/*

SelectFilter - Turns a multiple-select box into a filter interface.

Requires SelectBox.js and addevent.js.

*/

function findForm(node) {

    // returns the node of the form containing the given node

    if (node.tagName.toLowerCase() != 'form') {

        return findForm(node.parentNode);

    }

    return node;

}

var SelectFilter = {

    init: function(field_id) {

        var from_box = document.getElementById(field_id);

        from_box.id += '_from'; // change its ID

        // Create the INPUT input box

        var input_box = document.createElement('input');

        input_box.id = field_id + '_input';

        input_box.setAttribute('type', 'text');

        from_box.parentNode.insertBefore(input_box, from_box);

        from_box.parentNode.insertBefore(document.createElement('br'), input_box.nextSibling);

        // Create the TO box

        var to_box = document.createElement('select');

        to_box.id = field_id + '_to';

        to_box.setAttribute('multiple', 'multiple');

        to_box.setAttribute('size', from_box.size);

        from_box.parentNode.insertBefore(to_box, from_box.nextSibling);

        to_box.setAttribute('name', from_box.getAttribute('name'));

        from_box.setAttribute('name', from_box.getAttribute('name') + '_old');

        // Give the filters a CSS hook

        from_box.setAttribute('class', 'filtered');

        to_box.setAttribute('class', 'filtered');

        // Set up the JavaScript event handlers for the select box filter interface

        addEvent(input_box, 'keyup', function(e) { SelectFilter.filter_key_up(e, field_id); });

        addEvent(input_box, 'keydown', function(e) { SelectFilter.filter_key_down(e, field_id); });

        addEvent(from_box, 'dblclick', function() { SelectBox.move(field_id + '_from', field_id + '_to'); });

        addEvent(from_box, 'focus', function() { input_box.focus(); });

        addEvent(to_box, 'dblclick', function() { SelectBox.move(field_id + '_to', field_id + '_from'); });

        addEvent(findForm(from_box), 'submit', function() { SelectBox.select_all(field_id + '_to'); });

        SelectBox.init(field_id + '_from');

        SelectBox.init(field_id + '_to');

        // Move selected from_box options to to_box

        SelectBox.move(field_id + '_from', field_id + '_to');

    },

    filter_key_up: function(event, field_id) {

        from = document.getElementById(field_id + '_from');

        // don't submit form if user pressed Enter

        if ((event.which && event.which == 13) || (event.keyCode && event.keyCode == 13)) {

            from.selectedIndex = 0;

            SelectBox.move(field_id + '_from', field_id + '_to');

            from.selectedIndex = 0;

            return false;

        }

        var temp = from.selectedIndex;

        SelectBox.filter(field_id + '_from', document.getElementById(field_id + '_input').value);

        from.selectedIndex = temp;

        return true;

    },

    filter_key_down: function(event, field_id) {

        from = document.getElementById(field_id + '_from');

        // right arrow -- move across

        if ((event.which && event.which == 39) || (event.keyCode && event.keyCode == 39)) {

            var old_index = from.selectedIndex;

            SelectBox.move(field_id + '_from', field_id + '_to');

            from.selectedIndex = (old_index == from.length) ? from.length - 1 : old_index;

            return false;

        }

        // down arrow -- wrap around

        if ((event.which && event.which == 40) || (event.keyCode && event.keyCode == 40)) {

            from.selectedIndex = (from.length == from.selectedIndex + 1) ? 0 : from.selectedIndex + 1;

        }

        // up arrow -- wrap around

        if ((event.which && event.which == 38) || (event.keyCode && event.keyCode == 38)) {

            from.selectedIndex = (from.selectedIndex == 0) ? from.length - 1 : from.selectedIndex - 1;

        }

        return true;

    }

}