/*
 * API key, this should be initialized before any another function in this file is called.
 */
var is_initialized = false;

/*
 * Ensure Facebook app is initialized and call callback afterward
 *
 */
function ensure_init(callback) {
    if(!window.api_key) {
        window.alert("api_key is not set");
    }

    if(window.is_initialized) {
        callback();
    } else {
        FB_RequireFeatures(["XFBML", "CanvasUtil"], function() {
            FB.FBDebug.logLevel = 4;
            FB.FBDebug.isEnabled = true;
            // xd_receiver.php is a relative path here, because The Run Around
            // could be installed in a subdirectory
            // you should prefer an absolute URL (like "/xd_receiver.php") for more accuracy
            FB.Facebook.init(window.api_key, "xd_receiver.php");

            window.is_initialized = true;
            callback();
        });
    }
}

/*
 * The facebook_onload statement is printed out in the PHP. If the user's logged in
 * status has changed since the last page load, then refresh the page to pick up
 * the change.
 *
 * This helps enforce the concept of "single sign on", so that if a user is signed into
 * Facebook when they visit your site, they will be automatically logged in -
 * without any need to click the login button.
 *
 * @param already_logged_into_facebook  reports whether the server thinks the user
 *                                      is logged in, based on their cookies
 *
 */
function facebook_onload(already_logged_into_facebook) {
    // user state is either: has a session, or does not.
    // if the state has changed, detect that and reload.
    ensure_init(function() {
        FB.Facebook.get_sessionState().waitUntilReady(function(session) {
            var is_now_logged_into_facebook = session ? true : false;

            // if the new state is the same as the old (i.e., nothing changed)
            // then do nothing
            if (is_now_logged_into_facebook == already_logged_into_facebook) {
                return;
            }

            // otherwise, refresh to pick up the state change
            refresh_page();
        });
    });
}


function facebook_button_onclick() {

    ensure_init(function() {
        FB.Facebook.get_sessionState().waitUntilReady(function() {
            var user = FB.Facebook.apiClient.get_session() ?
            FB.Facebook.apiClient.get_session().uid :
            null;

            // probably should give some indication of failure to the user
            if (!user) {
                return;
            }

            // The Facebook Session has been set in the cookies,
            // which will be picked up by the server on the next page load
            // so refresh the page, and let all the account linking be
            // handled on the server side

            // This could be done a myriad of ways; for a page with more content,
            // you could do an ajax call for the account linking, and then
            // just replace content inline without a full page refresh.
            refresh_page();
        });
    });
}


/*
 * Prompts the user to grant a permission to the application.
 */
function facebook_prompt_permission(permission) {
    ensure_init(function() {
        FB.Connect.showPermissionDialog(permission);
    });
}

/*
 * Show the feed form. This would be typically called in response to the
 * onclick handler of a "Publish" button, or in the onload event after
 * the user submits a form with info that should be published.
 *
 */
function facebook_publish_feed_story(form_bundle_id, template_data) {
    // Load the feed form
    ensure_init(function() {
        FB.Connect.showFeedDialog(form_bundle_id, template_data);
        //FB.Connect.showFeedDialog(form_bundle_id, template_data, null, null, FB.FeedStorySize.shortStory, FB.RequireConnect.promptConnect);

        // hide the "Loading feed story ..." div
        ge('feed_loading').style.visibility = "hidden";
    });
}

/*
 * If a user is not connected, then the checkbox that says "Publish To Facebook"
 * is hidden in the "add run" form.
 *
 * This function detects whether the user is logged into facebook but just
 * not connected, and shows the checkbox if that's true.
 */
function facebook_show_feed_checkbox() {
    ensure_init(function() {
        FB.Connect.get_status().waitUntilReady(function(status) {
            if (status != FB.ConnectState.userNotLoggedIn) {
                // If the user is currently logged into Facebook, but has not
                // authorized the app, then go ahead and show them the feed dialog + upsell
                checkbox = ge('publish_fb_checkbox');
                if (checkbox) {
                    checkbox.style.visibility = "visible";
                }
            }
        });
    });
}