This class helps detect if a song has a low bitrate version on the server.

ELLowBitrateManager

//
//  ELLowBitrateManager.swift
//
//
//  Created by Eddie Espinal on 11/11/15.
//  Copyright © 2015 EspinalLab, LLC. All rights reserved.
//

import UIKit

let kAudioQualityKey = "audioQuality"

@objc enum BitrateType: Int {
    case HDBitrate
    case MidBitrate
    case LowBitrate
    
    func name() -> String {
        switch self {
            case .HDBitrate: return "HD"
            case .MidBitrate: return "-96k"
            case .LowBitrate: return "-64k"
        }
    }
}

@objc public class ELLowBitrateManager: NSObject {
    
    class func getAudioQualityFromSettings() -> BitrateType {
        let audioQuality = NSUserDefaults.standardUserDefaults().integerForKey(kAudioQualityKey)
        return BitrateType(rawValue: audioQuality)!
    }
    
    class func getLowBitrateURLStringFromString(fileURLString: String, bitrateType: BitrateType ) -> String {
        let fileURLString = fileURLString as NSString
        let fileExtension = fileURLString.pathExtension
        let lowBitrateFilePath = fileURLString.stringByDeletingPathExtension.stringByAppendingString(bitrateType.name())
        let tempFileURLString = lowBitrateFilePath.stringByAppendingFormat(".%@", fileExtension)
        let lowBitrateFileURLString = tempFileURLString.stringByReplacingOccurrencesOfString("http:/", withString: "http://", options: NSStringCompareOptions.LiteralSearch, range: nil)
        let escapedAddress = lowBitrateFileURLString.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())
        return escapedAddress!
    }
    
    class func checkIfFileExists(fileURLString: String, bitrateType: BitrateType , completionHandler: (success: Bool, fileSize: String?) -> Void) {
        let fileURLString = fileURLString as NSString
        let fileExtension = fileURLString.pathExtension
        let lowBitrateFilePath = fileURLString.stringByDeletingPathExtension.stringByAppendingString(bitrateType.name())
        let lowBitrateFileURLString = lowBitrateFilePath.stringByAppendingFormat(".%@", fileExtension)
        let escapedAddress = lowBitrateFileURLString.stringByAddingPercentEncodingWithAllowedCharacters(NSCharacterSet.URLQueryAllowedCharacterSet())
        
        let request = NSMutableURLRequest(URL: NSURL(string: escapedAddress!)!)
        request.HTTPMethod = "HEAD"
        
        
        var response: NSURLResponse?
        do {
            let data = try NSURLConnection.sendSynchronousRequest(request, returningResponse: &response)
            print(data)
        } catch (let error) {
            print(error)
        }
        
        if let httpResponse = response as? NSHTTPURLResponse {
            if httpResponse.statusCode == 200 {
                // File Exist
                if let contentType = httpResponse.allHeaderFields["Content-Length"] as? String {
                    completionHandler(success: true, fileSize: contentType)
                }
            } else {
                // File Doesn't Exist
                completionHandler(success: false, fileSize: nil)
            }
        } else {
            // Error loading URL
            completionHandler(success: false, fileSize: nil)
        }
        
    }
}