/**
 * 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;
	}
}