/**

     S3Ajax v0.1 - An AJAX wrapper package for Amazon S3

     http://decafbad.com/trac/wiki/S3Ajax

     l.m.orchard@pobox.com

     Share and Enjoy.

     Requires:

         http://pajhome.org.uk/crypt/md5/sha1.js

 */

 // TODO: Figure out if Safari doesn't support PUT and DELETE

 S3Ajax = {

     // Defeat caching with query params on GET requests?

     DEFEAT_CACHE: false,

     // Default ACL to use when uploading keys.

     DEFAULT_ACL: 'public-read',

     // Default content-type to use in uploading keys.

     DEFAULT_CONTENT_TYPE: 'text/plain',

     /**

         DANGER WILL ROBINSON - Do NOT fill in your KEY_ID and SECRET_KEY 

         here.  These should be supplied by client-side code, and not 

         stored in any server-side files.  Failure to protect your S3

         credentials will result in surly people doing nasty things

         on your tab.

         For example, scoop values up from un-submitted form fields like so:

         S3Ajax.KEY_ID     = $('key_id').value;

         S3Ajax.SECRET_KEY = $('secret_key').value;

     */

     URL:        'http://s3.amazonaws.com',

     KEY_ID:     '',

     SECRET_KEY: '',

     // Flip this to true to potentially get lots of wonky logging.

     DEBUG: false,

     /**

         Get contents of a key in a bucket.

     */

     get: function(bucket, key, cb, err_cb) {

         return this.httpClient({

             method:   'GET',

             resource: '/' + bucket + '/' + key,

             load: function(req, obj) {

                 if (cb)     return cb(req, req.responseText);

             },

             error: function(req, obj) {

                 if (err_cb) return err_cb(req, obj);

                 if (cb)     return cb(req, req.responseText);

             }

         })

     },

     /**

         Head the meta of a key in a bucket.

     */

     head: function(bucket, key, cb, err_cb) {

         return this.httpClient({

             method:   'HEAD',

             resource: '/' + bucket + '/' + key,

             load: function(req, obj) {

                 if (cb)     return cb(req, req.responseText);

             },

             error: function(req, obj) {

                 if (err_cb) return err_cb(req, obj);

                 if (cb)     return cb(req, req.responseText);

             }

         })

     },

     /**

         Put data into a key in a bucket.

     */

     put: function(bucket, key, content/*, [params], cb, [err_cb]*/) {

         // Process variable arguments for optional params.

         var idx = 3;

         var params = {};

         if (typeof arguments[idx] == 'object')

             params = arguments[idx++];

         var cb     = arguments[idx++];

         var err_cb = arguments[idx++];

         if (!params.content_type) 

             params.content_type = this.DEFAULT_CONTENT_TYPE;

         if (!params.acl)

             params.acl = this.DEFAULT_ACL;

         return this.httpClient({

             method:       'PUT',

             resource:     '/' + bucket + '/' + key,

             content:      content,

             content_type: params.content_type,

             meta:         params.meta,

             acl:          params.acl,

             load: function(req, obj) {

                 if (cb)     return cb(req);

             },

             error: function(req, obj) {

                 if (err_cb) return err_cb(req, obj);

                 if (cb)     return cb(req, obj);

             }

         });

     },

     /**

         List buckets belonging to the account.

     */

     listBuckets: function(cb, err_cb) {

         return this.httpClient({ 

             method:'GET', resource:'/', 

             force_lists: [ 'ListAllMyBucketsResult.Buckets.Bucket' ],

             load: cb, error:err_cb 

         });

     },

     /**

         Create a new bucket for this account.

     */

     createBucket: function(bucket, cb, err_cb) {

         return this.httpClient({ 

             method:'PUT', resource:'/'+bucket, load:cb, error:err_cb 

         });

     },

     /**

         Delete an empty bucket.

     */

     deleteBucket: function(bucket, cb, err_cb) {

         return this.httpClient({ 

             method:'DELETE', resource:'/'+bucket, load:cb, error:err_cb 

         });

     },

     /**

         Given a bucket name and parameters, list keys in the bucket.

     */

     listKeys: function(bucket, params, cb, err_cb) {

         return this.httpClient({

             method:'GET', resource: '/'+bucket, 

             force_lists: [ 'ListBucketResult.Contents' ],

             params:params, load:cb, error:err_cb

         });

     },

     /**

         Delete a single key in a bucket.

