MockURLProtocol.swift

//
//  MockURLProtocol.swift
//  SolutoHome
//
//  Created by Omer Levi Hevroni on 2/23/16.
//  Copyright © 2016 Soluto. All rights reserved.
//

import Foundation

/*
 Ispired by alamofire 
 See: https://github.com/Alamofire/Alamofire/blob/master/Tests/URLProtocolTests.swift
*/

class MockURLProtocol : NSURLProtocol {
    
    enum ResponseType{
        case Error(NSError)
        case Success(NSURLResponse)
    }
    
    internal static var lastRequest: NSURLRequest?
    static var responseType: ResponseType!
    
    // MARK: Properties
    struct PropertyKeys {
        static let HandledByForwarderURLProtocol = "HandledByProxyURLProtocol"
    }
    
    lazy var session: NSURLSession = {
        let configuration: NSURLSessionConfiguration = {
            let configuration = NSURLSessionConfiguration.ephemeralSessionConfiguration()
            return configuration
        }()
        
        let session = NSURLSession(configuration: configuration, delegate: self, delegateQueue: nil)
        return session
    }()
    
    var activeTask: NSURLSessionTask?

    // MARK: Class Request Methods
    override class func canInitWithRequest(request: NSURLRequest) -> Bool {
        if NSURLProtocol.propertyForKey(PropertyKeys.HandledByForwarderURLProtocol, inRequest: request) != nil {
            return false
        }
        return true
        
    }
    
    override class func canonicalRequestForRequest(request: NSURLRequest) -> NSURLRequest {
        return request
    }
    
    override class func requestIsCacheEquivalent(a: NSURLRequest, toRequest b: NSURLRequest) -> Bool {
        return false
    }
    
    // MARK: Loading Methods
    override func startLoading() {
        let mutableRequest = request.URLRequest
        NSURLProtocol.setProperty(true, forKey: PropertyKeys.HandledByForwarderURLProtocol, inRequest: mutableRequest)
        activeTask = session.dataTaskWithRequest(mutableRequest)
        activeTask?.resume()
    }

    override func stopLoading() {
        activeTask?.cancel()
    }
}



// MARK: -
extension MockURLProtocol: NSURLSessionDelegate {

    // MARK: NSURLSessionDelegate
    func URLSession(session: NSURLSession, dataTask: NSURLSessionDataTask, didReceiveData data: NSData) {
        client?.URLProtocol(self, didLoadData: data)
    }

    func URLSession(session: NSURLSession, task: NSURLSessionTask, didCompleteWithError error: NSError?) {
        MockURLProtocol.lastRequest = task.currentRequest
        switch(MockURLProtocol.responseType!){
        case let ResponseType.Error(err):
            client?.URLProtocol(self, didFailWithError: err)
            break
        case let ResponseType.Success(response):
            client?.URLProtocol(self, didReceiveResponse: response, cacheStoragePolicy: .NotAllowed)
            break
        }
        
        client?.URLProtocolDidFinishLoading(self)
    }
}

extension MockURLProtocol {
    static func responseWithFailure(){
        MockURLProtocol.responseType = ResponseType.Error(NSError(domain: NSURLErrorDomain, code: NSURLErrorFileDoesNotExist, userInfo: nil))
    }
    
    static func responseWithStatusCode(code : Int){
        MockURLProtocol.responseType = ResponseType.Success(NSHTTPURLResponse.init(URL: NSURL(fileURLWithPath: "http://www.google.com"), statusCode: code, HTTPVersion: nil, headerFields: nil)!)
    }
}