<?php

/**
 * Class JsonToArraySyntax
 *
 * @author Yurii Slobodeniuk <silencedis@gmail.com>
 */
class JsonToArraySyntax
{
    /**
     * @param string $json A JSON string
     *
     * @return string
     *
     * @throws \Exception An exception with last json error message if failed to decode the json string
     */
    public function convert(string $json): string
    {
        $array = json_decode($json, true);
        if ($array === null && json_last_error()) {
            throw new \Exception(json_last_error_msg());
        }

        return $this->getArraySyntax($array);
    }

    /**
     * @param array $array An array to print
     * @param int   $level An internal parameter
     *
     * @return string
     */
    private function getArraySyntax(array $array, int $level = 0): string
    {
        $strParts = [];

        $level++;

        $strParts[] = '[' . PHP_EOL;

        foreach ($array as $key => $value) {
            $strParts[] = str_repeat(' ', 4 * $level);

            if (!is_int($key)) {
                $strParts[] = "'$key' => ";
            }

            if (is_iterable($value)) {
                $strParts[] = $this->getArraySyntax($value, $level);
                $strParts[] = PHP_EOL;
            } elseif (is_numeric($value)) {
                $strParts[] = "$value," . PHP_EOL;
            } else {
                $strParts[] = sprintf("'%s',", addslashes($value)) . PHP_EOL;
            }
        }

        $strParts[] = str_repeat(' ', 4 * ($level - 1)) . ']' . (($level - 1) == 0 ? '' : ',');

        return implode('', $strParts);
    }
}