UIApplication.shared.isNetworkActivityIndicatorVisible = true

let fetchImage = URLSession.shared.dataTaskCC(.promise, with: url).compactMap{ UIImage(data: $0.data) }
let fetchLocation = CLLocationManager.requestLocationCC().lastValue

let context = firstly {
    when(fulfilled: fetchImage, fetchLocation)
}.done { image, location in
    self.imageView.image = image
    self.label.text = "\(location)"
}.ensure {
    UIApplication.shared.isNetworkActivityIndicatorVisible = false
}.catch(policy: .allErrors) { error in
    /* Will be invoked with a PromiseCancelledError when cancel is called on the context.
       Use the default policy of .allErrorsExceptCancellation to ignore cancellation errors. */
    self.show(UIAlertController(for: error), sender: self)
}.cancelContext

//…

// Cancel currently active tasks and reject all cancellable promises with PromiseCancelledError
context.cancel()

/* Note: Cancellable promises can be cancelled directly.  However by holding on to
   the CancelContext rather than a promise, each promise in the chain can be
   deallocated by ARC as it is resolved. */

use_frameworks!

target "Change Me!" do
  pod "PromiseKit", "~> 6.0"
  pod "CancelForPromiseKit", "~> 1.0"
end

let promise = firstly {
    /* Methods and functions with the CC (a.k.a. cancel chain) suffix initiate a
    cancellable promise chain by returning a CancellablePromise. */
    loginCC()
}.then { creds in
    /* 'fetch' in this example may return either Promise or CancellablePromise --
        If 'fetch' returns a CancellablePromise then the fetch task can be cancelled.
        If 'fetch' returns a standard Promise then the fetch task cannot be cancelled,
        however if cancel is called during the fetch then the promise chain will still be
        rejected with a PromiseCancelledError as soon as the 'fetch' task completes.
        
        Note: if 'fetch' returns a CancellablePromise then the convention is to name
        it 'fetchCC'. */
    fetch(avatar: creds.user)
}.done { image in
    self.imageView = image
}.catch(policy: .allErrors) { error in
    if error.isCancelled {
        // the chain has been cancelled!
    }
}

// …

/* 'promise' here refers to the last promise in the chain.  Calling 'cancel' on
   any promise in the chain cancels the entire chain.  Therefore cancelling the
   last promise in the chain cancels everything.
   
   Note: It may be desirable to hold on to the CancelContext directly rather than a
   promise so that the promise can be deallocated by ARC when it is resolved. */
promise.cancel()

let cancellablePromise = firstly {
    loginCC()
}
cancellablePromise.then { creds in
    // For this example 'fetch' returns a standard Promise
    fetch(avatar: creds.user)  
    
    /* Here, by calling 'promise.done' rather than 'done' the chain is converted from a
       cancellable promise chain to a standard Promise chain. In this case, calling
       'cancel' during the 'fetch' operation has no effect: */
}.promise.done { image in
    self.imageView = image
}.catch(policy: .allErrors) { error in
    if error.isCancelled {
        // the chain has been cancelled!
    }
}

// …

cancellablePromise.cancel()

Global functions (all returning CancellablePromise unless otherwise noted)
	afterCC(seconds:)
	afterCC(_ interval:)

	firstly(execute body:)       // Accepts body returning CancellableTheanble
	firstlyCC(execute body:)     // Accepts body returning Theanble

	hang(_ promise:)             // Accepts CancellablePromise
	
	race(_ thenables:)           // Accepts CancellableThenable
	race(_ guarantees:)          // Accepts CancellableGuarantee
	raceCC(_ thenables:)         // Accepts Theanable
	raceCC(_ guarantees:)        // Accepts Guarantee

	when(fulfilled thenables:)   // Accepts CancellableThenable
	when(fulfilled promiseIterator:concurrently:)   // Accepts CancellablePromise
	whenCC(fulfilled thenables:) // Accepts Thenable
	whenCC(fulfilled promiseIterator:concurrently:) // Accepts Promise

	// These functions return CancellableGuarantee
	when(resolved promises:)     // Accepts CancellablePromise
	when(_ guarantees:)          // Accepts CancellableGuarantee
	when(guarantees:)            // Accepts CancellableGuarantee
	whenCC(resolved promises:)   // Accepts Promise
	whenCC(_ guarantees:)        // Accepts Guarantee
	whenCC(guarantees:)          // Accepts Guarantee


CancellablePromise: CancellableThenable
	CancellablePromise.value(_ value:)
	init(task:resolver:)
	init(task:bridge:)
	init(task:error:)
	promise                      // The delegate Promise
	result

CancellableGuarantee: CancellableThenable
	CancellableGuarantee.value(_ value:)
	init(task:resolver:)
	init(task:bridge:)
	init(task:error:)
	guarantee                    // The delegate Guarantee
	result

