<?php
/**
 * @author  Eugene Serkin <jserkin@gmail.com>
 * @version $Id$
 */

class ArrayDividingTest extends PHPUnit_Framework_TestCase
{
    /**
     * @dataProvider dataProvider
     */
    public function testDividingAlgorithm( array $input, array $expected )
    {
        $this->assertEquals( $this->transformation( $input[0] ), $expected[0] );
    }

    public function dataProvider()
    {
        return array(
            // First run
            array(
                array(
                    array( 'a', 'b', 'c', )
                ),
                array(
                    array(
                        array( 'a', 'b', 'c', )
                    )
                ),
            ),
            // Second run
            array(
                array(
                    array( 'a', 'b', 'c', 'd', 'e', 'f', 'g', )
                ),
                array(
                    array(
                        array( 'a', 'd', 'f' ),
                        array( 'b', 'e', 'g' ),
                        array( 'c', '', '' )
                    )
                ),
            ),
            // Third run
            array(
                array(
                    array(
                        'a', 'b', 'c', 'd',
                        'e', 'f', 'g', 'h',
                        'i', 'j', 'k', 'l',
                    )
                ),
                array(
                    array(
                        array( 'a', 'e', 'i', ),
                        array( 'b', 'f', 'j', ),
                        array( 'c', 'g', 'k', ),
                        array( 'd', 'h', 'l', )
                    )
                ),
            ),
            // Fourth run
            array(
                array(
                    array(
                        'a', 'b',
                    )
                ),
                array(
                    array(
                        array( 'a', 'b', '', ),
                    )
                ),
            ),
            // Fifth run
            array(
                array(
                    array(
                        'a',
                    )
                ),
                array(
                    array(
                        array( 'a', '', '', ),
                    )
                ),
            ),
            // Sixth run
            array(
                array(
                    array(
                        'a', 'b', 'c',
                        'd', 'e',
                    )
                ),
                array(
                    array(
                        array( 'a', 'c', 'e', ),
                        array( 'b', 'd', '', ),
                    )
                ),
            ),
            // Seventh run
            array(
                array(
                    array(
                        'a', 'b', 'd', 'e', 'f',
                        'g', 'h', 'i', 'j', 'k', 'l'
                    )
                ),
                array(
                    array(
                        array( 'a', 'f', 'j', ),
                        array( 'b', 'g', 'k', ),
                        array( 'd', 'h', 'l', ),
                        array( 'e', 'i', '', ),
                    )
                ),
            ),
            // Eighth run
            array(
                array(
                    array(
                        'a', 'b', 'g', 'h',
                    )
                ),
                array(
                    array(
                        array( 'a', 'g', 'h', ),
                        array( 'b', '', '', ),
                    )
                ),
            ),
            // Nine run
            array(
                array(
                    array(
                        'a', 'b', 'c', 'd', 'e', 'f',
                    )
                ),
                array(
                    array(
                        array( 'a', 'c', 'e', ),
                        array( 'b', 'd', 'f', ),
                    )
                ),
            ),
        );
    }

    /**
     * @param array $toTransform
     * @param int $columnsMax
     * @return array
     */
    private function transformation( array $toTransform, $columnsMax = 3 )
    {
        // First divide array as you need
        $listlen   = count( $toTransform );
        $partlen   = floor( $listlen / $columnsMax );
        $partrem   = $listlen % $columnsMax;
        $partition = array();
        $mark      = 0;

        for ( $px = 0; $px < $columnsMax; $px++ )
        {
            $incr             = ( $px < $partrem ) ? $partlen + 1 : $partlen;
            $partition[ $px ] = array_slice( $toTransform, $mark, $incr );
            $mark             += $incr;
        }

        // Secondly fill empty slots for easy template use
        $result = array();

        for ( $i = 0; $i < count( $partition[0] ); $i++ )
        {
            $tmp = array();

            foreach ( $partition as $column )
            {
                if ( isset( $column[ $i ] ) )
                {
                    $tmp[] = $column[ $i ];
                }
                else
                {
                    $tmp[] = '';
                }
            }

            $result[] = $tmp;
        }

        return $result;
    }
}