<?php

/**
 * @package KantPHP
 * @author  Zhenqiang Zhang <zhenqiang.zhang@hotmail.com>
 * @copyright (c) KantPHP Studio, All rights reserved.
 * @license http://www.opensource.org/licenses/BSD-3-Clause  The BSD 3-Clause License
 */
namespace Kant\Grid;

use Kant\Kant;
use Closure;
use Kant\I18n\Formatter;
use Kant\Exception\InvalidConfigException;
use Kant\Helper\Url;
use Kant\Helper\Html;
use Kant\Helper\Json;
use Kant\Widget\BaseListView;
use Kant\Model\Model;

/**
 * The GridView widget is used to display data in a grid.
 *
 * It provides features like [[sorter|sorting]], [[pager|paging]] and also [[filterModel|filtering]] the data.
 *
 * A basic usage looks like the following:
 *
 * ```php
 * <?= GridView::widget([
 * 'dataProvider' => $dataProvider,
 * 'columns' => [
 * 'id',
 * 'name',
 * 'created_at:datetime',
 * // ...
 * ],
 * ]) ?>
 * ```
 *
 * The columns of the grid table are configured in terms of [[Column]] classes,
 * which are configured via [[columns]].
 *
 * The look and feel of a grid view can be customized using the large amount of properties.
 *
 * For more details and usage information on GridView, see the [guide article on data widgets](guide:output-data-widgets).
 *
 * @author Qiang Xue <qiang.xue@gmail.com>
 * @since 2.0
 */
class GridView extends BaseListView
{

    const FILTER_POS_HEADER = 'header';

    const FILTER_POS_FOOTER = 'footer';

    const FILTER_POS_BODY = 'body';

    /**
     *
     * @var string the default data column class if the class name is not explicitly specified when configuring a data column.
     *      Defaults to 'Kant\Grid\DataColumn'.
     */
    public $dataColumnClass;

    /**
     *
     * @var string the caption of the grid table
     * @see captionOptions
     */
    public $caption;

    /**
     *
     * @var array the HTML attributes for the caption element.
     * @see \Kant\Helper\Html::renderTagAttributes() for details on how attributes are being rendered.
     * @see caption
     */
    public $captionOptions = [];

    /**
     *
     * @var array the HTML attributes for the grid table element.
     * @see \Kant\Helper\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $tableOptions = [
        'class' => 'table table-striped table-bordered'
    ];

    /**
     *
     * @var array the HTML attributes for the container tag of the grid view.
     *      The "tag" element specifies the tag name of the container element and defaults to "div".
     * @see \Kant\Helper\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $options = [
        'class' => 'grid-view'
    ];

    /**
     *
     * @var array the HTML attributes for the table header row.
     * @see \Kant\Helper\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $headerRowOptions = [];

    /**
     *
     * @var array the HTML attributes for the table footer row.
     * @see \Kant\Helper\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $footerRowOptions = [];

    /**
     *
     * @var array|Closure the HTML attributes for the table body rows. This can be either an array
     *      specifying the common HTML attributes for all body rows, or an anonymous function that
     *      returns an array of the HTML attributes. The anonymous function will be called once for every
     *      data model returned by [[dataProvider]]. It should have the following signature:
     *     
     *      ```php
     *      function ($model, $key, $index, $grid)
     *      ```
     *     
     *      - `$model`: the current data model being rendered
     *      - `$key`: the key value associated with the current data model
     *      - `$index`: the zero-based index of the data model in the model array returned by [[dataProvider]]
     *      - `$grid`: the GridView object
     *     
     * @see \Kant\Helper\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $rowOptions = [];

    /**
     *
     * @var Closure an anonymous function that is called once BEFORE rendering each data model.
     *      It should have the similar signature as [[rowOptions]]. The return result of the function
     *      will be rendered directly.
     */
    public $beforeRow;

    /**
     *
     * @var Closure an anonymous function that is called once AFTER rendering each data model.
     *      It should have the similar signature as [[rowOptions]]. The return result of the function
     *      will be rendered directly.
     */
    public $afterRow;

    /**
     *
     * @var bool whether to show the header section of the grid table.
     */
    public $showHeader = true;

    /**
     *
     * @var bool whether to show the footer section of the grid table.
     */
    public $showFooter = false;

    /**
     *
     * @var bool whether to show the grid view if [[dataProvider]] returns no data.
     */
    public $showOnEmpty = true;

    /**
     *
     * @var array|Formatter the formatter used to format model attribute values into displayable texts.
     *      This can be either an instance of [[Formatter]] or an configuration array for creating the [[Formatter]]
     *      instance. If this property is not set, the "formatter" application component will be used.
     */
    public $formatter;

