<?php

/**
 *
 * Class for the creating "special" Matrices
 *
 * @copyright  Copyright (c) 2018 Mark Baker (https://github.com/MarkBaker/PHPMatrix)
 * @license    https://opensource.org/licenses/MIT    MIT
 */

namespace TablePress\Matrix;

/**
 * TablePress\Matrix Builder class.
 *
 * @package TablePress\Matrix
 */
class Builder
{
	/**
	 * Create a new matrix of specified dimensions, and filled with a specified value
	 * If the column argument isn't provided, then a square matrix will be created
	 *
	 * @param mixed $fillValue
	 * @param int $rows
	 * @param int|null $columns
	 * @return TablePress\Matrix
	 * @throws Exception
	 */
	public static function createFilledMatrix($fillValue, $rows, $columns = null)
	{
		if ($columns === null) {
			$columns = $rows;
		}

		$rows = Matrix::validateRow($rows);
		$columns = Matrix::validateColumn($columns);

		return new Matrix(
			array_fill(
				0,
				$rows,
				array_fill(
					0,
					$columns,
					$fillValue
				)
			)
		);
	}

	/**
	 * Create a new identity matrix of specified dimensions
	 * This will always be a square matrix, with the number of rows and columns matching the provided dimension
	 *
	 * @param int $dimensions
	 * @return TablePress\Matrix
	 * @throws Exception
	 */
	public static function createIdentityMatrix($dimensions, $fillValue = null)
	{
		$grid = static::createFilledMatrix($fillValue, $dimensions)->toArray();

		for ($x = 0; $x < $dimensions; ++$x) {
			$grid[$x][$x] = 1;
		}

		return new Matrix($grid);
	}
}