$(document).ready(initializeLazyContentLoading);

function prepareLazyLinks() {
    // iterate over all a-links
    // if pageTarget attribute is set, prepare link for lazy loading

    $.each( $('a'), function (key, value) {
        if ($(value).attr('pageTarget') !== undefined) {
            var pageTarget = $(value).attr('pageTarget');

            // link leads to # + base64 of page target
            $(value).attr('href', '#' + btoa(pageTarget));
            $(value).click(function () {
                // clear old content
                if (window.location.hash.slice(1) != btoa(pageTarget))
                    $('main').text('');
                return true;
            });
        }
    });
}

function prepareLazyForms() {
    // prepare all forms
    $.each( $('form'), function (key, value) {
        if ($(value).attr('actionTarget') !== undefined) {
            var actionTarget = $(value).attr('actionTarget');

            $(value).submit(function (event) {
                lazyPostForm(actionTarget, value);
                event.preventDefault();
            });
        }
    });
}

function initializeLazyContentLoading() {
    prepareLazyLinks();

    // watch changes in the location hashtag
    setTimeout(lazyContentLoadingTimer, 100);

    prepareLazyForms();
}

function lazyLoadPage(pageTarget) {
    $('main').load('lazy.php?page=' + pageTarget, function () {
        // there may be new lazy links / forms in the loaded content, so re-prepare everything
        prepareLazyLinks();
        prepareLazyForms();
    });
    updateActiveNavbarItem(pageTarget);
}

function lazyPostForm(actionTarget, form, targetID) {
    $.post('lazy.php?page=' + actionTarget, $(form).serialize()).done(function (data) {

        if (targetID !== undefined) {
            $('#' + targetID).html(data);
        } else {
            $('main').html(data);
        }
        // there may be new lazy links / forms in the loaded content, so re-prepare everything
        prepareLazyLinks();
        prepareLazyForms();
    });
}

function updateActiveNavbarItem(pageTarget) {
    if (pageTarget == "")
        return;
    $.each( $('li'), function (key, value) {
        if ($(value).attr('activeOnPage') !== undefined) {
            if ($(value).attr('activeOnPage') == pageTarget) {
                $(value).addClass('active');
            } else {
                $(value).removeClass('active');
            }
        }
    });
}

function lazyContentLoadingTimer() {
    if (lazyContentLoadingTimer.lastHash === undefined) {
        lazyContentLoadingTimer.lastHash = window.location.hash;
    }
    if (window.location.hash != lazyContentLoadingTimer.lastHash) {
        lazyContentLoadingTimer.lastHash = window.location.hash;
        lazyLoadPage(atob(window.location.hash.slice(1)));
    }
    
    setTimeout(lazyContentLoadingTimer, 100);
}