    /**
     *
     * @var array grid column configuration. Each array element represents the configuration
     *      for one particular grid column. For example,
     *     
     *      ```php
     *      [
     *      ['class' => SerialColumn::className()],
     *      [
     *      'class' => DataColumn::className(), // this line is optional
     *      'attribute' => 'name',
     *      'format' => 'text',
     *      'label' => 'Name',
     *      ],
     *      ['class' => CheckboxColumn::className()],
     *      ]
     *      ```
     *     
     *      If a column is of class [[DataColumn]], the "class" element can be omitted.
     *     
     *      As a shortcut format, a string may be used to specify the configuration of a data column
     *      which only contains [[DataColumn::attribute|attribute]], [[DataColumn::format|format]],
     *      and/or [[DataColumn::label|label]] options: `"attribute:format:label"`.
     *      For example, the above "name" column can also be specified as: `"name:text:Name"`.
     *      Both "format" and "label" are optional. They will take default values if absent.
     *     
     *      Using the shortcut format the configuration for columns in simple cases would look like this:
     *     
     *      ```php
     *      [
     *      'id',
     *      'amount:currency:Total Amount',
     *      'created_at:datetime',
     *      ]
     *      ```
     *     
     *      When using a [[dataProvider]] with active records, you can also display values from related records,
     *      e.g. the `name` attribute of the `author` relation:
     *     
     *      ```php
     *      // shortcut syntax
     *      'author.name',
     *      // full syntax
     *      [
     *      'attribute' => 'author.name',
     *      // ...
     *      ]
     *      ```
     */
    public $columns = [];

    /**
     *
     * @var string the HTML display when the content of a cell is empty.
     *      This property is used to render cells that have no defined content,
     *      e.g. empty footer or filter cells.
     *     
     *      Note that this is not used by the [[DataColumn]] if a data item is `null`. In that case
     *      the [[\Kant\I18n\Formatter::nullDisplay|nullDisplay]] property of the [[formatter]] will
     *      be used to indicate an empty data value.
     */
    public $emptyCell = '&nbsp;';

    /**
     *
     * @var \Kant\Model\Model the model that keeps the user-entered filter data. When this property is set,
     *      the grid view will enable column-based filtering. Each data column by default will display a text field
     *      at the top that users can fill in to filter the data.
     *     
     *      Note that in order to show an input field for filtering, a column must have its [[DataColumn::attribute]]
     *      property set and the attribute should be active in the current scenario of $filterModel or have
     *      [[DataColumn::filter]] set as the HTML code for the input field.
     *     
     *      When this property is not set (null) the filtering feature is disabled.
     */
    public $filterModel;

    /**
     *
     * @var string|array the URL for returning the filtering result. [[Url::to()]] will be called to
     *      normalize the URL. If not set, the current controller action will be used.
     *      When the user makes change to any filter input, the current filtering inputs will be appended
     *      as GET parameters to this URL.
     */
    public $filterUrl;

    /**
     *
     * @var string additional jQuery selector for selecting filter input fields
     */
    public $filterSelector;

    /**
     *
     * @var string whether the filters should be displayed in the grid view. Valid values include:
     *     
     *      - [[FILTER_POS_HEADER]]: the filters will be displayed on top of each column's header cell.
     *      - [[FILTER_POS_BODY]]: the filters will be displayed right below each column's header cell.
     *      - [[FILTER_POS_FOOTER]]: the filters will be displayed below each column's footer cell.
     */
    public $filterPosition = self::FILTER_POS_BODY;

    /**
     *
     * @var array the HTML attributes for the filter row element.
     * @see \Kant\Helper\Html::renderTagAttributes() for details on how attributes are being rendered.
     */
    public $filterRowOptions = [
        'class' => 'filters'
    ];

    /**
     *
     * @var array the options for rendering the filter error summary.
     *      Please refer to [[Html::errorSummary()]] for more details about how to specify the options.
     * @see renderErrors()
     */
    public $filterErrorSummaryOptions = [
        'class' => 'error-summary'
    ];

    /**
     *
     * @var array the options for rendering every filter error message.
     *      This is mainly used by [[Html::error()]] when rendering an error message next to every filter input field.
     */
    public $filterErrorOptions = [
        'class' => 'help-block'
    ];

    /**
     *
     * @var string the layout that determines how different sections of the list view should be organized.
     *      The following tokens will be replaced with the corresponding section contents:
     *     
     *      - `{summary}`: the summary section. See [[renderSummary()]].
     *      - `{errors}`: the filter model error summary. See [[renderErrors()]].
     *      - `{items}`: the list items. See [[renderItems()]].
     *      - `{sorter}`: the sorter. See [[renderSorter()]].
     *      - `{pager}`: the pager. See [[renderPager()]].
     */
    public $layout = "{summary}\n{items}\n{pager}";

