/**
 * Very simple and fast tree grid/table, compatible with dynamic loading and jQuery fixedHeaderTable
 * License: MPL 2.0+, (c) Vitaliy Filippov 2016
 */

/**
 * USAGE:
 *
 * var TG = new TreeGrid(items, header);
 * document.body.appendChild(TG.table);
 *
 * items: [ node={
 *   cells: [ 'html' or { innerHTML, style, className, title }, ... ],
 *   children: [ node... ],
 *   leaf: true/false,
 *   collapsed: true/false
 * }, ... ]
 *
 * header: [ 'html' or { innerHTML, style, className, title }, ... ]
 */
function TreeGrid(items, header)
{
    this.bindProps = { 'style': 1, 'className': 1, 'title': 1, 'innerHTML': 1 };
    this.levelIndent = 20;
    this.table = document.createElement('table');
    this.table.className = 'grid';
    this.thead = document.createElement('thead');
    this.tbody = document.createElement('tbody');
    this.table.appendChild(this.thead);
    this.table.appendChild(this.tbody);
    this.thead.appendChild(document.createElement('tr'));
    this.setHeader(header);
    new TreeGridNode({ children: items }, this);
}

TreeGrid.prototype.setHeader = function(newHeader)
{
    var tr = this.thead.rows[0];
    tr.innerHTML = '';
    for (var i = 0; i < newHeader.length; i++)
    {
        var th = document.createElement('th');
        this._setProps(th, newHeader[i]);
        tr.appendChild(th);
    }
    this.header = newHeader;
    // header change clears the whole grid by now
    if (this.root)
        this.root.setChildren([]);
}

TreeGrid.prototype.onExpand = function(node)
{
    // handle node expand/collapse here
    return true;
}

TreeGrid.prototype._setProps = function(el, props)
{
    if (typeof props == 'string')
        el.innerHTML = props;
    else
        for (var j in this.bindProps)
            if (props[j])
                el[j] = props[j];
}

function TreeGridNode(node, grid, level, insertBefore, startHidden)
{
    this.grid = grid;
    this.level = level;
    if (this.level === undefined)
        this.level = -1;
    if (!grid.root)
        grid.root = this;
    else
    {
        this.leaf = node.leaf;
        this.collapsed = node.collapsed || !node.leaf && (!node.children || !node.children.length);
        this.cells = node.cells || [];
        this.tr = document.createElement('tr');
        if (startHidden)
            this.tr.style.display = 'none';
        this.tr._level = this.level;
        for (var i = 0; i < this.grid.header.length; i++)
        {
            var td = document.createElement('td');
            if (this.cells[i])
                grid._setProps(td, this.cells[i]);
            this.tr.appendChild(td);
        }
        var collapser = document.createElement('div');
        if (this.leaf)
            collapser.className = 'collapser collapser-inactive';
        else
        {
            collapser.className = this.collapsed ? 'collapser collapser-collapsed' : 'collapser collapser-expanded';
            var self = this;
            addListener(collapser, 'click', function(e) { self._toggleHandler(); });
        }
        var c0 = this.tr.cells[0];
        c0.childNodes.length ? c0.insertBefore(collapser, c0.firstChild) : c0.appendChild(collapser);
        if (grid._initialPadding === undefined)
        {
            var p0 = curStyle(c0).paddingLeft || '';
            if (p0.substr(p0.length-2) == 'px')
                p0 = parseInt(p0.substr(0, p0.length-2));
            else
                p0 = 0;
            grid._initialPadding = p0;
        }
        c0.style.paddingLeft = (grid._initialPadding + grid.levelIndent * level) + 'px';
        insertBefore ? grid.tbody.insertBefore(this.tr, insertBefore) : grid.tbody.appendChild(this.tr);
    }
    this.children = [];
    if (node.children)
        for (var i = 0; i < node.children.length; i++)
            this.children.push(new TreeGridNode(node.children[i], grid, this.level+1, insertBefore, this.collapsed));
}

TreeGridNode.prototype._toggleHandler = function()
{
    if (!this.grid.onExpand(this))
        return;
    this.toggle();
}

TreeGridNode.prototype.toggle = function()
{
    if (this.leaf)
        return;
    this.collapsed = !this.collapsed;
    this.tr.cells[0].firstChild.className = this.collapsed ? 'collapser collapser-collapsed' : 'collapser collapser-expanded';
    if (this.collapsed)
    {
        // collapse all children
        var c = this.tr.nextSibling;
        while (c && c._level > this.level)
        {
            c.style.display = 'none';
            c = c.nextSibling;
        }
    }
    else
    {
        // expand all children except children of collapsed subnodes
        var st = this.children.concat([]);
        while (st.length)
        {
            var e = st.pop();
            e.tr.style.display = '';
            if (!e.collapsed)
                st = st.concat(e.children);
        }
    }
}

TreeGridNode.prototype.setChildren = function(isLeaf, newChildren)
{
    if (!this.tr)
        this.grid.tbody.innerHTML = '';
    else
        while (this.tr.nextSibling && this.tr.nextSibling._level > this.level)
            this.grid.tbody.removeChild(this.tr.nextSibling);
    this.leaf = isLeaf;
    if (this.leaf)
        this.tr.cells[0].firstChild.className = 'collapser collapser-inactive';
    else
        this.tr.cells[0].firstChild.className = this.collapsed ? 'collapser collapser-collapsed' : 'collapser collapser-expanded';
    this.children = [];
    var insertBefore = this.tr && this.tr.nextSibling;
    for (var i = 0; i < newChildren.length; i++)
        this.children.push(new TreeGridNode(newChildren[i], this.grid, this.level+1, insertBefore, this.collapsed));
}