Use a tab like interface to show Usage and config in the same page

[Kiougar]

Moved from #16 as a separate issue for clarity.

Research a little bit to see how to implement the tab interface that is widely used in LuCI modules. This will allow the Usage module to appear as a single menu entry and everything associated with it (i.e. config page) to exist in the same page.

[NaruZosa]

It seems that the tabs are just lists using CSS to style them, here's the CSS:

.tabs, .cbi-tabmenu {
    margin: 0 0 18px;
    padding: 0;
    list-style: none;
    zoom: 1;
}

.tabs:before,
.cbi-tabmenu:before,
.tabs:after,
.cbi-tabmenu:after {
    display: table;
    content: "";
    zoom: 1;
}

.tabs:after, .cbi-tabmenu:after {
    clear: both;
}

.tabs > li, .cbi-tabmenu > li {
    float: left;
}

.tabs > li > a, .cbi-tabmenu > li > a {
    display: block;
}

.tabs,
.cbi-tabmenu {
    border-color: #ddd;
    border-style: solid;
    border-width: 0 0 1px;
}

.tabs > li,
.cbi-tabmenu > li {
    position: relative;
    margin-bottom: -1px;
}

.cbi-tabmenu.map {
    margin: 0;
}

.cbi-tabmenu.map > li {
    font-size: 16.5px;
    font-weight: bold;
}

.cbi-tabcontainer > fieldset.cbi-section[id] > legend {
    display: none;
}

.tabs > li > a,
.cbi-tabmenu > li > a {
    padding: 0 15px;
    margin-right: 2px;
    line-height: 34px;
    border: 1px solid transparent;
    -webkit-border-radius: 4px 4px 0 0;
    -moz-border-radius: 4px 4px 0 0;
    border-radius: 4px 4px 0 0;
}

.tabs > li > a:hover,
.cbi-tabmenu > li > a:hover {
    text-decoration: none;
    background-color: #eee;
    border-color: #eee #eee #ddd;
}

.tabs .active > a, .tabs .active > a:hover,
.cbi-tabmenu .active > a, .cbi-tabmenu .active > a:hover,
.cbi-tab > a:link, .cbi-tab > a:hover {
    color: #808080;
    background-color: #ffffff;
    border: 1px solid #ddd;
    border-bottom-color: transparent;
    cursor: default;
}

.tabs .menu-dropdown, .tabs .dropdown-menu,
.cbi-tabmenu .menu-dropdown, .cbi-tabmenu .dropdown-menu {
    top: 35px;
    border-width: 1px;
    -webkit-border-radius: 0 6px 6px 6px;
    -moz-border-radius: 0 6px 6px 6px;
    border-radius: 0 6px 6px 6px;
}

.tabs a.menu:after, .tabs .dropdown-toggle:after,
.cbi-tabmenu a.menu:after, .cbi-tabmenu .dropdown-toggle:after {
    border-top-color: #999;
    margin-top: 15px;
    margin-left: 5px;
}

.tabs li.open.menu .menu, .tabs .open.dropdown .dropdown-toggle,
.cbi-tabmenu li.open.menu .menu, .cbi-tabmenu .open.dropdown .dropdown-toggle {
    border-color: #999;
}

.tabs li.open a.menu:after, .tabs .dropdown.open .dropdown-toggle:after,
.cbi-tabmenu li.open a.menu:after, .cbi-tabmenu .dropdown.open .dropdown-toggle:after {
    border-top-color: #555;
}

.tab-content > .tab-pane,
.tab-content > div {
    display: none;
}

.tab-content > .active {
    display: block;
}

Then the HTML looks like this (taken from the firewall page):

<ul class="tabs">
    <li class="tabmenu-item-zones active">
        <a href="/cgi-bin/luci/admin/network/firewall/zones">General Settings</a>
    </li>
    <li class="tabmenu-item-forwards ">
        <a href="/cgi-bin/luci/admin/network/firewall/forwards">Port Forwards</a>
    </li>
    <li class="tabmenu-item-rules ">
        <a href="/cgi-bin/luci/admin/network/firewall/rules">Traffic Rules</a>
    </li>
    <li class="tabmenu-item-custom ">
        <a href="/cgi-bin/luci/admin/network/firewall/custom">Custom Rules</a>
    </li>
</ul>

Here's a screenshot of how the tabs look: https://www.dropbox.com/s/dhh9jkqtgzkzxl9/FW%20Tabs.png

[Kiougar]

Note to self:

Investigate this even further by inspecting luci applications.

Notably: luci-app-firewall