/**
 * Get information about an (optionally installed) add-on compared against the add-ons server.
 *
 * @param addon The add-ons server entry information.
 * @param t     The local tracking status information.
 */
void get_addon_tracking_info(addon_info& addon, addon_tracking_info& t)
{
    const std::string& id = addon.id;

    t.can_publish = have_addon_pbl_info(id);
    t.in_version_control = have_addon_in_vcs_tree(id);
    t.installed_version = version_info();

    if(is_addon_installed(id)) {
        try {
            t.installed_version = get_addon_version_info(id);
            const version_info& remote_version = addon.version;

            if(remote_version == t.installed_version) {
                t.state = ADDON_INSTALLED;
            } else if(remote_version > t.installed_version) {
                t.state = ADDON_INSTALLED_UPGRADABLE;
            } else /* if(remote_version < t.installed_version) */ {
                t.state = ADDON_INSTALLED_OUTDATED;
            }
        } catch(version_info::not_sane_exception const&) {
            ERR_AC << "local add-on '" << name << "' has invalid or missing version info, skipping from updates check...\n";
            t.state = ADDON_NOT_TRACKED;
        }
    } else {
        t.state = ADDON_NONE;
    }
}