Tag Cloud in PHP

TagCloud.php

<?php

/*
 * This file is part of the PSSBlogBundle package.
 *
 * (c) Jakub Zalas <jakub@zalas.pl>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */

namespace PSS\Bundle\BlogBundle\Tag;

/**
 * Class solves a problem of a tag size calculation.
 *
 * Example usage:
 *
 * <code>
 * // List of tags with frequencies.
 * $tags = array(array('php' => 1, 'symfony' => 4, 'tdd' => 2, 'Symfony2' => 7));
 * // List of tag sizes ordered from smallest to the biggest
 * $sizes = array('small', 'big', 'large');
 *
 * $tagCloud = new TagCloud($tags, $sizes);
 * // Get size for frequency
 * $size = $tagCloud->getSize(4);
 * // Get size for tag
 * $size = $tagCloud->getSizeByTag('symfony');
 * </code>
 *
 * @author Jakub Zalas <jakub@zalas.pl>
 */
class TagCloud
{
    /**
     * @var array $tagFrequencies
     */
    private $tagFrequencies = array();

    /**
     * @var array $sizes
     */
    private $sizes = array();

    /**
     * @var integer $maxFrequency
     */
    private $maxFrequency = 0;

    /**
     * @var integer $minFrequency
     */
    private $minFrequency = 0;

    /**
     * @param array $tagFrequencies
     * @param array $sizes
     * @return null
     */
    public function __construct(array $tagFrequencies, array $sizes)
    {
        if (count($sizes) == 0) {
            throw new \InvalidArgumentException('You need to give a list of tag sizes');
        }

        $this->sizes = $sizes;

        $this->tagFrequencies = $tagFrequencies;

        $this->updateMinAndMaxFrequency();
    }

    /**
     * @return null
     */
    protected function updateMinAndMaxFrequency()
    {
        foreach ($this->tagFrequencies as $frequency) {
            if ($this->minFrequency > $frequency || 0 == $this->minFrequency) {
                $this->minFrequency = $frequency;
            }

            if ($this->maxFrequency < $frequency) {
                $this->maxFrequency = $frequency;
            }
        }
    }

    /**
     * @param integer $frequency
     * @return string
     */
    public function getSize($frequency)
    {
        if ($frequency <= $this->minFrequency) {
            return $this->sizes[0];
        }

        $maxSize = count($this->sizes);
        $size = ($maxSize * ($frequency - $this->minFrequency)) / ($this->maxFrequency - $this->minFrequency);
        $sizeIndex = $size - 1;

        return isset($this->sizes[$sizeIndex]) ? $this->sizes[$sizeIndex] : $this->sizes[$maxSize - 1];
    }

    /**
     * @param string $tag
     * @return string
     */
    public function getSizeByTag($tag)
    {
        return isset($this->tagFrequencies[$tag]) ? $this->getSize($this->tagFrequencies[$tag]) : $this->sizes[0];
    }
}

TagCloudTest.php

<?php

namespace PSS\Bundle\BlogBundle\Tests;

use PSS\Bundle\BlogBundle\Tag\TagCloud;

class TagCloudTest extends \PHPUnit_Framework_TestCase
{
    /**
     * @expectedException InvalidArgumentException
     */
    public function testThatAtLeastOneSizeIsRequired()
    {
        $tagCloud = new TagCloud(array('symfony' => 10), array());
    }

    public function testThatFrequencyOutOfRangeHasMaximumSize()
    {
        $tagCloud = new TagCloud(array('symfony' => 2, 'php' => 10), array('small', 'big', 'large'));

        $this->assertEquals('large', $tagCloud->getSize(400));
    }

    public function testThatTooSmallFrequencyHasMinimumSize()
    {
        $tagCloud = new TagCloud(array('symfony' => 200, 'php' => 300), array('small', 'big', 'large'));

        $this->assertEquals('small', $tagCloud->getSize(1));
    }

    public function testThatSizeCanBeRetrievedByTagName()
    {
        $tagCloud = new TagCloud(array('symfony' => 2, 'php' => 10), array('small', 'big', 'large'));

        $this->assertEquals('small', $tagCloud->getSizeByTag('symfony'));
        $this->assertEquals('large', $tagCloud->getSizeByTag('php'));
    }

    public function testThatSizeForTagOutsideOfCloudIsMinimal()
    {
        $tagCloud = new TagCloud(array('symfony' => 2, 'php' => 10), array('small', 'big', 'large'));

