<?php

namespace TablePress\PhpOffice\PhpSpreadsheet\Calculation\MathTrig;

use TablePress\PhpOffice\PhpSpreadsheet\Calculation\ArrayEnabled;
use TablePress\PhpOffice\PhpSpreadsheet\Calculation\Exception;
use TablePress\PhpOffice\PhpSpreadsheet\Calculation\Information\ExcelError;

class Arabic
{
	use ArrayEnabled;

	private const ROMAN_LOOKUP = [
		'M' => 1000,
		'D' => 500,
		'C' => 100,
		'L' => 50,
		'X' => 10,
		'V' => 5,
		'I' => 1,
	];

	/**
	 * Recursively calculate the arabic value of a roman numeral.
	 *
	 * @param int $sum
	 * @param int $subtract
	 *
	 * @return int
	 */
	private static function calculateArabic(array $roman, &$sum = 0, $subtract = 0)
	{
		$numeral = array_shift($roman);
		if (!isset(self::ROMAN_LOOKUP[$numeral])) {
			throw new Exception('Invalid character detected');
		}

		$arabic = self::ROMAN_LOOKUP[$numeral];
		if (count($roman) > 0 && isset(self::ROMAN_LOOKUP[$roman[0]]) && $arabic < self::ROMAN_LOOKUP[$roman[0]]) {
			$subtract += $arabic;
		} else {
			$sum += ($arabic - $subtract);
			$subtract = 0;
		}

		if (count($roman) > 0) {
			self::calculateArabic($roman, $sum, $subtract);
		}

		return $sum;
	}

	/**
	 * @param mixed $value
	 */
	private static function mollifyScrutinizer($value): array
	{
		return is_array($value) ? $value : [];
	}

	private static function strSplit(string $roman): array
	{
		$rslt = str_split($roman);

		return self::mollifyScrutinizer($rslt);
	}

	/**
	 * ARABIC.
	 *
	 * Converts a Roman numeral to an Arabic numeral.
	 *
	 * Excel Function:
	 *        ARABIC(text)
	 *
	 * @param mixed $roman Should be a string, or can be an array of strings
	 *
	 * @return array|int|string the arabic numberal contrived from the roman numeral
	 *         If an array of numbers is passed as the argument, then the returned result will also be an array
	 *            with the same dimensions
	 */
	public static function evaluate($roman)
	{
		if (is_array($roman)) {
			return self::evaluateSingleArgumentArray([self::class, __FUNCTION__], $roman);
		}

		// An empty string should return 0
		$roman = substr(trim(strtoupper((string) $roman)), 0, 255);
		if ($roman === '') {
			return 0;
		}

		// Convert the roman numeral to an arabic number
		$negativeNumber = $roman[0] === '-';
		if ($negativeNumber) {
			$roman = substr($roman, 1);
		}

		try {
			$arabic = self::calculateArabic(self::strSplit($roman));
		} catch (Exception $e) {
			return ExcelError::VALUE(); // Invalid character detected
		}

		if ($negativeNumber) {
			$arabic *= -1; // The number should be negative
		}

		return $arabic;
	}
}
