/**
 * @class Ext.layout.container.Table
 * @extends Ext.layout.container.Auto
 * 
This layout allows you to easily render content into an HTML table.  The total number of columns can be
 * specified, and rowspan and colspan can be used to create complex layouts within the table.
 * This class is intended to be extended or created via the layout: {type: 'table'}
 * {@link Ext.container.Container#layout} config, and should generally not need to be created directly via the new keyword.
 * 
Note that when creating a layout via config, the layout-specific config properties must be passed in via
 * the {@link Ext.container.Container#layout} object which will then be applied internally to the layout.  In the
 * case of TableLayout, the only valid layout config properties are {@link #columns} and {@link #tableAttrs}.
 * However, the items added to a TableLayout can supply the following table-specific config properties:
 * 

 * 
rowspan Applied to the table cell containing the item.
 * 
colspan Applied to the table cell containing the item.
 * 
cellId An id applied to the table cell containing the item.
 * 
cellCls A CSS class name added to the table cell containing the item.
 * 
 * 
The basic concept of building up a TableLayout is conceptually very similar to building up a standard
 * HTML table.  You simply add each panel (or "cell") that you want to include along with any span attributes
 * specified as the special config properties of rowspan and colspan which work exactly like their HTML counterparts.
 * Rather than explicitly creating and nesting rows and columns as you would in HTML, you simply specify the
 * total column count in the layoutConfig and start adding panels in their natural order from left to right,
 * top to bottom.  The layout will automatically figure out, based on the column count, rowspans and colspans,
 * how to position each panel within the table.  Just like with HTML tables, your rowspans and colspans must add
 * up correctly in your overall layout or you'll end up with missing and/or extra cells!  Example usage:
 * 

// This code will generate a layout table that is 3 columns by 2 rows
// with some spanning included.  The basic layout will be:
// +--------+-----------------+
// |   A    |   B             |
// |        |--------+--------|
// |        |   C    |   D    |
// +--------+--------+--------+
var table = new Ext.panel.Panel({
    title: 'Table Layout',
    layout: {
        type: 'table',
        // The total column count must be specified here
        columns: 3
    },
    defaults: {
        // applied to each contained panel
        bodyStyle:'padding:20px'
    },
    items: [{
        html: '<p>Cell A content</p>',
        rowspan: 2
    },{
        html: '<p>Cell B content</p>',
        colspan: 2
    },{
        html: '<p>Cell C content</p>',
        cellCls: 'highlight'
    },{
        html: '<p>Cell D content</p>'
    }]
});

 */

Ext.define('Ext.layout.container.Table', {

    /* Begin Definitions */

    alias: ['layout.table'],

    extend: 'Ext.layout.container.Auto',

    /* End Definitions */

    
/**
     * @cfg {Number} columns
     * The total number of columns to create in the table for this layout.  If not specified, all Components added to
     * this layout will be rendered into a single row using one column per Component.
     */

    // private
    monitorResize:false,

    type: 'table',

    targetCls: Ext.baseCSSPrefix + 'table-layout-ct',
    tableCls: Ext.baseCSSPrefix + 'table-layout',
    cellCls: Ext.baseCSSPrefix + 'table-layout-cell',

    
/**
     * @cfg {Object} tableAttrs
     * 
An object containing properties which are added to the {@link Ext.core.DomHelper DomHelper} specification
     * used to create the layout's <table> element. Example:

{
    xtype: 'panel',
    layout: {
        type: 'table',
        columns: 3,
        tableAttrs: {
            style: {
                width: '100%'
            }
        }
    }
}
     */
    tableAttrs:null,

    /**
     * @private
     * Iterates over all passed items, ensuring they are rendered in a cell in the proper
     * location in the table structure.
     */
    renderItems: function(items) {
        var tbody = this.getTable().tBodies[0],
            rows = tbody.rows,
            cells,
            curCell,
            rowIdx,
            cellIdx,
            item,
            trEl,
            tdEl,
            i = 0,
            len = items.length;

        // Calculate the correct cell structure for the current items
        cells = this.calculateCells(items);

        // Loop over each cell and compare to the current cells in the table, inserting/
        // removing/moving cells as needed, and making sure each item is rendered into
        // the correct cell.
        for (; i < len; i++) {
            curCell = cells[i];
            rowIdx = curCell.rowIdx;
            cellIdx = curCell.cellIdx;
            item = items[i];

            // If no row present, create and insert one
            trEl = rows[rowIdx];
            if (!trEl) {
                trEl = tbody.insertRow(rowIdx);
            }

            // If no cell present, create and insert one
            tdEl = trEl.cells[cellIdx];
            if (!tdEl) {
                tdEl = trEl.insertCell(cellIdx);
            }
            tdEl = Ext.get(tdEl);

            // Render or move the component into the cell
            if (!item.rendered) {
                this.renderItem(item, tdEl, 0);
            }
            else if (!this.isValidParent(item, tdEl, 0)) {
                this.moveItem(item, tdEl, 0);
            }

            // Set the cell properties
            tdEl.set({
                colSpan: item.colspan || 1,
                rowSpan: item.rowspan || 1,
                id: item.cellId || '',
                cls: this.cellCls + ' ' + (item.cellCls || '')
            });

            // If at the end of a row, remove any extra cells
            if (!cells[i + 1] || cells[i + 1].rowIdx !== rowIdx) {
                cellIdx++;
                while (trEl.cells[cellIdx]) {
                    trEl.deleteCell(cellIdx);
                }
            }
        }

        // Delete any extra rows
        rowIdx++;
        while (tbody.rows[rowIdx]) {
            tbody.deleteRow(rowIdx);
        }
    },



    /**
     * @private
     * Determine the row and cell indexes for each component, taking into consideration
     * the number of columns and each item's configured colspan/rowspan values.
     * @param {Array} items The layout components
     * @return {Array} List of row and cell indexes for each of the components
     */
    calculateCells: function(items) {
        var cells = [],
            rowIdx = 0,
            colIdx = 0,
            cellIdx = 0,
            totalCols = this.columns || Infinity,
            rowspans = [], //rolling list of active rowspans for each column
            i = 0, j,
            len = items.length,
            item;

        for (; i < len; i++) {
            item = items[i];

            // Find the first available row/col slot not taken up by a spanning cell
            while (colIdx >= totalCols || rowspans[colIdx] > 0) {
                if (colIdx >= totalCols) {
                    // move down to next row
                    colIdx = 0;
                    cellIdx = 0;
                    rowIdx++;

                    // decrement all rowspans
                    for (j = 0; j < totalCols; j++) {
                        if (rowspans[j] > 0) {
                            rowspans[j]--;
                        }
                    }
                } else {
                    colIdx++;
                }
            }

            // Add the cell info to the list
            cells.push({
                rowIdx: rowIdx,
                cellIdx: cellIdx
            });

            // Increment
            rowspans[colIdx] = item.rowspan || 1;
            colIdx += item.colspan || 1;
            cellIdx++;
        }

        return cells;
    },



    /**
     * @private
     * Return the layout's table element, creating it if necessary.
     */
    getTable: function() {
        var table = this.table;
        if (!table) {
            table = this.table = this.getTarget().createChild(
                Ext.apply({
                    tag: 'table',
                    role: 'presentation',
                    cls: this.tableCls,
                    cellspacing: 0, //TODO should this be specified or should CSS handle it?
                    cn: {tag: 'tbody'}
                }, this.tableAttrs),
                null, true
            );
        }
        return table;
    }

    
/**
     * @property activeItem
     * @hide
     */
});