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<?php
/**
* Piwik - Open source web analytics
*
* @link http://piwik.org
* @license http://www.gnu.org/licenses/gpl-3.0.html GPL v3 or later
*
* @category Piwik
* @package Piwik
*/
namespace Piwik\DataTable\Filter;
use Piwik\DataTable;
use Piwik\DataTable\Row;
use Piwik\Site;
use Piwik\DataTable\Filter\ColumnCallbackAddColumnPercentage;
/**
* A DataTable filter that calculates the evolution of a metric and adds
* it to each row as a percentage.
*
* This filter cannot be used as a normal filter since it requires
* corresponding data from another datatable. Instead, to use it,
* you must manually perform a binary filter (see the MultiSites API).
*
* The evolution metric is calculated as:
* <code>((currentValue - pastValue) / pastValue) * 100</code>
*/
class CalculateEvolutionFilter extends ColumnCallbackAddColumnPercentage
{
/**
* The the DataTable that contains past data.
*/
private $pastDataTable;
/**
* Tells if column being added is the revenue evolution column.
*/
private $isRevenueEvolution = null;
/**
* Constructor.
*
* @param DataTable $table The DataTable being filtered.
* @param string $pastDataTable
* @param string $columnToAdd
* @param string $columnToRead
* @param int $quotientPrecision
*/
function __construct($table, $pastDataTable, $columnToAdd, $columnToRead, $quotientPrecision = 0)
{
parent::__construct(
$table, $columnToAdd, $columnToRead, $columnToRead, $quotientPrecision, $shouldSkipRows = true);
$this->pastDataTable = $pastDataTable;
$this->isRevenueEvolution = $columnToAdd == 'revenue_evolution';
}
/**
* Returns the difference between the column in the specific row and its
* sister column in the past DataTable.
*
* @param Row $row
* @return int|float
*/
protected function getDividend($row)
{
$currentValue = $row->getColumn($this->columnValueToRead);
// if the site this is for doesn't support ecommerce & this is for the revenue_evolution column,
// we don't add the new column
if ($currentValue === false
&& $this->isRevenueEvolution
&& !Site::isEcommerceEnabledFor($row->getColumn('label'))
) {
return false;
}
$pastRow = $this->getPastRowFromCurrent($row);
if ($pastRow) {
$pastValue = $pastRow->getColumn($this->columnValueToRead);
} else {
$pastValue = 0;
}
return $currentValue - $pastValue;
}
/**
* Returns the value of the column in $row's sister row in the past
* DataTable.
*
* @param Row $row
* @return int|float
*/
protected function getDivisor($row)
{
$pastRow = $this->getPastRowFromCurrent($row);
if (!$pastRow) return 0;
return $pastRow->getColumn($this->columnNameUsedAsDivisor);
}
/**
* Calculates and formats a quotient based on a divisor and dividend.
*
* Unlike ColumnCallbackAddColumnPercentage's,
* version of this method, this method will return 100% if the past
* value of a metric is 0, and the current value is not 0. For a
* value representative of an evolution, this makes sense.
*
* @param int|float $value The dividend.
* @param int|float $divisor
* @return string
*/
protected function formatValue($value, $divisor)
{
$value = self::getPercentageValue($value, $divisor, $this->quotientPrecision);
$value = self::appendPercentSign($value);
return $value;
}
/**
* Utility function. Returns the current row in the past DataTable.
*
* @param Row $row The row in the 'current' DataTable.
*/
private function getPastRowFromCurrent($row)
{
return $this->pastDataTable->getRowFromLabel($row->getColumn('label'));
}
/**
* Calculates the evolution percentage for two arbitrary values.
*
* @param float|int $currentValue The current metric value.
* @param float|int $pastValue The value of the metric in the past. We measure the % change
* from this value to $currentValue.
* @param float|int $quotientPrecision The quotient precision to round to.
*
* @return string The evolution percent 15%
*/
public static function calculate($currentValue, $pastValue, $quotientPrecision = 0)
{
$number = self::getPercentageValue($currentValue - $pastValue, $pastValue, $quotientPrecision);
$number = self::appendPercentSign($number);
return $number;
}
public static function appendPercentSign($number)
{
$number = $number . '%';
return $number;
}
public static function prependPlusSignToNumber($number)
{
if ($number > 0) {
$number = '+' . $number;
}
return $number;
}
/**
* Returns an evolution percent based on a value & divisor.
*/
private static function getPercentageValue($value, $divisor, $quotientPrecision)
{
if ($value == 0) {
$evolution = 0;
} elseif ($divisor == 0) {
$evolution = 100;
} else {
$evolution = ($value / $divisor) * 100;
}
$evolution = round($evolution, $quotientPrecision);
return $evolution;
}
}
|
