function initTagPage()
{
    // initial page load - setup page elements based on
    // what is selected in the option list.
    // (initial page load has nothing selected, of course,
    // but we need to check anyway for 'back' button stuff.)
    var list = document.getElementById("tags");
    if (list) tagselect(list);
}

function toggle_actions(enable, just_rename)
{
    var form = document.getElementById("tagform");
    if (! form) return;

    // names of form elements to disable/enable
    // on item selections
    var toggle_elements = new Array("rename", "rename_field", "delete", "show posts");

    for ( $i = 0; $i < toggle_elements.length; $i++ ) {
        var ele = form.elements[ toggle_elements[$i] ];
        if (just_rename && $i > 1) continue;  // FIXME: remove after merge is decided
        ele.disabled = ! enable;
    }
}

function tagselect(list)
{
    if (! list) return;

    var selected_num = 0;        // counter
    var selected = new Array();  // tagnames, for display

    var selected_id;             // tag id if only one selected
    var id_re = /^\d+/;

    for ( $i = 0; $i < list.options.length; $i++ ) {
        if (list.options[$i].selected) {
            var val = list.options[$i].value.replace( /&/g, "&amp;" );
            selected[selected_num] = val.substring( val.indexOf('_')+1 );
            selected_num++;
            selected_id = val.match(id_re);
        }
    }

    var form = document.getElementById("tagform");
    if (! form) return;

    var tagfield   = document.getElementById("selected_tags");
    var tagprops   = document.getElementById("tag_props");
    var rename_btn = form.elements[ "rename" ];
    if (! tagfield || ! tagprops || ! rename_btn) return;

    // reset any 'red' fields
    reset_field( form.elements[ "rename_field" ]);
    reset_field( form.elements[ "add_field" ]);

    // no selections
    if (! selected_num) {
        toggle_actions(false);
        rename_btn.value = "Rename";
        show_props(tagprops);
    } else {
        toggle_actions(true);
        tagfield.innerHTML = selected.join(", ");

        // exactly one selection
        if (selected_num == 1) {
            rename_btn.value = "Rename";
            show_props(tagprops, selected_id);
        }

        // multiple items selected
        else {
            // FIXME: enable after merging is decided
            //rename_btn.value = "Merge";
            toggle_actions(false, 1); // FIXME: delete after merging is decided
            show_props(tagprops);
        }
    }

}

// just check for non-space characters or 'bad phrase',
// change css on problems.
function validate_input(btn, field_name, badtext)
{
    var form = document.getElementById("tagform");
    if (! form) return true;  // let submit happen
    var field = form.elements[ field_name ];
    if (! field) return true;

    var re = /\S/;
    if (! field.value.match(re) || field.value.indexOf(badtext) != -1) {
        field.className = 'tagfield_error';
        return false;
    }

    return true;
}

function reset_field(field, resettext)
{
    if ( !field ) return;
    field.className = 'tagfield';
    if (resettext && field.value.indexOf(resettext) != -1) field.value = '';
}

// update tag properties - display with
// security counts.  right now, we have a
// JS array with everything in tags.bml.
// eventually, this needs to be some xml-rpc goodness,
// with JS caching on the results of rpc calls.
function show_props(div, id)
{
    var tag = tags[id];
    var out;

    if (! tag) tag = [ 'n/a', 'n/a', '-', '-', '-', '-', '-' ];

    var secimg = '&nbsp; <img align="middle" src="/img/';
    if (tag[1] == "public") {
        secimg = secimg + "userinfo.gif";
    }
    else if (tag[1] == "private") {
        secimg = secimg + "icon_private.gif";
    }
    else if (tag[1] == "friends") {
        secimg = secimg + "icon_protected.gif";
    }
    else {
        secimg = secimg + "icon_protected.gif";
    }
    secimg = secimg + '" />';
    if (tag[1] == "n/a") secimg = "";

    out = "<table class='proptbl' cellspacing='0'>";
    out = out + "<tr><td class='h' colspan='2'>counts and security</td></tr>";
    out = out + "<tr><td class='t'>public</td><td class='c'>" + tag[2] + "</td></tr>";
    out = out + "<tr><td class='t'>private</td><td class='c'>" + tag[3] + "</td></tr>";
    out = out + "<tr><td class='t'>friends</td><td class='c'>" + tag[4] + "</td></tr>";
    out = out + "<tr><td class='t'>custom groups</td><td class='c'>" + tag[5] + "</td></tr>";
    out = out + "<tr><td class='r'>total</td><td class='rv'>" + tag[6] + "</td></tr>";
    out = out + "<tr><td class='r' style='height: 16px'>security</td><td class='rv' align='middle'>" + tag[1] + secimg + "</td></tr>";
    out = out + "</table>";

    div.innerHTML = out;
    return;
}

// for edittags.bml
function edit_tagselect(list)
{

    //alert('aaaaaa');

    if (! list) return;

    var selected = new Array();  // tagnames, for display
    selected_num = 0;

    for ( $i = 0; $i < list.options.length; $i++ ) {
        if (list.options[$i].selected) {
            selected[selected_num] = list.options[$i].value;
            selected_num++;
        }
    }

    var form = document.getElementById("edit_tagform");
    if (! form) return;

    var tagfield = form.elements[ "tagfield" ];
    if (! tagfield ) return;

    // merge selected and current tags into new array
    var cur_tags = new Array();
    cur_tags = cur_taglist.split(", ");

    var taglist = new Array();

    for ( $i = 0; $i < selected.length; $i++ ) {
        var sel_tag = selected[$i];
        var seen = 0;
        for ( $j = 0; $j < cur_tags.length; $j++ ) {
            if (sel_tag == cur_tags[$j]) seen = 1;
        }
        if (seen == 0) taglist.push(sel_tag);
    }

    if (taglist.length) {
        if (cur_taglist.length > 0) {
            tagfield.value = cur_taglist + ", " + taglist.join(", ");
        } else {
            tagfield.value = taglist.join(", ");
        }
    } else {
        tagfield.value = cur_taglist;
    }

    return;
}