YoutubeID Parser

//
//  YTBParser.swift
//  SideloadExt
//
//  Created by chen he on 2020/7/30.
//  Copyright © 2020 chen he. All rights reserved.
//

import Foundation

struct YTBParser {
    static func videoID(fromVideoURL videoURL: URL) -> String? {
        if videoURL.host == "youtu.be" {
             return videoURL.pathComponents.second
        } else if videoURL.absoluteString.contains("www.youtube.com/embed") {
            return videoURL.pathComponents.third
        } else if videoURL.host?.contains("youtube.googleapis.com") == true || videoURL.pathComponents.first == "www.youtube.com" {
            return videoURL.pathComponents.third
        } else {
            return videoURL.extractedParamsFromQuery["v"]?.first
        }
    }
}

extension Array {
    var second: Element? {
        return count >= 2 ? self[1] : nil
    }
    var third: Element? {
        return count >= 3 ? self[2] : nil
    }
}
extension URL {
    var extractedParamsFromQuery: [AnyHashable: [String]] {
        return query?.dictionaryFromQueryStringComponents() ?? [:]
    }
}
extension String {
    func stringBydecodingURLFormat() -> String? {
        return replacingOccurrences(of: "+", with: " ").removingPercentEncoding
    }
    
    func dictionaryFromQueryStringComponents() -> [String: [String]] {        
        var params: [String: [String]] = [:]
        for key in components(separatedBy: "&") {
            let keyValue = key.components(separatedBy: "=")
            if let key = keyValue.first, let value = keyValue.second {
                var values = params[key] ?? []
                values.append(value)
                params[key] = values
            }
        }
        return params
    }
}