     */

     deleteKey: function(bucket, key, cb, err_cb) {

         return this.httpClient({

             method:'DELETE', resource: '/'+bucket+'/'+key, load:cb, error:err_cb

         });

     },

     /**

         Delete a list of keys in a bucket, with optional callbacks

         for each deleted key and when list deletion is complete.

     */

     deleteKeys: function(bucket, list, one_cb, all_cb) {

         var _this = this;

         // If the list is empty, then fire off the callback.

         if (!list.length && all_cb) return all_cb();

         // Fire off key deletion with a callback to delete the 

         // next part of list.

         var key = list.shift();

         this.deleteKey(bucket, key, function() {

             if (one_cb) one_cb(key);

             _this.deleteKeys(bucket, list, one_cb, all_cb);

         });

     },

     /**

         Perform an authenticated S3 HTTP query.

     */

     httpClient: function(kwArgs) {

         var _this = this;

         // If need to defeat cache, toss in a date param on GET.

         if (this.DEFEAT_CACHE && ( kwArgs.method == "GET" || kwArgs.method == "HEAD" ) ) {

             if (!kwArgs.params) kwArgs.params = {};

             kwArgs.params["___"] = new Date().getTime();

         }

         // Prepare the query string and URL for this request.

         var qs   = (kwArgs.params) ? '?'+queryString(kwArgs.params) : '';

         var url  = this.URL + kwArgs.resource + qs;

         var hdrs = {};

         // Handle Content-Type header

         if (!kwArgs.content_type && kwArgs.method == 'PUT') 

             kwArgs.content_type = 'text/plain';

         if (kwArgs.content_type)

             hdrs['Content-Type'] = kwArgs.content_type;

         else

             kwArgs.content_type = '';

         // Set the timestamp for this request.

         var http_date = this.httpDate();

         hdrs['Date']  = http_date;

         var content_MD5 = '';

         /*

         // TODO: Fix this Content-MD5 stuff.

         if (kwArgs.content && kwArgs.content.hashMD5) {

             content_MD5 = kwArgs.content.hashMD5();

             hdrs['Content-MD5'] = content_MD5;

         }

         */

         // Handle the ACL parameter

         var acl_header_to_sign = '';

         if (kwArgs.acl) {

             hdrs['x-amz-acl'] = kwArgs.acl;

             acl_header_to_sign = "x-amz-acl:"+kwArgs.acl+"\n";

         }

         // Handle the metadata headers

         var meta_to_sign = '';

         if (kwArgs.meta) {

             for (var k in kwArgs.meta) {

                 hdrs['x-amz-meta-'+k] = kwArgs.meta[k];

                 meta_to_sign += "x-amz-meta-"+k+":"+kwArgs.meta[k]+"\n";

             }

         }

         // Only perform authentication if non-anonymous and credentials available

         if (kwArgs['anonymous'] != true && this.KEY_ID && this.SECRET_KEY) {

             // Build the string to sign for authentication.

             var s; 

             s  = kwArgs.method + "\n";

             s += content_MD5 + "\n";

             s += kwArgs.content_type + "\n";

             s += http_date + "\n";

             s += acl_header_to_sign;

             s += meta_to_sign;

             s += kwArgs.resource;

             // Sign the string with our SECRET_KEY.

             var signature = this.hmacSHA1(s, this.SECRET_KEY);

             hdrs['Authorization'] = "AWS "+this.KEY_ID+":"+signature;

         }

         // Perform the HTTP request.

         var req = getXMLHttpRequest();

         req.open(kwArgs.method, url, true);

         for (var k in hdrs) req.setRequestHeader(k, hdrs[k]);

         req.onreadystatechange = function() {

             if (req.readyState == 4) {

                 // Pre-digest the XML if needed.

                 var obj = null;

                 if (req.responseXML && kwArgs.parseXML != false)

                     obj = _this.xmlToObj(req.responseXML, kwArgs.force_lists);

                 // Stash away the last request details, if DEBUG active.

                 if (_this.DEBUG) {

                     window._lastreq = req;

                     window._lastobj = obj;

                 }

                 // Dispatch to appropriate handler callback

                 if ( (req.status >= 400 || (obj && obj.Error) ) && kwArgs.error)

                     return kwArgs.error(req, obj);

                 else

                     return kwArgs.load(req, obj);

             }

         }

         req.send(kwArgs.content);

         return req;

     },

     /**

         Turn a simple structure of nested XML elements into a 

         JavaScript object.

