function setPreference(cname, cvalue) {
    var params = "set=1" + "&name=" + cname + "&value=" + cvalue;

    var req = new XMLHttpRequest();
    req.open('POST', '/preferences', true); 
    req.setRequestHeader("X-CSRFToken", get_csrf_token());
    req.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    req.onreadystatechange = function (aEvt) {
	if (req.readyState == 4 && req.status != 200) {
	    alert('Error setting preference');
	}
    };
    req.send(params);
}

function getPreference(cname) {
    var params = "get=1" + "&name=" + cname;

    var req = new XMLHttpRequest();
    req.open('POST', '/preferences', false); 
    req.setRequestHeader("X-CSRFToken", get_csrf_token());
    req.setRequestHeader("Content-type", "application/x-www-form-urlencoded");
    req.send(params);
    if(req.status == 200)
	return JSON.parse(req.responseText)[cname];
    return null;
}

function set_visible(id, visible, display="block")
{
    widget = document.getElementById(id);
    if (visible)
    {
	widget.style.display = display;
	widget.style.visibility = "visible";
    }
    else
    {
	widget.style.display = "none";
	widget.style.visibility = "hidden";
    }

    return widget;
}

function updateHiddenCategories(cat_id, add)
{
    if (hidden_categories == null)
	hidden_categories = [];
    
    for(i=0; i<hidden_categories.length; i++)
    {
	if (hidden_categories[i] == cat_id)
	{
	    if (add) return;
	    hidden_categories.splice(i, 1);
	    break;
	}
    }

    if (add)
	hidden_categories.push(cat_id);

    setPreference('hidden_categories', hidden_categories.join(","));
}

function hide_category(cat_id, update_cookie=true)
{
    set_visible("content_" + cat_id, false);
    set_visible("minus_" + cat_id, false);
    set_visible("plus_" + cat_id, true, "inline-block");

    if (update_cookie)
	updateHiddenCategories(cat_id, true);
}

function show_category(cat_id, update_cookie=true)
{
    set_visible("content_" + cat_id, true);
    set_visible("minus_" + cat_id, true, "inline-block");
    set_visible("plus_" + cat_id, false);

    if (update_cookie)
	updateHiddenCategories(cat_id, false);
}

function category_setup()
{
    if (hidden_categories == null)
	hidden_categories = [];

    categories = document.getElementById("categories");

    for(i=0; i<categories.childNodes.length; i++)
    {
	category = categories.childNodes[i];
	if (category.nodeType != Node.ELEMENT_NODE) continue;
	categoryId = category.getAttribute("category_id");
	hide = false;
	for(a=0; a<hidden_categories.length;a++)
	{
	    if (hidden_categories[a] == categoryId)
	    {
		hide = true;
		break;
	    }
	}
	if (hide)
	    hide_category(categoryId, false);
	else
	    show_category(categoryId, false);
    }
}

function startup()
{
    category_setup();
}

function edit_category(cat_id, name)
{
    set_visible("category_" + cat_id, false);
    set_visible("edit_category_" + cat_id, true);
    
    input = document.getElementById("cat_name_" + cat_id);    
    input.value = name;
    input.focus();
}

function end_edit_category(cat_id)
{
    set_visible("category_" + cat_id, true);
    set_visible("edit_category_" + cat_id, false);
}

function submit_category_name(cat_id, orig)
{
    me = document.getElementById("cat_name_" + cat_id);
    if (me.value.localeCompare(orig) != 0)
    {
	form = document.getElementById("edit_category_" + cat_id);
    	form.submit();
    	return true;
    }
    else
	return false;

    return false;
}

function handleKeyPress(e, cat_id, orig){
    var key=e.keyCode || e.which;
    if (key==13)
	submit_category_name(cat_id, orig);
}

function edit_note()
{
    document.body.scrollTop = document.documentElement.scrollTop = 0;
    set_visible("title", false);
    set_visible("transformed_content", false);
    set_visible("edit_button", false);
    set_visible("form_delete", false);
    set_visible("div_edit", true);
}

function cancel_edit_note()
{
    document.body.scrollTop = document.documentElement.scrollTop = 0;
    set_visible("title", true);
    set_visible("transformed_content", true);
    set_visible("edit_button", true, "inline");
    set_visible("form_delete", true, "inline");
    set_visible("div_edit", false);
}