<?php

namespace Elastica\Facet;

use Elastica\Exception\InvalidException;

/**
 * Implements the statistical facet on a per term basis.
 *
 * @category Xodoa
 * @package Elastica
 * @author Tom Michaelis <tom.michaelis@gmail.com>
 * @link http://www.elasticsearch.org/guide/reference/api/search/facets/terms-stats-facet.html
 */
class TermsStats extends AbstractFacet
{

    /**
     * Holds the types of ordering which are allowed
     * by Elasticsearch.
     *
     * @var array
     */
    protected $_orderTypes = array('term', 'reverse_term', 'count', 'reverse_count',
        'total', 'reverse_total', 'min', 'reverse_min', 'max', 'reverse_max', 'mean',
        'reverse_mean');

    /**
     * Sets the key field for the query.
     *
     * @param  string                         $keyField The key field name for the query.
     * @return \Elastica\Facet\TermsStats
     */
    public function setKeyField( $keyField )
    {
        return $this->setParam( 'key_field', $keyField );
    }

    /**
     * Sets a script to calculate statistical information on a per term basis
     *
     * @param  string                         $valueScript The script to do calculations on the statistical values
     * @return \Elastica\Facet\TermsStats
     */
    public function setValueScript( $valueScript )
    {
        return $this->setParam( 'value_script', $valueScript );
    }

    /**
     * Sets the ordering type for this facet. Elasticsearch
     * internal default is count.
     *
     * @param  string                              $type The order type to set use for sorting of the terms.
     * @throws \Elastica\Exception\InvalidException When an invalid order type was set.
     * @return \Elastica\Facet\TermsStats
     */
    public function setOrder($type)
    {
        if (!in_array($type, $this->_orderTypes)) {
            throw new InvalidException('Invalid order type: ' . $type);
        }

        return $this->setParam('order', $type);
    }

    /**
     * Sets a field to compute basic statistical results on
     *
     * @param  string                         $valueField The field to compute statistical values for
     * @return \Elastica\Facet\TermsStats
     */
    public function setValueField( $valueField )
    {
        return $this->setParam( 'value_field', $valueField );
    }

    /**
     * Sets the amount of terms to be returned.
     *
     * @param  int                            $size The amount of terms to be returned.
     * @return \Elastica\Facet\Terms
     */
    public function setSize($size)
    {
        return $this->setParam('size', (int) $size);
    }

    /**
     * Creates the full facet definition, which includes the basic
     * facet definition of the parent.
     *
     * @see \Elastica\Facet\AbstractFacet::toArray()
     * @return array
     */
    public function toArray()
    {
        $this->_setFacetParam( 'terms_stats', $this->_params );

        return parent::toArray();
    }

}