YUI.add('datatable-head', function (Y, NAME) {

/**

View class responsible for rendering the `<thead>` section of a table. Used as

the default `headerView` for `Y.DataTable.Base` and `Y.DataTable` classes.

@module datatable

@submodule datatable-head

@since 3.5.0

**/

var Lang = Y.Lang,

    fromTemplate = Lang.sub,

    isArray = Lang.isArray,

    toArray = Y.Array;

/**

View class responsible for rendering the `<thead>` section of a table. Used as

the default `headerView` for `Y.DataTable.Base` and `Y.DataTable` classes.

Translates the provided array of column configuration objects into a rendered

`<thead>` based on the data in those objects.

The structure of the column data is expected to be a single array of objects,

where each object corresponds to a `<th>`.  Those objects may contain a

`children` property containing a similarly structured array to indicate the

nested cells should be grouped under the parent column's colspan in a separate

row of header cells. E.g.

<pre><code>

new Y.DataTable.HeaderView({

  container: tableNode,

  columns: [

    { key: 'id' }, // no nesting

    { key: 'name', children: [

      { key: 'firstName', label: 'First' },

      { key: 'lastName',  label: 'Last' } ] }

  ]

}).render();

</code></pre>

This would translate to the following visualization:

<pre>

---------------------

|    |     name     |

|    |---------------

| id | First | Last |

---------------------

</pre>

Supported properties of the column objects include:

  * `label`     - The HTML content of the header cell.

  * `key`       - If `label` is not specified, the `key` is used for content.

  * `children`  - Array of columns to appear below this column in the next

                  row.

  * `headerTemplate` - Overrides the instance's `CELL_TEMPLATE` for cells in this

    column only.

  * `abbr`      - The content of the 'abbr' attribute of the `<th>`

  * `title`     - The content of the 'title' attribute of the `<th>`

  * `className` - Adds this string of CSS classes to the column header

Through the life of instantiation and rendering, the column objects will have

the following properties added to them:

  * `id`       - (Defaulted by DataTable) The id to assign the rendered column

  * `_colspan` - To supply the `<th>` attribute

  * `_rowspan` - To supply the `<th>` attribute

  * `_parent`  - (Added by DataTable) If the column is a child of another

    column, this points to its parent column

The column object is also used to provide values for {placeholder} tokens in the

instance's `CELL_TEMPLATE`, so you can modify the template and include other

column object properties to populate them.

@class HeaderView

@namespace DataTable

@extends View

@since 3.5.0

**/

Y.namespace('DataTable').HeaderView = Y.Base.create('tableHeader', Y.View, [], {

    // -- Instance properties -------------------------------------------------

    /**

    Template used to create the table's header cell markup.  Override this to

    customize how header cell markup is created.

    @property CELL_TEMPLATE

    @type {String}

    @default '<th id="{id}" colspan="{_colspan}" rowspan="{_rowspan}" class="{className}" scope="col" {_id}{abbr}{title}>{content}</th>'

    @since 3.5.0

    **/

    CELL_TEMPLATE:

        '<th id="{id}" colspan="{_colspan}" rowspan="{_rowspan}" class="{className}" scope="col" {_id}{abbr}{title}>{content}</th>',

    /**

    The data representation of the header rows to render.  This is assigned by

    parsing the `columns` configuration array, and is used by the render()

    method.

    @property columns

    @type {Array[]}

    @default (initially unset)

    @since 3.5.0

    **/

    //TODO: should this be protected?

    //columns: null,

    /**

    Template used to create the table's header row markup.  Override this to

    customize the row markup.

    @property ROW_TEMPLATE

    @type {String}

    @default '<tr>{content}</tr>'

    @since 3.5.0

    **/

    ROW_TEMPLATE:

        '<tr>{content}</tr>',

    /**

    The object that serves as the source of truth for column and row data.

    This property is assigned at instantiation from the `source` property of

    the configuration object passed to the constructor.

    @property source

    @type {Object}

    @default (initially unset)

    @since 3.5.0

    **/

    //TODO: should this be protected?

