    if (strstr($request->accept,'text/json')) {
        header('Content-Type: text/json');
        header('ETag: ' . $entry->eTag);
        header('Last-Modified' . date('r', $entry->dateModified));
        print $entry->toJSON();
        return;
    }
    
    header('Content-Type: text/html');
    header('ETag: ' . $entry->eTag);
    header('Last-Modified' . date('r', $entry->dateModified));
    
    print '<h1>' . $entry->id . "</h1>\n";
    print '<span class="author">'  . $entry->author  . "</span> :\n";
    print '<span class="message">' . $entry->message . "</span> :\n";
        
}

//-------------------------------------------------------------------
// update an entry in the collection
//-------------------------------------------------------------------
function handleItemPut($request, $resourceName) {
}

//-------------------------------------------------------------------
// delete an entry in the collection
//-------------------------------------------------------------------
function handleItemDelete($request, $resourceName) {
}

//-------------------------------------------------------------------
// main processing starts here
//-------------------------------------------------------------------

//-------------------------------------------------------------------
// create the data accessor object
//-------------------------------------------------------------------
$db = new GRESTbookDB();

//-------------------------------------------------------------------
// create the request object
//-------------------------------------------------------------------
$request = new Request();
$request->db = $db;

// $request->dump();

// de-multiplex the request into either a collection or entry operation
if ('' == $request->resourceName) {
    handleCollection($request);
}
else {
    handleItem($request, $request->resourceName);
}

//-------------------------------------------------------------------
//
//-------------------------------------------------------------------
// phpinfo();

?>