<?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;
	}
}