    //source: null,

    /**

    HTML templates used to create the `<thead>` containing the table headers.

    @property THEAD_TEMPLATE

    @type {String}

    @default '<thead class="{className}">{content}</thead>'

    @since 3.6.0

    **/

    THEAD_TEMPLATE: '<thead class="{className}"></thead>',

    // -- Public methods ------------------------------------------------------

    /**

    Returns the generated CSS classname based on the input.  If the `host`

    attribute is configured, it will attempt to relay to its `getClassName`

    or use its static `NAME` property as a string base.

    If `host` is absent or has neither method nor `NAME`, a CSS classname

    will be generated using this class's `NAME`.

    @method getClassName

    @param {String} token* Any number of token strings to assemble the

        classname from.

    @return {String}

    @protected

    **/

    getClassName: function () {

        // TODO: add attribute with setter? to host to use property this.host

        // for performance

        var host = this.host,

            NAME = (host && host.constructor.NAME) ||

                    this.constructor.NAME;

        if (host && host.getClassName) {

            return host.getClassName.apply(host, arguments);

        } else {

            return Y.ClassNameManager.getClassName

                .apply(Y.ClassNameManager,

                       [NAME].concat(toArray(arguments, 0, true)));

        }

    },

    /**

    Creates the `<thead>` Node content by assembling markup generated by

    populating the `ROW_TEMPLATE` and `CELL_TEMPLATE` templates with content

    from the `columns` property.

    @method render

    @chainable

    @since 3.5.0

    **/

    render: function () {

        var table    = this.get('container'),

            thead    = this.theadNode ||

                        (this.theadNode = this._createTHeadNode()),

            columns  = this.columns,

            defaults = {

                _colspan: 1,

                _rowspan: 1,

                abbr: '',

                title: ''

            },

            i, len, j, jlen, col, html, content, values;

        if (thead && columns) {

            html = '';

            if (columns.length) {

                for (i = 0, len = columns.length; i < len; ++i) {

                    content = '';

                    for (j = 0, jlen = columns[i].length; j < jlen; ++j) {

                        col = columns[i][j];

                        values = Y.merge(

                            defaults,

                            col, {

                                className: this.getClassName('header'),

                                content  : col.label || col.key ||

                                           ("Column " + (j + 1))

                            }

                        );

                        values._id = col._id ?

                            ' data-yui3-col-id="' + col._id + '"' : '';

                        if (col.abbr) {

                            values.abbr = ' abbr="' + col.abbr + '"';

                        }

                        if (col.title) {

                            values.title = ' title="' + col.title + '"';

                        }

                        if (col.className) {

                            values.className += ' ' + col.className;

                        }

                        if (col._first) {

                            values.className += ' ' + this.getClassName('first', 'header');

                        }

                        if (col._id) {

                            values.className +=

                                ' ' + this.getClassName('col', col._id);

                        }

                        content += fromTemplate(

                            col.headerTemplate || this.CELL_TEMPLATE, values);

                    }

                    html += fromTemplate(this.ROW_TEMPLATE, {

                        content: content

                    });

                }

            }

            thead.setHTML(html);

            if (thead.get('parentNode') !== table) {

                table.insertBefore(thead, table.one('tfoot, tbody'));

            }

        }

        this.bindUI();

        return this;

    },

    // -- Protected and private properties and methods ------------------------

    /**

    Handles changes in the source's columns attribute.  Redraws the headers.

    @method _afterColumnsChange

    @param {EventFacade} e The `columnsChange` event object

    @protected

    @since 3.5.0

    **/

    _afterColumnsChange: function (e) {

        this.columns = this._parseColumns(e.newVal);

        this.render();

    },

    /**

    Binds event subscriptions from the UI and the source (if assigned).

    @method bindUI

    @protected

    @since 3.5.0

    **/

    bindUI: function () {

        if (!this._eventHandles.columnsChange) {

            // TODO: How best to decouple this?

            this._eventHandles.columnsChange =

                this.after('columnsChange',

                    Y.bind('_afterColumnsChange', this));

        }

    },

    /**

    Creates the `<thead>` node that will store the header rows and cells.