    /**
     * Initializes the grid view.
     * This method will initialize required property values and instantiate [[columns]] objects.
     */
    public function init()
    {
        parent::init();
        if ($this->formatter === null) {
            $this->formatter = Kant::$app->getFormatter();
        } elseif (is_array($this->formatter)) {
            $this->formatter = Kant::createObject($this->formatter);
        }
        if (!$this->formatter instanceof Formatter) {
            throw new InvalidConfigException('The "formatter" property must be either a Format object or a configuration array.');
        }
        if (!isset($this->filterRowOptions['id'])) {
            $this->filterRowOptions['id'] = $this->options['id'] . '-filters';
        }
        
        $this->initColumns();
    }

    /**
     * Runs the widget.
     */
    public function run()
    {
        $id = $this->options['id'];
        $options = Json::htmlEncode($this->getClientOptions());
        $view = $this->getView();
        GridViewAsset::register($view);
        $view->registerJs("jQuery('#$id').kantGridView($options);");
        parent::run();
    }

    /**
     * Renders validator errors of filter model.
     * 
     * @return string the rendering result.
     */
    public function renderErrors()
    {
        if ($this->filterModel instanceof Model && $this->filterModel->hasErrors()) {
            return Html::errorSummary($this->filterModel, $this->filterErrorSummaryOptions);
        } else {
            return '';
        }
    }

    /**
     * @inheritdoc
     */
    public function renderSection($name)
    {
        switch ($name) {
            case '{errors}':
                return $this->renderErrors();
            default:
                return parent::renderSection($name);
        }
    }

    /**
     * Returns the options for the grid view JS widget.
     * 
     * @return array the options
     */
    protected function getClientOptions()
    {
        $filterUrl = isset($this->filterUrl) ? $this->filterUrl : Kant::$app->request->fullUrl();
        $id = $this->filterRowOptions['id'];
        $filterSelector = "#$id input, #$id select";
        if (isset($this->filterSelector)) {
            $filterSelector .= ', ' . $this->filterSelector;
        }
        
        return [
            'filterUrl' => Url::to($filterUrl),
            'filterSelector' => $filterSelector
        ];
    }

    /**
     * Renders the data models for the grid view.
     */
    public function renderItems()
    {
        $caption = $this->renderCaption();
        $columnGroup = $this->renderColumnGroup();
        $tableHeader = $this->showHeader ? $this->renderTableHeader() : false;
        $tableBody = $this->renderTableBody();
        $tableFooter = $this->showFooter ? $this->renderTableFooter() : false;
        $content = array_filter([
            $caption,
            $columnGroup,
            $tableHeader,
            $tableFooter,
            $tableBody
        ]);
        
        return Html::tag('table', implode("\n", $content), $this->tableOptions);
    }

    /**
     * Renders the caption element.
     * 
     * @return bool|string the rendered caption element or `false` if no caption element should be rendered.
     */
    public function renderCaption()
    {
        if (!empty($this->caption)) {
            return Html::tag('caption', $this->caption, $this->captionOptions);
        } else {
            return false;
        }
    }

    /**
     * Renders the column group HTML.
     * 
     * @return bool|string the column group HTML or `false` if no column group should be rendered.
     */
    public function renderColumnGroup()
    {
        $requireColumnGroup = false;
        foreach ($this->columns as $column) {
            /* @var $column Column */
            if (!empty($column->options)) {
                $requireColumnGroup = true;
                break;
            }
        }
        if ($requireColumnGroup) {
            $cols = [];
            foreach ($this->columns as $column) {
                $cols[] = Html::tag('col', '', $column->options);
            }
            
            return Html::tag('colgroup', implode("\n", $cols));
        } else {
            return false;
        }
    }

    /**
     * Renders the table header.
     * 
     * @return string the rendering result.
     */
    public function renderTableHeader()
    {
        $cells = [];
        foreach ($this->columns as $column) {
            /* @var $column Column */
            $cells[] = $column->renderHeaderCell();
        }
        $content = Html::tag('tr', implode('', $cells), $this->headerRowOptions);
        if ($this->filterPosition === self::FILTER_POS_HEADER) {
            $content = $this->renderFilters() . $content;
        } elseif ($this->filterPosition === self::FILTER_POS_BODY) {
            $content .= $this->renderFilters();
        }
        
