// ============================================================================
// Developed by Kernel Team.
// http://kernel-team.com
// ============================================================================

function KT_rotationEngineStartup(tp, wp) {
    KT_rotationEngineStartup._THUMBS = {};
    if (window['KT_rotationEngineWaitPeriod']) {
        KT_rotationEngineStartup._ROTATION_PERIOD_MS = window['KT_rotationEngineWaitPeriod'] * 1000;
    } else {
        KT_rotationEngineStartup._ROTATION_PERIOD_MS = wp * 1000;
    }
    KT_rotationEngineStartup._ROTATION_ID = null;
    KT_rotationEngineStartup._ROTATION_UID = null;
    KT_rotationEngineStartup._DUMMY = tp;
}

function KT_rotationStop(image) {
    if (KT_rotationEngineStartup._ROTATION_ID) {
        var thumbData = KT_rotationEngineStartup._THUMBS[KT_rotationEngineStartup._ROTATION_ID];
        if (thumbData && thumbData['thumb'] && thumbData['thumbInitial']) {
            thumbData['thumb'].src = thumbData['thumbInitial'];
        }
    }
    KT_rotationEngineStartup._ROTATION_ID = null;
    KT_rotationEngineStartup._ROTATION_UID = null;
    KT_rotationEngineStartup._DUMMY = image;
}

function KT_rotationStart(image, urlPrefix, thumbCount, thumbExt) {
    KT_rotationStop(null);

    if (image) {
        var currentThumbUrl = image.src;

        var thumbId = image.id;
        if (!thumbId) {
            thumbId = 'KT_rotationEngineStartup_' + new Date().getTime();
            image.id = thumbId
        }
        var initialIdx = 1;
        if (image.src.indexOf(urlPrefix + initialIdx + (thumbExt ? thumbExt : '.jpg'))>=0)
        {
            initialIdx = 2;
        }
        KT_rotationEngineStartup._THUMBS[thumbId] = {
            thumb: image,
            thumbInitial: currentThumbUrl,
            prefix: urlPrefix,
            count: thumbCount,
            ext: thumbExt,
            idx: initialIdx - 1
        };

        if (KT_rotationEngineStartup._THUMBS[thumbId]['thumb']) {
            KT_rotationEngineStartup._ROTATION_UID = new Date().getTime();
            KT_rotationEngineStartup._ROTATION_ID = thumbId;
            KT_rotationInvoke(thumbId, KT_rotationEngineStartup._ROTATION_UID);
        }
    }
}

function KT_rotationInvoke(thumbId, uid) {
    var thumbData = KT_rotationEngineStartup._THUMBS[thumbId];
    if (thumbData) {
        var thumb = thumbData['thumb'];
        var prefix = thumbData['prefix'];
        var count = thumbData['count'];
        var ext = thumbData['ext'];
        var idx = thumbData['idx'];

        idx = (idx == count ? 1 : idx + 1);
        thumbData['idx'] = idx;

        var url = prefix + idx + (ext ? ext : '.jpg');
        var img = new Image();
        img.onload = function() {
            if ((thumbId == KT_rotationEngineStartup._ROTATION_ID) && (uid == KT_rotationEngineStartup._ROTATION_UID)) {
                if (img.width == 0) {
                    KT_rotationInvoke(thumbId, uid);
                }
                thumb.src = url;
                setTimeout('KT_rotationInvoke(\'' + thumbId + '\', ' + uid + ')', KT_rotationEngineStartup._ROTATION_PERIOD_MS);
            }
        };
        img.onerror = function() {
            if ((thumbId == KT_rotationEngineStartup._ROTATION_ID) && (uid == KT_rotationEngineStartup._ROTATION_UID)) {
                KT_rotationInvoke(thumbId, uid);
            }
        };
        img.src = url;
        KT_rotationEngineStartup._THUMBS[thumbId] = thumbData;
    }
}