var Tooltip = {
    followMouse: true,
    offX: 8,
    offY: 12,
    tipID: "tipDiv",
    showDelay: 100,
    hideDelay: 200,

    ready: false, timer: null, tip: null,

    init: function() {
        if (document.createElement && document.body && typeof document.body.appendChild != "undefined") {
            if (!document.getElementById(this.tipID)) {
                var el = document.createElement("DIV");
                el.id = this.tipID; document.body.appendChild(el);
            }
            this.ready = true;
        }
    },

    show: function(e, msg) {
        if (this.timer) { clearTimeout(this.timer); this.timer = 0; }
        this.tip = document.getElementById(this.tipID);
        if (this.followMouse) // set up mousemove 
            dw_event.add(document, "mousemove", this.trackMouse, true);
        this.writeTip("");  // for mac ie
        this.writeTip(msg);
        viewport.getAll();
        this.positionTip(e);
        this.timer = setTimeout("Tooltip.toggleVis('" + this.tipID + "', 'visible')", this.showDelay);
    },

    writeTip: function(msg) {
        if (this.tip && typeof this.tip.innerHTML != "undefined") this.tip.innerHTML = msg;
    },

    positionTip: function(e) {
        if (this.tip && this.tip.style) {
            // put e.pageX/Y first! (for Safari)
            var x = e.pageX ? e.pageX : e.clientX + viewport.scrollX;
            var y = e.pageY ? e.pageY : e.clientY + viewport.scrollY;

            if (x + this.tip.offsetWidth + this.offX > viewport.width + viewport.scrollX) {
                x = x - this.tip.offsetWidth - this.offX;
                if (x < 0) x = 0;
            } else x = x + this.offX;

            if (y + this.tip.offsetHeight + this.offY > viewport.height + viewport.scrollY) {
                y = y - this.tip.offsetHeight - this.offY;
                if (y < viewport.scrollY) y = viewport.height + viewport.scrollY - this.tip.offsetHeight;
            } else y = y + this.offY;

            this.tip.style.left = x + "px"; this.tip.style.top = y + "px";
        }
    },

    hide: function() {
        if (this.timer) { clearTimeout(this.timer); this.timer = 0; }
        this.timer = setTimeout("Tooltip.toggleVis('" + this.tipID + "', 'hidden')", this.hideDelay);
        if (this.followMouse) // release mousemove
            dw_event.remove(document, "mousemove", this.trackMouse, true);
        this.tip = null;
    },

    toggleVis: function(id, vis) { // to check for el, prevent (rare) errors
        var el = document.getElementById(id);
        if (el) el.style.visibility = vis;
    },

    trackMouse: function(e) {
        e = dw_event.DOMit(e);
        Tooltip.positionTip(e);
    }

}