function coverScraper(size, useLocalStorage, sendUpdates, enabled) {

    var self = this;
    var timer_running = false;
    var formObjects = [];
    var numAlbums = 0;
    var albums_without_cover = 0;
    var infotext = $('#infotext');
    var statusobj = $('#status');
    var imgparams = null;
    var covertimer = null;
    var scrolling = false;
    var ignorelocal = false;

    // I need to try and limit the number of lookups per second I do to last.fm
    // Otherwise they will set the lions on me - hence the use of setTimeout

    // Pass the img name to this function
    this.GetNewAlbumArt = function(params) {
        if (enabled) {
            formObjects.push(params);
            numAlbums = (formObjects.length)-1;
            if (timer_running == false) {
                doNextImage(1);
            }
        } else {
            imgparams = self.getImageSearchParams(params);
            setDefaultImage(imgparams);
        }
    }

    this.toggle = function(o) {
        enabled = o;
    }

    this.reset = function(awc) {
        numAlbums = 0;
        if (awc > -1) {
            albums_without_cover = awc;
        }
        formObjects = [];
        timer_running = false;
        self.updateInfo(0);
        if (typeof aADownloadFinished == 'function') {
            aADownloadFinished();
        }
    }

    this.updateInfo = function(n) {
        if (sendUpdates) {
            albums_without_cover = albums_without_cover - n;
            infotext.html(albums_without_cover+" "+language.gettext("albumart_nocovercount"));
        }
    }

    this.toggleScrolling = function(s) {
        scrolling = s;
    }

    this.toggleLocal = function(s) {
        ignorelocal = s;
    }

    this.getImageSearchParams =  function(imgobj) {
        if (imgobj.hasOwnProperty('cb')) {
            // pre-populated data from the playlist
            return imgobj;
        } else {
            var key = imgobj.attr('name');
            var artist =  imgobj.parent().find('input[name="artist"]').val();
            var album =  imgobj.parent().find('input[name="album"]').val();
            if (artist) {
                return {key: '', artist: decodeURIComponent(artist), album: decodeURIComponent(album), imgkey: imgobj.attr('name')};
            } else {
                return {key: key, artist: '', album: '', imgkey: imgobj.attr('name')};
            }
        }
    }

    // Is there something else I could be doing?

    function doNextImage(time) {
        clearTimeout(covertimer);
        if (formObjects.length > 0) {
            debug.log("COVERSCRAPER","Next Image, delay time is",time);
            timer_running = true;
            covertimer = setTimeout(processForm, time);
        } else {
            $(statusobj).empty();
            timer_running = false;
            if (typeof aADownloadFinished == 'function') {
                aADownloadFinished();
            }
        }
    }

    function processForm() {

        if (formObjects.length == 0) {
            return 0;
        }

        image = formObjects.shift();
        if (image.hasOwnProperty('cb') && image.cb === null) {
            // Callbacks are nullified when the playlist repopulates, which means we don't need to
            // look for these any more, as if they are still in the playlist they'll have been re-added to formObjects.
            // Rather than do some horrid splicing of formObjects in clearCallbacks, just skip them here.
            debug.trace("COVERSCRAPER","Skipping cleared playlist image");
            doNextImage(500);
            return false;
        }
        imgparams = self.getImageSearchParams(image);
        imgparams.ignorelocal = ignorelocal;
        debug.log("COVERSCRAPER","Getting Cover for", imgparams.imgkey);

        if (sendUpdates) {
            var x = image.prev('input').val();
            statusobj.empty().html(language.gettext("albumart_getting")+" "+decodeURIComponent(x));
            var percent = ((numAlbums - formObjects.length)/numAlbums)*100;
            progress.rangechooser('setProgress', percent.toFixed(2));
            if (scrolling) {
                $('#coverslist').mCustomScrollbar("scrollTo",$('img[name="'+imgparams.imgkey+'"]'));
            }
         }

        animateWaiting();

        // Munge params here as we can't pass the 'callback' (cb) parameter to $.post
        var postparams = cloneObject(imgparams);
        delete postparams.cb;
        $.post("getalbumcover.php", postparams)
        .done( gotImage )
        .fail( revertCover );

    }

    function animateWaiting() {
        $('img.notexist[name="'+imgparams.imgkey+'"]').removeClass('nospin').addClass('spinner').removeAttr('src');
    }

    function stopAnimation() {
        $('img[name="'+imgparams.imgkey+'"]').removeClass('spinner').addClass('nospin').removeAttr('src');
    }

    // Hello

    function gotImage(data) {
        debug.trace("COVERSCRAPER","Result Is", data);
        stopAnimation();
        if (data.small) {
            self.updateInfo(1);
            if (useLocalStorage) {
                sendLocalStorageEvent(imgparams.imgkey, data);
            }
            finaliseImage(data);
            doNextImage(data.delaytime);
        } else {
            if (setDefaultImage(imgparams)) {
                doNextImage(data.delaytime);
            } else {
                revertCover(data.delaytime);
            }
        }
   }

   function finaliseImage(data) {
        update_ui_images(imgparams.imgkey, data);
        if (typeof (imgparams.cb) == 'function') {
            debug.trace("COVERSCRAPER","calling back for",imgparams.imgkey,data);
            imgparams.cb(data);
        }
    }

    function revertCover(delaytime) {
        if (!delaytime) {
            delaytime = 800;
        }
        debug.log("COVERSCRAPER","No Cover Found. Reverting to the blank icon");
        update_failed_ui_images(imgparams.imagekey);
        if (useLocalStorage) {
            sendLocalStorageEvent("!"+imgparams.imgkey);
        }
        doNextImage(delaytime);
    }

    function setDefaultImage(imgparams) {
        if (sendUpdates) {
            // Dont' do this if we're using the album art manager
            return false;
        }
        // Although getalbumcover does return a default for streams, this is here
        // mainly for the case where auto art download is disabled - this will set a
        // sensible default for streams
        var def = null;
        if (imgparams.type) {
            switch (imgparams.type) {
                case 'stream':
                    def = 'newimages/broadcast.svg';
                    break;

                case 'podcast':
                    def = 'newimages/podcast-logo.svg';
                    break;
            }
        } else {
            switch (imgparams.artist) {
                case 'STREAM':
                    def = 'newimages/broadcast.svg';
                    break;

                case 'PODCAST':
                    def = 'newimages/podcast-logo.svg';
                    break;
            }
        }
        if (def) {
            debug.log("COVERSCRAPER", "Returning default image of",def);
            var images = {
                small: def,
                medium: def,
                asdownloaded: def
            }
            finaliseImage(images);
            return true;
        } else {
            return false;
        }
    }

    this.clearCallbacks = function() {
        for (var j in formObjects) {
            if (formObjects[j].hasOwnProperty('cb')) {
                formObjects[j].cb = null;
            }
        }
    }

}

function sendLocalStorageEvent(key, data) {
    if (data && data.small) {
        localStorage.setItem("albumimg_"+key, JSON.stringify(data));
    }
    debug.trace("COVERSCRAPER","Sending local storage event",key);
    // Event only fires when the key value actually CHANGES
    localStorage.setItem("key", "Blerugh");
    localStorage.setItem("key", key);
}