//
//  FeedlyLogoutOperationTests.swift
//  AccountTests
//
//  Created by Kiel Gillard on 15/11/19.
//  Copyright © 2019 Ranchero Software, LLC. All rights reserved.
//

import XCTest
@testable import Account

class FeedlyLogoutOperationTests: XCTestCase {

	private var account: Account!
	private let support = FeedlyTestSupport()
	
	override func setUp() {
		super.setUp()
		account = support.makeTestAccount()
	}
	
	override func tearDown() {
		if let account = account {
			support.destroy(account)
		}
		super.tearDown()
	}
	
	private func getTokens(for account: Account) throws -> (accessToken: Credentials, refreshToken: Credentials) {
		guard let accessToken = try account.retrieveCredentials(type: .oauthAccessToken), let refreshToken = try account.retrieveCredentials(type: .oauthRefreshToken) else {
			XCTFail("Unable to retrieve access and/or refresh token from account.")
			throw CredentialsError.incompleteCredentials
		}
		return (accessToken, refreshToken)
	}
	
	class TestFeedlyLogoutService: FeedlyLogoutService {
		var mockResult: Result<Void, Error>?
		var logoutExpectation: XCTestExpectation?
		
		func logout(completionHandler: @escaping (Result<Void, Error>) -> ()) {
			guard let result = mockResult else {
				XCTFail("Missing mock result. Test may time out because the completion will not be called.")
				return
			}
			DispatchQueue.main.async {
				completionHandler(result)
				self.logoutExpectation?.fulfill()
			}
		}
	}
	
	func testCancel() {
		let service = TestFeedlyLogoutService()
		service.logoutExpectation = expectation(description: "Did Call Logout")
		service.logoutExpectation?.isInverted = true
		
		let accessToken: Credentials
		let refreshToken: Credentials
		do {
			(accessToken, refreshToken) = try getTokens(for: account)
		} catch {
			XCTFail("Could not retrieve credentials to verify their integrity later.")
			return
		}
		
		let logout = FeedlyLogoutOperation(account: account, service: service, log: support.log)
		
		// If this expectation is not fulfilled, the operation is not calling `didFinish`.
		let completionExpectation = expectation(description: "Did Finish")
		logout.completionBlock = {
			completionExpectation.fulfill()
		}
		
		OperationQueue.main.addOperation(logout)
		
		logout.cancel()
		
		waitForExpectations(timeout: 1)
		
		XCTAssertTrue(logout.isCancelled)
		XCTAssertTrue(logout.isFinished)
		
		do {
			let accountAccessToken = try account.retrieveCredentials(type: .oauthAccessToken)
			let accountRefreshToken = try account.retrieveCredentials(type: .oauthRefreshToken)
			
			XCTAssertEqual(accountAccessToken, accessToken)
			XCTAssertEqual(accountRefreshToken, refreshToken)
		} catch {
			XCTFail("Could not verify tokens were left intact. Did the operation delete them?")
		}
	}
	
	func testLogoutSuccess() {
		let service = TestFeedlyLogoutService()
		service.logoutExpectation = expectation(description: "Did Call Logout")
		service.mockResult = .success(())
		
		let logout = FeedlyLogoutOperation(account: account, service: service, log: support.log)
		
		// If this expectation is not fulfilled, the operation is not calling `didFinish`.
		let completionExpectation = expectation(description: "Did Finish")
		logout.completionBlock = {
			completionExpectation.fulfill()
		}
		
		OperationQueue.main.addOperation(logout)
		
		waitForExpectations(timeout: 1)
		
		XCTAssertFalse(logout.isCancelled)
		
		do {
			let accountAccessToken = try account.retrieveCredentials(type: .oauthAccessToken)
			let accountRefreshToken = try account.retrieveCredentials(type: .oauthRefreshToken)
			
			XCTAssertNil(accountAccessToken)
			XCTAssertNil(accountRefreshToken)
		} catch {
			XCTFail("Could not verify tokens were deleted.")
		}
	}
	
	class TestLogoutDelegate: FeedlyOperationDelegate {
		var error: Error?
		var didFailExpectation: XCTestExpectation?
		
		func feedlyOperation(_ operation: FeedlyOperation, didFailWith error: Error) {
			self.error = error
			didFailExpectation?.fulfill()
		}
	}
	
	func testLogoutMissingAccessToken() {
		support.removeCredentials(matching: .oauthAccessToken, from: account)
		
		let (_, service) = support.makeMockNetworkStack()
		service.credentials = nil
		
		let logout = FeedlyLogoutOperation(account: account, service: service, log: support.log)
		
		let delegate = TestLogoutDelegate()
		delegate.didFailExpectation = expectation(description: "Did Fail")
		
		logout.delegate = delegate
		
		// If this expectation is not fulfilled, the operation is not calling `didFinish`.
		let completionExpectation = expectation(description: "Did Finish")
		logout.completionBlock = {
			completionExpectation.fulfill()
		}
		
		OperationQueue.main.addOperation(logout)
		
		waitForExpectations(timeout: 1)
		
		XCTAssertFalse(logout.isCancelled)
		
		do {
			let accountAccessToken = try account.retrieveCredentials(type: .oauthAccessToken)			
			XCTAssertNil(accountAccessToken)
		} catch {
			XCTFail("Could not verify tokens were deleted.")
		}
		
		XCTAssertNotNil(delegate.error, "Should have failed with error.")
		if let error = delegate.error {
			switch error {
			case CredentialsError.incompleteCredentials:
				break
			default:
				XCTFail("Expected \(CredentialsError.incompleteCredentials)")
			}
		}
	}
	
	func testLogoutFailure() {
		let service = TestFeedlyLogoutService()
		service.logoutExpectation = expectation(description: "Did Call Logout")
		service.mockResult = .failure(URLError(.timedOut))
		
		let accessToken: Credentials
		let refreshToken: Credentials
		do {
			(accessToken, refreshToken) = try getTokens(for: account)
		} catch {
			XCTFail("Could not retrieve credentials to verify their integrity later.")
			return
		}
		
		let logout = FeedlyLogoutOperation(account: account, service: service, log: support.log)
		
		// If this expectation is not fulfilled, the operation is not calling `didFinish`.
		let completionExpectation = expectation(description: "Did Finish")
		logout.completionBlock = {
			completionExpectation.fulfill()
		}
		
		OperationQueue.main.addOperation(logout)
				
		waitForExpectations(timeout: 1)
		
		XCTAssertFalse(logout.isCancelled)
		
		do {
			let accountAccessToken = try account.retrieveCredentials(type: .oauthAccessToken)
			let accountRefreshToken = try account.retrieveCredentials(type: .oauthRefreshToken)
			
			XCTAssertEqual(accountAccessToken, accessToken)
			XCTAssertEqual(accountRefreshToken, refreshToken)
		} catch {
			XCTFail("Could not verify tokens were left intact. Did the operation delete them?")
		}
	}
}