        $this->assertEquals('small', $tagCloud->getSizeByTag('tdd'));
    }

    /**
     * @dataProvider getTags
     */
    public function testSizeDistribution($sizes, $tags, $expectedSizes)
    {
        $tagCloud = new TagCloud($tags, $sizes);

        foreach ($expectedSizes as $tagSlug => $size) {
            $this->assertEquals($size, $tagCloud->getSize($tags[$tagSlug]), sprintf('Tag "%s" is "%s"', $tagSlug, $size));
        }
    }

    public static function getTags()
    {
        return array(
            array(
                array('small'),
                array('symfony' => 1),
                array('symfony' => 'small')
            ),
            array(
                array('small'),
                array('symfony' => 1, 'Symfony2' => 2),
                array('symfony' => 'small', 'Symfony2' => 'small')
            ),
            array(
                array('small'),
                array('symfony' => 1, 'Symfony2' => 2, 'php' => 3),
                array('symfony' => 'small', 'Symfony2' => 'small', 'php' => 'small')
            ),

            array(
                array('small', 'big'),
                array('symfony' => 1),
                array('symfony' => 'small')
            ),
            array(
                array('small', 'big'),
                array('symfony' => 1, 'Symfony2' => 2),
                array('symfony' => 'small', 'Symfony2' => 'big')
            ),
            array(
                array('small', 'big'),
                array('symfony' => 1, 'Symfony2' => 2, 'php' => 3),
                array('symfony' => 'small', 'Symfony2' => 'small', 'php' => 'big')
            ),
            array(
                array('small', 'big'),
                array('symfony' => 1, 'Symfony2' => 2, 'php' => 3, 'tdd' => 4),
                array('symfony' => 'small', 'Symfony2' => 'small', 'php' => 'small', 'tdd' => 'big')
            ),
            array(
                array('small', 'big', 'large'),
                array('symfony' => 1),
                array('symfony' => 'small')
            ),
            array(
                array('small', 'big', 'large'),
                array('symfony' => 1, 'Symfony2' => 2),
                array('symfony' => 'small', 'Symfony2' => 'large')
            ),
            array(
                array('small', 'big', 'large'),
                array('symfony' => 1, 'Symfony2' => 2, 'php' => 3),
                array('symfony' => 'small', 'Symfony2' => 'small', 'php' => 'large')
            ),
            array(
                array('small', 'big', 'large'),
                array('symfony' => 1, 'Symfony2' => 2, 'php' => 3, 'tdd' => 4),
                array('symfony' => 'small', 'Symfony2' => 'small', 'php' => 'big', 'tdd' => 'large')
            ),
            array(
                array('small', 'big', 'large'),
                array('symfony' => 1, 'Symfony2' => 2, 'php' => 3, 'tdd' => 4, 'bdd' => 5),
                array('symfony' => 'small', 'Symfony2' => 'small', 'php' => 'small', 'tdd' => 'big', 'bdd' => 'large')
            ),
            array(
                array('small', 'big', 'large'),
                array('symfony' => 1, 'Symfony2' => 2, 'php' => 3, 'tdd' => 4, 'bdd' => 5, 'ui' => 6),
                array('symfony' => 'small', 'Symfony2' => 'small', 'php' => 'small', 'tdd' => 'small', 'bdd' => 'big', 'ui' => 'large')
            ),
            array(
                array('small', 'big', 'large'),
                array('symfony' => 1, 'Symfony2' => 2, 'php' => 3, 'tdd' => 4, 'bdd' => 5, 'ui' => 6, 'phpunit' => 7),
                array('symfony' => 'small', 'Symfony2' => 'small', 'php' => 'small', 'tdd' => 'small', 'bdd' => 'big', 'ui' => 'big', 'phpunit' => 'large')
            ),
            array(
                array('small', 'big', 'large'),
                array('symfony' => 1, 'Symfony2' => 2, 'php' => 3, 'tdd' => 4, 'bdd' => 5, 'ui' => 6, 'phpunit' => 7, 'lime' => 8),
                array('symfony' => 'small', 'Symfony2' => 'small', 'php' => 'small', 'tdd' => 'small', 'bdd' => 'small', 'ui' => 'big', 'phpunit' => 'big', 'lime' => 'large')
            ),
            array(
                array('small', 'big', 'large'),
                array('symfony' => 1, 'Symfony2' => 2, 'php' => 3, 'tdd' => 4, 'bdd' => 5, 'ui' => 6, 'phpunit' => 7, 'lime' => 8, 'ddd' => 9),
                array('symfony' => 'small', 'Symfony2' => 'small', 'php' => 'small', 'tdd' => 'small', 'bdd' => 'small', 'ui' => 'small', 'phpunit' => 'big', 'lime' => 'big', 'ddd' => 'large')
            ),
        );
    }
}