        return "<thead>\n" . $content . "\n</thead>";
    }

    /**
     * Renders the table footer.
     * 
     * @return string the rendering result.
     */
    public function renderTableFooter()
    {
        $cells = [];
        foreach ($this->columns as $column) {
            /* @var $column Column */
            $cells[] = $column->renderFooterCell();
        }
        $content = Html::tag('tr', implode('', $cells), $this->footerRowOptions);
        if ($this->filterPosition === self::FILTER_POS_FOOTER) {
            $content .= $this->renderFilters();
        }
        
        return "<tfoot>\n" . $content . "\n</tfoot>";
    }

    /**
     * Renders the filter.
     * 
     * @return string the rendering result.
     */
    public function renderFilters()
    {
        if ($this->filterModel !== null) {
            $cells = [];
            foreach ($this->columns as $column) {
                /* @var $column Column */
                $cells[] = $column->renderFilterCell();
            }
            
            return Html::tag('tr', implode('', $cells), $this->filterRowOptions);
        } else {
            return '';
        }
    }

    /**
     * Renders the table body.
     * 
     * @return string the rendering result.
     */
    public function renderTableBody()
    {
        $models = array_values($this->dataProvider->getModels());
        $keys = $this->dataProvider->getKeys();
        $rows = [];
        foreach ($models as $index => $model) {
            $key = $keys[$index];
            if ($this->beforeRow !== null) {
                $row = call_user_func($this->beforeRow, $model, $key, $index, $this);
                if (!empty($row)) {
                    $rows[] = $row;
                }
            }
            
            $rows[] = $this->renderTableRow($model, $key, $index);
            
            if ($this->afterRow !== null) {
                $row = call_user_func($this->afterRow, $model, $key, $index, $this);
                if (!empty($row)) {
                    $rows[] = $row;
                }
            }
        }
        
        if (empty($rows)) {
            $colspan = count($this->columns);
            
            return "<tbody>\n<tr><td colspan=\"$colspan\">" . $this->renderEmpty() . "</td></tr>\n</tbody>";
        } else {
            return "<tbody>\n" . implode("\n", $rows) . "\n</tbody>";
        }
    }

    /**
     * Renders a table row with the given data model and key.
     * 
     * @param mixed $model
     *            the data model to be rendered
     * @param mixed $key
     *            the key associated with the data model
     * @param int $index
     *            the zero-based index of the data model among the model array returned by [[dataProvider]].
     * @return string the rendering result
     */
    public function renderTableRow($model, $key, $index)
    {
        $cells = [];
        /* @var $column Column */
        foreach ($this->columns as $column) {
            $cells[] = $column->renderDataCell($model, $key, $index);
        }
        if ($this->rowOptions instanceof Closure) {
            $options = call_user_func($this->rowOptions, $model, $key, $index, $this);
        } else {
            $options = $this->rowOptions;
        }
        $options['data-key'] = is_array($key) ? json_encode($key) : (string) $key;
        
        return Html::tag('tr', implode('', $cells), $options);
    }

    /**
     * Creates column objects and initializes them.
     */
    protected function initColumns()
    {
        if (empty($this->columns)) {
            $this->guessColumns();
        }
        foreach ($this->columns as $i => $column) {
            if (is_string($column)) {
                $column = $this->createDataColumn($column);
            } else {
                $column = Kant::createObject(array_merge([
                    'class' => $this->dataColumnClass ?  : DataColumn::className(),
                    'grid' => $this
                ], $column));
            }
            if (!$column->visible) {
                unset($this->columns[$i]);
                continue;
            }
            $this->columns[$i] = $column;
        }
    }

    /**
     * Creates a [[DataColumn]] object based on a string in the format of "attribute:format:label".
     * 
     * @param string $text
     *            the column specification string
     * @return DataColumn the column instance
     * @throws InvalidConfigException if the column specification is invalid
     */
    protected function createDataColumn($text)
    {
        if (!preg_match('/^([^:]+)(:(\w*))?(:(.*))?$/', $text, $matches)) {
            throw new InvalidConfigException('The column must be specified in the format of "attribute", "attribute:format" or "attribute:format:label"');
        }
        
        return Kant::createObject([
            'class' => $this->dataColumnClass ?  : DataColumn::className(),
            'grid' => $this,
            'attribute' => $matches[1],
            'format' => isset($matches[3]) ? $matches[3] : 'text',
            'label' => isset($matches[5]) ? $matches[5] : null
        ]);
    }

    /**
     * This function tries to guess the columns to show from the given data
     * if [[columns]] are not explicitly specified.
     */
    protected function guessColumns()
    {
        $models = $this->dataProvider->getModels();
        $model = reset($models);
        if (is_array($model) || is_object($model)) {
            foreach ($model as $name => $value) {
                if ($value === null || is_scalar($value) || is_callable([
                    $value,
                    '__toString'
                ])) {
                    $this->columns[] = (string) $name;
                }
            }
        }
    }
}