CancellableThenable
	thenable                     // The delegate Thenable
	cancel(error:)               // Accepts optional Error to use for cancellation
	cancelContext                // CancelContext for the cancel chain we are a member of
	isCancelled
	cancelAttempted
	cancelledError
	appendCancellableTask(task:reject:)
	appendCancelContext(from:)
	
	then(on:_ body:)             // Accepts body returning CancellableThenable or Thenable
	map(on:_ transform:)
	compactMap(on:_ transform:)
	done(on:_ body:)
	get(on:_ body:)
	asVoid()
	
	error
	isPending
	isResolved
	isFulfilled
	isRejected
	value
	
	mapValues(on:_ transform:)
	flatMapValues(on:_ transform:)
	compactMapValues(on:_ transform:)
	thenMap(on:_ transform:)     // Accepts transform returning CancellableThenable or Thenable
	thenFlatMap(on:_ transform:) // Accepts transform returning CancellableThenable or Thenable
	filterValues(on:_ isIncluded:)
	firstValue
	lastValue
	sortedValues(on:)

CancellableCatchable
	catchable                    // The delegate Catchable
	recover(on:policy:_ body:)   // Accepts body returning CancellableThenable or Thenable
	recover(on:_ body:)          // Accepts body returning Void
	ensure(on:_ body:)
	ensureThen(on:_ body:)
	finally(_ body:)
	cauterize()

pod "CancelForPromiseKit/MapKit"
# MKDirections().calculateCC().then { /*…*/ }

pod "CancelForPromiseKit/CoreLocation"
# CLLocationManager.requestLocationCC().then { /*…*/ }

Alamofire.DataRequest
	responseCC(_:queue:)
	responseDataCC(queue:)
	responseStringCC(queue:)
	responseJSONCC(queue:options:)
	responsePropertyListCC(queue:options:)
	responseDecodableCC(queue::decoder:)
	responseDecodableCC(_ type:queue:decoder:)

Alamofire.DownloadRequest
	responseCC(_:queue:)
	responseDataCC(queue:)

Process
	launchCC(_:)
		
URLSession
	dataTaskCC(_:with:)
	uploadTaskCC(_:with:from:)
	uploadTaskCC(_:with:fromFile:)
	downloadTaskCC(_:with:to:)

pod "CancelForPromiseKit/CorePromise", "~> 1.0"

// pod 'CancelForPromiseKit/Alamofire'
// # https://github.com/dougzilla32/CancelForPromiseKit-Alamofire

let context = firstly {
    Alamofire
        .request("http://example.com", method: .post, parameters: params)
        .responseDecodableCC(Foo.self, cancel: context)
}.done { foo in
    //…
}.catch { error in
    //…
}.cancelContext

//…

context.cancel()

// pod 'CancelForPromiseKit/OMGHTTPURLRQ'
// # https://github.com/dougzilla32/CancelForPromiseKit-OMGHTTPURLRQ

let context = firstly {
    URLSession.shared.POSTCC("http://example.com", JSON: params)
}.map {
    try JSONDecoder().decoder(Foo.self, with: $0.data)
}.done { foo in
    //…
}.catch { error in
    //…
}.cancelContext

//…

context.cancel()

// pod 'CancelForPromiseKit/Foundation'
// # https://github.com/dougzilla32/CancelForPromiseKit-Foundation

let context = firstly {
    URLSession.shared.dataTaskCC(.promise, with: try makeUrlRequest())
}.map {
    try JSONDecoder().decode(Foo.self, with: $0.data)
}.done { foo in
    //…
}.catch { error in
    //…
}.cancelContext

//…

context.cancel()

func makeUrlRequest() throws -> URLRequest {
    var rq = URLRequest(url: url)
    rq.httpMethod = "POST"
    rq.addValue("application/json", forHTTPHeaderField: "Content-Type")
    rq.addValue("application/json", forHTTPHeaderField: "Accept")
    rq.httpBody = try JSONSerialization.jsonData(with: obj)
    return rq
}

let promise = firstly {
    loginCC() // Use CC (a.k.a. cancel chain) methods or CancellablePromise to
              // initiate a cancellable promise chain
}.then { creds in
    fetch(avatar: creds.user)
}.done { image in
    self.imageView = image
}.catch(policy: .allErrors) { error in
    if error.isCancelled {
        // the chain has been cancelled!
    }
}
//…
promise.cancel()

import Alamofire
import PromiseKit
import CancelForPromiseKit

func updateWeather(forCity searchName: String) {
    refreshButton.startAnimating()
    let context = firstly {
        getForecast(forCity: searchName)
    }.done { response in
        updateUI(forecast: response)
    }.ensure {
        refreshButton.stopAnimating()
    }.catch { error in
        // Cancellation errors are ignored by default
        showAlert(error: error) 
    }.cancelContext

    //…

    // **** Cancels EVERYTHING (however the 'ensure' block always executes regardless)
    context.cancel()
}

func getForecast(forCity name: String) -> CancellablePromise<WeatherInfo> {
    return firstly {
        Alamofire.request("https://autocomplete.weather.com/\(name)")
            .responseDecodableCC(AutoCompleteCity.self)
    }.then { city in
        Alamofire.request("https://forecast.weather.com/\(city.name)")
            .responseDecodableCC(WeatherResponse.self)
    }.map { response in
        format(response)
    }
}