function register_huddle_onclick(zephyr_row, sender) {
    zephyr_row.find(".zephyr_sender").click(function (e) {
        prepare_huddle(sender);
        // The sender span is inside the messagebox, which also has an
        // onclick handler. We don't want to trigger the messagebox
        // handler.
        e.stopPropagation();

        // switch to the replybox hotkey handler
        keydown_handler = process_key_in_input;
    });
}

function register_onclick(zephyr_row, zephyr_id) {
    zephyr_row.find(".messagebox").click(function (e) {
        if (!(clicking && mouse_moved)) {
            // Was a click (not a click-and-drag).
            select_zephyr_by_id(zephyr_id);
            respond_to_zephyr();
        }
        mouse_moved = false;
        clicking = false;
    });
}

/* We use 'visibility' rather than 'display' and jQuery's show() / hide(),
   because we want to reserve space for the email address.  This avoids
   things jumping around slightly when the email address is shown. */

function hide_email() {
    $('.zephyr_sender_email').addClass('invisible');
}

function show_email(zephyr_id) {
    hide_email();
    get_zephyr_row(zephyr_id).find('.zephyr_sender_email').removeClass('invisible');
}

function report_error(response, xhr, status_box) {
    if (xhr.status.toString().charAt(0) === "4") {
        // Only display the error response for 4XX, where we've crafted
        // a nice response.
        response += ": " + $.parseJSON(xhr.responseText).msg;
    }

    status_box.removeClass(status_classes).addClass('alert-error')
              .text(response).stop(true).fadeTo(0, 1);
    status_box.show();
}

var clicking = false;
var mouse_moved = false;

function zephyr_mousedown() {
    mouse_moved = false;
    clicking = true;
}

function zephyr_mousemove() {
    if (clicking) {
        mouse_moved = true;
    }
}

function go_to_high_water_mark() {
    select_and_show_by_id(high_water_mark);
}

var autocomplete_needs_update = false;

function update_autocomplete() {
    class_list.sort();
    instance_list.sort();
    people_list.sort();

    // limit number of items so the list doesn't fall off the screen
    $( "#class" ).typeahead({
        source: class_list,
        items: 3,
    });
    $( "#instance" ).typeahead({
        source: instance_list,
        items: 2,
    });
    $( "#recipient" ).typeahead({
        source: people_list,
        items: 4,
    });

    autocomplete_needs_update = false;
}

$(function () {
    // NB: This just binds to current elements, and won't bind to elements
    // created after ready() is called.
    $('input, textarea, button').focus(function () {
        keydown_handler = process_key_in_input;
    });
    $('input, textarea, button').blur(function () {
        keydown_handler = process_hotkey;
    });

    $('#zephyr-type-tabs a[href="#class-message"]').on('shown', function (e) {
        $('#class-message input:not(:hidden):first').focus().select();
    });
    $('#zephyr-type-tabs a[href="#personal-message"]').on('shown', function (e) {
        $('#personal-message input:not(:hidden):first').focus().select();
    });

    // Prepare the click handler for subbing to a new class to which
    // you have composed a zephyr.
    $('#create-it').click(function () {
        sub_from_home(compose_class_name(), $('#class-dne'));
    });

    // Prepare the click handler for subbing to an existing class.
    $('#sub-it').click(function () {
        sub_from_home(compose_class_name(), $('#class-nosub'));
    });

    var last_mousewheel = 0;
    $("#main_div").mousewheel(function () {
        var time = $.now();
        if (time - last_mousewheel > 50) {
            keep_pointer_in_view();
            last_mousewheel = time;
        }
    });

    $('.button-slide').click(function () {
        show_compose('class', $("#class"));
    });
});