         TODO: Handle attributes?

     */

     xmlToObj: function(parent, force_lists, path) {

         var obj = {};

         var cdata = '';

         var is_struct = false;

         for(var i=0,node; node=parent.childNodes[i]; i++) {

             if (3 == node.nodeType) { 

                 cdata += node.nodeValue;

             } else {

                 is_struct = true;

                 var name  = node.nodeName;

                 var cpath = (path) ? path+'.'+name : name;

                 var val   = arguments.callee(node, force_lists, cpath);

                 if (!obj[name]) {

                     var do_force_list = false;

                     if (force_lists) {

                         for (var j=0,item; item=force_lists[j]; j++) {

                             if (item == cpath) {

                                 do_force_list=true; break;

                             }

                         }

                     }

                     obj[name] = (do_force_list) ? [ val ] : val;

                 } else if (obj[name].length) {

                     // This is a list of values to append this one to the end.

                     obj[name].push(val);

                 } else {

                     // Has been a single value up till now, so convert to list.

                     obj[name] = [ obj[name], val ];

                 }

             }

         }

         // If any subnodes were found, return a struct - else return cdata.

         return (is_struct) ? obj : cdata;

     },

     /**

         Abstract HMAC SHA1 signature calculation.

     */

     hmacSHA1: function(data, secret) {

         // TODO: Alternate Dojo implementation?

         return b64_hmac_sha1(secret, data)+'=';

     },

     /**

         Return a date formatted appropriately for HTTP Date header.

         Inspired by: http://www.svendtofte.com/code/date_format/

         TODO: Should some/all of this go into common.js?

     */

     httpDate: function(d) {

         // Use now as default date/time.

         if (!d) d = new Date();

         // Date abbreviations.

         var daysShort   = ["Sun", "Mon", "Tue", "Wed",

                            "Thu", "Fri", "Sat"];

         var monthsShort = ["Jan", "Feb", "Mar", "Apr", "May", "Jun", 

                            "Jul", "Aug", "Sep", "Oct", "Nov", "Dec"];

         // See: http://www.quirksmode.org/js/introdate.html#sol

         function takeYear(theDate) {

             var x = theDate.getYear();

             var y = x % 100;

             y += (y < 38) ? 2000 : 1900;

             return y;

         };

         // Number padding function

         function zeropad(num, sz) { 

             return ( (sz - (""+num).length) > 0 ) ? 

                 arguments.callee("0"+num, sz) : num; 

         };

         function gmtTZ(d) {

             // Difference to Greenwich time (GMT) in hours

             var os = Math.abs(d.getTimezoneOffset());

             var h = ""+Math.floor(os/60);

             var m = ""+(os%60);

             h.length == 1? h = "0"+h:1;

             m.length == 1? m = "0"+m:1;

             return d.getTimezoneOffset() < 0 ? "+"+h+m : "-"+h+m;

         };

         var s;

         s  = daysShort[d.getDay()] + ", ";

         s += d.getDate() + " ";

         s += monthsShort[d.getMonth()] + " ";

         s += takeYear(d) + " ";

         s += zeropad(d.getHours(), 2) + ":";

         s += zeropad(d.getMinutes(), 2) + ":";

         s += zeropad(d.getSeconds(), 2) + " ";

         s += gmtTZ(d);

         return s;

     },

     /* Help protect against errant end-commas */

     EOF: null

 };

 if (!window['queryString']) {

     // Swiped from MochiKit

     function queryString(params) {

         var l = [];

         for (k in params) 

             l.push(k+'='+encodeURIComponent(params[k]))

         return l.join("&");

     }

 }

 if (!window['getXMLHttpRequest']) {

     // Shamelessly swiped from MochiKit/Async.js

     function getXMLHttpRequest() {

         var self = arguments.callee;

         if (!self.XMLHttpRequest) {

             var tryThese = [

                 function () { return new XMLHttpRequest(); },

                 function () { return new ActiveXObject('Msxml2.XMLHTTP'); },

                 function () { return new ActiveXObject('Microsoft.XMLHTTP'); },

                 function () { return new ActiveXObject('Msxml2.XMLHTTP.4.0'); },

                 function () { return null; }

             ];

             for (var i = 0; i < tryThese.length; i++) {

                 var func = tryThese[i];

                 try {

                     self.XMLHttpRequest = func;

                     return func();

                 } catch (e) {

                     // pass

                 }

             }

         }

         return self.XMLHttpRequest();

     }

 }