    @method _createTHeadNode

    @return {Node}

    @protected

    @since 3.6.0

    **/

    _createTHeadNode: function () {

        return Y.Node.create(fromTemplate(this.THEAD_TEMPLATE, {

            className: this.getClassName('columns')

        }));

    },

    /**

    Destroys the instance.

    @method destructor

    @protected

    @since 3.5.0

    **/

    destructor: function () {

        (new Y.EventHandle(Y.Object.values(this._eventHandles))).detach();

    },

    /**

    Holds the event subscriptions needing to be detached when the instance is

    `destroy()`ed.

    @property _eventHandles

    @type {Object}

    @default undefined (initially unset)

    @protected

    @since 3.5.0

    **/

    //_eventHandles: null,

    /**

    Initializes the instance. Reads the following configuration properties:

      * `columns` - (REQUIRED) The initial column information

      * `host`    - The object to serve as source of truth for column info

    @method initializer

    @param {Object} config Configuration data

    @protected

    @since 3.5.0

    **/

    initializer: function (config) {

        this.host  = config.host;

        this.columns = this._parseColumns(config.columns);

        this._eventHandles = [];

    },

    /**

    Translate the input column format into a structure useful for rendering a

    `<thead>`, rows, and cells.  The structure of the input is expected to be a

    single array of objects, where each object corresponds to a `<th>`.  Those

    objects may contain a `children` property containing a similarly structured

    array to indicate the nested cells should be grouped under the parent

    column's colspan in a separate row of header cells. E.g.

    <pre><code>

    [

      { key: 'id' }, // no nesting

      { key: 'name', children: [

        { key: 'firstName', label: 'First' },

        { key: 'lastName',  label: 'Last' } ] }

    ]

    </code></pre>

    would indicate two header rows with the first column 'id' being assigned a

    `rowspan` of `2`, the 'name' column appearing in the first row with a

    `colspan` of `2`, and the 'firstName' and 'lastName' columns appearing in

    the second row, below the 'name' column.

    <pre>

    ---------------------

    |    |     name     |

    |    |---------------

    | id | First | Last |

    ---------------------

    </pre>

    Supported properties of the column objects include:

      * `label`    - The HTML content of the header cell.

      * `key`      - If `label` is not specified, the `key` is used for content.

      * `children` - Array of columns to appear below this column in the next

                     row.

      * `abbr`     - The content of the 'abbr' attribute of the `<th>`

      * `title`    - The content of the 'title' attribute of the `<th>`

      * `headerTemplate` - Overrides the instance's `CELL_TEMPLATE` for cells

        in this column only.

    The output structure is basically a simulation of the `<thead>` structure

    with arrays for rows and objects for cells.  Column objects have the

    following properties added to them:

      * `id`       - (Defaulted by DataTable) The id to assign the rendered

                     column

      * `_colspan` - Per the `<th>` attribute

      * `_rowspan` - Per the `<th>` attribute

      * `_parent`  - (Added by DataTable) If the column is a child of another

        column, this points to its parent column

    The column object is also used to provide values for {placeholder}

    replacement in the `CELL_TEMPLATE`, so you can modify the template and

    include other column object properties to populate them.

    @method _parseColumns

    @param {Object[]} data Array of column object data

    @return {Array[]} An array of arrays corresponding to the header row

            structure to render

    @protected

    @since 3.5.0

    **/

    _parseColumns: function (data) {

        var columns = [],

            stack = [],

            rowSpan = 1,

            entry, row, col, children, parent, i, len, j;

        if (isArray(data) && data.length) {

            // don't modify the input array

            data = data.slice();

            // First pass, assign colspans and calculate row count for

            // non-nested headers' rowspan

            stack.push([data, -1]);

            while (stack.length) {

                entry = stack[stack.length - 1];

                row   = entry[0];

                i     = entry[1] + 1;

                for (len = row.length; i < len; ++i) {

                    row[i] = col = Y.merge(row[i]);

                    children = col.children;