makeShuffledArray

Array+.Swift

//
//  Array+.swift
//  MusicScale
//
//  Created by yoonbumtae on 2022/06/05.
//

import Foundation

enum ShuffleArrayError: Error {
    case totalCountIsGreaterThanArrayCount, newArrayCountAndTotalCountNotSame
}

extension Array {
    
    func makeShuffledArray(totalCount: Int) throws -> Self {
        guard self.count < totalCount else {
            throw ShuffleArrayError.totalCountIsGreaterThanArrayCount
        }
        
        var newArray = self
        let repeatCount = (totalCount / self.count - 1)
        if repeatCount >= 1 {
            for _ in 0..<repeatCount {
                let shuffledArray = self.shuffled()
                newArray += shuffledArray
            }
        }
        
        // 남은 개수 이어붙이기
        
        let remainCount = totalCount - newArray.count
        newArray += Array(self[0..<remainCount])
        
        guard newArray.count == totalCount else {
            throw ShuffleArrayError.newArrayCountAndTotalCountNotSame
        }
        
        return newArray
    }
}